Recon Coverage Report

Files 34 files

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90%

1773 / 1968

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87% lib/openzeppelin-contracts/contracts/metatx/ERC2771Context.sol

Lines covered: 7 / 8 (87%)

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (metatx/ERC2771Context.sol)

pragma solidity ^0.8.9;

import "../utils/Context.sol";

/**
 * @dev Context variant with ERC2771 support.
 */
abstract contract ERC2771Context is Context {
    /// @custom:oz-upgrades-unsafe-allow state-variable-immutable
    address private immutable _trustedForwarder;

    /// @custom:oz-upgrades-unsafe-allow constructor
    constructor(address trustedForwarder) {
        _trustedForwarder = trustedForwarder;
    }

    function isTrustedForwarder(address forwarder) public view virtual returns (bool) {
        return forwarder == _trustedForwarder;
    }

    function _msgSender() internal view virtual override returns (address sender) {
        if (isTrustedForwarder(msg.sender)) {
            // The assembly code is more direct than the Solidity version using `abi.decode`.
            /// @solidity memory-safe-assembly
            assembly {
                sender := shr(96, calldataload(sub(calldatasize(), 20)))
            }
        } else {
            return super._msgSender();
        }
    }

    function _msgData() internal view virtual override returns (bytes calldata) {
        if (isTrustedForwarder(msg.sender)) {
            return msg.data[:msg.data.length - 20];
        } else {
            return super._msgData();
        }
    }
}

8% lib/openzeppelin-contracts/contracts/proxy/utils/UUPSUpgradeable.sol

Lines covered: 1 / 12 (8%)

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (proxy/utils/UUPSUpgradeable.sol)

pragma solidity ^0.8.0;

import "../../interfaces/draft-IERC1822.sol";
import "../ERC1967/ERC1967Upgrade.sol";

/**
 * @dev An upgradeability mechanism designed for UUPS proxies. The functions included here can perform an upgrade of an
 * {ERC1967Proxy}, when this contract is set as the implementation behind such a proxy.
 *
 * A security mechanism ensures that an upgrade does not turn off upgradeability accidentally, although this risk is
 * reinstated if the upgrade retains upgradeability but removes the security mechanism, e.g. by replacing
 * `UUPSUpgradeable` with a custom implementation of upgrades.
 *
 * The {_authorizeUpgrade} function must be overridden to include access restriction to the upgrade mechanism.
 *
 * _Available since v4.1._
 */
abstract contract UUPSUpgradeable is IERC1822Proxiable, ERC1967Upgrade {
    /// @custom:oz-upgrades-unsafe-allow state-variable-immutable state-variable-assignment
    address private immutable __self = address(this);

    /**
     * @dev Check that the execution is being performed through a delegatecall call and that the execution context is
     * a proxy contract with an implementation (as defined in ERC1967) pointing to self. This should only be the case
     * for UUPS and transparent proxies that are using the current contract as their implementation. Execution of a
     * function through ERC1167 minimal proxies (clones) would not normally pass this test, but is not guaranteed to
     * fail.
     */
    modifier onlyProxy() {
        require(address(this) != __self, "Function must be called through delegatecall");
        require(_getImplementation() == __self, "Function must be called through active proxy");
        _;
    }

    /**
     * @dev Check that the execution is not being performed through a delegate call. This allows a function to be
     * callable on the implementing contract but not through proxies.
     */
    modifier notDelegated() {
        require(address(this) == __self, "UUPSUpgradeable: must not be called through delegatecall");
        _;
    }

    /**
     * @dev Implementation of the ERC1822 {proxiableUUID} function. This returns the storage slot used by the
     * implementation. It is used to validate the implementation's compatibility when performing an upgrade.
     *
     * IMPORTANT: A proxy pointing at a proxiable contract should not be considered proxiable itself, because this risks
     * bricking a proxy that upgrades to it, by delegating to itself until out of gas. Thus it is critical that this
     * function revert if invoked through a proxy. This is guaranteed by the `notDelegated` modifier.
     */
    function proxiableUUID() external view virtual override notDelegated returns (bytes32) {
        return _IMPLEMENTATION_SLOT;
    }

    /**
     * @dev Upgrade the implementation of the proxy to `newImplementation`.
     *
     * Calls {_authorizeUpgrade}.
     *
     * Emits an {Upgraded} event.
     *
     * @custom:oz-upgrades-unsafe-allow-reachable delegatecall
     */
    function upgradeTo(address newImplementation) public virtual onlyProxy {
        _authorizeUpgrade(newImplementation);
        _upgradeToAndCallUUPS(newImplementation, new bytes(0), false);
    }

    /**
     * @dev Upgrade the implementation of the proxy to `newImplementation`, and subsequently execute the function call
     * encoded in `data`.
     *
     * Calls {_authorizeUpgrade}.
     *
     * Emits an {Upgraded} event.
     *
     * @custom:oz-upgrades-unsafe-allow-reachable delegatecall
     */
    function upgradeToAndCall(address newImplementation, bytes memory data) public payable virtual onlyProxy {
        _authorizeUpgrade(newImplementation);
        _upgradeToAndCallUUPS(newImplementation, data, true);
    }

    /**
     * @dev Function that should revert when `msg.sender` is not authorized to upgrade the contract. Called by
     * {upgradeTo} and {upgradeToAndCall}.
     *
     * Normally, this function will use an xref:access.adoc[access control] modifier such as {Ownable-onlyOwner}.
     *
     * ```solidity
     * function _authorizeUpgrade(address) internal override onlyOwner {}
     * ```
     */
    function _authorizeUpgrade(address newImplementation) internal virtual;
}

36% lib/openzeppelin-contracts/contracts/token/ERC20/ERC20.sol

Lines covered: 28 / 77 (36%)

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/ERC20.sol)

pragma solidity ^0.8.0;

import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.sol";

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * The default value of {decimals} is 18. To change this, you should override
 * this function so it returns a different value.
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20, IERC20Metadata {
    mapping(address => uint256) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * All two of these values are immutable: they can only be set once during
     * construction.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the default value returned by this function, unless
     * it's overridden.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address to, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
     * `transferFrom`. This is semantically equivalent to an infinite approval.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * NOTE: Does not update the allowance if the current allowance
     * is the maximum `uint256`.
     *
     * Requirements:
     *
     * - `from` and `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     * - the caller must have allowance for ``from``'s tokens of at least
     * `amount`.
     */
    function transferFrom(address from, address to, uint256 amount) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, allowance(owner, spender) + addedValue);
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        address owner = _msgSender();
        uint256 currentAllowance = allowance(owner, spender);
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(owner, spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    /**
     * @dev Moves `amount` of tokens from `from` to `to`.
     *
     * This internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     */
    function _transfer(address from, address to, uint256 amount) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[from] = fromBalance - amount;
            // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
            // decrementing then incrementing.
            _balances[to] += amount;
        }

        emit Transfer(from, to, amount);

        _afterTokenTransfer(from, to, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        unchecked {
            // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
            _balances[account] += amount;
        }
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
            // Overflow not possible: amount <= accountBalance <= totalSupply.
            _totalSupply -= amount;
        }

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Updates `owner` s allowance for `spender` based on spent `amount`.
     *
     * Does not update the allowance amount in case of infinite allowance.
     * Revert if not enough allowance is available.
     *
     * Might emit an {Approval} event.
     */
    function _spendAllowance(address owner, address spender, uint256 amount) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "ERC20: insufficient allowance");
            unchecked {
                _approve(owner, spender, currentAllowance - amount);
            }
        }
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual {}

    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(address from, address to, uint256 amount) internal virtual {}
}

33% lib/openzeppelin-contracts/contracts/token/ERC20/presets/ERC20PresetFixedSupply.sol

Lines covered: 1 / 3 (33%)

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/presets/ERC20PresetFixedSupply.sol)
pragma solidity ^0.8.0;

import "../extensions/ERC20Burnable.sol";

/**
 * @dev {ERC20} token, including:
 *
 *  - Preminted initial supply
 *  - Ability for holders to burn (destroy) their tokens
 *  - No access control mechanism (for minting/pausing) and hence no governance
 *
 * This contract uses {ERC20Burnable} to include burn capabilities - head to
 * its documentation for details.
 *
 * _Available since v3.4._
 *
 * _Deprecated in favor of https://wizard.openzeppelin.com/[Contracts Wizard]._
 */
contract ERC20PresetFixedSupply is ERC20Burnable {
    /**
     * @dev Mints `initialSupply` amount of token and transfers them to `owner`.
     *
     * See {ERC20-constructor}.
     */
    constructor(string memory name, string memory symbol, uint256 initialSupply, address owner) ERC20(name, symbol) {
        _mint(owner, initialSupply);
    }
}

87% lib/openzeppelin-contracts/contracts/token/ERC20/utils/SafeERC20.sol

Lines covered: 7 / 8 (87%)

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../extensions/IERC20Permit.sol";
import "../../../utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    /**
     * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    /**
     * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
     * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
     */
    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    /**
     * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 oldAllowance = token.allowance(address(this), spender);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance + value));
    }

    /**
     * @dev Decrease the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance - value));
        }
    }

    /**
     * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful. Compatible with tokens that require the approval to be set to
     * 0 before setting it to a non-zero value.
     */
    function forceApprove(IERC20 token, address spender, uint256 value) internal {
        bytes memory approvalCall = abi.encodeWithSelector(token.approve.selector, spender, value);

        if (!_callOptionalReturnBool(token, approvalCall)) {
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, 0));
            _callOptionalReturn(token, approvalCall);
        }
    }

    /**
     * @dev Use a ERC-2612 signature to set the `owner` approval toward `spender` on `token`.
     * Revert on invalid signature.
     */
    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address-functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        require(returndata.length == 0 || abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     *
     * This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
     */
    function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We cannot use {Address-functionCall} here since this should return false
        // and not revert is the subcall reverts.

        (bool success, bytes memory returndata) = address(token).call(data);
        return
            success && (returndata.length == 0 || abi.decode(returndata, (bool))) && Address.isContract(address(token));
    }
}

62% lib/openzeppelin-contracts/contracts/utils/Address.sol

Lines covered: 18 / 29 (62%)

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     *
     * Furthermore, `isContract` will also return true if the target contract within
     * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
     * which only has an effect at the end of a transaction.
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://consensys.net/diligence/blog/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.8.0/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // Look for revert reason and bubble it up if present
        if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

100% lib/openzeppelin-contracts/contracts/utils/Context.sol

Lines covered: 2 / 2 (100%)

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

81% src/AddressDriver.sol

Lines covered: 26 / 32 (81%)

// SPDX-License-Identifier: GPL-3.0-only
pragma solidity ^0.8.20;

import {AccountMetadata, Drips, StreamReceiver, IERC20, SplitsReceiver} from "./Drips.sol";
import {Managed} from "./Managed.sol";
import {DriverTransferUtils} from "./DriverTransferUtils.sol";

/// @notice A Drips driver implementing address-based account identification.
/// Each address can use `AddressDriver` to control a single account ID derived from that address.
/// No registration is required, an `AddressDriver`-based account ID
/// for each address is available upfront.
contract AddressDriver is DriverTransferUtils, Managed {
    /// @notice The Drips address used by this driver.
    Drips public immutable drips;
    /// @notice The driver ID which this driver uses when calling Drips.
    uint32 public immutable driverId;

    /// @param drips_ The Drips contract to use.
    /// @param forwarder The ERC-2771 forwarder to trust. May be the zero address.
    /// @param driverId_ The driver ID to use when calling Drips.
    constructor(Drips drips_, address forwarder, uint32 driverId_) DriverTransferUtils(forwarder) {
        drips = drips_;
        driverId = driverId_;
    }

    /// @notice Calculates the account ID for an address.
    /// Every account ID is a 256-bit integer constructed by concatenating:
    /// `driverId (32 bits) | zeros (64 bits) | addr (160 bits)`.
    /// @param addr The address
    /// @return accountId The account ID
    function calcAccountId(address addr) public view returns (uint256 accountId) {
        // By assignment we get `accountId` value:
        // `zeros (224 bits) | driverId (32 bits)`
        accountId = driverId;
        // By bit shifting we get `accountId` value:
        // `driverId (32 bits) | zeros (224 bits)`
        // By bit masking we get `accountId` value:
        // `driverId (32 bits) | zeros (64 bits) | addr (160 bits)`
        accountId = (accountId << 224) | uint160(addr);
    }

    /// @notice Calculates the account ID for the message sender
    /// @return accountId The account ID
    function _callerAccountId() internal view returns (uint256 accountId) {
        return calcAccountId(_msgSender());
    }

    /// @notice Collects the account's received already split funds
    /// and transfers them out of the Drips contract.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @param transferTo The address to send collected funds to
    /// @return amt The collected amount
    function collect(IERC20 erc20, address transferTo) public whenNotPaused returns (uint128 amt) {
        return _collectAndTransfer(drips, _callerAccountId(), erc20, transferTo);
    }

    /// @notice Gives funds from the message sender to the receiver.
    /// The receiver can split and collect them immediately.
    /// Transfers the funds to be given from the message sender's wallet to the Drips contract.
    /// @param receiver The receiver account ID.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @param amt The given amount
    function give(uint256 receiver, IERC20 erc20, uint128 amt) public whenNotPaused {
        _giveAndTransfer(drips, _callerAccountId(), receiver, erc20, amt);
    }

    /// @notice Sets the message sender's streams configuration.
    /// Transfers funds between the message sender's wallet and the Drips contract
    /// to fulfil the change of the streams balance.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @param currReceivers The current streams receivers list.
    /// It must be exactly the same as the last list set for the sender with `setStreams`.
    /// If this is the first update, pass an empty array.
    /// @param balanceDelta The streams balance change to be applied.
    /// If it's positive, the balance is increased by `balanceDelta`.
    /// If it's zero, the balance doesn't change.
    /// If it's negative, the balance is decreased by `balanceDelta`,
    /// but the change is capped at the current balance amount, so it doesn't go below 0.
    /// Passing `type(int128).min` always decreases the current balance to 0.
    /// @param newReceivers The list of the streams receivers of the sender to be set.
    /// Must be sorted by the account IDs and then by the stream configurations,
    /// without identical elements and without 0 amtPerSecs.
    /// @param maxEndHint1 An optional parameter allowing gas optimization, pass `0` to ignore it.
    /// The first hint for finding the maximum end time when all streams stop due to funds
    /// running out after the balance is updated and the new receivers list is applied.
    /// Hints have no effect on the results of calling this function, except potentially saving gas.
    /// Hints are Unix timestamps used as the starting points for binary search for the time
    /// when funds run out in the range of timestamps from the current block's to `2^32`.
    /// Hints lower than the current timestamp are ignored.
    /// You can provide zero, one or two hints. The order of hints doesn't matter.
    /// Hints are the most effective when one of them is lower than or equal to
    /// the last timestamp when funds are still streamed, and the other one is strictly larger
    /// than that timestamp,the smaller the difference between such hints, the higher gas savings.
    /// The savings are the highest possible when one of the hints is equal to
    /// the last timestamp when funds are still streamed, and the other one is larger by 1.
    /// It's worth noting that the exact timestamp of the block in which this function is executed
    /// may affect correctness of the hints, especially if they're precise.
    /// Hints don't provide any benefits when balance is not enough to cover
    /// a single second of streaming or is enough to cover all streams until timestamp `2^32`.
    /// Even inaccurate hints can be useful, and providing a single hint
    /// or two hints that don't enclose the time when funds run out can still save some gas.
    /// Providing poor hints that don't reduce the number of binary search steps
    /// may cause slightly higher gas usage than not providing any hints.
    /// @param maxEndHint2 An optional parameter allowing gas optimization, pass `0` to ignore it.
    /// The second hint for finding the maximum end time, see `maxEndHint1` docs for more details.
    /// @param transferTo The address to send funds to in case of decreasing balance
    /// @return realBalanceDelta The actually applied streams balance change.
    /// It's equal to the passed `balanceDelta`, unless it's negative
    /// and it gets capped at the current balance amount.
    function setStreams(
        IERC20 erc20,
        StreamReceiver[] calldata currReceivers,
        int128 balanceDelta,
        StreamReceiver[] calldata newReceivers,
        // slither-disable-next-line similar-names
        uint32 maxEndHint1,
        uint32 maxEndHint2,
        address transferTo
    ) public whenNotPaused returns (int128 realBalanceDelta) {
        return _setStreamsAndTransfer(
            drips,
            _callerAccountId(),
            erc20,
            currReceivers,
            balanceDelta,
            newReceivers,
            maxEndHint1,
            maxEndHint2,
            transferTo
        );
    }

    /// @notice Sets the account splits configuration.
    /// The configuration is common for all ERC-20 tokens.
    /// Nothing happens to the currently splittable funds, but when they are split
    /// after this function finishes, the new splits configuration will be used.
    /// Because anybody can call `split` on `Drips`, calling this function may be frontrun
    /// and all the currently splittable funds will be split using the old splits configuration.
    /// @param receivers The list of the account's splits receivers to be set.
    /// Must be sorted by the account IDs, without duplicate account IDs and without 0 weights.
    /// Each splits receiver will be getting `weight / TOTAL_SPLITS_WEIGHT`
    /// share of the funds collected by the account.
    /// If the sum of weights of all receivers is less than `_TOTAL_SPLITS_WEIGHT`,
    /// some funds won't be split, but they will be left for the account to collect.
    /// Fractions of tokens are always rounder either up or down depending on the amount
    /// being split, the receiver's position on the list and the other receivers' weights.
    /// It's valid to include the account's own `accountId` in the list of receivers,
    /// but funds split to themselves return to their splittable balance and are not collectable.
    /// This is usually unwanted, because if splitting is repeated,
    /// funds split to themselves will be again split using the current configuration.
    /// Splitting 100% to self effectively blocks splitting unless the configuration is updated.
    function setSplits(SplitsReceiver[] calldata receivers) public whenNotPaused {
        drips.setSplits(_callerAccountId(), receivers);
    }

    /// @notice Emits the account metadata for the message sender.
    /// The keys and the values are not standardized by the protocol, it's up to the users
    /// to establish and follow conventions to ensure compatibility with the consumers.
    /// @param accountMetadata The list of account metadata.
    function emitAccountMetadata(AccountMetadata[] calldata accountMetadata) public whenNotPaused {
        if (accountMetadata.length != 0) {
            drips.emitAccountMetadata(_callerAccountId(), accountMetadata);
        }
    }
}

80% src/Drips.sol

Lines covered: 117 / 146 (80%)

// SPDX-License-Identifier: GPL-3.0-only
pragma solidity ^0.8.20;

import {
    Streams, StreamConfig, StreamsHistory, StreamConfigImpl, StreamReceiver
} from "./Streams.sol";
import {Managed} from "./Managed.sol";
import {Splits, SplitsReceiver} from "./Splits.sol";
import {IERC20, SafeERC20} from "openzeppelin-contracts/token/ERC20/utils/SafeERC20.sol";

using SafeERC20 for IERC20;

/// @notice The account metadata.
/// The key and the value are not standardized by the protocol, it's up to the users
/// to establish and follow conventions to ensure compatibility with the consumers.
struct AccountMetadata {
    /// @param key The metadata key
    bytes32 key;
    /// @param value The metadata value
    bytes value;
}

/// @notice Drips protocol contract. Automatically streams and splits funds between accounts.
///
/// The account can transfer some funds to their streams balance in the contract
/// and configure a list of receivers, to whom they want to stream these funds.
/// As soon as the streams balance is enough to cover at least 1 second of streaming
/// to the configured receivers, the funds start streaming automatically.
/// Every second funds are deducted from the streams balance and moved to their receivers.
/// The process stops automatically when the streams balance is not enough to cover another second.
///
/// Every account has a receiver balance, in which they have funds received from other accounts.
/// The streamed funds are added to the receiver balances in global cycles.
/// Every `cycleSecs` seconds the protocol adds streamed funds to the receivers' balances,
/// so recently streamed funds may not be receivable immediately.
/// `cycleSecs` is a constant configured when the Drips contract is deployed.
/// The receiver balance is independent from the streams balance,
/// to stream received funds they need to be first collected and then added to the streams balance.
///
/// The account can share collected funds with other accounts by using splits.
/// When collecting, the account gives each of their splits receivers
/// a fraction of the received funds.
/// Funds received from splits are available for collection immediately regardless of the cycle.
/// They aren't exempt from being split, so they too can be split when collected.
/// Accounts can build chains and networks of splits between each other.
/// Anybody can request collection of funds for any account,
/// which can be used to enforce the flow of funds in the network of splits.
///
/// The concept of something happening periodically, e.g. every second or every `cycleSecs` are
/// only high-level abstractions for the account, Ethereum isn't really capable of scheduling work.
/// The actual implementation emulates that behavior by calculating the results of the scheduled
/// events based on how many seconds have passed and only when the account needs their outcomes.
///
/// The contract can store at most `type(int128).max` which is `2 ^ 127 - 1` units of each token.
contract Drips is Managed, Streams, Splits {
    /// @notice Maximum number of streams receivers of a single account.
    /// Limits cost of changes in streams configuration.
    uint256 public constant MAX_STREAMS_RECEIVERS = _MAX_STREAMS_RECEIVERS;
    /// @notice The additional decimals for all amtPerSec values.
    uint8 public constant AMT_PER_SEC_EXTRA_DECIMALS = _AMT_PER_SEC_EXTRA_DECIMALS;
    /// @notice The multiplier for all amtPerSec values.
    uint160 public constant AMT_PER_SEC_MULTIPLIER = _AMT_PER_SEC_MULTIPLIER;
    /// @notice Maximum number of splits receivers of a single account.
    /// Limits the cost of splitting.
    uint256 public constant MAX_SPLITS_RECEIVERS = _MAX_SPLITS_RECEIVERS;
    /// @notice The total splits weight of an account
    uint32 public constant TOTAL_SPLITS_WEIGHT = _TOTAL_SPLITS_WEIGHT;
    /// @notice The offset of the controlling driver ID in the account ID.
    /// In other words the controlling driver ID is the highest 32 bits of the account ID.
    /// Every account ID is a 256-bit integer constructed by concatenating:
    /// `driverId (32 bits) | driverCustomData (224 bits)`.
    uint8 public constant DRIVER_ID_OFFSET = 224;
    /// @notice The total amount the protocol can store of each token.
    /// It's the minimum of _MAX_STREAMS_BALANCE and _MAX_SPLITS_BALANCE.
    uint128 public constant MAX_TOTAL_BALANCE = _MAX_STREAMS_BALANCE;
    /// @notice On every timestamp `T`, which is a multiple of `cycleSecs`, the receivers
    /// gain access to steams received during `T - cycleSecs` to `T - 1`.
    /// Always higher than 1.
    uint32 public immutable cycleSecs;
    /// @notice The minimum amtPerSec of a stream. It's 1 token per cycle.
    uint160 public immutable minAmtPerSec;
    /// @notice The ERC-1967 storage slot holding a single `DripsStorage` structure.
    bytes32 private immutable _dripsStorageSlot = _erc1967Slot("eip1967.drips.storage");

    /// @notice Emitted when a driver is registered
    /// @param driverId The driver ID
    /// @param driverAddr The driver address
    event DriverRegistered(uint32 indexed driverId, address indexed driverAddr);

    /// @notice Emitted when a driver address is updated
    /// @param driverId The driver ID
    /// @param oldDriverAddr The old driver address
    /// @param newDriverAddr The new driver address
    event DriverAddressUpdated(
        uint32 indexed driverId, address indexed oldDriverAddr, address indexed newDriverAddr
    );

    /// @notice Emitted when funds are withdrawn.
    /// @param erc20 The used ERC-20 token.
    /// @param receiver The address that the funds are sent to.
    /// @param amt The withdrawn amount.
    event Withdrawn(IERC20 indexed erc20, address indexed receiver, uint256 amt);

    /// @notice Emitted by the account to broadcast metadata.
    /// The key and the value are not standardized by the protocol, it's up to the users
    /// to establish and follow conventions to ensure compatibility with the consumers.
    /// @param accountId The ID of the account emitting metadata
    /// @param key The metadata key
    /// @param value The metadata value
    event AccountMetadataEmitted(uint256 indexed accountId, bytes32 indexed key, bytes value);

    struct DripsStorage {
        /// @notice The next driver ID that will be used when registering.
        uint32 nextDriverId;
        /// @notice Driver addresses.
        mapping(uint32 driverId => address) driverAddresses;
        /// @notice The balance of each token currently stored in the protocol.
        mapping(IERC20 erc20 => Balance) balances;
    }

    /// @notice The balance currently stored in the protocol.
    struct Balance {
        /// @notice The balance currently stored in the protocol in streaming.
        /// It's the sum of all the funds of all the users
        /// that are in the streams balances, are squeezable or are receivable.
        uint128 streams;
        /// @notice The balance currently stored in the protocol in splitting.
        /// It's the sum of all the funds of all the users that are splittable or are collectable.
        uint128 splits;
    }

    /// @param cycleSecs_ The length of cycleSecs to be used in the contract instance.
    /// Low value makes funds more available by shortening the average time
    /// of funds being frozen between being taken from the accounts'
    /// streams balance and being receivable by their receivers.
    /// High value makes receiving cheaper by making it process less cycles for a given time range.
    /// Must be higher than 1.
    constructor(uint32 cycleSecs_)
        Streams(cycleSecs_, _erc1967Slot("eip1967.streams.storage"))
        Splits(_erc1967Slot("eip1967.splits.storage"))
    {
        cycleSecs = Streams._cycleSecs;
        minAmtPerSec = Streams._minAmtPerSec;
    }

    /// @notice A modifier making functions callable only by the driver controlling the account.
    /// @param accountId The account ID.
    modifier onlyDriver(uint256 accountId) {
        // `accountId` has value:
        // `driverId (32 bits) | driverCustomData (224 bits)`
        // By bit shifting we get value:
        // `zeros (224 bits) | driverId (32 bits)`
        // By casting down we get value:
        // `driverId (32 bits)`
        uint32 driverId = uint32(accountId >> DRIVER_ID_OFFSET);
        _assertCallerIsDriver(driverId);
        _;
    }

    /// @notice Verifies that the caller controls the given driver ID and reverts otherwise.
    /// @param driverId The driver ID.
    function _assertCallerIsDriver(uint32 driverId) internal view {
        require(driverAddress(driverId) == msg.sender, "Callable only by the driver");
    }

    /// @notice Registers a driver.
    /// The driver is assigned a unique ID and a range of account IDs it can control.
    /// That range consists of all 2^224 account IDs with highest 32 bits equal to the driver ID.
    /// Every account ID is a 256-bit integer constructed by concatenating:
    /// `driverId (32 bits) | driverCustomData (224 bits)`.
    /// Every driver ID is assigned only to a single address,
    /// but a single address can have multiple driver IDs assigned to it.
    /// @param driverAddr The address of the driver. Must not be zero address.
    /// It should be a smart contract capable of dealing with the Drips API.
    /// It shouldn't be an EOA because the API requires making multiple calls per transaction.
    /// @return driverId The registered driver ID.
    function registerDriver(address driverAddr) public whenNotPaused returns (uint32 driverId) {
        require(driverAddr != address(0), "Driver registered for 0 address");
        DripsStorage storage dripsStorage = _dripsStorage();
        driverId = dripsStorage.nextDriverId++;
        dripsStorage.driverAddresses[driverId] = driverAddr;
        emit DriverRegistered(driverId, driverAddr);
    }

    /// @notice Returns the driver address.
    /// @param driverId The driver ID to look up.
    /// @return driverAddr The address of the driver.
    /// If the driver hasn't been registered yet, returns address 0.
    function driverAddress(uint32 driverId) public view returns (address driverAddr) {
        return _dripsStorage().driverAddresses[driverId];
    }

    /// @notice Updates the driver address. Must be called from the current driver address.
    /// @param driverId The driver ID.
    /// @param newDriverAddr The new address of the driver.
    /// It should be a smart contract capable of dealing with the Drips API.
    /// It shouldn't be an EOA because the API requires making multiple calls per transaction.
    function updateDriverAddress(uint32 driverId, address newDriverAddr) public whenNotPaused {
        _assertCallerIsDriver(driverId);
        _dripsStorage().driverAddresses[driverId] = newDriverAddr;
        emit DriverAddressUpdated(driverId, msg.sender, newDriverAddr);
    }

    /// @notice Returns the driver ID which will be assigned for the next registered driver.
    /// @return driverId The next driver ID.
    function nextDriverId() public view returns (uint32 driverId) {
        return _dripsStorage().nextDriverId;
    }

    /// @notice Returns the amount currently stored in the protocol of the given token.
    /// The sum of streaming and splitting balances can never exceed `MAX_TOTAL_BALANCE`.
    /// The amount of tokens held by the Drips contract exceeding the sum of
    /// streaming and splitting balances can be `withdraw`n.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @return streamsBalance The balance currently stored in the protocol in streaming.
    /// It's the sum of all the funds of all the users
    /// that are in the streams balances, are squeezable or are receivable.
    /// @return splitsBalance The balance currently stored in the protocol in splitting.
    /// It's the sum of all the funds of all the users that are splittable or are collectable.
    function balances(IERC20 erc20)
        public
        view
        returns (uint128 streamsBalance, uint128 splitsBalance)
    {
        Balance storage balance = _dripsStorage().balances[erc20];
        return (balance.streams, balance.splits);
    }

    /// @notice Increases the balance of the given token currently stored in streams.
    /// No funds are transferred, all the tokens are expected to be already held by Drips.
    /// The new total balance is verified to have coverage in the held tokens
    /// and to be within the limit of `MAX_TOTAL_BALANCE`.
    /// @param erc20 The used ERC-20 token.
    /// @param amt The amount to increase the streams balance by.
    function _increaseStreamsBalance(IERC20 erc20, uint128 amt) internal {
        _verifyBalanceIncrease(erc20, amt);
        _dripsStorage().balances[erc20].streams += amt;
    }

    /// @notice Decreases the balance of the given token currently stored in streams.
    /// No funds are transferred, but the tokens held by Drips
    /// above the total balance become withdrawable.
    /// @param erc20 The used ERC-20 token.
    /// @param amt The amount to decrease the streams balance by.
    function _decreaseStreamsBalance(IERC20 erc20, uint128 amt) internal {
        _dripsStorage().balances[erc20].streams -= amt;
    }

    /// @notice Increases the balance of the given token currently stored in splits.
    /// No funds are transferred, all the tokens are expected to be already held by Drips.
    /// The new total balance is verified to have coverage in the held tokens
    /// and to be within the limit of `MAX_TOTAL_BALANCE`.
    /// @param erc20 The used ERC-20 token.
    /// @param amt The amount to increase the splits balance by.
    function _increaseSplitsBalance(IERC20 erc20, uint128 amt) internal {
        _verifyBalanceIncrease(erc20, amt);
        _dripsStorage().balances[erc20].splits += amt;
    }

    /// @notice Decreases the balance of the given token currently stored in splits.
    /// No funds are transferred, but the tokens held by Drips
    /// above the total balance become withdrawable.
    /// @param erc20 The used ERC-20 token.
    /// @param amt The amount to decrease the splits balance by.
    function _decreaseSplitsBalance(IERC20 erc20, uint128 amt) internal {
        _dripsStorage().balances[erc20].splits -= amt;
    }

    /// @notice Moves the balance of the given token currently stored in streams to splits.
    /// No funds are transferred, all the tokens are already held by Drips.
    /// @param erc20 The used ERC-20 token.
    /// @param amt The amount to decrease the splits balance by.
    function _moveBalanceFromStreamsToSplits(IERC20 erc20, uint128 amt) internal {
        Balance storage balance = _dripsStorage().balances[erc20];
        balance.streams -= amt;
        balance.splits += amt;
    }

    /// @notice Verifies that the balance of streams or splits can be increased by the given amount.
    /// The sum of streaming and splitting balances is checked to not exceed
    /// `MAX_TOTAL_BALANCE` or the amount of tokens held by the Drips.
    /// @param erc20 The used ERC-20 token.
    /// @param amt The amount to increase the streams or splits balance by.
    function _verifyBalanceIncrease(IERC20 erc20, uint128 amt) internal view {
        (uint256 streamsBalance, uint128 splitsBalance) = balances(erc20);
        uint256 newTotalBalance = streamsBalance + splitsBalance + amt;
        require(newTotalBalance <= MAX_TOTAL_BALANCE, "Total balance too high");
        require(newTotalBalance <= _tokenBalance(erc20), "Token balance too low");
    }

    /// @notice Transfers withdrawable funds to an address.
    /// The withdrawable funds are held by the Drips contract,
    /// but not used in the protocol, so they are free to be transferred out.
    /// Anybody can call `withdraw`, so all withdrawable funds should be withdrawn
    /// or used in the protocol before any 3rd parties have a chance to do that.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @param receiver The address to send withdrawn funds to.
    /// @param amt The withdrawn amount.
    /// It must be at most the difference between the balance of the token held by the Drips
    /// contract address and the sum of balances managed by the protocol as indicated by `balances`.
    function withdraw(IERC20 erc20, address receiver, uint256 amt) public {
        (uint128 streamsBalance, uint128 splitsBalance) = balances(erc20);
        uint256 withdrawable = _tokenBalance(erc20) - streamsBalance - splitsBalance;
        require(amt <= withdrawable, "Withdrawal amount too high");
        emit Withdrawn(erc20, receiver, amt);
        erc20.safeTransfer(receiver, amt);
    }

    function _tokenBalance(IERC20 erc20) internal view returns (uint256) {
        return erc20.balanceOf(address(this));
    }

    /// @notice Counts cycles from which streams can be collected.
    /// This function can be used to detect that there are
    /// too many cycles to analyze in a single transaction.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @return cycles The number of cycles which can be flushed
    function receivableStreamsCycles(uint256 accountId, IERC20 erc20)
        public
        view
        returns (uint32 cycles)
    {
        return Streams._receivableStreamsCycles(accountId, erc20);
    }

    /// @notice Calculate effects of calling `receiveStreams` with the given parameters.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @param maxCycles The maximum number of received streams cycles.
    /// If too low, receiving will be cheap, but may not cover many cycles.
    /// If too high, receiving may become too expensive to fit in a single transaction.
    /// @return receivableAmt The amount which would be received
    function receiveStreamsResult(uint256 accountId, IERC20 erc20, uint32 maxCycles)
        public
        view
        returns (uint128 receivableAmt)
    {
        (receivableAmt,,,,) = Streams._receiveStreamsResult(accountId, erc20, maxCycles);
    }

    /// @notice Receive streams for the account.
    /// Received streams cycles won't need to be analyzed ever again.
    /// Calling this function does not collect but makes the funds ready to be split and collected.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @param maxCycles The maximum number of received streams cycles.
    /// If too low, receiving will be cheap, but may not cover many cycles.
    /// If too high, receiving may become too expensive to fit in a single transaction.
    /// @return receivedAmt The received amount
    function receiveStreams(uint256 accountId, IERC20 erc20, uint32 maxCycles)
        public
        whenNotPaused
        returns (uint128 receivedAmt)
    {
        receivedAmt = Streams._receiveStreams(accountId, erc20, maxCycles);
        if (receivedAmt != 0) {
            _moveBalanceFromStreamsToSplits(erc20, receivedAmt);
            Splits._addSplittable(accountId, erc20, receivedAmt);
        }
    }

    /// @notice Receive streams from the currently running cycle from a single sender.
    /// It doesn't receive streams from the finished cycles, to do that use `receiveStreams`.
    /// Squeezed funds won't be received in the next calls to `squeezeStreams` or `receiveStreams`.
    /// Only funds streamed before `block.timestamp` can be squeezed.
    /// @param accountId The ID of the account receiving streams to squeeze funds for.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @param senderId The ID of the streaming account to squeeze funds from.
    /// @param historyHash The sender's history hash that was valid right before
    /// they set up the sequence of configurations described by `streamsHistory`.
    /// @param streamsHistory The sequence of the sender's streams configurations.
    /// It can start at an arbitrary past configuration, but must describe all the configurations
    /// which have been used since then including the current one, in the chronological order.
    /// Only streams described by `streamsHistory` will be squeezed.
    /// If `streamsHistory` entries have no receivers, they won't be squeezed.
    /// @return amt The squeezed amount.
    function squeezeStreams(
        uint256 accountId,
        IERC20 erc20,
        uint256 senderId,
        bytes32 historyHash,
        StreamsHistory[] memory streamsHistory
    ) public whenNotPaused returns (uint128 amt) {
        amt = Streams._squeezeStreams(accountId, erc20, senderId, historyHash, streamsHistory);
        if (amt != 0) {
            _moveBalanceFromStreamsToSplits(erc20, amt);
            Splits._addSplittable(accountId, erc20, amt);
        }
    }

    /// @notice Calculate effects of calling `squeezeStreams` with the given parameters.
    /// See its documentation for more details.
    /// @param accountId The ID of the account receiving streams to squeeze funds for.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @param senderId The ID of the streaming account to squeeze funds from.
    /// @param historyHash The sender's history hash that was valid right before `streamsHistory`.
    /// @param streamsHistory The sequence of the sender's streams configurations.
    /// @return amt The squeezed amount.
    function squeezeStreamsResult(
        uint256 accountId,
        IERC20 erc20,
        uint256 senderId,
        bytes32 historyHash,
        StreamsHistory[] memory streamsHistory
    ) public view returns (uint128 amt) {
        (amt,,,,) =
            Streams._squeezeStreamsResult(accountId, erc20, senderId, historyHash, streamsHistory);
    }

    /// @notice Returns account's received but not split yet funds.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @return amt The amount received but not split yet.
    function splittable(uint256 accountId, IERC20 erc20) public view returns (uint128 amt) {
        return Splits._splittable(accountId, erc20);
    }

    /// @notice Calculate the result of splitting an amount using the current splits configuration.
    /// Fractions of tokens are always rounder either up or down depending on the amount
    /// being split, the receiver's position on the list and the other receivers' weights.
    /// @param accountId The account ID.
    /// @param currReceivers The list of the account's current splits receivers.
    /// It must be exactly the same as the last list set for the account with `setSplits`.
    /// If the splits have never been set, pass an empty array.
    /// @param amount The amount being split.
    /// @return collectableAmt The amount made collectable for the account
    /// on top of what was collectable before.
    /// @return splitAmt The amount split to the account's splits receivers
    function splitResult(uint256 accountId, SplitsReceiver[] memory currReceivers, uint128 amount)
        public
        view
        returns (uint128 collectableAmt, uint128 splitAmt)
    {
        return Splits._splitResult(accountId, currReceivers, amount);
    }

    /// @notice Splits the account's splittable funds among receivers.
    /// The entire splittable balance of the given ERC-20 token is split.
    /// Fractions of tokens are always rounder either up or down depending on the amount
    /// being split, the receiver's position on the list and the other receivers' weights.
    /// All split funds are split using the current splits configuration.
    /// Because the account can update their splits configuration at any time,
    /// it is possible that calling this function will be frontrun,
    /// and all the splittable funds will become splittable only using the new configuration.
    /// The account must be trusted with how funds sent to them will be splits,
    /// in the end they can do with their funds whatever they want by changing the configuration.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @param currReceivers The list of the account's current splits receivers.
    /// It must be exactly the same as the last list set for the account with `setSplits`.
    /// If the splits have never been set, pass an empty array.
    /// @return collectableAmt The amount made collectable for the account
    /// on top of what was collectable before.
    /// @return splitAmt The amount split to the account's splits receivers
    function split(uint256 accountId, IERC20 erc20, SplitsReceiver[] memory currReceivers)
        public
        whenNotPaused
        returns (uint128 collectableAmt, uint128 splitAmt)
    {
        return Splits._split(accountId, erc20, currReceivers);
    }

    /// @notice Returns account's received funds already split and ready to be collected.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @return amt The collectable amount.
    function collectable(uint256 accountId, IERC20 erc20) public view returns (uint128 amt) {
        return Splits._collectable(accountId, erc20);
    }

    /// @notice Collects account's received already split funds and makes them withdrawable.
    /// Anybody can call `withdraw`, so all withdrawable funds should be withdrawn
    /// or used in the protocol before any 3rd parties have a chance to do that.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @return amt The collected amount
    function collect(uint256 accountId, IERC20 erc20)
        public
        whenNotPaused
        onlyDriver(accountId)
        returns (uint128 amt)
    {
        amt = Splits._collect(accountId, erc20);
        if (amt != 0) _decreaseSplitsBalance(erc20, amt);
    }

    /// @notice Gives funds from the account to the receiver.
    /// The receiver can split and collect them immediately.
    /// Requires that the tokens used to give are already sent to Drips and are withdrawable.
    /// Anybody can call `withdraw`, so all withdrawable funds should be withdrawn
    /// or used in the protocol before any 3rd parties have a chance to do that.
    /// @param accountId The account ID.
    /// @param receiver The receiver account ID.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @param amt The given amount
    function give(uint256 accountId, uint256 receiver, IERC20 erc20, uint128 amt)
        public
        whenNotPaused
        onlyDriver(accountId)
    {
        if (amt != 0) _increaseSplitsBalance(erc20, amt);
        Splits._give(accountId, receiver, erc20, amt);
    }

    /// @notice Current account streams state.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @return streamsHash The current streams receivers list hash, see `hashStreams`
    /// @return streamsHistoryHash The current streams history hash, see `hashStreamsHistory`.
    /// @return updateTime The time when streams have been configured for the last time.
    /// @return balance The balance when streams have been configured for the last time.
    /// @return maxEnd The current maximum end time of streaming.
    function streamsState(uint256 accountId, IERC20 erc20)
        public
        view
        returns (
            bytes32 streamsHash,
            bytes32 streamsHistoryHash,
            uint32 updateTime,
            uint128 balance,
            uint32 maxEnd
        )
    {
        return Streams._streamsState(accountId, erc20);
    }

    /// @notice The account's streams balance at the given timestamp.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @param currReceivers The current streams receivers list.
    /// It must be exactly the same as the last list set for the account with `setStreams`.
    /// @param timestamp The timestamp for which balance should be calculated.
    /// It can't be lower than the timestamp of the last call to `setStreams`.
    /// If it's bigger than `block.timestamp`, then it's a prediction assuming
    /// that `setStreams` won't be called before `timestamp`.
    /// @return balance The account balance on `timestamp`
    function balanceAt(
        uint256 accountId,
        IERC20 erc20,
        StreamReceiver[] memory currReceivers,
        uint32 timestamp
    ) public view returns (uint128 balance) {
        return Streams._balanceAt(accountId, erc20, currReceivers, timestamp);
    }

    /// @notice Sets the account's streams configuration.
    /// Requires that the tokens used to increase the streams balance
    /// are already sent to Drips and are withdrawable.
    /// If the streams balance is decreased, the released tokens become withdrawable.
    /// Anybody can call `withdraw`, so all withdrawable funds should be withdrawn
    /// or used in the protocol before any 3rd parties have a chance to do that.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @param currReceivers The current streams receivers list.
    /// It must be exactly the same as the last list set for the account with `setStreams`.
    /// If this is the first update, pass an empty array.
    /// @param balanceDelta The streams balance change to be applied.
    /// If it's positive, the balance is increased by `balanceDelta`.
    /// If it's zero, the balance doesn't change.
    /// If it's negative, the balance is decreased by `balanceDelta`,
    /// but the change is capped at the current balance amount, so it doesn't go below 0.
    /// Passing `type(int128).min` always decreases the current balance to 0.
    /// @param newReceivers The list of the streams receivers of the account to be set.
    /// Must be sorted by the account IDs and then by the stream configurations,
    /// without identical elements and without 0 amtPerSecs.
    /// @param maxEndHint1 An optional parameter allowing gas optimization, pass `0` to ignore it.
    /// The first hint for finding the maximum end time when all streams stop due to funds
    /// running out after the balance is updated and the new receivers list is applied.
    /// Hints have no effect on the results of calling this function, except potentially saving gas.
    /// Hints are Unix timestamps used as the starting points for binary search for the time
    /// when funds run out in the range of timestamps from the current block's to `2^32`.
    /// Hints lower than the current timestamp are ignored.
    /// You can provide zero, one or two hints. The order of hints doesn't matter.
    /// Hints are the most effective when one of them is lower than or equal to
    /// the last timestamp when funds are still streamed, and the other one is strictly larger
    /// than that timestamp,the smaller the difference between such hints, the higher gas savings.
    /// The savings are the highest possible when one of the hints is equal to
    /// the last timestamp when funds are still streamed, and the other one is larger by 1.
    /// It's worth noting that the exact timestamp of the block in which this function is executed
    /// may affect correctness of the hints, especially if they're precise.
    /// Hints don't provide any benefits when balance is not enough to cover
    /// a single second of streaming or is enough to cover all streams until timestamp `2^32`.
    /// Even inaccurate hints can be useful, and providing a single hint
    /// or two hints that don't enclose the time when funds run out can still save some gas.
    /// Providing poor hints that don't reduce the number of binary search steps
    /// may cause slightly higher gas usage than not providing any hints.
    /// @param maxEndHint2 An optional parameter allowing gas optimization, pass `0` to ignore it.
    /// The second hint for finding the maximum end time, see `maxEndHint1` docs for more details.
    /// @return realBalanceDelta The actually applied streams balance change.
    /// It's equal to the passed `balanceDelta`, unless it's negative
    /// and it gets capped at the current balance amount.
    /// If it's lower than zero, it's the negative of the amount that became withdrawable.
    function setStreams(
        uint256 accountId,
        IERC20 erc20,
        StreamReceiver[] memory currReceivers,
        int128 balanceDelta,
        StreamReceiver[] memory newReceivers,
        // slither-disable-next-line similar-names
        uint32 maxEndHint1,
        uint32 maxEndHint2
    ) public whenNotPaused onlyDriver(accountId) returns (int128 realBalanceDelta) {
        if (balanceDelta > 0) _increaseStreamsBalance(erc20, uint128(balanceDelta));
        realBalanceDelta = Streams._setStreams(
            accountId, erc20, currReceivers, balanceDelta, newReceivers, maxEndHint1, maxEndHint2
        );
        if (realBalanceDelta < 0) _decreaseStreamsBalance(erc20, uint128(-realBalanceDelta));
    }

    /// @notice Calculates the hash of the streams configuration.
    /// It's used to verify if streams configuration is the previously set one.
    /// @param receivers The list of the streams receivers.
    /// Must be sorted by the account IDs and then by the stream configurations,
    /// without identical elements and without 0 amtPerSecs.
    /// If the streams have never been set, pass an empty array.
    /// @return streamsHash The hash of the streams configuration
    function hashStreams(StreamReceiver[] memory receivers)
        public
        pure
        returns (bytes32 streamsHash)
    {
        return Streams._hashStreams(receivers);
    }

    /// @notice Calculates the hash of the streams history
    /// after the streams configuration is updated.
    /// @param oldStreamsHistoryHash The history hash
    /// that was valid before the streams were updated.
    /// The `streamsHistoryHash` of the account before they set streams for the first time is `0`.
    /// @param streamsHash The hash of the streams receivers being set.
    /// @param updateTime The timestamp when the streams were updated.
    /// @param maxEnd The maximum end of the streams being set.
    /// @return streamsHistoryHash The hash of the updated streams history.
    function hashStreamsHistory(
        bytes32 oldStreamsHistoryHash,
        bytes32 streamsHash,
        uint32 updateTime,
        uint32 maxEnd
    ) public pure returns (bytes32 streamsHistoryHash) {
        return Streams._hashStreamsHistory(oldStreamsHistoryHash, streamsHash, updateTime, maxEnd);
    }

    /// @notice Sets the account splits configuration.
    /// The configuration is common for all ERC-20 tokens.
    /// Nothing happens to the currently splittable funds, but when they are split
    /// after this function finishes, the new splits configuration will be used.
    /// Because anybody can call `split`, calling this function may be frontrun
    /// and all the currently splittable funds will be split using the old splits configuration.
    /// @param accountId The account ID.
    /// @param receivers The list of the account's splits receivers to be set.
    /// Must be sorted by the account IDs, without duplicate account IDs and without 0 weights.
    /// Each splits receiver will be getting `weight / TOTAL_SPLITS_WEIGHT`
    /// share of the funds collected by the account.
    /// If the sum of weights of all receivers is less than `_TOTAL_SPLITS_WEIGHT`,
    /// some funds won't be split, but they will be left for the account to collect.
    /// Fractions of tokens are always rounder either up or down depending on the amount
    /// being split, the receiver's position on the list and the other receivers' weights.
    /// It's valid to include the account's own `accountId` in the list of receivers,
    /// but funds split to themselves return to their splittable balance and are not collectable.
    /// This is usually unwanted, because if splitting is repeated,
    /// funds split to themselves will be again split using the current configuration.
    /// Splitting 100% to self effectively blocks splitting unless the configuration is updated.
    function setSplits(uint256 accountId, SplitsReceiver[] memory receivers)
        public
        whenNotPaused
        onlyDriver(accountId)
    {
        Splits._setSplits(accountId, receivers);
    }

    /// @notice Current account's splits hash, see `hashSplits`.
    /// @param accountId The account ID.
    /// @return currSplitsHash The current account's splits hash
    function splitsHash(uint256 accountId) public view returns (bytes32 currSplitsHash) {
        return Splits._splitsHash(accountId);
    }

    /// @notice Calculates the hash of the list of splits receivers.
    /// @param receivers The list of the splits receivers.
    /// Must be sorted by the account IDs, without duplicate account IDs and without 0 weights.
    /// @return receiversHash The hash of the list of splits receivers.
    function hashSplits(SplitsReceiver[] memory receivers)
        public
        pure
        returns (bytes32 receiversHash)
    {
        return Splits._hashSplits(receivers);
    }

    /// @notice Emits account metadata.
    /// The keys and the values are not standardized by the protocol, it's up to the users
    /// to establish and follow conventions to ensure compatibility with the consumers.
    /// @param accountId The account ID.
    /// @param accountMetadata The list of account metadata.
    function emitAccountMetadata(uint256 accountId, AccountMetadata[] calldata accountMetadata)
        public
        whenNotPaused
        onlyDriver(accountId)
    {
        unchecked {
            for (uint256 i = 0; i < accountMetadata.length; i++) {
                AccountMetadata calldata metadata = accountMetadata[i];
                emit AccountMetadataEmitted(accountId, metadata.key, metadata.value);
            }
        }
    }

    /// @notice Returns the Drips storage.
    /// @return storageRef The storage.
    function _dripsStorage() internal view returns (DripsStorage storage storageRef) {
        bytes32 slot = _dripsStorageSlot;
        // slither-disable-next-line assembly
        assembly {
            storageRef.slot := slot
        }
    }
}

100% src/DriverTransferUtils.sol

Lines covered: 16 / 16 (100%)

// SPDX-License-Identifier: GPL-3.0-only
pragma solidity ^0.8.20;

import {Drips, StreamReceiver, IERC20, SafeERC20} from "./Drips.sol";
import {ERC2771Context} from "openzeppelin-contracts/metatx/ERC2771Context.sol";

/// @notice ERC-20 token transfer utilities for drivers.
/// Encapsulates the logic for token transfers made by drivers implementing user identities.
/// All funds going into Drips are transferred ad-hoc from the caller (`msg.sender`),
/// and all funds going out of Drips are transferred in full to the provided address.
/// Compatible with `Caller` by supporting ERC-2771.
abstract contract DriverTransferUtils is ERC2771Context {
    /// @param forwarder The ERC-2771 forwarder to trust. May be the zero address.
    constructor(address forwarder) ERC2771Context(forwarder) {}

    /// @notice Collects the account's received already split funds
    /// and transfers them out of the Drips contract.
    /// @param drips The Drips contract to use.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @param transferTo The address to send collected funds to
    /// @return amt The collected amount
    function _collectAndTransfer(Drips drips, uint256 accountId, IERC20 erc20, address transferTo)
        internal
        returns (uint128 amt)
    {
        amt = drips.collect(accountId, erc20);
        if (amt > 0) drips.withdraw(erc20, transferTo, amt);
    }

    /// @notice Gives funds from the message sender to the receiver.
    /// The receiver can split and collect them immediately.
    /// Transfers the funds to be given from the message sender's wallet to the Drips contract.
    /// @param drips The Drips contract to use.
    /// @param receiver The receiver account ID.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @param amt The given amount
    function _giveAndTransfer(
        Drips drips,
        uint256 accountId,
        uint256 receiver,
        IERC20 erc20,
        uint128 amt
    ) internal {
        if (amt > 0) _transferFromCaller(drips, erc20, amt);
        drips.give(accountId, receiver, erc20, amt);
    }

    /// @notice Sets the message sender's streams configuration.
    /// Transfers funds between the message sender's wallet and the Drips contract
    /// to fulfil the change of the streams balance.
    /// @param drips The Drips contract to use.
    /// @param erc20 The used ERC-20 token.
    /// It must preserve amounts, so if some amount of tokens is transferred to
    /// an address, then later the same amount must be transferable from that address.
    /// Tokens which rebase the holders' balances, collect taxes on transfers,
    /// or impose any restrictions on holding or transferring tokens are not supported.
    /// If you use such tokens in the protocol, they can get stuck or lost.
    /// @param currReceivers The current streams receivers list.
    /// It must be exactly the same as the last list set for the sender with `setStreams`.
    /// If this is the first update, pass an empty array.
    /// @param balanceDelta The streams balance change to be applied.
    /// If it's positive, the balance is increased by `balanceDelta`.
    /// If it's zero, the balance doesn't change.
    /// If it's negative, the balance is decreased by `balanceDelta`,
    /// but the change is capped at the current balance amount, so it doesn't go below 0.
    /// Passing `type(int128).min` always decreases the current balance to 0.
    /// @param newReceivers The list of the streams receivers of the sender to be set.
    /// Must be sorted by the account IDs and then by the stream configurations,
    /// without identical elements and without 0 amtPerSecs.
    /// @param maxEndHint1 An optional parameter allowing gas optimization, pass `0` to ignore it.
    /// The first hint for finding the maximum end time when all streams stop due to funds
    /// running out after the balance is updated and the new receivers list is applied.
    /// Hints have no effect on the results of calling this function, except potentially saving gas.
    /// Hints are Unix timestamps used as the starting points for binary search for the time
    /// when funds run out in the range of timestamps from the current block's to `2^32`.
    /// Hints lower than the current timestamp are ignored.
    /// You can provide zero, one or two hints. The order of hints doesn't matter.
    /// Hints are the most effective when one of them is lower than or equal to
    /// the last timestamp when funds are still streamed, and the other one is strictly larger
    /// than that timestamp,the smaller the difference between such hints, the higher gas savings.
    /// The savings are the highest possible when one of the hints is equal to
    /// the last timestamp when funds are still streamed, and the other one is larger by 1.
    /// It's worth noting that the exact timestamp of the block in which this function is executed
    /// may affect correctness of the hints, especially if they're precise.
    /// Hints don't provide any benefits when balance is not enough to cover
    /// a single second of streaming or is enough to cover all streams until timestamp `2^32`.
    /// Even inaccurate hints can be useful, and providing a single hint
    /// or two hints that don't enclose the time when funds run out can still save some gas.
    /// Providing poor hints that don't reduce the number of binary search steps
    /// may cause slightly higher gas usage than not providing any hints.
    /// @param maxEndHint2 An optional parameter allowing gas optimization, pass `0` to ignore it.
    /// The second hint for finding the maximum end time, see `maxEndHint1` docs for more details.
    /// @param transferTo The address to send funds to in case of decreasing balance
    /// @return realBalanceDelta The actually applied streams balance change.
    /// It's equal to the passed `balanceDelta`, unless it's negative
    /// and it gets capped at the current balance amount.
    function _setStreamsAndTransfer(
        Drips drips,
        uint256 accountId,
        IERC20 erc20,
        StreamReceiver[] calldata currReceivers,
        int128 balanceDelta,
        StreamReceiver[] calldata newReceivers,
        // slither-disable-next-line similar-names
        uint32 maxEndHint1,
        uint32 maxEndHint2,
        address transferTo
    ) internal returns (int128 realBalanceDelta) {
        if (balanceDelta > 0) _transferFromCaller(drips, erc20, uint128(balanceDelta));
        realBalanceDelta = drips.setStreams(
            accountId, erc20, currReceivers, balanceDelta, newReceivers, maxEndHint1, maxEndHint2
        );
        if (realBalanceDelta < 0) drips.withdraw(erc20, transferTo, uint128(-realBalanceDelta));
    }

    /// @notice Transfers tokens from the sender to Drips.
    /// @param drips The Drips contract to use.
    /// @param erc20 The used ERC-20 token.
    /// @param amt The transferred amount
    function _transferFromCaller(Drips drips, IERC20 erc20, uint128 amt) internal {
        SafeERC20.safeTransferFrom(erc20, _msgSender(), address(drips), amt);
    }
}

22% src/Managed.sol

Lines covered: 12 / 53 (22%)

// SPDX-License-Identifier: GPL-3.0-only
pragma solidity ^0.8.20;

import {UUPSUpgradeable} from "openzeppelin-contracts/proxy/utils/UUPSUpgradeable.sol";
import {ERC1967Proxy} from "openzeppelin-contracts/proxy/ERC1967/ERC1967Proxy.sol";
import {EnumerableSet} from "openzeppelin-contracts/utils/structs/EnumerableSet.sol";
import {StorageSlot} from "openzeppelin-contracts/utils/StorageSlot.sol";

using EnumerableSet for EnumerableSet.AddressSet;

/// @notice A mix-in for contract pausing, upgrading and admin management.
/// It can't be used directly, only via a proxy. It uses the upgrade-safe ERC-1967 storage scheme.
///
/// Managed uses the ERC-1967 admin slot to store the admin address.
/// All instances of the contracts have admin address `0x00` and are forever paused.
/// When a proxy uses such contract via delegation, the proxy should define
/// the initial admin address and the contract is initially unpaused.
abstract contract Managed is UUPSUpgradeable {
    /// @notice The pointer to the storage slot holding a single `ManagedStorage` structure.
    bytes32 private immutable _managedStorageSlot = _erc1967Slot("eip1967.managed.storage");

    /// @notice Emitted when a new admin of the contract is proposed.
    /// The proposed admin must call `acceptAdmin` to finalize the change.
    /// @param currentAdmin The current admin address.
    /// @param newAdmin The proposed admin address.
    event NewAdminProposed(address indexed currentAdmin, address indexed newAdmin);

    /// @notice Emitted when the pauses role is granted.
    /// @param pauser The address that the pauser role was granted to.
    /// @param admin The address of the admin that triggered the change.
    event PauserGranted(address indexed pauser, address indexed admin);

    /// @notice Emitted when the pauses role is revoked.
    /// @param pauser The address that the pauser role was revoked from.
    /// @param admin The address of the admin that triggered the change.
    event PauserRevoked(address indexed pauser, address indexed admin);

    /// @notice Emitted when the pause is triggered.
    /// @param pauser The address that triggered the change.
    event Paused(address indexed pauser);

    /// @notice Emitted when the pause is lifted.
    /// @param pauser The address that triggered the change.
    event Unpaused(address indexed pauser);

    struct ManagedStorage {
        bool isPaused;
        EnumerableSet.AddressSet pausers;
        address proposedAdmin;
    }

    /// @notice Throws if called by any caller other than the admin.
    modifier onlyAdmin() {
        require(admin() == msg.sender, "Caller not the admin");
        _;
    }

    /// @notice Throws if called by any caller other than the admin or a pauser.
    modifier onlyAdminOrPauser() {
        require(admin() == msg.sender || isPauser(msg.sender), "Caller not the admin or a pauser");
        _;
    }

    /// @notice Modifier to make a function callable only when the contract is not paused.
    modifier whenNotPaused() {
        require(!isPaused(), "Contract paused");
        _;
    }

    /// @notice Modifier to make a function callable only when the contract is paused.
    modifier whenPaused() {
        require(isPaused(), "Contract not paused");
        _;
    }

    /// @notice Initializes the contract in paused state and with no admin.
    /// The contract instance can be used only as a call delegation target for a proxy.
    constructor() {
        _managedStorage().isPaused = true;
    }

    /// @notice Returns the current implementation address.
    function implementation() public view returns (address) {
        return _getImplementation();
    }

    /// @notice Returns the address of the current admin.
    function admin() public view returns (address) {
        return _getAdmin();
    }

    /// @notice Returns the proposed address to change the admin to.
    function proposedAdmin() public view returns (address) {
        return _managedStorage().proposedAdmin;
    }

    /// @notice Proposes a change of the admin of the contract.
    /// The proposed new admin must call `acceptAdmin` to finalize the change.
    /// To cancel a proposal propose a different address, e.g. the zero address.
    /// Can only be called by the current admin.
    /// @param newAdmin The proposed admin address.
    function proposeNewAdmin(address newAdmin) public onlyAdmin {
        emit NewAdminProposed(msg.sender, newAdmin);
        _managedStorage().proposedAdmin = newAdmin;
    }

    /// @notice Applies a proposed change of the admin of the contract.
    /// Sets the proposed admin to the zero address.
    /// Can only be called by the proposed admin.
    function acceptAdmin() public {
        require(proposedAdmin() == msg.sender, "Caller not the proposed admin");
        _updateAdmin(msg.sender);
    }

    /// @notice Changes the admin of the contract to address zero.
    /// It's no longer possible to change the admin or upgrade the contract afterwards.
    /// Can only be called by the current admin.
    function renounceAdmin() public onlyAdmin {
        _updateAdmin(address(0));
    }

    /// @notice Sets the current admin of the contract and clears the proposed admin.
    /// @param newAdmin The admin address being set. Can be the zero address.
    function _updateAdmin(address newAdmin) internal {
        emit AdminChanged(admin(), newAdmin);
        _managedStorage().proposedAdmin = address(0);
        StorageSlot.getAddressSlot(_ADMIN_SLOT).value = newAdmin;
    }

    /// @notice Grants the pauser role to an address. Callable only by the admin.
    /// @param pauser The granted address.
    function grantPauser(address pauser) public onlyAdmin {
        require(_managedStorage().pausers.add(pauser), "Address already is a pauser");
        emit PauserGranted(pauser, msg.sender);
    }

    /// @notice Revokes the pauser role from an address. Callable only by the admin.
    /// @param pauser The revoked address.
    function revokePauser(address pauser) public onlyAdmin {
        require(_managedStorage().pausers.remove(pauser), "Address is not a pauser");
        emit PauserRevoked(pauser, msg.sender);
    }

    /// @notice Checks if an address is a pauser.
    /// @param pauser The checked address.
    /// @return isAddrPauser True if the address is a pauser.
    function isPauser(address pauser) public view returns (bool isAddrPauser) {
        return _managedStorage().pausers.contains(pauser);
    }

    /// @notice Returns all the addresses with the pauser role.
    /// @return pausersList The list of all the pausers, ordered arbitrarily.
    /// The list's order may change after granting or revoking the pauser role.
    function allPausers() public view returns (address[] memory pausersList) {
        return _managedStorage().pausers.values();
    }

    /// @notice Returns true if the contract is paused, and false otherwise.
    function isPaused() public view returns (bool) {
        return _managedStorage().isPaused;
    }

    /// @notice Triggers stopped state. Callable only by the admin or a pauser.
    function pause() public onlyAdminOrPauser whenNotPaused {
        _managedStorage().isPaused = true;
        emit Paused(msg.sender);
    }

    /// @notice Returns to normal state. Callable only by the admin or a pauser.
    function unpause() public onlyAdminOrPauser whenPaused {
        _managedStorage().isPaused = false;
        emit Unpaused(msg.sender);
    }

    /// @notice Calculates the quasi ERC-1967 slot pointer.
    /// @param name The name of the slot, should be globally unique
    /// @return slot The slot pointer
    function _erc1967Slot(string memory name) internal pure returns (bytes32 slot) {
        // The original ERC-1967 subtracts 1 from the hash to get 1 storage slot
        // under an index without a known hash preimage which is enough to store a single address.
        // This implementation subtracts 1024 to get 1024 slots without a known preimage
        // allowing securely storing much larger structures.
        return bytes32(uint256(keccak256(bytes(name))) - 1024);
    }

    /// @notice Returns the Managed storage.
    /// @return storageRef The storage.
    function _managedStorage() internal view returns (ManagedStorage storage storageRef) {
        bytes32 slot = _managedStorageSlot;
        // slither-disable-next-line assembly
        assembly {
            storageRef.slot := slot
        }
    }

    /// @notice Authorizes the contract upgrade. See `UUPSUpgradeable` docs for more details.
    function _authorizeUpgrade(address /* newImplementation */ ) internal view override onlyAdmin {
        return;
    }
}

/// @notice A generic proxy for contracts implementing `Managed`.
contract ManagedProxy is ERC1967Proxy {
    constructor(Managed logic, address admin) ERC1967Proxy(address(logic), new bytes(0)) {
        _changeAdmin(admin);
    }
}

100% src/Splits.sol

Lines covered: 87 / 87 (100%)

// SPDX-License-Identifier: GPL-3.0-only
pragma solidity ^0.8.20;

import {IERC20} from "openzeppelin-contracts/token/ERC20/IERC20.sol";

/// @notice A splits receiver
struct SplitsReceiver {
    /// @notice The account ID.
    uint256 accountId;
    /// @notice The splits weight. Must never be zero.
    /// The account will be getting `weight / _TOTAL_SPLITS_WEIGHT`
    /// share of the funds collected by the splitting account.
    uint32 weight;
}

/// @notice Splits can keep track of at most `type(uint128).max`
/// which is `2 ^ 128 - 1` units of each ERC-20 token.
/// It's up to the caller to guarantee that this limit is never exceeded,
/// failing to do so may result in a total protocol collapse.
abstract contract Splits {
    /// @notice Maximum number of splits receivers of a single account.
    /// Limits the cost of splitting.
    uint256 internal constant _MAX_SPLITS_RECEIVERS = 200;
    /// @notice The total splits weight of an account.
    uint32 internal constant _TOTAL_SPLITS_WEIGHT = 1_000_000;
    /// @notice The amount the contract can keep track of each ERC-20 token.
    // slither-disable-next-line unused-state
    uint128 internal constant _MAX_SPLITS_BALANCE = type(uint128).max;
    /// @notice The storage slot holding a single `SplitsStorage` structure.
    bytes32 private immutable _splitsStorageSlot;

    /// @notice Emitted when an account collects funds
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// @param collected The collected amount
    event Collected(uint256 indexed accountId, IERC20 indexed erc20, uint128 collected);

    /// @notice Emitted when funds are split from an account to a receiver.
    /// This is caused by the account collecting received funds.
    /// @param accountId The account ID.
    /// @param receiver The splits receiver account ID
    /// @param erc20 The used ERC-20 token.
    /// @param amt The amount split to the receiver
    event Split(
        uint256 indexed accountId, uint256 indexed receiver, IERC20 indexed erc20, uint128 amt
    );

    /// @notice Emitted when funds are made collectable after splitting.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// @param amt The amount made collectable for the account
    /// on top of what was collectable before.
    event Collectable(uint256 indexed accountId, IERC20 indexed erc20, uint128 amt);

    /// @notice Emitted when funds are given from the account to the receiver.
    /// @param accountId The account ID.
    /// @param receiver The receiver account ID.
    /// @param erc20 The used ERC-20 token.
    /// @param amt The given amount
    event Given(
        uint256 indexed accountId, uint256 indexed receiver, IERC20 indexed erc20, uint128 amt
    );

    /// @notice Emitted when the account's splits are updated.
    /// @param accountId The account ID.
    /// @param receiversHash The splits receivers list hash
    event SplitsSet(uint256 indexed accountId, bytes32 indexed receiversHash);

    /// @notice Emitted when an account is seen in a splits receivers list.
    /// @param receiversHash The splits receivers list hash
    /// @param accountId The account ID.
    /// @param weight The splits weight. Must never be zero.
    /// The account will be getting `weight / _TOTAL_SPLITS_WEIGHT`
    /// share of the funds collected by the splitting account.
    event SplitsReceiverSeen(
        bytes32 indexed receiversHash, uint256 indexed accountId, uint32 weight
    );

    struct SplitsStorage {
        /// @notice Account splits states.
        mapping(uint256 accountId => SplitsState) splitsStates;
    }

    struct SplitsState {
        /// @notice The account's splits configuration hash, see `hashSplits`.
        bytes32 splitsHash;
        /// @notice The account's splits balances.
        mapping(IERC20 erc20 => SplitsBalance) balances;
    }

    struct SplitsBalance {
        /// @notice The not yet split balance, must be split before collecting by the account.
        uint128 splittable;
        /// @notice The already split balance, ready to be collected by the account.
        uint128 collectable;
    }

    /// @param splitsStorageSlot The storage slot to holding a single `SplitsStorage` structure.
    constructor(bytes32 splitsStorageSlot) {
        _splitsStorageSlot = splitsStorageSlot;
    }

    function _addSplittable(uint256 accountId, IERC20 erc20, uint128 amt) internal {
        // This will not overflow if the requirement of tracking in the contract
        // no more than `_MAX_SPLITS_BALANCE` of each token is followed.
        _splitsStorage().splitsStates[accountId].balances[erc20].splittable += amt;
    }

    /// @notice Returns account's received but not split yet funds.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// @return amt The amount received but not split yet.
    function _splittable(uint256 accountId, IERC20 erc20) internal view returns (uint128 amt) {
        return _splitsStorage().splitsStates[accountId].balances[erc20].splittable;
    }

    /// @notice Calculate the result of splitting an amount using the current splits configuration.
    /// @param accountId The account ID.
    /// @param currReceivers The list of the account's current splits receivers.
    /// It must be exactly the same as the last list set for the account with `_setSplits`.
    /// If the splits have never been set, pass an empty array.
    /// @param amount The amount being split.
    /// @return collectableAmt The amount made collectable for the account
    /// on top of what was collectable before.
    /// @return splitAmt The amount split to the account's splits receivers
    function _splitResult(uint256 accountId, SplitsReceiver[] memory currReceivers, uint128 amount)
        internal
        view
        returns (uint128 collectableAmt, uint128 splitAmt)
    {
        _assertCurrSplits(accountId, currReceivers);
        if (amount == 0) {
            return (0, 0);
        }
        unchecked {
            uint256 splitsWeight = 0;
            for (uint256 i = currReceivers.length; i != 0;) {
                splitsWeight += currReceivers[--i].weight;
            }
            splitAmt = uint128(amount * splitsWeight / _TOTAL_SPLITS_WEIGHT);
            collectableAmt = amount - splitAmt;
        }
    }

    /// @notice Splits the account's splittable funds among receivers.
    /// The entire splittable balance of the given ERC-20 token is split.
    /// All split funds are split using the current splits configuration.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// @param currReceivers The list of the account's current splits receivers.
    /// It must be exactly the same as the last list set for the account with `_setSplits`.
    /// If the splits have never been set, pass an empty array.
    /// @return collectableAmt The amount made collectable for the account
    /// on top of what was collectable before.
    /// @return splitAmt The amount split to the account's splits receivers
    function _split(uint256 accountId, IERC20 erc20, SplitsReceiver[] memory currReceivers)
        internal
        returns (uint128 collectableAmt, uint128 splitAmt)
    {
        _assertCurrSplits(accountId, currReceivers);
        SplitsBalance storage balance = _splitsStorage().splitsStates[accountId].balances[erc20];

        collectableAmt = balance.splittable;
        if (collectableAmt == 0) {
            return (0, 0);
        }
        balance.splittable = 0;

        unchecked {
            uint256 splitsWeight = 0;
            for (uint256 i = 0; i < currReceivers.length; i++) {
                splitsWeight += currReceivers[i].weight;
                uint128 currSplitAmt = splitAmt;
                splitAmt = uint128(collectableAmt * splitsWeight / _TOTAL_SPLITS_WEIGHT);
                currSplitAmt = splitAmt - currSplitAmt;
                uint256 receiver = currReceivers[i].accountId;
                _addSplittable(receiver, erc20, currSplitAmt);
                emit Split(accountId, receiver, erc20, currSplitAmt);
            }
            collectableAmt -= splitAmt;
            // This will not overflow if the requirement of tracking in the contract
            // no more than `_MAX_SPLITS_BALANCE` of each token is followed.
            balance.collectable += collectableAmt;
        }
        emit Collectable(accountId, erc20, collectableAmt);
    }

    /// @notice Returns account's received funds already split and ready to be collected.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// @return amt The collectable amount.
    function _collectable(uint256 accountId, IERC20 erc20) internal view returns (uint128 amt) {
        return _splitsStorage().splitsStates[accountId].balances[erc20].collectable;
    }

    /// @notice Collects account's received already split funds.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// @return amt The collected amount
    function _collect(uint256 accountId, IERC20 erc20) internal returns (uint128 amt) {
        SplitsBalance storage balance = _splitsStorage().splitsStates[accountId].balances[erc20];
        amt = balance.collectable;
        balance.collectable = 0;
        emit Collected(accountId, erc20, amt);
    }

    /// @notice Gives funds from the account to the receiver.
    /// The receiver can split and collect them immediately.
    /// @param accountId The account ID.
    /// @param receiver The receiver account ID.
    /// @param erc20 The used ERC-20 token.
    /// @param amt The given amount
    function _give(uint256 accountId, uint256 receiver, IERC20 erc20, uint128 amt) internal {
        _addSplittable(receiver, erc20, amt);
        emit Given(accountId, receiver, erc20, amt);
    }

    /// @notice Sets the account splits configuration.
    /// The configuration is common for all ERC-20 tokens.
    /// Nothing happens to the currently splittable funds, but when they are split
    /// after this function finishes, the new splits configuration will be used.
    /// @param accountId The account ID.
    /// @param receivers The list of the account's splits receivers to be set.
    /// Must be sorted by the account IDs, without duplicate account IDs and without 0 weights.
    /// Each splits receiver will be getting `weight / _TOTAL_SPLITS_WEIGHT`
    /// share of the funds collected by the account.
    /// If the sum of weights of all receivers is less than `_TOTAL_SPLITS_WEIGHT`,
    /// some funds won't be split, but they will be left for the account to collect.
    /// Fractions of tokens are always rounder either up or down depending on the amount
    /// being split, the receiver's position on the list and the other receivers' weights.
    /// It's valid to include the account's own `accountId` in the list of receivers,
    /// but funds split to themselves return to their splittable balance and are not collectable.
    /// This is usually unwanted, because if splitting is repeated,
    /// funds split to themselves will be again split using the current configuration.
    /// Splitting 100% to self effectively blocks splitting unless the configuration is updated.
    function _setSplits(uint256 accountId, SplitsReceiver[] memory receivers) internal {
        SplitsState storage state = _splitsStorage().splitsStates[accountId];
        bytes32 newSplitsHash = _hashSplits(receivers);
        if (newSplitsHash == state.splitsHash) return;
        emit SplitsSet(accountId, newSplitsHash);
        _assertSplitsValid(receivers, newSplitsHash);
        state.splitsHash = newSplitsHash;
    }

    /// @notice Validates a list of splits receivers and emits events for them
    /// @param receivers The list of splits receivers
    /// @param receiversHash The hash of the list of splits receivers.
    /// Must be sorted by the account IDs, without duplicate account IDs and without 0 weights.
    function _assertSplitsValid(SplitsReceiver[] memory receivers, bytes32 receiversHash) private {
        unchecked {
            require(receivers.length <= _MAX_SPLITS_RECEIVERS, "Too many splits receivers");
            uint256 totalWeight = 0;
            uint256 prevAccountId = 0;
            for (uint256 i = 0; i < receivers.length; i++) {
                SplitsReceiver memory receiver = receivers[i];
                uint32 weight = receiver.weight;
                require(weight != 0, "Splits receiver weight is zero");
                totalWeight += weight;
                uint256 accountId = receiver.accountId;
                if (accountId <= prevAccountId) require(i == 0, "Splits receivers not sorted");
                prevAccountId = accountId;
                emit SplitsReceiverSeen(receiversHash, accountId, weight);
            }
            require(totalWeight <= _TOTAL_SPLITS_WEIGHT, "Splits weights sum too high");
        }
    }

    /// @notice Asserts that the list of splits receivers is the account's currently used one.
    /// @param accountId The account ID.
    /// @param currReceivers The list of the account's current splits receivers.
    /// If the splits have never been set, pass an empty array.
    function _assertCurrSplits(uint256 accountId, SplitsReceiver[] memory currReceivers)
        internal
        view
    {
        require(
            _hashSplits(currReceivers) == _splitsHash(accountId), "Invalid current splits receivers"
        );
    }

    /// @notice Current account's splits hash, see `hashSplits`.
    /// @param accountId The account ID.
    /// @return currSplitsHash The current account's splits hash
    function _splitsHash(uint256 accountId) internal view returns (bytes32 currSplitsHash) {
        return _splitsStorage().splitsStates[accountId].splitsHash;
    }

    /// @notice Calculates the hash of the list of splits receivers.
    /// @param receivers The list of the splits receivers.
    /// If the splits have never been set, pass an empty array.
    /// @return receiversHash The hash of the list of splits receivers.
    function _hashSplits(SplitsReceiver[] memory receivers)
        internal
        pure
        returns (bytes32 receiversHash)
    {
        if (receivers.length == 0) {
            return bytes32(0);
        }
        return keccak256(abi.encode(receivers));
    }

    /// @notice Returns the Splits storage.
    /// @return splitsStorage The storage.
    function _splitsStorage() private view returns (SplitsStorage storage splitsStorage) {
        bytes32 slot = _splitsStorageSlot;
        // slither-disable-next-line assembly
        assembly {
            splitsStorage.slot := slot
        }
    }
}

99% src/Streams.sol

Lines covered: 414 / 416 (99%)

// SPDX-License-Identifier: GPL-3.0-only
pragma solidity ^0.8.20;

import {IERC20} from "openzeppelin-contracts/token/ERC20/IERC20.sol";

/// @notice A stream receiver
struct StreamReceiver {
    /// @notice The account ID.
    uint256 accountId;
    /// @notice The stream configuration.
    StreamConfig config;
}

/// @notice The sender streams history entry, used when squeezing streams.
struct StreamsHistory {
    /// @notice Streams receivers list hash, see `_hashStreams`.
    /// If it's non-zero, `receivers` must be empty.
    bytes32 streamsHash;
    /// @notice The streams receivers. If it's non-empty, `streamsHash` must be `0`.
    /// If it's empty, this history entry will be skipped when squeezing streams
    /// and `streamsHash` will be used when verifying the streams history validity.
    /// Skipping a history entry allows cutting gas usage on analysis
    /// of parts of the streams history which are not worth squeezing.
    /// The hash of an empty receivers list is `0`, so when the sender updates
    /// their receivers list to be empty, the new `StreamsHistory` entry will have
    /// both the `streamsHash` equal to `0` and the `receivers` empty making it always skipped.
    /// This is fine, because there can't be any funds to squeeze from that entry anyway.
    StreamReceiver[] receivers;
    /// @notice The time when streams have been configured
    uint32 updateTime;
    /// @notice The maximum end time of streaming.
    uint32 maxEnd;
}

/// @notice Describes a streams configuration.
/// It's a 256-bit integer constructed by concatenating the configuration parameters:
/// `streamId (32 bits) | amtPerSec (160 bits) | start (32 bits) | duration (32 bits)`.
/// `streamId` is an arbitrary number used to identify a stream.
/// It's a part of the configuration but the protocol doesn't use it.
/// `amtPerSec` is the amount per second being streamed. Must never be zero.
/// It must have additional `Streams._AMT_PER_SEC_EXTRA_DECIMALS` decimals and can have fractions.
/// To achieve that its value must be multiplied by `Streams._AMT_PER_SEC_MULTIPLIER`.
/// `start` is the timestamp when streaming should start.
/// If zero, use the timestamp when the stream is configured.
/// `duration` is the duration of streaming.
/// If zero, stream until balance runs out.
type StreamConfig is uint256;

using StreamConfigImpl for StreamConfig global;

library StreamConfigImpl {
    /// @notice Create a new StreamConfig.
    /// @param streamId_ An arbitrary number used to identify a stream.
    /// It's a part of the configuration but the protocol doesn't use it.
    /// @param amtPerSec_ The amount per second being streamed. Must never be zero.
    /// It must have additional `Streams._AMT_PER_SEC_EXTRA_DECIMALS`
    /// decimals and can have fractions.
    /// To achieve that the passed value must be multiplied by `Streams._AMT_PER_SEC_MULTIPLIER`.
    /// @param start_ The timestamp when streaming should start.
    /// If zero, use the timestamp when the stream is configured.
    /// @param duration_ The duration of streaming. If zero, stream until the balance runs out.
    function create(uint32 streamId_, uint160 amtPerSec_, uint32 start_, uint32 duration_)
        internal
        pure
        returns (StreamConfig)
    {
        // By assignment we get `config` value:
        // `zeros (224 bits) | streamId (32 bits)`
        uint256 config = streamId_;
        // By bit shifting we get `config` value:
        // `zeros (64 bits) | streamId (32 bits) | zeros (160 bits)`
        // By bit masking we get `config` value:
        // `zeros (64 bits) | streamId (32 bits) | amtPerSec (160 bits)`
        config = (config << 160) | amtPerSec_;
        // By bit shifting we get `config` value:
        // `zeros (32 bits) | streamId (32 bits) | amtPerSec (160 bits) | zeros (32 bits)`
        // By bit masking we get `config` value:
        // `zeros (32 bits) | streamId (32 bits) | amtPerSec (160 bits) | start (32 bits)`
        config = (config << 32) | start_;
        // By bit shifting we get `config` value:
        // `streamId (32 bits) | amtPerSec (160 bits) | start (32 bits) | zeros (32 bits)`
        // By bit masking we get `config` value:
        // `streamId (32 bits) | amtPerSec (160 bits) | start (32 bits) | duration (32 bits)`
        config = (config << 32) | duration_;
        return StreamConfig.wrap(config);
    }

    /// @notice Extracts streamId from a `StreamConfig`
    function streamId(StreamConfig config) internal pure returns (uint32) {
        // `config` has value:
        // `streamId (32 bits) | amtPerSec (160 bits) | start (32 bits) | duration (32 bits)`
        // By bit shifting we get value:
        // `zeros (224 bits) | streamId (32 bits)`
        // By casting down we get value:
        // `streamId (32 bits)`
        return uint32(StreamConfig.unwrap(config) >> 224);
    }

    /// @notice Extracts amtPerSec from a `StreamConfig`
    function amtPerSec(StreamConfig config) internal pure returns (uint160) {
        // `config` has value:
        // `streamId (32 bits) | amtPerSec (160 bits) | start (32 bits) | duration (32 bits)`
        // By bit shifting we get value:
        // `zeros (64 bits) | streamId (32 bits) | amtPerSec (160 bits)`
        // By casting down we get value:
        // `amtPerSec (160 bits)`
        return uint160(StreamConfig.unwrap(config) >> 64);
    }

    /// @notice Extracts start from a `StreamConfig`
    function start(StreamConfig config) internal pure returns (uint32) {
        // `config` has value:
        // `streamId (32 bits) | amtPerSec (160 bits) | start (32 bits) | duration (32 bits)`
        // By bit shifting we get value:
        // `zeros (32 bits) | streamId (32 bits) | amtPerSec (160 bits) | start (32 bits)`
        // By casting down we get value:
        // `start (32 bits)`
        return uint32(StreamConfig.unwrap(config) >> 32);
    }

    /// @notice Extracts duration from a `StreamConfig`
    function duration(StreamConfig config) internal pure returns (uint32) {
        // `config` has value:
        // `streamId (32 bits) | amtPerSec (160 bits) | start (32 bits) | duration (32 bits)`
        // By casting down we get value:
        // `duration (32 bits)`
        return uint32(StreamConfig.unwrap(config));
    }

    /// @notice Compares two `StreamConfig`s.
    /// First compares `streamId`s, then `amtPerSec`s, then `start`s and finally `duration`s.
    /// @return isLower True if `config` is strictly lower than `otherConfig`.
    function lt(StreamConfig config, StreamConfig otherConfig)
        internal
        pure
        returns (bool isLower)
    {
        // Both configs have value:
        // `streamId (32 bits) | amtPerSec (160 bits) | start (32 bits) | duration (32 bits)`
        // Comparing them as integers is equivalent to comparing their fields from left to right.
        return StreamConfig.unwrap(config) < StreamConfig.unwrap(otherConfig);
    }
}

/// @notice Streams can keep track of at most `type(int128).max`
/// which is `2 ^ 127 - 1` units of each ERC-20 token.
/// It's up to the caller to guarantee that this limit is never exceeded,
/// failing to do so may result in a total protocol collapse.
abstract contract Streams {
    /// @notice Maximum number of streams receivers of a single account.
    /// Limits cost of changes in streams configuration.
    uint256 internal constant _MAX_STREAMS_RECEIVERS = 100;
    /// @notice The additional decimals for all amtPerSec values.
    uint8 internal constant _AMT_PER_SEC_EXTRA_DECIMALS = 9;
    /// @notice The multiplier for all amtPerSec values. It's `10 ** _AMT_PER_SEC_EXTRA_DECIMALS`.
    uint160 internal constant _AMT_PER_SEC_MULTIPLIER = 1_000_000_000;
    /// @notice The amount the contract can keep track of each ERC-20 token.
    uint128 internal constant _MAX_STREAMS_BALANCE = uint128(type(int128).max);
    /// @notice On every timestamp `T`, which is a multiple of `cycleSecs`, the receivers
    /// gain access to streams received during `T - cycleSecs` to `T - 1`.
    /// Always higher than 1.
    // slither-disable-next-line naming-convention
    uint32 internal immutable _cycleSecs;
    /// @notice The minimum amtPerSec of a stream. It's 1 token per cycle.
    // slither-disable-next-line naming-convention
    uint160 internal immutable _minAmtPerSec;
    /// @notice The storage slot holding a single `StreamsStorage` structure.
    bytes32 private immutable _streamsStorageSlot;

    /// @notice Emitted when the streams configuration of an account is updated.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// @param receiversHash The streams receivers list hash
    /// @param streamsHistoryHash The streams history hash that was valid right before the update.
    /// @param balance The account's streams balance. These funds will be streamed to the receivers.
    /// @param maxEnd The maximum end time of streaming, when funds run out.
    /// If funds run out after the timestamp `type(uint32).max`, it's set to `type(uint32).max`.
    /// If the balance is 0 or there are no receivers, it's set to the current timestamp.
    event StreamsSet(
        uint256 indexed accountId,
        IERC20 indexed erc20,
        bytes32 indexed receiversHash,
        bytes32 streamsHistoryHash,
        uint128 balance,
        uint32 maxEnd
    );

    /// @notice Emitted when an account is seen in a streams receivers list.
    /// @param receiversHash The streams receivers list hash
    /// @param accountId The account ID.
    /// @param config The streams configuration.
    event StreamReceiverSeen(
        bytes32 indexed receiversHash, uint256 indexed accountId, StreamConfig config
    );

    /// @notice Emitted when streams are received.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// @param amt The received amount.
    /// @param receivableCycles The number of cycles which still can be received.
    event ReceivedStreams(
        uint256 indexed accountId, IERC20 indexed erc20, uint128 amt, uint32 receivableCycles
    );

    /// @notice Emitted when streams are squeezed.
    /// @param accountId The squeezing account ID.
    /// @param erc20 The used ERC-20 token.
    /// @param senderId The ID of the streaming account from whom funds are squeezed.
    /// @param amt The squeezed amount.
    /// @param streamsHistoryHashes The history hashes of all squeezed streams history entries.
    /// Each history hash matches `streamsHistoryHash` emitted in its `StreamsSet`
    /// when the squeezed streams configuration was set.
    /// Sorted in the oldest streams configuration to the newest.
    event SqueezedStreams(
        uint256 indexed accountId,
        IERC20 indexed erc20,
        uint256 indexed senderId,
        uint128 amt,
        bytes32[] streamsHistoryHashes
    );

    struct StreamsStorage {
        /// @notice Account streams states.
        mapping(IERC20 erc20 => mapping(uint256 accountId => StreamsState)) states;
    }

    struct StreamsState {
        /// @notice The streams history hash, see `_hashStreamsHistory`.
        bytes32 streamsHistoryHash;
        /// @notice The next squeezable timestamps.
        /// Each `N`th element of the array is the next squeezable timestamp
        /// of the `N`th sender's streams configuration in effect in the current cycle.
        mapping(uint256 accountId => uint32[2 ** 32]) nextSqueezed;
        /// @notice The streams receivers list hash, see `_hashStreams`.
        bytes32 streamsHash;
        /// @notice The next cycle to be received
        uint32 nextReceivableCycle;
        /// @notice The time when streams have been configured for the last time.
        uint32 updateTime;
        /// @notice The maximum end time of streaming.
        uint32 maxEnd;
        /// @notice The balance when streams have been configured for the last time.
        uint128 balance;
        /// @notice The number of streams configurations seen in the cycle
        /// during which streams have been configured for the last time.
        uint32 lastUpdatedCycleConfigs;
        /// @notice The changes of the received amounts in each cycle.
        /// The keys are cycles, each cycle `C` becomes receivable on timestamp `C * cycleSecs`.
        /// Each cycle is described by 2 deltas, the cycle's `thisCycle` and the previous cycle's
        /// `nextCycle`, so to get the change of the amount sent during the cycle `C`,
        /// you need to calculate `amtDeltas[C].thisCycle + amtDeltas[C-1].nextCycle`.
        /// To calculate the absolute amount streamed in the cycle `C`, you need to take the
        /// amount streamed during the cycle `C - 1` and add the change applied in the cycle `C`.
        /// Values for cycles before `nextReceivableCycle` are guaranteed to be zeroed.
        /// This means that the value of `amtDeltas[nextReceivableCycle].thisCycle` is always
        /// relative to 0 or in other words it's an absolute value independent from other cycles.
        mapping(uint32 cycle => AmtDelta) amtDeltas;
    }

    /// @notice The change of the received amounts in the given cycle and the cycle after it.
    struct AmtDelta {
        /// @notice Amount delta applied in this cycle.
        int128 thisCycle;
        /// @notice Amount delta applied on the next cycle.
        int128 nextCycle;
    }

    /// @param cycleSecs The length of cycleSecs to be used in the contract instance.
    /// Low value makes funds more available by shortening the average time
    /// of funds being frozen between being taken from the accounts'
    /// streams balance and being receivable by their receivers.
    /// High value makes receiving cheaper by making it process less cycles for a given time range.
    /// Must be higher than 1.
    /// @param streamsStorageSlot The storage slot to holding a single `StreamsStorage` structure.
    constructor(uint32 cycleSecs, bytes32 streamsStorageSlot) {
        require(cycleSecs > 1, "Cycle length too low");
        _cycleSecs = cycleSecs;
        _minAmtPerSec = (_AMT_PER_SEC_MULTIPLIER + cycleSecs - 1) / cycleSecs;
        _streamsStorageSlot = streamsStorageSlot;
    }

    /// @notice Receive streams from unreceived cycles of the account.
    /// Received streams cycles won't need to be analyzed ever again.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// @param maxCycles The maximum number of received streams cycles.
    /// If too low, receiving will be cheap, but may not cover many cycles.
    /// If too high, receiving may become too expensive to fit in a single transaction.
    /// @return receivedAmt The received amount
    function _receiveStreams(uint256 accountId, IERC20 erc20, uint32 maxCycles)
        internal
        returns (uint128 receivedAmt)
    {
        uint32 receivableCycles;
        uint32 fromCycle;
        uint32 toCycle;
        int128 finalAmtPerCycle;
        (receivedAmt, receivableCycles, fromCycle, toCycle, finalAmtPerCycle) =
            _receiveStreamsResult(accountId, erc20, maxCycles);
        if (fromCycle != toCycle) {
            StreamsState storage state = _streamsStorage().states[erc20][accountId];
            state.nextReceivableCycle = toCycle;
            mapping(uint32 cycle => AmtDelta) storage amtDeltas = state.amtDeltas;
            unchecked {
                for (uint32 cycle = fromCycle; cycle < toCycle; cycle++) {
                    delete amtDeltas[cycle];
                }
                // The next cycle delta must be relative to the last received cycle, which deltas
                // got zeroed. In other words the next cycle delta must be an absolute value.
                if (finalAmtPerCycle != 0) {
                    amtDeltas[toCycle].thisCycle += finalAmtPerCycle;
                }
            }
        }
        emit ReceivedStreams(accountId, erc20, receivedAmt, receivableCycles);
    }

    /// @notice Calculate effects of calling `_receiveStreams` with the given parameters.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// @param maxCycles The maximum number of received streams cycles.
    /// If too low, receiving will be cheap, but may not cover many cycles.
    /// If too high, receiving may become too expensive to fit in a single transaction.
    /// @return receivedAmt The amount which would be received
    /// @return receivableCycles The number of cycles which would still be receivable after the call
    /// @return fromCycle The cycle from which funds would be received
    /// @return toCycle The cycle to which funds would be received
    /// @return amtPerCycle The amount per cycle when `toCycle` starts.
    function _receiveStreamsResult(uint256 accountId, IERC20 erc20, uint32 maxCycles)
        internal
        view
        returns (
            uint128 receivedAmt,
            uint32 receivableCycles,
            uint32 fromCycle,
            uint32 toCycle,
            int128 amtPerCycle
        )
    {
        unchecked {
            (fromCycle, toCycle) = _receivableStreamsCyclesRange(accountId, erc20);
            if (toCycle - fromCycle > maxCycles) {
                receivableCycles = toCycle - fromCycle - maxCycles;
                toCycle -= receivableCycles;
            }
            mapping(uint32 cycle => AmtDelta) storage amtDeltas =
                _streamsStorage().states[erc20][accountId].amtDeltas;
            for (uint32 cycle = fromCycle; cycle < toCycle; cycle++) {
                AmtDelta memory amtDelta = amtDeltas[cycle];
                amtPerCycle += amtDelta.thisCycle;
                // This will not overflow if the requirement of tracking in the contract
                // no more than `_MAX_STREAMS_BALANCE` of each token is followed.
                receivedAmt += uint128(amtPerCycle);
                amtPerCycle += amtDelta.nextCycle;
            }
        }
    }

    /// @notice Counts cycles from which streams can be received.
    /// This function can be used to detect that there are
    /// too many cycles to analyze in a single transaction.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// @return cycles The number of cycles which can be flushed
    function _receivableStreamsCycles(uint256 accountId, IERC20 erc20)
        internal
        view
        returns (uint32 cycles)
    {
        unchecked {
            (uint32 fromCycle, uint32 toCycle) = _receivableStreamsCyclesRange(accountId, erc20);
            return toCycle - fromCycle;
        }
    }

    /// @notice Calculates the cycles range from which streams can be received.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// @return fromCycle The cycle from which funds can be received
    /// @return toCycle The cycle to which funds can be received
    function _receivableStreamsCyclesRange(uint256 accountId, IERC20 erc20)
        private
        view
        returns (uint32 fromCycle, uint32 toCycle)
    {
        fromCycle = _streamsStorage().states[erc20][accountId].nextReceivableCycle;
        toCycle = _cycleOf(_currTimestamp());
        // slither-disable-next-line timestamp
        if (fromCycle == 0 || toCycle < fromCycle) {
            toCycle = fromCycle;
        }
    }

    /// @notice Receive streams from the currently running cycle from a single sender.
    /// It doesn't receive streams from the finished cycles, to do that use `_receiveStreams`.
    /// Squeezed funds won't be received in the next calls
    /// to `_squeezeStreams` or `_receiveStreams`.
    /// Only funds streamed before `block.timestamp` can be squeezed.
    /// @param accountId The ID of the account receiving streams to squeeze funds for.
    /// @param erc20 The used ERC-20 token.
    /// @param senderId The ID of the streaming account to squeeze funds from.
    /// @param historyHash The sender's history hash that was valid right before
    /// they set up the sequence of configurations described by `streamsHistory`.
    /// @param streamsHistory The sequence of the sender's streams configurations.
    /// It can start at an arbitrary past configuration, but must describe all the configurations
    /// which have been used since then including the current one, in the chronological order.
    /// Only streams described by `streamsHistory` will be squeezed.
    /// If `streamsHistory` entries have no receivers, they won't be squeezed.
    /// @return amt The squeezed amount.
    function _squeezeStreams(
        uint256 accountId,
        IERC20 erc20,
        uint256 senderId,
        bytes32 historyHash,
        StreamsHistory[] memory streamsHistory
    ) internal returns (uint128 amt) {
        unchecked {
            uint256 squeezedNum;
            uint256[] memory squeezedRevIdxs;
            bytes32[] memory historyHashes;
            uint256 currCycleConfigs;
            (amt, squeezedNum, squeezedRevIdxs, historyHashes, currCycleConfigs) =
                _squeezeStreamsResult(accountId, erc20, senderId, historyHash, streamsHistory);
            bytes32[] memory squeezedHistoryHashes = new bytes32[](squeezedNum);
            StreamsState storage state = _streamsStorage().states[erc20][accountId];
            uint32[2 ** 32] storage nextSqueezed = state.nextSqueezed[senderId];
            for (uint256 i = 0; i < squeezedNum; i++) {
                // `squeezedRevIdxs` are sorted from the newest configuration to the oldest,
                // but we need to consume them from the oldest to the newest.
                uint256 revIdx = squeezedRevIdxs[squeezedNum - i - 1];
                squeezedHistoryHashes[i] = historyHashes[historyHashes.length - revIdx];
                nextSqueezed[currCycleConfigs - revIdx] = _currTimestamp();
            }
            uint32 cycleStart = _currCycleStart();
            _addDeltaRange(
                state, cycleStart, cycleStart + 1, -int160(amt * _AMT_PER_SEC_MULTIPLIER)
            );
            emit SqueezedStreams(accountId, erc20, senderId, amt, squeezedHistoryHashes);
        }
    }

    /// @notice Calculate effects of calling `_squeezeStreams` with the given parameters.
    /// See its documentation for more details.
    /// @param accountId The ID of the account receiving streams to squeeze funds for.
    /// @param erc20 The used ERC-20 token.
    /// @param senderId The ID of the streaming account to squeeze funds from.
    /// @param historyHash The sender's history hash that was valid right before `streamsHistory`.
    /// @param streamsHistory The sequence of the sender's streams configurations.
    /// @return amt The squeezed amount.
    /// @return squeezedNum The number of squeezed history entries.
    /// @return squeezedRevIdxs The indexes of the squeezed history entries.
    /// The indexes are reversed, meaning that to get the actual index in an array,
    /// they must counted from the end of arrays, as in `arrayLength - squeezedRevIdxs[i]`.
    /// These indexes can be safely used to access `streamsHistory`, `historyHashes`
    /// and `nextSqueezed` regardless of their lengths.
    /// `squeezeRevIdxs` is sorted ascending, from pointing at the most recent entry to the oldest.
    /// @return historyHashes The history hashes valid
    /// for squeezing each of `streamsHistory` entries.
    /// In other words history hashes which had been valid right before each streams
    /// configuration was set, matching `streamsHistoryHash` emitted in its `StreamsSet`.
    /// The first item is always equal to `historyHash`.
    /// @return currCycleConfigs The number of the sender's
    /// streams configurations which have been seen in the current cycle.
    /// This is also the number of used entries in each of the sender's `nextSqueezed` arrays.
    function _squeezeStreamsResult(
        uint256 accountId,
        IERC20 erc20,
        uint256 senderId,
        bytes32 historyHash,
        StreamsHistory[] memory streamsHistory
    )
        internal
        view
        returns (
            uint128 amt,
            uint256 squeezedNum,
            uint256[] memory squeezedRevIdxs,
            bytes32[] memory historyHashes,
            uint256 currCycleConfigs
        )
    {
        {
            StreamsState storage sender = _streamsStorage().states[erc20][senderId];
            historyHashes =
                _verifyStreamsHistory(historyHash, streamsHistory, sender.streamsHistoryHash);
            // If the last update was not in the current cycle,
            // there's only the single latest history entry to squeeze in the current cycle.
            currCycleConfigs = 1;
            // slither-disable-next-line timestamp
            if (sender.updateTime >= _currCycleStart()) {
                currCycleConfigs = sender.lastUpdatedCycleConfigs;
            }
        }
        squeezedRevIdxs = new uint256[](streamsHistory.length);
        uint32[2 ** 32] storage nextSqueezed =
            _streamsStorage().states[erc20][accountId].nextSqueezed[senderId];
        uint32 squeezeEndCap = _currTimestamp();
        unchecked {
            for (uint256 i = 1; i <= streamsHistory.length && i <= currCycleConfigs; i++) {
                StreamsHistory memory historyEntry = streamsHistory[streamsHistory.length - i];
                if (historyEntry.receivers.length != 0) {
                    uint32 squeezeStartCap = nextSqueezed[currCycleConfigs - i];
                    if (squeezeStartCap < _currCycleStart()) squeezeStartCap = _currCycleStart();
                    if (squeezeStartCap < historyEntry.updateTime) {
                        squeezeStartCap = historyEntry.updateTime;
                    }
                    if (squeezeStartCap < squeezeEndCap) {
                        squeezedRevIdxs[squeezedNum++] = i;
                        // This will not overflow if the requirement of tracking in the contract
                        // no more than `_MAX_STREAMS_BALANCE` of each token is followed.
                        amt += _squeezedAmt(accountId, historyEntry, squeezeStartCap, squeezeEndCap);
                    }
                }
                squeezeEndCap = historyEntry.updateTime;
            }
        }
    }

    /// @notice Verify a streams history and revert if it's invalid.
    /// @param historyHash The account's history hash that was valid right before `streamsHistory`.
    /// @param streamsHistory The sequence of the account's streams configurations.
    /// @param finalHistoryHash The history hash at the end of `streamsHistory`.
    /// @return historyHashes The history hashes valid
    /// for squeezing each of `streamsHistory` entries.
    /// In other words history hashes which had been valid right before each streams
    /// configuration was set, matching `streamsHistoryHash`es emitted in `StreamsSet`.
    /// The first item is always equal to `historyHash` and `finalHistoryHash` is never included.
    function _verifyStreamsHistory(
        bytes32 historyHash,
        StreamsHistory[] memory streamsHistory,
        bytes32 finalHistoryHash
    ) private pure returns (bytes32[] memory historyHashes) {
        historyHashes = new bytes32[](streamsHistory.length);
        for (uint256 i = 0; i < streamsHistory.length; i++) {
            StreamsHistory memory historyEntry = streamsHistory[i];
            bytes32 streamsHash = historyEntry.streamsHash;
            if (historyEntry.receivers.length != 0) {
                require(streamsHash == 0, "Entry with hash and receivers");
                streamsHash = _hashStreams(historyEntry.receivers);
            }
            historyHashes[i] = historyHash;
            historyHash = _hashStreamsHistory(
                historyHash, streamsHash, historyEntry.updateTime, historyEntry.maxEnd
            );
        }
        // slither-disable-next-line incorrect-equality,timestamp
        require(historyHash == finalHistoryHash, "Invalid streams history");
    }

    /// @notice Calculate the amount squeezable by an account from a single streams history entry.
    /// @param accountId The ID of the account to squeeze streams for.
    /// @param historyEntry The squeezed history entry.
    /// @param squeezeStartCap The squeezed time range start.
    /// @param squeezeEndCap The squeezed time range end.
    /// @return squeezedAmt The squeezed amount.
    function _squeezedAmt(
        uint256 accountId,
        StreamsHistory memory historyEntry,
        uint32 squeezeStartCap,
        uint32 squeezeEndCap
    ) private view returns (uint128 squeezedAmt) {
        unchecked {
            StreamReceiver[] memory receivers = historyEntry.receivers;
            // Binary search for the `idx` of the first occurrence of `accountId`
            uint256 idx = 0;
            for (uint256 idxCap = receivers.length; idx < idxCap;) {
                uint256 idxMid = (idx + idxCap) / 2;
                if (receivers[idxMid].accountId < accountId) {
                    idx = idxMid + 1;
                } else {
                    idxCap = idxMid;
                }
            }
            uint32 updateTime = historyEntry.updateTime;
            uint32 maxEnd = historyEntry.maxEnd;
            uint256 amt = 0;
            for (; idx < receivers.length; idx++) {
                StreamReceiver memory receiver = receivers[idx];
                if (receiver.accountId != accountId) break;
                (uint32 start, uint32 end) =
                    _streamRange(receiver, updateTime, maxEnd, squeezeStartCap, squeezeEndCap);
                // This will not overflow if the requirement of tracking in the contract
                // no more than `_MAX_STREAMS_BALANCE` of each token is followed.
                amt += _streamedAmt(receiver.config.amtPerSec(), start, end);
            }
            return uint128(amt);
        }
    }

    /// @notice Current account streams state.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// @return streamsHash The current streams receivers list hash, see `_hashStreams`
    /// @return streamsHistoryHash The current streams history hash, see `_hashStreamsHistory`.
    /// @return updateTime The time when streams have been configured for the last time.
    /// @return balance The balance when streams have been configured for the last time.
    /// @return maxEnd The current maximum end time of streaming.
    function _streamsState(uint256 accountId, IERC20 erc20)
        internal
        view
        returns (
            bytes32 streamsHash,
            bytes32 streamsHistoryHash,
            uint32 updateTime,
            uint128 balance,
            uint32 maxEnd
        )
    {
        StreamsState storage state = _streamsStorage().states[erc20][accountId];
        return (
            state.streamsHash,
            state.streamsHistoryHash,
            state.updateTime,
            state.balance,
            state.maxEnd
        );
    }

    /// @notice The account's streams balance at the given timestamp.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// @param currReceivers The current streams receivers list.
    /// It must be exactly the same as the last list set for the account with `_setStreams`.
    /// @param timestamp The timestamp for which balance should be calculated.
    /// It can't be lower than the timestamp of the last call to `_setStreams`.
    /// If it's bigger than `block.timestamp`, then it's a prediction assuming
    /// that `_setStreams` won't be called before `timestamp`.
    /// @return balance The account balance on `timestamp`
    function _balanceAt(
        uint256 accountId,
        IERC20 erc20,
        StreamReceiver[] memory currReceivers,
        uint32 timestamp
    ) internal view returns (uint128 balance) {
        StreamsState storage state = _streamsStorage().states[erc20][accountId];
        require(timestamp >= state.updateTime, "Timestamp before the last update");
        _verifyStreamsReceivers(currReceivers, state);
        return _calcBalance(state.balance, state.updateTime, state.maxEnd, currReceivers, timestamp);
    }

    /// @notice Calculates the streams balance at a given timestamp.
    /// @param lastBalance The balance when streaming started.
    /// @param lastUpdate The timestamp when streaming started.
    /// @param maxEnd The maximum end time of streaming.
    /// @param receivers The list of streams receivers.
    /// @param timestamp The timestamp for which balance should be calculated.
    /// It can't be lower than `lastUpdate`.
    /// If it's bigger than `block.timestamp`, then it's a prediction assuming
    /// that `_setStreams` won't be called before `timestamp`.
    /// @return balance The account balance on `timestamp`
    function _calcBalance(
        uint128 lastBalance,
        uint32 lastUpdate,
        uint32 maxEnd,
        StreamReceiver[] memory receivers,
        uint32 timestamp
    ) private view returns (uint128 balance) {
        unchecked {
            balance = lastBalance;
            for (uint256 i = 0; i < receivers.length; i++) {
                StreamReceiver memory receiver = receivers[i];
                (uint32 start, uint32 end) = _streamRange({
                    receiver: receiver,
                    updateTime: lastUpdate,
                    maxEnd: maxEnd,
                    startCap: lastUpdate,
                    endCap: timestamp
                });
                balance -= uint128(_streamedAmt(receiver.config.amtPerSec(), start, end));
            }
        }
    }

    /// @notice Sets the account's streams configuration.
    /// @param accountId The account ID.
    /// @param erc20 The used ERC-20 token.
    /// @param currReceivers The current streams receivers list.
    /// It must be exactly the same as the last list set for the account with `_setStreams`.
    /// If this is the first update, pass an empty array.
    /// @param balanceDelta The streams balance change to be applied.
    /// If it's positive, the balance is increased by `balanceDelta`.
    /// If it's zero, the balance doesn't change.
    /// If it's negative, the balance is decreased by `balanceDelta`,
    /// but the change is capped at the current balance amount, so it doesn't go below 0.
    /// Passing `type(int128).min` always decreases the current balance to 0.
    /// @param newReceivers The list of the streams receivers of the account to be set.
    /// Must be sorted by the account IDs and then by the stream configurations,
    /// without identical elements and without 0 amtPerSecs.
    /// @param maxEndHint1 An optional parameter allowing gas optimization, pass `0` to ignore it.
    /// The first hint for finding the maximum end time when all streams stop due to funds
    /// running out after the balance is updated and the new receivers list is applied.
    /// Hints have no effect on the results of calling this function, except potentially saving gas.
    /// Hints are Unix timestamps used as the starting points for binary search for the time
    /// when funds run out in the range of timestamps from the current block's to `2^32`.
    /// Hints lower than the current timestamp are ignored.
    /// You can provide zero, one or two hints. The order of hints doesn't matter.
    /// Hints are the most effective when one of them is lower than or equal to
    /// the last timestamp when funds are still streamed, and the other one is strictly larger
    /// than that timestamp,the smaller the difference between such hints, the higher gas savings.
    /// The savings are the highest possible when one of the hints is equal to
    /// the last timestamp when funds are still streamed, and the other one is larger by 1.
    /// It's worth noting that the exact timestamp of the block in which this function is executed
    /// may affect correctness of the hints, especially if they're precise.
    /// Hints don't provide any benefits when balance is not enough to cover
    /// a single second of streaming or is enough to cover all streams until timestamp `2^32`.
    /// Even inaccurate hints can be useful, and providing a single hint
    /// or two hints that don't enclose the time when funds run out can still save some gas.
    /// Providing poor hints that don't reduce the number of binary search steps
    /// may cause slightly higher gas usage than not providing any hints.
    /// @param maxEndHint2 An optional parameter allowing gas optimization, pass `0` to ignore it.
    /// The second hint for finding the maximum end time, see `maxEndHint1` docs for more details.
    /// @return realBalanceDelta The actually applied streams balance change.
    /// It's equal to the passed `balanceDelta`, unless it's negative
    /// and it gets capped at the current balance amount.
    function _setStreams(
        uint256 accountId,
        IERC20 erc20,
        StreamReceiver[] memory currReceivers,
        int128 balanceDelta,
        StreamReceiver[] memory newReceivers,
        // slither-disable-next-line similar-names
        uint32 maxEndHint1,
        uint32 maxEndHint2
    ) internal returns (int128 realBalanceDelta) {
        unchecked {
            StreamsState storage state = _streamsStorage().states[erc20][accountId];
            _verifyStreamsReceivers(currReceivers, state);
            uint32 lastUpdate = state.updateTime;
            uint128 newBalance;
            uint32 newMaxEnd;
            {
                uint32 currMaxEnd = state.maxEnd;
                int128 currBalance = int128(
                    _calcBalance(
                        state.balance, lastUpdate, currMaxEnd, currReceivers, _currTimestamp()
                    )
                );
                realBalanceDelta = balanceDelta;
                // Cap `realBalanceDelta` at withdrawal of the entire `currBalance`
                if (realBalanceDelta < -currBalance) {
                    realBalanceDelta = -currBalance;
                }
                // This will not overflow if the requirement of tracking in the contract
                // no more than `_MAX_STREAMS_BALANCE` of each token is followed.
                newBalance = uint128(currBalance + realBalanceDelta);
                newMaxEnd = _calcMaxEnd(newBalance, newReceivers, maxEndHint1, maxEndHint2);
                _updateReceiverStates(
                    _streamsStorage().states[erc20],
                    currReceivers,
                    lastUpdate,
                    currMaxEnd,
                    newReceivers,
                    newMaxEnd
                );
            }
            state.updateTime = _currTimestamp();
            state.maxEnd = newMaxEnd;
            state.balance = newBalance;
            bytes32 streamsHistory = state.streamsHistoryHash;
            // slither-disable-next-line timestamp
            if (streamsHistory != 0 && _cycleOf(lastUpdate) != _cycleOf(_currTimestamp())) {
                state.lastUpdatedCycleConfigs = 2;
            } else {
                state.lastUpdatedCycleConfigs++;
            }
            bytes32 newStreamsHash = _hashStreams(newReceivers);
            state.streamsHistoryHash =
                _hashStreamsHistory(streamsHistory, newStreamsHash, _currTimestamp(), newMaxEnd);
            emit StreamsSet(accountId, erc20, newStreamsHash, streamsHistory, newBalance, newMaxEnd);
            // slither-disable-next-line timestamp
            if (newStreamsHash != state.streamsHash) {
                state.streamsHash = newStreamsHash;
                for (uint256 i = 0; i < newReceivers.length; i++) {
                    StreamReceiver memory receiver = newReceivers[i];
                    emit StreamReceiverSeen(newStreamsHash, receiver.accountId, receiver.config);
                }
            }
        }
    }

    /// @notice Verifies that the provided list of receivers is currently active for the account.
    /// @param currReceivers The verified list of receivers.
    /// @param state The account's state.
    function _verifyStreamsReceivers(
        StreamReceiver[] memory currReceivers,
        StreamsState storage state
    ) private view {
        require(_hashStreams(currReceivers) == state.streamsHash, "Invalid streams receivers list");
    }

    /// @notice Calculates the maximum end time of all streams.
    /// @param balance The balance when streaming starts.
    /// @param receivers The list of streams receivers.
    /// Must be sorted by the account IDs and then by the stream configurations,
    /// without identical elements and without 0 amtPerSecs.
    /// @param hint1 The first hint for finding the maximum end time.
    /// See `_setStreams` docs for `maxEndHint1` for more details.
    /// @param hint2 The second hint for finding the maximum end time.
    /// See `_setStreams` docs for `maxEndHint2` for more details.
    /// @return maxEnd The maximum end time of streaming.
    function _calcMaxEnd(
        uint128 balance,
        StreamReceiver[] memory receivers,
        uint32 hint1,
        uint32 hint2
    ) private view returns (uint32 maxEnd) {
        (uint256[] memory configs, uint256 configsLen) = _buildConfigs(receivers);

        uint256 enoughEnd = _currTimestamp();
        // slither-disable-start incorrect-equality,timestamp
        if (configsLen == 0 || balance == 0) {
            return uint32(enoughEnd);
        }

        uint256 notEnoughEnd = type(uint32).max;
        if (_isBalanceEnough(balance, configs, configsLen, notEnoughEnd)) {
            return uint32(notEnoughEnd);
        }

        if (hint1 > enoughEnd && hint1 < notEnoughEnd) {
            if (_isBalanceEnough(balance, configs, configsLen, hint1)) {
                enoughEnd = hint1;
            } else {
                notEnoughEnd = hint1;
            }
        }

        if (hint2 > enoughEnd && hint2 < notEnoughEnd) {
            if (_isBalanceEnough(balance, configs, configsLen, hint2)) {
                enoughEnd = hint2;
            } else {
                notEnoughEnd = hint2;
            }
        }

        while (true) {
            uint256 end;
            unchecked {
                end = (enoughEnd + notEnoughEnd) / 2;
            }
            if (end == enoughEnd) {
                return uint32(end);
            }
            if (_isBalanceEnough(balance, configs, configsLen, end)) {
                enoughEnd = end;
            } else {
                notEnoughEnd = end;
            }
        }
        // slither-disable-end incorrect-equality,timestamp
    }

    /// @notice Check if a given balance is enough to cover all streams with the given `maxEnd`.
    /// @param balance The balance when streaming starts.
    /// @param configs The list of streams configurations.
    /// @param configsLen The length of `configs`.
    /// @param maxEnd The maximum end time of streaming.
    /// @return isEnough `true` if the balance is enough, `false` otherwise.
    function _isBalanceEnough(
        uint256 balance,
        uint256[] memory configs,
        uint256 configsLen,
        uint256 maxEnd
    ) private view returns (bool isEnough) {
        unchecked {
            uint256 spent = 0;
            for (uint256 i = 0; i < configsLen; i++) {
                (uint256 amtPerSec, uint256 start, uint256 end) = _getConfig(configs, i);
                // slither-disable-next-line timestamp
                if (maxEnd <= start) {
                    continue;
                }
                // slither-disable-next-line timestamp
                if (end > maxEnd) {
                    end = maxEnd;
                }
                spent += _streamedAmt(amtPerSec, start, end);
                if (spent > balance) {
                    return false;
                }
            }
            return true;
        }
    }

    /// @notice Build a preprocessed list of streams configurations from receivers.
    /// @param receivers The list of streams receivers.
    /// Must be sorted by the account IDs and then by the stream configurations,
    /// without identical elements and without 0 amtPerSecs.
    /// @return configs The list of streams configurations
    /// @return configsLen The length of `configs`
    function _buildConfigs(StreamReceiver[] memory receivers)
        private
        view
        returns (uint256[] memory configs, uint256 configsLen)
    {
        unchecked {
            require(receivers.length <= _MAX_STREAMS_RECEIVERS, "Too many streams receivers");
            configs = new uint256[](receivers.length);
            for (uint256 i = 0; i < receivers.length; i++) {
                StreamReceiver memory receiver = receivers[i];
                if (i > 0) {
                    require(_isOrdered(receivers[i - 1], receiver), "Streams receivers not sorted");
                }
                configsLen = _addConfig(configs, configsLen, receiver);
            }
        }
    }

    /// @notice Preprocess and add a stream receiver to the list of configurations.
    /// @param configs The list of streams configurations
    /// @param configsLen The length of `configs`
    /// @param receiver The added stream receiver.
    /// @return newConfigsLen The new length of `configs`
    function _addConfig(
        uint256[] memory configs,
        uint256 configsLen,
        StreamReceiver memory receiver
    ) private view returns (uint256 newConfigsLen) {
        uint160 amtPerSec = receiver.config.amtPerSec();
        require(amtPerSec >= _minAmtPerSec, "Stream receiver amtPerSec too low");
        (uint32 start, uint32 end) =
            _streamRangeInFuture(receiver, _currTimestamp(), type(uint32).max);
        // slither-disable-next-line incorrect-equality,timestamp
        if (start == end) {
            return configsLen;
        }
        // By assignment we get `config` value:
        // `zeros (96 bits) | amtPerSec (160 bits)`
        uint256 config = amtPerSec;
        // By bit shifting we get `config` value:
        // `zeros (64 bits) | amtPerSec (160 bits) | zeros (32 bits)`
        // By bit masking we get `config` value:
        // `zeros (64 bits) | amtPerSec (160 bits) | start (32 bits)`
        config = (config << 32) | start;
        // By bit shifting we get `config` value:
        // `zeros (32 bits) | amtPerSec (160 bits) | start (32 bits) | zeros (32 bits)`
        // By bit masking we get `config` value:
        // `zeros (32 bits) | amtPerSec (160 bits) | start (32 bits) | end (32 bits)`
        config = (config << 32) | end;
        configs[configsLen] = config;
        unchecked {
            return configsLen + 1;
        }
    }

    /// @notice Load a streams configuration from the list.
    /// @param configs The list of streams configurations
    /// @param idx The loaded configuration index. It must be smaller than the `configs` length.
    /// @return amtPerSec The amount per second being streamed.
    /// @return start The timestamp when streaming starts.
    /// @return end The maximum timestamp when streaming ends.
    function _getConfig(uint256[] memory configs, uint256 idx)
        private
        pure
        returns (uint256 amtPerSec, uint256 start, uint256 end)
    {
        uint256 config;
        // `config` has value:
        // `zeros (32 bits) | amtPerSec (160 bits) | start (32 bits) | end (32 bits)`
        // slither-disable-next-line assembly
        assembly ("memory-safe") {
            config := mload(add(32, add(configs, shl(5, idx))))
        }
        // By bit shifting we get value:
        // `zeros (96 bits) | amtPerSec (160 bits)`
        amtPerSec = config >> 64;
        // By bit shifting we get value:
        // `zeros (64 bits) | amtPerSec (160 bits) | start (32 bits)`
        // By casting down we get value:
        // `start (32 bits)`
        start = uint32(config >> 32);
        // By casting down we get value:
        // `end (32 bits)`
        end = uint32(config);
    }

    /// @notice Calculates the hash of the streams configuration.
    /// It's used to verify if streams configuration is the previously set one.
    /// @param receivers The list of the streams receivers.
    /// If the streams have never been set, pass an empty array.
    /// @return streamsHash The hash of the streams configuration
    function _hashStreams(StreamReceiver[] memory receivers)
        internal
        pure
        returns (bytes32 streamsHash)
    {
        if (receivers.length == 0) {
            return bytes32(0);
        }
        return keccak256(abi.encode(receivers));
    }

    /// @notice Calculates the hash of the streams history
    /// after the streams configuration is updated.
    /// @param oldStreamsHistoryHash The history hash
    /// that was valid before the streams were updated.
    /// The `streamsHistoryHash` of an account before they set streams for the first time is `0`.
    /// @param streamsHash The hash of the streams receivers being set.
    /// @param updateTime The timestamp when the streams were updated.
    /// @param maxEnd The maximum end of the streams being set.
    /// @return streamsHistoryHash The hash of the updated streams history.
    function _hashStreamsHistory(
        bytes32 oldStreamsHistoryHash,
        bytes32 streamsHash,
        uint32 updateTime,
        uint32 maxEnd
    ) internal pure returns (bytes32 streamsHistoryHash) {
        return keccak256(abi.encode(oldStreamsHistoryHash, streamsHash, updateTime, maxEnd));
    }

    /// @notice Applies the effects of the change of the streams on the receivers' streams state.
    /// Only affects `amtDeltas` and `nextReceivableCycle` of the accounts
    /// present either in `currReceivers` or in `newReceivers`.
    /// @param states The streams states for the used ERC-20 token.
    /// @param currReceivers The list of the streams receivers
    /// set in the last streams update of the account.
    /// If this is the first update, pass an empty array.
    /// @param lastUpdate the last time the sender updated the streams.
    /// If this is the first update, pass zero.
    /// @param currMaxEnd The maximum end time of streaming according to the last streams update.
    /// @param newReceivers  The list of the streams receivers of the account to be set.
    /// Must be sorted by the account IDs and then by the stream configurations,
    /// without identical elements and without 0 amtPerSecs.
    /// @param newMaxEnd The maximum end time of streaming according to the new configuration.
    // slither-disable-next-line cyclomatic-complexity
    function _updateReceiverStates(
        mapping(uint256 accountId => StreamsState) storage states,
        StreamReceiver[] memory currReceivers,
        uint32 lastUpdate,
        uint32 currMaxEnd,
        StreamReceiver[] memory newReceivers,
        uint32 newMaxEnd
    ) private {
        uint256 currIdx = 0;
        uint256 newIdx = 0;
        while (true) {
            bool pickCurr = currIdx < currReceivers.length;
            // slither-disable-next-line uninitialized-local
            StreamReceiver memory currRecv;
            if (pickCurr) {
                currRecv = currReceivers[currIdx];
            }

            bool pickNew = newIdx < newReceivers.length;
            // slither-disable-next-line uninitialized-local
            StreamReceiver memory newRecv;
            if (pickNew) {
                newRecv = newReceivers[newIdx];
            }

            // Limit picking both curr and new to situations when they
            // differ only by the stream ID, the start or the duration.
            if (pickCurr && pickNew) {
                if (
                    currRecv.accountId != newRecv.accountId
                        || currRecv.config.amtPerSec() != newRecv.config.amtPerSec()
                ) {
                    pickCurr = _isOrdered(currRecv, newRecv);
                    pickNew = !pickCurr;
                }
            }

            if (pickCurr && pickNew) {
                // Shift the existing stream to fulfil the new configuration
                StreamsState storage state = states[currRecv.accountId];
                (uint32 currStart, uint32 currEnd) =
                    _streamRangeInFuture(currRecv, lastUpdate, currMaxEnd);
                (uint32 newStart, uint32 newEnd) =
                    _streamRangeInFuture(newRecv, _currTimestamp(), newMaxEnd);
                int256 amtPerSec = int256(uint256(currRecv.config.amtPerSec()));
                // Move the start and end times if updated. This has the same effects as calling
                // _addDeltaRange(state, currStart, currEnd, -amtPerSec);
                // _addDeltaRange(state, newStart, newEnd, amtPerSec);
                // but it allows skipping storage access if there's no change to the starts or ends.
                _addDeltaRange(state, currStart, newStart, -amtPerSec);
                _addDeltaRange(state, currEnd, newEnd, amtPerSec);
                // Ensure that the account receives the updated cycles
                uint32 currStartCycle = _cycleOf(currStart);
                uint32 newStartCycle = _cycleOf(newStart);
                // The `currStartCycle > newStartCycle` check is just an optimization.
                // If it's false, then `state.nextReceivableCycle > newStartCycle` must be
                // false too, there's no need to pay for the storage access to check it.
                // slither-disable-next-line timestamp
                if (currStartCycle > newStartCycle && state.nextReceivableCycle > newStartCycle) {
                    state.nextReceivableCycle = newStartCycle;
                }
            } else if (pickCurr) {
                // Remove an existing stream
                // slither-disable-next-line similar-names
                StreamsState storage state = states[currRecv.accountId];
                (uint32 start, uint32 end) = _streamRangeInFuture(currRecv, lastUpdate, currMaxEnd);
                // slither-disable-next-line similar-names
                int256 amtPerSec = int256(uint256(currRecv.config.amtPerSec()));
                _addDeltaRange(state, start, end, -amtPerSec);
            } else if (pickNew) {
                // Create a new stream
                StreamsState storage state = states[newRecv.accountId];
                // slither-disable-next-line uninitialized-local
                (uint32 start, uint32 end) =
                    _streamRangeInFuture(newRecv, _currTimestamp(), newMaxEnd);
                int256 amtPerSec = int256(uint256(newRecv.config.amtPerSec()));
                _addDeltaRange(state, start, end, amtPerSec);
                // Ensure that the account receives the updated cycles
                uint32 startCycle = _cycleOf(start);
                // slither-disable-next-line timestamp
                uint32 nextReceivableCycle = state.nextReceivableCycle;
                if (nextReceivableCycle == 0 || nextReceivableCycle > startCycle) {
                    state.nextReceivableCycle = startCycle;
                }
            } else {
                break;
            }

            unchecked {
                if (pickCurr) {
                    currIdx++;
                }
                if (pickNew) {
                    newIdx++;
                }
            }
        }
    }

    /// @notice Calculates the time range in the future in which a receiver will be streamed to.
    /// @param receiver The stream receiver.
    /// @param maxEnd The maximum end time of streaming.
    function _streamRangeInFuture(StreamReceiver memory receiver, uint32 updateTime, uint32 maxEnd)
        private
        view
        returns (uint32 start, uint32 end)
    {
        return _streamRange(receiver, updateTime, maxEnd, _currTimestamp(), type(uint32).max);
    }

    /// @notice Calculates the time range in which a receiver is to be streamed to.
    /// This range is capped to provide a view on the stream through a specific time window.
    /// @param receiver The stream receiver.
    /// @param updateTime The time when the stream is configured.
    /// @param maxEnd The maximum end time of streaming.
    /// @param startCap The timestamp the streaming range start should be capped to.
    /// @param endCap The timestamp the streaming range end should be capped to.
    function _streamRange(
        StreamReceiver memory receiver,
        uint32 updateTime,
        uint32 maxEnd,
        uint32 startCap,
        uint32 endCap
    ) private pure returns (uint32 start, uint32 end_) {
        start = receiver.config.start();
        // slither-disable-start timestamp
        if (start == 0) {
            start = updateTime;
        }
        uint40 end;
        unchecked {
            end = uint40(start) + receiver.config.duration();
        }
        // slither-disable-next-line incorrect-equality
        if (end == start || end > maxEnd) {
            end = maxEnd;
        }
        if (start < startCap) {
            start = startCap;
        }
        if (end > endCap) {
            end = endCap;
        }
        if (end < start) {
            end = start;
        }
        // slither-disable-end timestamp
        return (start, uint32(end));
    }

    /// @notice Adds funds received by an account in a given time range
    /// @param state The account state
    /// @param start The timestamp from which the delta takes effect
    /// @param end The timestamp until which the delta takes effect
    /// @param amtPerSec The streaming rate
    function _addDeltaRange(StreamsState storage state, uint32 start, uint32 end, int256 amtPerSec)
        private
    {
        // slither-disable-next-line incorrect-equality,timestamp
        if (start == end) {
            return;
        }
        mapping(uint32 cycle => AmtDelta) storage amtDeltas = state.amtDeltas;
        _addDelta(amtDeltas, start, amtPerSec);
        _addDelta(amtDeltas, end, -amtPerSec);
    }

    /// @notice Adds delta of funds received by an account at a given time
    /// @param amtDeltas The account amount deltas
    /// @param timestamp The timestamp when the deltas need to be added
    /// @param amtPerSec The streaming rate
    function _addDelta(
        mapping(uint32 cycle => AmtDelta) storage amtDeltas,
        uint256 timestamp,
        int256 amtPerSec
    ) private {
        unchecked {
            // In order to set a delta on a specific timestamp it must be introduced in two cycles.
            // These formulas follow the logic from `_streamedAmt`, see it for more details.
            int256 amtPerSecMultiplier = int160(_AMT_PER_SEC_MULTIPLIER);
            int256 fullCycle = (int256(uint256(_cycleSecs)) * amtPerSec) / amtPerSecMultiplier;
            // slither-disable-next-line weak-prng
            int256 nextCycle = (int256(timestamp % _cycleSecs) * amtPerSec) / amtPerSecMultiplier;
            AmtDelta storage amtDelta = amtDeltas[_cycleOf(uint32(timestamp))];
            // Any over- or under-flows are fine, they're guaranteed to be fixed by a matching
            // under- or over-flow from the other call to `_addDelta` made by `_addDeltaRange`.
            // This is because the total balance of `Streams` can never exceed `type(int128).max`,
            // so in the end no amtDelta can have delta higher than `type(int128).max`.
            amtDelta.thisCycle += int128(fullCycle - nextCycle);
            amtDelta.nextCycle += int128(nextCycle);
        }
    }

    /// @notice Checks if two receivers fulfil the sortedness requirement of the receivers list.
    /// @param prev The previous receiver
    /// @param next The next receiver
    function _isOrdered(StreamReceiver memory prev, StreamReceiver memory next)
        private
        pure
        returns (bool)
    {
        if (prev.accountId != next.accountId) {
            return prev.accountId < next.accountId;
        }
        return prev.config.lt(next.config);
    }

    /// @notice Calculates the amount streamed over a time range.
    /// The amount streamed in the `N`th second of each cycle is:
    /// `(N + 1) * amtPerSec / AMT_PER_SEC_MULTIPLIER - N * amtPerSec / AMT_PER_SEC_MULTIPLIER`.
    /// For a range of `N`s from `0` to `M` the sum of the streamed amounts is calculated as:
    /// `M * amtPerSec / AMT_PER_SEC_MULTIPLIER` assuming that `M <= cycleSecs`.
    /// For an arbitrary time range across multiple cycles the amount
    /// is calculated as the sum of the amount streamed in the start cycle,
    /// each of the full cycles in between and the end cycle.
    /// This algorithm has the following properties:
    /// - During every second full units are streamed, there are no partially streamed units.
    /// - Unstreamed fractions are streamed when they add up into full units.
    /// - Unstreamed fractions don't add up across cycle end boundaries.
    /// - Some seconds stream 1 unit more to emulate streaming fractions of the unit.
    /// - Every `N`th second of each cycle streams the same amount.
    /// - Every full cycle streams the same amount.
    /// - The amount streamed in a given second is independent from the streaming start and end.
    /// - Streaming over time ranges `A:B` and then `B:C` is equivalent to streaming over `A:C`.
    /// - Different streams existing in the system don't interfere with each other.
    /// @param amtPerSec The streaming rate
    /// @param start The streaming start time
    /// @param end The streaming end time
    /// @return amt The streamed amount
    function _streamedAmt(uint256 amtPerSec, uint256 start, uint256 end)
        private
        view
        returns (uint256 amt)
    {
        // This function is written in Yul because it can be called thousands of times
        // per transaction and it needs to be optimized as much as possible.
        // As of Solidity 0.8.13, rewriting it in unchecked Solidity triples its gas cost.
        uint256 cycleSecs = _cycleSecs;
        // slither-disable-next-line assembly
        assembly {
            let endedCycles := sub(div(end, cycleSecs), div(start, cycleSecs))
            // slither-disable-next-line divide-before-multiply
            let amtPerCycle := div(mul(cycleSecs, amtPerSec), _AMT_PER_SEC_MULTIPLIER)
            amt := mul(endedCycles, amtPerCycle)
            // slither-disable-next-line weak-prng
            let amtEnd := div(mul(mod(end, cycleSecs), amtPerSec), _AMT_PER_SEC_MULTIPLIER)
            amt := add(amt, amtEnd)
            // slither-disable-next-line weak-prng
            let amtStart := div(mul(mod(start, cycleSecs), amtPerSec), _AMT_PER_SEC_MULTIPLIER)
            amt := sub(amt, amtStart)
        }
    }

    /// @notice Calculates the cycle containing the given timestamp.
    /// @param timestamp The timestamp.
    /// @return cycle The cycle containing the timestamp.
    function _cycleOf(uint32 timestamp) private view returns (uint32 cycle) {
        unchecked {
            return timestamp / _cycleSecs + 1;
        }
    }

    /// @notice The current timestamp, casted to the contract's internal representation.
    /// @return timestamp The current timestamp
    function _currTimestamp() private view returns (uint32 timestamp) {
        return uint32(block.timestamp);
    }

    /// @notice The current cycle start timestamp, casted to the contract's internal representation.
    /// @return timestamp The current cycle start timestamp
    function _currCycleStart() private view returns (uint32 timestamp) {
        unchecked {
            uint32 currTimestamp = _currTimestamp();
            // slither-disable-next-line weak-prng
            return currTimestamp - (currTimestamp % _cycleSecs);
        }
    }

    /// @notice Returns the Streams storage.
    /// @return streamsStorage The storage.
    function _streamsStorage() private view returns (StreamsStorage storage streamsStorage) {
        bytes32 slot = _streamsStorageSlot;
        // slither-disable-next-line assembly
        assembly {
            streamsStorage.slot := slot
        }
    }
}

0% src/echidna/Echidna.sol

Lines covered: 0 / 1 (0%)

// SPDX-License-Identifier: MIT

import "./EchidnaInvariantTests.sol";
import "./EchidnaBasicTests.sol";
import "./EchidnaSplitsTests.sol";
import "./EchidnaStreamsTests.sol";
import "./EchidnaSqueezeTests.sol";

/**
 * @title Echidna contract for testing the Drips contract
 * @author Rappie <rappie@perimetersec.io>
 * @dev Running the tests:
 * For Echidna use `echidna . --contract Echidna --config echidna-config.yaml`.
 * For Medusa use `medusa fuzz`.
 * The tests are split into multiple files to be able to toggle the fuzzing
 * of specific features on and off. This is done by commenting out the
 * corresponding inherited contract in the Echidna contract below.
 * Basic tests contain basic features like giving, receiving, splitting and
 * collecting.
 * Splits tests contain tests for splitting.
 * Streams tests contain tests for receiving streams.
 * Squeeze tests contain tests for squeezing.
 * Invariant tests contain tests for invariant properties of the system. These
 * make most sense with all other tests enabled.
 * For further performance improvements, resource heavy tests can be toggled.
 * To do so, change the value of TOGGLE_HEAVY_TESTS_ENABLED in EchidnaConfig.
 */
contract Echidna is
    EchidnaBasicTests,
    EchidnaSplitsTests,
    EchidnaStreamsTests,
    EchidnaSqueezeTests,
    EchidnaInvariantTests
{

}

97% src/echidna/EchidnaBasicHelpers.sol

Lines covered: 48 / 49 (97%)

// SPDX-License-Identifier: MIT

import "./base/EchidnaBase.sol";

/**
 * @title Mixin containing basic helper functions
 * @author Rappie <rappie@perimetersec.io>
 */
contract EchidnaBasicHelpers is EchidnaBase {
    /**
     * @notice Give balance to an account
     * @param fromAccId Account id of the giver
     * @param toAccId Account id of the receiver
     * @param amount Amount to give
     */
    function give(
        uint8 fromAccId,
        uint8 toAccId,
        uint128 amount
    ) public {
        address from = getAccount(fromAccId);
        address to = getAccount(toAccId);

        uint256 toDripsAccId = getDripsAccountId(to);

        hevm.prank(from);
        driver.give(toDripsAccId, token, amount);
    }

    /**
     * @notice Give a clamped amount to an account
     * @param fromAccId Account id of the giver
     * @param toAccId Account id of the receiver
     * @param amount Amount to give
     */
    function giveClampedAmount(
        uint8 fromAccId,
        uint8 toAccId,
        uint128 amount
    ) public {
        address from = getAccount(fromAccId);

        uint128 min = 1000;
        uint128 max = uint128(token.balanceOf(from));
        uint128 clampedAmount = min + (amount % (max - min + 1));

        give(fromAccId, toAccId, clampedAmount);
    }

    /**
     * @notice Receive streams
     * @param targetAccId Account id of the receiver
     * @param maxCycles Maximum number of cycles to receive
     * @return Amount received
     * @dev Receiving means moving receivable (already streamed) balance to
     * splittable (available for splitting) balance
     */
    function receiveStreams(uint8 targetAccId, uint32 maxCycles)
        public
        returns (uint128)
    {
        address target = getAccount(targetAccId);
        uint256 targetDripsAccId = getDripsAccountId(target);

        uint128 receivedAmt = drips.receiveStreams(
            targetDripsAccId,
            token,
            maxCycles
        );

        return receivedAmt;
    }

    /**
     * @notice Receive streams for all possible cycles
     * @param targetAccId Account id of the receiver
     * @return Amount received
     * @dev We pass maxuint32 to receive all possible cycles
     */
    function receiveStreamsAllCycles(uint8 targetAccId)
        public
        returns (uint128)
    {
        return receiveStreams(targetAccId, type(uint32).max);
    }

    /**
     * @notice Split received funds
     * @param targetAccId Account to have their funds split
     * @return Amount collectable and amount split
     * @dev Splitting means moving splittable (available for splitting) balance
     * to collectable (available for collecting) balance
     */
    function split(uint8 targetAccId) public returns (uint128, uint128) {
        address target = getAccount(targetAccId);
        uint256 targetDripsAccId = getDripsAccountId(target);

        (uint128 collectableAmt, uint128 splitAmt) = drips.split(
            targetDripsAccId,
            token,
            getSplitsReceivers(target)
        );

        return (collectableAmt, splitAmt);
    }

    /**
     * @notice Collect funds
     * @param fromAccId Account id of the giver
     * @param toAccId Account id of the receiver
     * @return Amount collected
     * @dev Collecting means moving withdrawing collectable funds to actual
     * balance of the erc20 token
     */
    function collect(uint8 fromAccId, uint8 toAccId) public returns (uint128) {
        address from = getAccount(fromAccId);
        address to = getAccount(toAccId);

        hevm.prank(from);
        uint128 collected = driver.collect(token, to);

        return collected;
    }

    /**
     * @notice Collect funds to self
     * @param targetAccId Target account
     */
    function collectToSelf(uint8 targetAccId) public {
        collect(targetAccId, targetAccId);
    }

    /**
     * @notice Split and collect funds to self
     * @param targetAccId Target account
     * @dev Extra helper that narrows the search space for the fuzzer
     */
    function splitAndCollectToSelf(uint8 targetAccId) public {
        split(targetAccId);
        collectToSelf(targetAccId);
    }

    /**
     * @notice Receive streams, split and collect funds to self
     * @param targetAccId Target account
     * @dev Extra helper that narrows the search space for the fuzzer
     */
    function receiveStreamsSplitAndCollectToSelf(uint8 targetAccId) public {
        receiveStreamsAllCycles(targetAccId);
        splitAndCollectToSelf(targetAccId);
    }
}

95% src/echidna/EchidnaBasicTests.sol

Lines covered: 66 / 69 (95%)

// SPDX-License-Identifier: MIT

import "./base/EchidnaBase.sol";
import "./EchidnaBasicHelpers.sol";

/**
 * @title Mixin containing basic tests
 * @author Rappie <rappie@perimetersec.io>
 */
contract EchidnaBasicTests is EchidnaBase, EchidnaBasicHelpers {
    /**
     * @notice Giving an amount `<=` token balance should never revert
     * @param fromAccId Account id of the giver
     * @param toAccId Account id of the receiver
     * @param amount Amount to give
     */
    function testGiveShouldNotRevert(
        uint8 fromAccId,
        uint8 toAccId,
        uint128 amount
    ) public {
        address from = getAccount(fromAccId);
        address to = getAccount(toAccId);

        uint256 toDripsAccId = getDripsAccountId(to);

        require(amount <= token.balanceOf(from));

        hevm.prank(from);
        try driver.give(toDripsAccId, token, amount) {} catch {
            assert(false);
        }
    }

    /**
     * @notice Test internal accounting after receiving streams
     * @param targetAccId Account id of the receiver
     * @param maxCycles Maximum number of cycles to receive
     */
    function testReceiveStreams(uint8 targetAccId, uint32 maxCycles) public {
        address target = getAccount(targetAccId);
        uint256 targetDripsAccId = getDripsAccountId(target);

        uint128 splittableBefore = drips.splittable(targetDripsAccId, token);
        uint128 receivedAmt = receiveStreams(targetAccId, maxCycles);
        uint128 splittableAfter = drips.splittable(targetDripsAccId, token);

        assert(splittableAfter == splittableBefore + receivedAmt);

        if (receivedAmt > 0) {
            assert(splittableAfter > splittableBefore);
        } else {
            assert(splittableAfter == splittableBefore);
        }
    }

    /**
     * @notice Receiving streams should never revert
     * @param targetAccId Account id of the receiver
     */
    function testReceiveStreamsShouldNotRevert(uint8 targetAccId) public {
        address target = getAccount(targetAccId);
        uint256 targetDripsAccId = getDripsAccountId(target);

        try
            drips.receiveStreams(targetDripsAccId, token, type(uint32).max)
        {} catch {
            assert(false);
        }
    }

    /**
     * @notice If there is a receivable amount, there should be at least one
     * receivable cycle
     * @param targetAccId Account id of the receiver
     * @param maxCycles Maximum number of cycles to receive
     */
    function testReceiveStreamsViewConsistency(
        uint8 targetAccId,
        uint32 maxCycles
    ) public {
        address target = getAccount(targetAccId);
        uint256 targetDripsAccId = getDripsAccountId(target);

        require(maxCycles > 0);

        uint128 receivable = drips.receiveStreamsResult(
            targetDripsAccId,
            token,
            maxCycles
        );
        uint32 receivableCycles = drips.receivableStreamsCycles(
            targetDripsAccId,
            token
        );

        if (receivable > 0) assert(receivableCycles > 0);

        // this does not hold because you can have cycles with 0 amount receivable
        // if (receivableCycles > 0) assert(receivable > 0);
    }

    /**
     * @notice `drips.receiveStreamsResult` should match actual received amount
     * @param targetAccId Account id of the receiver
     * @param maxCycles Maximum number of cycles to receive
     */
    function testReceiveStreamsViewVsActual(uint8 targetAccId, uint32 maxCycles)
        public
    {
        address target = getAccount(targetAccId);
        uint256 targetDripsAccId = getDripsAccountId(target);

        uint128 receivable = drips.receiveStreamsResult(
            targetDripsAccId,
            token,
            maxCycles
        );

        uint128 received = drips.receiveStreams(
            targetDripsAccId,
            token,
            maxCycles
        );

        assert(receivable == received);
    }

    /**
     * @notice Test internal accounting after collecting
     * @param fromAccId Account id of the collector
     * @param toAccId Account id of the receiving account
     */
    function testCollect(uint8 fromAccId, uint8 toAccId) public {
        address from = getAccount(fromAccId);
        address to = getAccount(toAccId);

        uint256 fromDripsAccId = getDripsAccountId(from);

        uint128 colBalBefore = drips.collectable(fromDripsAccId, token);
        uint256 tokenBalBefore = token.balanceOf(to);

        uint128 collected = collect(fromAccId, toAccId);

        uint128 colBalAfter = drips.collectable(fromDripsAccId, token);
        uint256 tokenBalAfter = token.balanceOf(to);

        assert(colBalAfter == colBalBefore - collected);
        assert(tokenBalAfter == tokenBalBefore + collected);
    }

    /**
     * @notice Collecting should never revert
     * @param fromAccId Account id of the collector
     * @param toAccId Account id of the receiving account
     */
    function testCollectShouldNotRevert(uint8 fromAccId, uint8 toAccId) public {
        address from = getAccount(fromAccId);
        address to = getAccount(toAccId);

        hevm.prank(from);
        try driver.collect(token, to) {} catch {
            assert(false);
        }
    }
}

97% src/echidna/EchidnaInvariantTests.sol

Lines covered: 69 / 71 (97%)

// SPDX-License-Identifier: MIT

import "./EchidnaBasicHelpers.sol";
import "./EchidnaSplitsHelpers.sol";
import "./EchidnaStreamsHelpers.sol";
import "./EchidnaSqueezeHelpers.sol";

/**
 * @title Mixin containing invariant tests
 * @author Rappie <rappie@perimetersec.io>
 */
contract EchidnaInvariantTests is
    EchidnaBasicHelpers,
    EchidnaSplitsHelpers,
    EchidnaStreamsHelpers,
    EchidnaSqueezeHelpers
{
    /**
     * @notice Withdrawing any amount directly from Drips should fail
     * @param amount Amount to withdraw
     */
    function invariantWithdrawShouldAlwaysFail(uint256 amount) public {
        require(amount > 0, "withdraw amount must be > 0");

        try drips.withdraw(token, address(this), amount) {
            assert(false);
        } catch {}
    }

    /**
     * @notice `amtPerSec` should never be lower than `drips.minAmtPerSec()`
     * @param targetAccId Account id of the receiver
     * @param index Index of the receiver
     */
    function invariantAmtPerSecVsMinAmtPerSec(uint8 targetAccId, uint256 index)
        public
    {
        address target = getAccount(targetAccId);

        StreamReceiver[] memory receivers = getStreamReceivers(target);
        require(receivers.length > 0, "no receivers");

        index = index % receivers.length;
        uint160 amtPerSec = receivers[index].config.amtPerSec();

        assert(amtPerSec >= drips.minAmtPerSec());
    }

    /**
     * @notice The total of all internal balances should match token balance
     * of the Drips contract
     */
    function invariantAccountingVsTokenBalance() public {
        uint256 tokenBalance = token.balanceOf(address(drips));
        uint256 dripsBalancesTotal = getDripsBalancesTotalForAllUsers();

        assert(tokenBalance == dripsBalancesTotal);
    }

    /**
     * @notice Check internal and external balances after withdrawing all funds
     * from the system
     */
    function invariantWithdrawAllTokens() external heavy {
        // remove all splits to prevent tokens from getting stuck in case
        // there are splits to self
        removeAllSplits(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER0]);
        removeAllSplits(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER1]);
        removeAllSplits(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER2]);
        removeAllSplits(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER3]);

        squeezeAllSenders(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER0]);
        squeezeAllSenders(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER1]);
        squeezeAllSenders(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER2]);
        squeezeAllSenders(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER3]);

        receiveStreamsSplitAndCollectToSelf(
            ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER0]
        );
        receiveStreamsSplitAndCollectToSelf(
            ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER1]
        );
        receiveStreamsSplitAndCollectToSelf(
            ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER2]
        );
        receiveStreamsSplitAndCollectToSelf(
            ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER3]
        );

        setStreamBalanceWithdrawAll(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER0]);
        setStreamBalanceWithdrawAll(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER1]);
        setStreamBalanceWithdrawAll(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER2]);
        setStreamBalanceWithdrawAll(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER3]);

        uint256 dripsBalance = token.balanceOf(address(drips));
        uint256 user0Balance = token.balanceOf(ADDRESS_USER0);
        uint256 user1Balance = token.balanceOf(ADDRESS_USER1);
        uint256 user2Balance = token.balanceOf(ADDRESS_USER2);
        uint256 user3Balance = token.balanceOf(ADDRESS_USER3);

        uint256 totalUserBalance = user0Balance +
            user1Balance +
            user2Balance +
            user3Balance;

        assert(dripsBalance == 0);
        assert(totalUserBalance == STARTING_BALANCE * 4);
    }

    /**
     * @notice Withdrawing all funds from the system should never revert
     */
    function invariantWithdrawAllTokensShouldNotRevert() public heavy {
        try
            EchidnaInvariantTests(address(this)).invariantWithdrawAllTokens()
        {} catch {
            assert(false);
        }
    }

    /**
     * @notice The sum of all `amtDelta`s for an account should be zero
     * @param targetAccId Target account to perform the test on
     */
    function invariantSumAmtDeltaIsZero(uint8 targetAccId) public heavy {
        address target = getAccount(targetAccId);
        uint256 targetDripsAccId = getDripsAccountId(target);

        uint32 maxEnd = getMaxEndForAllUsers();

        uint32 firstCycle = getCycleFromTimestamp(STARTING_TIMESTAMP);
        uint32 lastCycle = getCycleFromTimestamp(maxEnd);

        require(maxEnd > 0, "no cycles");
        require(firstCycle != lastCycle, "only one cycle");

        // limit amount of cycles for gas & memory savings
        require(lastCycle - firstCycle < 1000, "too many cycles");

        int256 sumAmtDelta = 0;

        for (uint32 cycle = firstCycle; cycle <= lastCycle; cycle++) {
            (int128 thisCycle, int128 nextCycle) = drips.getAmtDeltaForCycle(
                targetDripsAccId,
                token,
                cycle
            );

            sumAmtDelta += int256(thisCycle);
            sumAmtDelta += int256(nextCycle);
        }

        assert(sumAmtDelta == 0);
    }
}

98% src/echidna/EchidnaSplitsHelpers.sol

Lines covered: 54 / 55 (98%)

// SPDX-License-Identifier: MIT

import "./base/EchidnaBase.sol";

/**
 * @title Mixin containing helpers for splitting
 * @author Rappie <rappie@perimetersec.io>
 */
contract EchidnaSplitsHelpers is EchidnaBase {
    /**
     * @notice Internal helper function to set splits receivers
     * @param senderAccId Account id of the sender
     * @param unsortedReceivers Receivers list to set
     * @dev This function also sorts the receivers list
     */
    function _setSplits(
        uint8 senderAccId,
        SplitsReceiver[] memory unsortedReceivers
    ) internal {
        address sender = getAccount(senderAccId);

        SplitsReceiver[] memory newReceivers = bubbleSortSplitsReceivers(
            unsortedReceivers
        );

        updateSplitsReceivers(sender, newReceivers);

        hevm.prank(sender);
        driver.setSplits(newReceivers);
    }

    /**
     * @notice Set splits, overwriting the current receivers list
     * @param senderAccId Account id of the sender
     * @param receiverAccId Account id of the receiver in the receivers list
     * @param weight Weight of the receiver
     */
    function setSplits(
        uint8 senderAccId,
        uint8 receiverAccId,
        uint32 weight
    ) public {
        address sender = getAccount(senderAccId);
        address receiver = getAccount(receiverAccId);
        uint256 receiverDripsAccId = getDripsAccountId(receiver);

        SplitsReceiver[] memory receivers = new SplitsReceiver[](1);
        receivers[0] = SplitsReceiver({
            accountId: receiverDripsAccId,
            weight: weight
        });
        updateSplitsReceivers(sender, receivers);

        _setSplits(senderAccId, receivers);
    }

    /**
     * @notice Set splits, overwriting the current receivers list
     * @param senderAccId Account id of the sender
     * @param receiverAccId Account id of the receiver in the receivers list
     * @param weight Weight of the receiver
     * @dev This function clamps the weight between the minimum and maximum
     * allowed values
     */
    function setSplitsWithClamping(
        uint8 senderAccId,
        uint8 receiverAccId,
        uint32 weight
    ) public {
        weight = clampSplitWeight(weight, 0); // there are no existing weights
        setSplits(senderAccId, receiverAccId, weight);
    }

    /**
     * @notice Add a splits receiver to the existing list of receivers
     * @param senderAccId Account id of the sender
     * @param receiverAccId Account id of the receiver to add
     * @param weight Weight of the receiver
     */
    function addSplitsReceiver(
        uint8 senderAccId,
        uint8 receiverAccId,
        uint32 weight
    ) public {
        address sender = getAccount(senderAccId);
        address receiver = getAccount(receiverAccId);
        uint256 senderDripsAccId = getDripsAccountId(sender);
        uint256 receiverDripsAccId = getDripsAccountId(receiver);

        SplitsReceiver[] memory oldReceivers = getSplitsReceivers(sender);

        SplitsReceiver memory addedReceiver = SplitsReceiver({
            accountId: receiverDripsAccId,
            weight: weight
        });

        SplitsReceiver[] memory newReceivers = new SplitsReceiver[](
            oldReceivers.length + 1
        );
        for (uint256 i = 0; i < oldReceivers.length; i++) {
            newReceivers[i] = oldReceivers[i];
        }
        newReceivers[newReceivers.length - 1] = addedReceiver;

        _setSplits(senderAccId, newReceivers);
    }

    /**
     * @notice Add a splits receiver to the existing list of receivers
     * @param senderAccId Account id of the sender
     * @param receiverAccId Account id of the receiver to add
     * @param weight Weight of the receiver
     * @dev This function clamps the weight between the minimum and maximum
     * allowed values
     */
    function addSplitsReceiverWithClamping(
        uint8 senderAccId,
        uint8 receiverAccId,
        uint32 weight
    ) public {
        address sender = getAccount(senderAccId);

        // sum all the existing weights
        uint32 existingWeights;
        SplitsReceiver[] memory receivers = getSplitsReceivers(sender);
        for (uint256 i = 0; i < receivers.length; i++) {
            existingWeights += receivers[i].weight;
        }

        // we can't add a receiver if it makes the total weight go over the
        // maximum allowed
        if (existingWeights >= drips.TOTAL_SPLITS_WEIGHT()) return;

        weight = clampSplitWeight(weight, existingWeights);

        addSplitsReceiver(senderAccId, receiverAccId, weight);
    }

    /**
     * @notice Remove any existing splits
     * @param targetAccId Target account id
     */
    function removeAllSplits(uint8 targetAccId) public {
        SplitsReceiver[] memory receivers = new SplitsReceiver[](0);
        _setSplits(targetAccId, receivers);
    }

    /**
     * @notice Clamp the weight between the minimum and maximum allowed values
     * @param weight Weight to clamp
     * @param existingWeights Sum of all the existing weights
     * @return Clamped weight
     */
    function clampSplitWeight(uint32 weight, uint32 existingWeights)
        public
        view
        returns (uint32)
    {
        return (weight % (drips.TOTAL_SPLITS_WEIGHT() - existingWeights)) + 1;
    }
}

96% src/echidna/EchidnaSplitsTests.sol

Lines covered: 99 / 103 (96%)

// SPDX-License-Identifier: MIT

import "./base/EchidnaBase.sol";
import "./EchidnaBasicHelpers.sol";
import "./EchidnaSplitsHelpers.sol";

/**
 * @title Mixin containing tests for splitting
 * @author Rappie <rappie@perimetersec.io>
 */
contract EchidnaSplitsTests is
    EchidnaBase,
    EchidnaBasicHelpers,
    EchidnaSplitsHelpers
{
    /**
     * @notice Test internal accounting for splittable amount after splitting
     * @param targetAccId Account id execute split on
     */
    function testSplittableAfterSplit(uint8 targetAccId) public {
        address target = getAccount(targetAccId);
        uint256 targetDripsAccId = getDripsAccountId(target);

        uint128 splittableBefore = drips.splittable(targetDripsAccId, token);

        // check if we are splitting to ourselves
        uint32 splitToSelfWeight;
        SplitsReceiver[] memory receivers = getSplitsReceivers(target);
        for (uint256 i = 0; i < receivers.length; i++) {
            if (receivers[i].accountId == targetDripsAccId) {
                splitToSelfWeight += receivers[i].weight;
            }
        }

        // calculate amount to split to self
        uint128 splitToSelfAmount = uint128(
            (splittableBefore * splitToSelfWeight) / drips.TOTAL_SPLITS_WEIGHT()
        );

        (uint128 collectableAmt, uint128 splitAmt) = split(targetAccId);

        uint128 splittableAfter = drips.splittable(targetDripsAccId, token);

        // sanity check
        assert((splitAmt + collectableAmt) <= splittableBefore);

        if (splitToSelfWeight == 0) {
            // if we're not splitting to ourselves, things are simple
            assert(
                splittableAfter == splittableBefore - splitAmt - collectableAmt
            );
        } else {
            // if we ARE splitting to ourselves, there are rounding errors
            // to take into account.

            // calculate expected amount after the split
            uint128 expectedSplittableAfter = splittableBefore -
                splitAmt -
                collectableAmt +
                splitToSelfAmount;

            // calculate difference between expected and actual
            int256 difference = int256(uint256(splittableAfter)) -
                int256(uint256(expectedSplittableAfter));

            // check if difference is within tolerance
            assert(
                difference >= -int256(SPLIT_ROUNDING_TOLERANCE) &&
                    difference <= int256(SPLIT_ROUNDING_TOLERANCE)
            );
        }
    }

    /**
     * @notice Test internal accounting for collectable amount after splitting
     * @param targetAccId Account id execute split on
     */
    function testCollectableAfterSplit(uint8 targetAccId) public {
        address target = getAccount(targetAccId);
        uint256 targetDripsAccId = getDripsAccountId(target);

        uint128 colBalBefore = drips.collectable(targetDripsAccId, token);
        (uint128 collectableAmt, ) = split(targetAccId);
        uint128 colBalAfter = drips.collectable(targetDripsAccId, token);

        assert(colBalAfter == colBalBefore + collectableAmt);
    }

    /**
     * @notice After splitting, all receivers should have their splittable
     * amount increased by the amount they were supposed to receive
     * @param targetAccId Account id execute split on
     */
    function testReceiversReceivedSplit(uint8 targetAccId) public {
        address target = getAccount(targetAccId);
        uint256 targetDripsAccId = getDripsAccountId(target);

        uint128 amountToBeSplit = drips.splittable(targetDripsAccId, token);
        SplitsReceiver[] memory receivers = getSplitsReceivers(target);

        // storage for all receivers
        uint128[] memory splittableBefore = new uint128[](receivers.length);
        uint128[] memory splittableAfter = new uint128[](receivers.length);
        uint32[] memory weights = new uint32[](receivers.length);
        uint128[] memory amounts = new uint128[](receivers.length);

        for (uint256 i = 0; i < receivers.length; i++) {
            // store splittable before
            splittableBefore[i] = drips.splittable(
                receivers[i].accountId,
                token
            );

            // calculate amount the receiver should get
            weights[i] = receivers[i].weight;
            amounts[i] = uint128(
                (amountToBeSplit * weights[i]) / drips.TOTAL_SPLITS_WEIGHT()
            );
        }

        // split
        (uint128 collectableAmt, uint128 splitAmt) = split(targetAccId);

        // store splittable after
        for (uint256 i = 0; i < receivers.length; i++) {
            splittableAfter[i] = drips.splittable(
                receivers[i].accountId,
                token
            );
        }

        for (uint256 i = 0; i < receivers.length; i++) {
            // calculate expected amount after the split
            uint128 expectedAfter;
            if (receivers[i].accountId != targetDripsAccId) {
                // splitting so someone else is trivial
                expectedAfter = splittableBefore[i] + amounts[i];
            } else {
                // splitting to self needs to take into account that the splittable
                // amount before contains the actual amount that was split to all
                // the receivers. we should end up with only the amount that was
                // split to ourselves
                expectedAfter =
                    splittableBefore[i] -
                    amountToBeSplit +
                    amounts[i];
            }

            // calculate difference between expected and actual
            int256 difference = int256(uint256(splittableAfter[i])) -
                int256(uint256(expectedAfter));

            // check if difference is within tolerance
            assert(
                difference >= -int256(SPLIT_ROUNDING_TOLERANCE) &&
                    difference <= int256(SPLIT_ROUNDING_TOLERANCE)
            );
        }
    }

    /**
     * @notice `drips.splitResult` should match actual split amount
     * @param targetAccId Account id execute split on
     */
    function testSplitViewVsActual(uint8 targetAccId) public {
        address target = getAccount(targetAccId);
        uint256 targetDripsAccId = getDripsAccountId(target);

        uint128 splittable = drips.splittable(targetDripsAccId, token);

        (uint128 collectableAmtView, uint128 splitAmtView) = drips.splitResult(
            targetDripsAccId,
            getSplitsReceivers(target),
            splittable
        );

        (uint128 collectableAmtActual, uint128 splitAmtActual) = split(
            targetAccId
        );

        assert(collectableAmtView == collectableAmtActual);
        assert(splitAmtView == splitAmtActual);
    }

    /**
     * @notice Splitting should never revert
     * @param targetAccId Account id execute split on
     */
    function testSplitShouldNotRevert(uint8 targetAccId) public {
        address target = getAccount(targetAccId);
        uint256 targetDripsAccId = getDripsAccountId(target);

        try EchidnaBasicHelpers(address(this)).split(targetAccId) {} catch {
            assert(false);
        }
    }

    /**
     * @notice Setting splits with sane defaults should not revert
     * @param senderAccId Account id of the sender
     * @param receiverAccId Account id of the receiver in the receivers list
     * @param weight Weight of the receiver
     */
    function testSetSplitsShouldNotRevert(
        uint8 senderAccId,
        uint8 receiverAccId,
        uint32 weight
    ) public {
        try
            EchidnaSplitsHelpers(address(this)).setSplitsWithClamping(
                senderAccId,
                receiverAccId,
                weight
            )
        {} catch {
            assert(false);
        }
    }

    /**
     * @notice Adding splits with sane defaults should not revert
     * @param senderAccId Account id of the sender
     * @param receiverAccId Account id of the receiver in the receivers list
     * @param weight Weight of the receiver
     */
    function testAddSplitsShouldNotRevert(
        uint8 senderAccId,
        uint8 receiverAccId,
        uint32 weight
    ) public {
        try
            EchidnaSplitsHelpers(address(this)).addSplitsReceiverWithClamping(
                senderAccId,
                receiverAccId,
                weight
            )
        {} catch (bytes memory reason) {
            bytes4 errorSelector = bytes4(reason);
            if (errorSelector == EchidnaStorage.DuplicateError.selector) {
                // ignore this case, it means we tried to add a duplicate stream
            } else {
                assert(false);
            }
        }
    }
}

98% src/echidna/EchidnaSqueezeHelpers.sol

Lines covered: 75 / 76 (98%)

// SPDX-License-Identifier: MIT

import "./base/EchidnaBase.sol";
import "./EchidnaBasicHelpers.sol";

/**
 * @title Mixin containing helpers for squeezing
 * @author Rappie <rappie@perimetersec.io>
 */
contract EchidnaSqueezeHelpers is EchidnaBase, EchidnaBasicHelpers {
    /**
     * @notice Internal helper function to squeeze streams
     * @param receiverAccId Account id of the receiver
     * @param senderAccId Account id of the sender
     * @param historyHash Hash of the streams history
     * @param history Streams history array
     * @return Amount squeezed
     */
    function _squeeze(
        uint8 receiverAccId,
        uint8 senderAccId,
        bytes32 historyHash,
        StreamsHistory[] memory history
    ) internal returns (uint128) {
        address receiver = getAccount(receiverAccId);
        address sender = getAccount(senderAccId);
        uint256 receiverDripsAccId = getDripsAccountId(receiver);
        uint256 senderDripsAccId = getDripsAccountId(sender);

        uint128 amount = drips.squeezeStreams(
            receiverDripsAccId,
            token,
            senderDripsAccId,
            historyHash,
            history
        );

        return amount;
    }

    /**
     * @notice Squeeze streams with default history (all StreamHistory entries)
     * @param receiverAccId Account id of the receiver
     * @param senderAccId Account id of the sender
     * @return Amount squeezed
     */
    function squeezeWithDefaultHistory(uint8 receiverAccId, uint8 senderAccId)
        public
        returns (uint128)
    {
        return
            _squeeze(
                receiverAccId,
                senderAccId,
                bytes32(0),
                getStreamsHistory(getAccount(senderAccId))
            );
    }

    /**
     * @notice Squeeze streams with a fuzzed history
     * @param receiverAccId Account id of the receiver
     * @param senderAccId Account id of the sender
     * @param hashIndex Index of the history hash to use
     * @param receiversRandomSeed Random seed used for fuzzing the history
     * @return Amount squeezed
     * @dev This function will use the seed to make random changes to the history.
     * These include changing the starting point of the history, and hashing
     * certain history entries to leave them out of the squeeze.
     */
    function squeezeWithFuzzedHistory(
        uint8 receiverAccId,
        uint8 senderAccId,
        uint256 hashIndex,
        bytes32 receiversRandomSeed
    ) public returns (uint128) {
        address receiver = getAccount(receiverAccId);
        address sender = getAccount(senderAccId);
        uint256 receiverDripsAccId = getDripsAccountId(receiver);
        uint256 senderDripsAccId = getDripsAccountId(sender);

        (
            bytes32 historyHash,
            StreamsHistory[] memory history
        ) = getFuzzedStreamsHistory(
                senderAccId,
                hashIndex,
                receiversRandomSeed
            );

        return _squeeze(receiverAccId, senderAccId, historyHash, history);
    }

    /**
     * @notice Squeeze streams sent to self
     * @param targetAccId Account id of the sender
     */
    function squeezeToSelf(uint8 targetAccId) public {
        squeezeWithDefaultHistory(targetAccId, targetAccId);
    }

    /**
     * @notice Squeeze streams from all possible senders to target
     * @param targetAccId Account id of the receiver
     * @dev This can be used to test extracting all value from the system
     */
    function squeezeAllSenders(uint8 targetAccId) public {
        squeezeWithDefaultHistory(
            targetAccId,
            ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER0]
        );
        squeezeWithDefaultHistory(
            targetAccId,
            ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER1]
        );
        squeezeWithDefaultHistory(
            targetAccId,
            ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER2]
        );
        squeezeWithDefaultHistory(
            targetAccId,
            ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER3]
        );
    }

    /**
     * @notice Squeeze all senders, receive streams, split and collect funds to self
     * @param targetAccId Target account
     * @dev Extra helper that narrows the search space for the fuzzer
     */
    function squeezeAllAndReceiveAndSplitAndCollectToSelf(uint8 targetAccId)
        public
    {
        squeezeAllSenders(targetAccId);
        receiveStreamsSplitAndCollectToSelf(targetAccId);
    }

    /**
     * @notice Helper to create a fuzzed version of a sender's streams history
     * @param targetAccId Account id of the sender
     * @param hashIndex Index of the history entry to be used as the starting point
     * @param receiversRandomSeed Random seed used to determine which history entries
     * to leave out of the squeeze (by hashing them)
     * @return Hash of the history, and the fuzzed streams history array
     */
    function getFuzzedStreamsHistory(
        uint8 targetAccId,
        uint256 hashIndex,
        bytes32 receiversRandomSeed
    ) internal returns (bytes32, StreamsHistory[] memory) {
        address target = getAccount(targetAccId);

        // get the history structs and hashes
        StreamsHistory[] memory historyStructs = getStreamsHistory(target);
        bytes32[] memory historyHashes = getStreamsHistoryHashes(target);

        // having a hashed history requires at least 2 history entries
        require(historyStructs.length >= 2, "need at least 2 history entries");

        // hashIndex must be within bounds and cant be the last entry
        hashIndex = hashIndex % (historyHashes.length - 1);

        // get the history hash at the index
        bytes32 historyHash = historyHashes[hashIndex];

        // create a history array with all entries after the hashIndex
        StreamsHistory[] memory history = new StreamsHistory[](
            historyStructs.length - 1 - hashIndex
        );
        for (uint256 i = hashIndex + 1; i < historyStructs.length; i++) {
            history[i - hashIndex - 1] = historyStructs[i];
        }

        // hash receivers based on 'receiversRandomSeed'
        for (uint256 i = 0; i < history.length; i++) {
            receiversRandomSeed = keccak256(bytes.concat(receiversRandomSeed));
            bool hashBool = (uint256(receiversRandomSeed) % 2) == 0
                ? false
                : true;

            if (hashBool) {
                history[i].streamsHash = drips.hashStreams(
                    history[i].receivers
                );
                history[i].receivers = new StreamReceiver[](0);
            }
        }

        return (historyHash, history);
    }
}

97% src/echidna/EchidnaSqueezeTests.sol

Lines covered: 110 / 113 (97%)

// SPDX-License-Identifier: MIT

import "./EchidnaBasicHelpers.sol";
import "./EchidnaSplitsHelpers.sol";
import "./EchidnaStreamsHelpers.sol";
import "./EchidnaSqueezeHelpers.sol";

/**
 * @title Mixin containing tests for squeezing
 * @author Rappie <rappie@perimetersec.io>
 */
contract EchidnaSqueezeTests is
    EchidnaBasicHelpers,
    EchidnaSplitsHelpers,
    EchidnaStreamsHelpers,
    EchidnaSqueezeHelpers
{
    /**
     * @notice Test internal accounting after squeezing
     * @param receiverAccId Account id of the receiver
     * @param senderAccId Account id of the sender
     */
    function testSqueeze(uint8 receiverAccId, uint8 senderAccId) public {
        address receiver = getAccount(receiverAccId);
        address sender = getAccount(senderAccId);

        uint256 receiverDripsAccId = getDripsAccountId(receiver);

        uint128 squeezableBefore = getSqueezableAmount(sender, receiver);
        uint128 splittableBefore = drips.splittable(receiverDripsAccId, token);

        uint128 squeezedAmt = squeezeWithDefaultHistory(
            receiverAccId,
            senderAccId
        );

        uint128 squeezableAfter = getSqueezableAmount(sender, receiver);
        uint128 splittableAfter = drips.splittable(receiverDripsAccId, token);

        assert(squeezableAfter == squeezableBefore - squeezedAmt);
        assert(splittableAfter == splittableBefore + squeezedAmt);

        if (squeezedAmt > 0) {
            assert(squeezableAfter < squeezableBefore);
            assert(splittableAfter > splittableBefore);
        } else {
            assert(squeezableAfter == squeezableBefore);
            assert(splittableAfter == splittableBefore);
        }
    }

    /**
     * @notice `drips.squeezeStreamsResult` should match actual squeezed amount
     * @param receiverAccId Account id of the receiver
     * @param senderAccId Account id of the sender
     */
    function testSqueezeViewVsActual(uint8 receiverAccId, uint8 senderAccId)
        public
    {
        address receiver = getAccount(receiverAccId);
        address sender = getAccount(senderAccId);

        uint128 squeezable = getSqueezableAmount(sender, receiver);
        uint128 squeezed = squeezeWithDefaultHistory(
            receiverAccId,
            senderAccId
        );

        assert(squeezable == squeezed);
    }

    /**
     * @notice Squeezable amount should be equal to receivable amount in the future
     * @param targetAccId Account id of the receiver
     */
    function testSqueezableVsReceived(uint8 targetAccId) public heavy {
        address target = getAccount(targetAccId);

        // store the current squeezable and receivable amount
        uint128 squeezable = getTotalSqueezableAmountForUser(target);
        uint128 receivableBefore = getReceivableAmountForUser(target);

        // remove all streaming balance from the system, so that warping to
        // the future will not increase the receivable/squeezable amount
        setStreamBalanceWithdrawAll(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER0]);
        setStreamBalanceWithdrawAll(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER1]);
        setStreamBalanceWithdrawAll(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER2]);
        setStreamBalanceWithdrawAll(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER3]);

        // warp to the point in time where the streams are receivable
        hevm.warp(getCurrentCycleEnd() + 1);

        uint128 receivableAfter = getReceivableAmountForUser(target);

        // sanity check
        assert(receivableAfter >= receivableBefore);

        uint128 receiveableDelta = receivableAfter - receivableBefore;

        // squeezable before should match receivable now
        assert(squeezable == receiveableDelta);
    }

    /**
     * @notice Squeezing with a fully hashed history should do nothing
     * @param receiverAccId Account id of the receiver
     * @param senderAccId Account id of the sender
     */
    function testSqueezeWithFullyHashedHistory(
        uint8 receiverAccId,
        uint8 senderAccId
    ) public {
        address receiver = getAccount(receiverAccId);
        address sender = getAccount(senderAccId);

        uint128 squeezableBefore = getSqueezableAmount(sender, receiver);

        StreamsHistory[] memory history = getStreamsHistory(sender);
        for (uint256 i = 0; i < history.length; i++) {
            history[i].streamsHash = drips.hashStreams(history[i].receivers);
            history[i].receivers = new StreamReceiver[](0);
        }

        uint128 squeezedAmt = _squeeze(
            receiverAccId,
            senderAccId,
            bytes32(0),
            history
        );

        uint128 squeezableAfter = getSqueezableAmount(sender, receiver);

        assert(squeezedAmt == 0);
        assert(squeezableAfter == squeezableBefore);
    }

    /**
     * @notice Squeezing the same part(s) of history should only work the first time
     * @param receiverAccId Account id of the receiver
     * @param senderAccId Account id of the sender
     * @param hashIndex Index of the history entry to squeeze
     * @param receiversRandomSeed Random seed used to determine which history entries
     * to leave out of the squeeze (by hashing them)
     */
    function testSqueezeTwice(
        uint8 receiverAccId,
        uint8 senderAccId,
        uint256 hashIndex,
        bytes32 receiversRandomSeed
    ) external {
        address receiver = getAccount(receiverAccId);
        address sender = getAccount(senderAccId);

        uint128 amount0 = squeezeWithFuzzedHistory(
            receiverAccId,
            senderAccId,
            hashIndex,
            receiversRandomSeed
        );

        uint128 amount1 = squeezeWithFuzzedHistory(
            receiverAccId,
            senderAccId,
            hashIndex,
            receiversRandomSeed
        );

        assert(amount1 == 0);
    }

    /**
     * @notice Already streamed (and therefore squeezable) balance should not be
     * affected changing the stream receivers
     * @param receiverAccId Account id of the receiver
     * @param senderAccId Account id of the sender
     * @param amountPerSec Amount per second to stream
     * @param startTime Start time for the stream
     * @param duration Duration for the stream
     * @param balanceDelta Amount to update stream balance with
     */
    function testSqueezableAmountCantBeUndone(
        uint8 receiverAccId,
        uint8 senderAccId,
        uint160 amountPerSec,
        uint32 startTime,
        uint32 duration,
        int128 balanceDelta
    ) external {
        address receiver = getAccount(receiverAccId);
        address sender = getAccount(senderAccId);

        uint128 squeezableBefore = getSqueezableAmount(sender, receiver);

        setStreams(
            receiverAccId,
            senderAccId,
            amountPerSec,
            startTime,
            duration,
            balanceDelta
        );

        uint128 squeezableAfter = getSqueezableAmount(sender, receiver);

        assert(squeezableAfter == squeezableBefore);
    }

    /**
     * @notice Already streamed (and therefore squeezable) balance should not be
     * affected by withdrawing all streaming balance
     * @param receiverAccId Account id of the receiver
     * @param senderAccId Account id of the sender
     */
    function testSqueezableAmountCantBeWithdrawn(
        uint8 receiverAccId,
        uint8 senderAccId
    ) external {
        address receiver = getAccount(receiverAccId);
        address sender = getAccount(senderAccId);

        uint128 squeezableBefore = getSqueezableAmount(sender, receiver);

        setStreamBalanceWithdrawAll(senderAccId);

        uint128 squeezableAfter = getSqueezableAmount(sender, receiver);

        assert(squeezableAfter == squeezableBefore);
    }

    /**
     * @notice Squeezing with default history (all history entries) should
     * not revert
     * @param receiverAccId Account id of the receiver
     * @param senderAccId Account id of the sender
     */
    function testSqueezeWithDefaultHistoryShouldNotRevert(
        uint8 receiverAccId,
        uint8 senderAccId
    ) public {
        try
            EchidnaSqueezeHelpers(address(this)).squeezeWithDefaultHistory(
                receiverAccId,
                senderAccId
            )
        {} catch {
            assert(false);
        }
    }

    /**
     * @notice Squeezing with fuzzed history should not revert
     * @param receiverAccId Account id of the receiver
     * @param senderAccId Account id of the sender
     * @param hashIndex Index of the history entry to squeeze
     * @param receiversRandomSeed Random seed used to determine which history entries
     * to leave out of the squeeze (by hashing them)
     */
    function testSqueezeWithFuzzedHistoryShouldNotRevert(
        uint8 receiverAccId,
        uint8 senderAccId,
        uint256 hashIndex,
        bytes32 receiversRandomSeed
    ) public {
        address sender = getAccount(senderAccId);
        require(
            getStreamsHistory(sender).length >= 2,
            "need at least 2 history entries"
        );

        try
            EchidnaSqueezeHelpers(address(this)).squeezeWithFuzzedHistory(
                receiverAccId,
                senderAccId,
                hashIndex,
                receiversRandomSeed
            )
        {} catch {
            assert(false);
        }
    }

}

98% src/echidna/EchidnaStreamsHelpers.sol

Lines covered: 163 / 165 (98%)

// SPDX-License-Identifier: MIT

import "./base/EchidnaBase.sol";

/**
 * @title Mixin containing helpers for streams
 * @author Rappie <rappie@perimetersec.io>
 */
contract EchidnaStreamsHelpers is EchidnaBase {
    // Internal variables to store maxEndHint1 and maxEndHint2. These are used
    // as hints to the Drips contract to speed up the setStreams call.
    //
    // Instead of fuzzing these directly, we use the `setMaxEndHints` helper
    // function to set these values. This makes fuzzing these toggleable and
    // also makes debugging easier because the values don't have to be passed
    // as arguments to all functions calling `setStreams`.
    //
    uint32 internal maxEndHint1;
    uint32 internal maxEndHint2;

    /**
     * @notice Internal helper function to set streams receivers
     * @param from Account to set streams for
     * @param currReceivers Current stream receivers (Drips needs this)
     * @param balanceDelta Balance delta to set
     * @param unsortedNewReceivers New receivers list to set
     * @return Real balance delta
     * @dev This function also sorts the receivers list
     */
    function _setStreams(
        address from,
        StreamReceiver[] memory currReceivers,
        int128 balanceDelta,
        StreamReceiver[] memory unsortedNewReceivers
    ) internal returns (int128) {
        StreamReceiver[] memory newReceivers = bubbleSortStreamReceivers(
            unsortedNewReceivers
        );

        hevm.prank(from);
        int128 realBalanceDelta = driver.setStreams(
            token,
            currReceivers,
            balanceDelta,
            newReceivers,
            maxEndHint1,
            maxEndHint2,
            from
        );

        updateStreamReceivers(from, newReceivers);

        return realBalanceDelta;
    }

    /**
     * @notice Set streams, overwriting the current receivers list
     * @param fromAccId Account id of the sender
     * @param toAccId Account id of the receiver in the receivers list
     * @param amountPerSec Amount per second to stream
     * @param startTime Start time of the stream
     * @param duration Duration of the stream
     * @param balanceDelta Balance delta to set
     * @return Real balance delta
     */
    function setStreams(
        uint8 fromAccId,
        uint8 toAccId,
        uint160 amountPerSec,
        uint32 startTime,
        uint32 duration,
        int128 balanceDelta
    ) public returns (int128) {
        address from = getAccount(fromAccId);
        address to = getAccount(toAccId);

        StreamReceiver[] memory receivers = new StreamReceiver[](1);
        receivers[0] = StreamReceiver(
            getDripsAccountId(to),
            StreamConfigImpl.create(
                0, // streamId is arbitrary and can be ignored
                amountPerSec,
                startTime,
                duration
            )
        );

        int128 realBalanceDelta = _setStreams(
            from,
            getStreamReceivers(from),
            balanceDelta,
            receivers
        );

        return realBalanceDelta;
    }

    /**
     * @notice Set streams, overwriting the current receivers list
     * @param fromAccId Account id of the sender
     * @param toAccId Account id of the receiver in the receivers list
     * @param amountPerSec Amount per second to stream
     * @param startTime Start time of the stream
     * @param duration Duration of the stream
     * @param balanceDelta Balance delta to set
     * @return Real balance delta
     * @dev This function clamps the amountPerSec, startTime, duration and
     * balanceDelta between the minimum and maximum allowed values
     */
    function setStreamsWithClamping(
        uint8 fromAccId,
        uint8 toAccId,
        uint160 amountPerSec,
        uint32 startTime,
        uint32 duration,
        int128 balanceDelta
    ) public returns (int128) {
        address from = getAccount(fromAccId);
        address to = getAccount(toAccId);

        amountPerSec = clampAmountPerSec(amountPerSec);
        startTime = clampStartTime(startTime);
        duration = clampDuration(duration);
        balanceDelta = clampBalanceDelta(balanceDelta, from);

        setStreams(
            fromAccId,
            toAccId,
            amountPerSec,
            startTime,
            duration,
            balanceDelta
        );
    }

    /**
     * @notice Add a stream receiver to the existing list of receivers
     * @param fromAccId Account id of the sender
     * @param toAccId Account id of the receiver to add
     * @param amountPerSec Amount per second to stream
     * @param startTime Start time of the stream
     * @param duration Duration of the stream
     * @param balanceDelta Balance delta to set
     * @return Real balance delta
     */
    function addStream(
        uint8 fromAccId,
        uint8 toAccId,
        uint160 amountPerSec,
        uint32 startTime,
        uint32 duration,
        int128 balanceDelta
    ) public returns (int128) {
        address from = getAccount(fromAccId);
        address to = getAccount(toAccId);

        StreamReceiver[] memory oldReceivers = getStreamReceivers(from);

        StreamReceiver memory addedReceiver = StreamReceiver(
            getDripsAccountId(to),
            StreamConfigImpl.create(
                0, // streamId is arbitrary and can be ignored
                amountPerSec,
                startTime,
                duration
            )
        );

        StreamReceiver[] memory newReceivers = new StreamReceiver[](
            oldReceivers.length + 1
        );
        for (uint256 i = 0; i < oldReceivers.length; i++) {
            newReceivers[i] = oldReceivers[i];
        }
        newReceivers[newReceivers.length - 1] = addedReceiver;

        int128 realBalanceDelta = _setStreams(
            from,
            oldReceivers,
            balanceDelta,
            newReceivers
        );

        return realBalanceDelta;
    }

    /**
     * @notice Add a stream receiver to the existing list of receivers
     * @param fromAccId Account id of the sender
     * @param toAccId Account id of the receiver to add
     * @param amountPerSec Amount per second to stream
     * @param startTime Start time of the stream
     * @param duration Duration of the stream
     * @param balanceDelta Balance delta to set
     * @dev This function clamps the amountPerSec, startTime, duration and
     * balanceDelta between the minimum and maximum allowed values
     */
    function addStreamWithClamping(
        uint8 fromAccId,
        uint8 toAccId,
        uint160 amountPerSec,
        uint32 startTime,
        uint32 duration,
        int128 balanceDelta
    ) public returns (int128) {
        address from = getAccount(fromAccId);

        amountPerSec = clampAmountPerSec(amountPerSec);
        startTime = clampStartTime(startTime);
        duration = clampDuration(duration);
        balanceDelta = clampBalanceDelta(balanceDelta, from);

        return
            addStream(
                fromAccId,
                toAccId,
                amountPerSec,
                startTime,
                duration,
                balanceDelta
            );
    }

    /**
     * @notice Add a stream receiver to the existing list of receivers, making sure
     * it is immediately squeezable in a transaction after this call
     * @param fromAccId Account id of the sender
     * @param toAccId Account id of the receiver to add
     * @param amountPerSec Amount per second to stream
     * @dev This is meant as a helper to quickly seed the corpus with situations
     * where there is something to squeeze in the next transaction
     */
    function addStreamImmediatelySqueezable(
        uint8 fromAccId,
        uint8 toAccId,
        uint160 amountPerSec
    ) public {
        address receiver = getAccount(toAccId);
        address sender = getAccount(fromAccId);

        // calculate amount per second so there will be something to squeeze
        // this cycle
        uint160 minAmtPerSec = drips.minAmtPerSec() * SECONDS_PER_CYCLE;
        amountPerSec =
            minAmtPerSec +
            (amountPerSec % (MAX_AMOUNT_PER_SEC - minAmtPerSec + 1));

        // deposit 100 times the amount of 'amountPerSec' so chances are high
        // that there is enough balance to stream this cycle
        int128 balanceDelta = (int128(uint128(amountPerSec)) * 100) / 1e9;
        if (uint128(balanceDelta) > token.balanceOf(sender)) {
            balanceDelta = int128(uint128(token.balanceOf(sender)));
        }

        // add the stream
        addStream(fromAccId, toAccId, amountPerSec, 0, 0, balanceDelta);

        // warp 1 second forward so there is something to squeeze
        hevm.warp(block.timestamp + 1);
    }

    /**
     * @notice Remove a stream receiver from the existing list of receivers
     * @param targetAccId Account id of the receiver to remove
     * @param indexSeed Random seed used to determine which receiver to remove
     */
    function removeStream(uint8 targetAccId, uint256 indexSeed) public {
        address target = getAccount(targetAccId);

        StreamReceiver[] memory oldReceivers = getStreamReceivers(target);

        uint256 index = indexSeed % oldReceivers.length;

        StreamReceiver[] memory newReceivers = new StreamReceiver[](
            oldReceivers.length - 1
        );
        uint256 j = 0;
        for (uint256 i = 0; i < oldReceivers.length; i++) {
            if (i != index) {
                newReceivers[j] = oldReceivers[i];
                j++;
            }
        }

        _setStreams(target, oldReceivers, 0, newReceivers);
    }

    /**
     * @notice Update stream balance by calling `setStreams` with the same
     * receivers list
     * @param targetAccId Account id of the sender
     * @param balanceDelta Balance delta to set
     * @return Real balance delta
     */
    function setStreamBalance(uint8 targetAccId, int128 balanceDelta)
        public
        returns (int128)
    {
        address target = getAccount(targetAccId);

        int128 realBalanceDelta = _setStreams(
            target,
            getStreamReceivers(target),
            balanceDelta,
            getStreamReceivers(target)
        );

        return realBalanceDelta;
    }

    /**
     * @notice Update stream balance by calling `setStreams` with the same
     * receivers list
     * @param targetAccId Account id of the sender
     * @param balanceDelta Balance delta to set
     * @dev This function clamps the balanceDelta between the minimum and
     * maximum allowed values
     */
    function setStreamBalanceWithClamping(
        uint8 targetAccId,
        int128 balanceDelta
    ) public {
        address target = getAccount(targetAccId);
        balanceDelta = clampBalanceDelta(balanceDelta, target);
        setStreamBalance(targetAccId, balanceDelta);
    }

    /**
     * @notice Withdraw all stream balance by calling `setStreams` with the same
     * receivers list and using min int128 as balance delta
     * @param targetAccId Account id of the sender
     * @return Real balance delta
     */
    function setStreamBalanceWithdrawAll(uint8 targetAccId)
        public
        returns (int128)
    {
        address target = getAccount(targetAccId);
        uint256 targetDripsAccId = getDripsAccountId(target);

        int128 realBalanceDelta = _setStreams(
            target,
            getStreamReceivers(target),
            type(int128).min,
            getStreamReceivers(target)
        );
    }

    /**
     * @notice Helper function to update the values used as maxEnd hints
     * @param _maxEndHint1 New value for maxEndHint1
     * @param _maxEndHint2 New value for maxEndHint2
     * @dev Can be toggled on/off with TOGGLE_MAXENDHINTS_ENABLED
     */
    function setMaxEndHints(uint32 _maxEndHint1, uint32 _maxEndHint2) public {
        require(TOGGLE_MAXENDHINTS_ENABLED);
        maxEndHint1 = _maxEndHint1;
        maxEndHint2 = _maxEndHint2;
    }

    /**
     * @notice Clamp the amountPerSec between the minimum and maximum allowed values
     * @param amountPerSec Amount per second to clamp
     * @return Clamped amountPerSec
     */
    function clampAmountPerSec(uint160 amountPerSec)
        internal
        returns (uint160)
    {
        return
            drips.minAmtPerSec() +
            (amountPerSec % (MAX_AMOUNT_PER_SEC - drips.minAmtPerSec() + 1));
    }

    /**
     * @notice Clamp the startTime between the minimum and maximum allowed values
     * @param startTime Start time to clamp
     * @return Clamped startTime
     */
    function clampStartTime(uint32 startTime) internal returns (uint32) {
        if (startTime == 0) return 0;

        // We want to make sure that the start time does not go below 1
        uint32 minStartTime;
        if (CYCLE_FUZZING_BUFFER_SECONDS >= block.timestamp) {
            minStartTime = 1;
        } else {
            minStartTime =
                uint32(block.timestamp) -
                CYCLE_FUZZING_BUFFER_SECONDS;
        }

        uint32 maxStartTime = uint32(block.timestamp) +
            CYCLE_FUZZING_BUFFER_SECONDS;

        return minStartTime + (startTime % (maxStartTime - minStartTime + 1));
    }

    /**
     * @notice Clamp the duration between the minimum and maximum allowed values
     * @param duration Duration to clamp
     * @return Clamped duration
     */
    function clampDuration(uint32 duration) internal returns (uint32) {
        if (duration == 0) return 0;

        return duration % (MAX_STREAM_DURATION + 1);
    }

    /**
     * @notice Clamp the balanceDelta between the minimum and maximum allowed values
     * @param balanceDelta Balance delta to clamp
     * @param from Account performing the setStreams action
     * @return Clamped balanceDelta
     */
    function clampBalanceDelta(int128 balanceDelta, address from)
        internal
        returns (int128)
    {
        if (balanceDelta > 0) {
            balanceDelta =
                balanceDelta %
                (int128(uint128(token.balanceOf(from))) + 1);
        } else {
            balanceDelta = balanceDelta % int128(uint128(STARTING_BALANCE));
        }
        return balanceDelta;
    }
}

92% src/echidna/EchidnaStreamsTests.sol

Lines covered: 109 / 118 (92%)

// SPDX-License-Identifier: MIT

import "./base/EchidnaBase.sol";
import "./EchidnaStreamsHelpers.sol";

/**
 * @title Mixin containing tests for streams
 * @author Rappie <rappie@perimetersec.io>
 */
contract EchidnaStreamsTests is EchidnaBase, EchidnaStreamsHelpers {
    /**
     * @notice Test internal accounting after updating stream balance
     * @param targetAccId Account id of the sender
     * @param balanceDelta Amount to update stream balance with
     */
    function testSetStreamBalance(uint8 targetAccId, int128 balanceDelta)
        public
    {
        address target = getAccount(targetAccId);
        uint256 targetDripsAccId = getDripsAccountId(target);

        uint256 tokenBalanceBefore = token.balanceOf(target);
        uint128 streamBalanceBefore = drips.balanceAt(
            targetDripsAccId,
            token,
            getStreamReceivers(target),
            uint32(block.timestamp)
        );

        int128 realBalanceDelta = setStreamBalance(targetAccId, balanceDelta);

        uint256 tokenBalanceAfter = token.balanceOf(target);
        uint128 streamBalanceAfter = drips.balanceAt(
            targetDripsAccId,
            token,
            getStreamReceivers(target),
            uint32(block.timestamp)
        );

        if (balanceDelta >= 0) {
            assert(realBalanceDelta == balanceDelta);
        } else {
            assert(realBalanceDelta <= 0);
            assert(realBalanceDelta >= balanceDelta);
        }

        assert(
            int256(tokenBalanceAfter) ==
                int256(tokenBalanceBefore) - realBalanceDelta
        );
        assert(
            int128(streamBalanceAfter) ==
                int128(streamBalanceBefore) + realBalanceDelta
        );
    }

    /**
     * @notice Check balances before and after adding a stream, warping to the
     * future, and receiving the stream.
     * @param fromAccId Account id of the sender
     * @param toAccId Account id to be added as receiver
     * @param amtPerSecAdded Amount per second for the stream to be added
     * @dev This test is resource heavy because it contains lots of logic and
     * warping to the future.
     */
    function testBalanceAtInFuture(
        uint8 fromAccId,
        uint8 toAccId,
        uint160 amtPerSecAdded
    ) public heavy {
        address from = getAccount(fromAccId);
        address to = getAccount(toAccId);
        uint256 fromDripsAccId = getDripsAccountId(from);
        uint256 toDripsAccId = getDripsAccountId(to);

        amtPerSecAdded = clampAmountPerSec(amtPerSecAdded);

        // the timestamps we are comparing
        uint256 currentTimestamp = block.timestamp;
        uint256 futureTimestamp = getCurrentCycleEnd() + 1;

        // retrieve initial balances
        uint128 balanceInitial = getStreamBalanceForUser(
            from,
            uint32(block.timestamp)
        );
        uint128 receivableInitial = getReceivableAmountForAllUsers();

        // look at balances in the future if we wouldnt do anything
        hevm.warp(futureTimestamp);
        uint128 balanceBaseline = getStreamBalanceForUser(
            from,
            uint32(block.timestamp)
        );
        uint128 receivableBaseline = getReceivableAmountForAllUsers();
        hevm.warp(currentTimestamp);

        // add a stream
        // make sure we add enough balance to complete the cycle
        uint128 balanceAdded = uint128(amtPerSecAdded) * SECONDS_PER_CYCLE;
        balanceAdded = uint128(clampBalanceDelta(int128(balanceAdded), from));
        require(balanceAdded / amtPerSecAdded >= SECONDS_PER_CYCLE);
        addStream(
            fromAccId,
            toAccId,
            amtPerSecAdded,
            0,
            0,
            int128(balanceAdded)
        );

        // retrieve balances after adding stream
        uint128 balanceBefore = getStreamBalanceForUser(
            from,
            uint32(block.timestamp)
        );
        uint128 receivableBefore = getReceivableAmountForAllUsers();

        // jump to future
        hevm.warp(futureTimestamp);

        // retrieve balances in the future after adding the stream
        uint128 balanceAfter = getStreamBalanceForUser(
            from,
            uint32(block.timestamp)
        );
        uint128 receivableAfter = getReceivableAmountForAllUsers();

        // sanity checks
        assert(balanceInitial >= balanceBaseline);
        assert(balanceBefore >= balanceAfter);
        assert(receivableAfter >= receivableBaseline);

        // the amount that would have been streamed if we do nothing
        uint128 baselineBalanceStreamed = balanceInitial - balanceBaseline;

        // calculate expected balance change including the effect of the
        // added stream
        uint128 expectedBalanceChange = balanceBefore -
            balanceAfter -
            baselineBalanceStreamed;
        uint128 expectedReceivedChange = receivableAfter - receivableBaseline;

        assert(expectedBalanceChange == expectedReceivedChange);
    }

    /**
     * @notice Setting streams with sane defaults should not revert
     * @param fromAccId Account id of the sender
     * @param toAccId Account id of the receiver
     * @param amountPerSec Amount per second for the stream
     * @param startTime Start time for the stream
     * @param duration Duration for the stream
     * @param balanceDelta Amount to update stream balance with
     */
    function testSetStreamsShouldNotRevert(
        uint8 fromAccId,
        uint8 toAccId,
        uint160 amountPerSec,
        uint32 startTime,
        uint32 duration,
        int128 balanceDelta
    ) public {
        try
            EchidnaStreamsHelpers(address(this)).setStreamsWithClamping(
                fromAccId,
                toAccId,
                amountPerSec,
                startTime,
                duration,
                balanceDelta
            )
        {} catch {
            assert(false);
        }
    }

    /**
     * @notice Adding streams with sane defaults should not revert
     * @param fromAccId Account id of the sender
     * @param toAccId Account id of the receiver
     * @param amountPerSec Amount per second for the stream
     * @param startTime Start time for the stream
     * @param duration Duration for the stream
     * @param balanceDelta Amount to update stream balance with
     */
    function testAddStreamShouldNotRevert(
        uint8 fromAccId,
        uint8 toAccId,
        uint160 amountPerSec,
        uint32 startTime,
        uint32 duration,
        int128 balanceDelta
    ) public {
        try
            EchidnaStreamsHelpers(address(this)).addStreamWithClamping(
                fromAccId,
                toAccId,
                amountPerSec,
                startTime,
                duration,
                balanceDelta
            )
        {} catch (bytes memory reason) {
            bytes4 errorSelector = bytes4(reason);
            if (errorSelector == EchidnaStorage.DuplicateError.selector) {
                // ignore this case, it means we tried to add a duplicate stream
            } else {
                assert(false);
            }
        }
    }

    /*
     * @notice Removing streams should not revert
     * @param targetAccId Account id of the sender
     * @param indexSeed Random seed used to determine which receiver to remove
     */
    function testRemoveStreamShouldNotRevert(
        uint8 targetAccId,
        uint256 indexSeed
    ) public {
        address target = getAccount(targetAccId);
        require(getStreamReceivers(target).length > 0);

        try
            EchidnaStreamsHelpers(address(this)).removeStream(
                targetAccId,
                indexSeed
            )
        {} catch {
            assert(false);
        }
    }

    /**
     * @notice Updating stream balance with sane defaults should not revert
     * @param targetAccId Account id of the sender
     * @param balanceDelta Amount to update stream balance with
     */
    function testSetStreamBalanceShouldNotRevert(
        uint8 targetAccId,
        int128 balanceDelta
    ) public {
        try
            EchidnaStreamsHelpers(address(this)).setStreamBalanceWithClamping(
                targetAccId,
                balanceDelta
            )
        {} catch {
            assert(false);
        }
    }

    /**
     * @notice Withdrawing all stream balance should not revert
     * @param targetAccId Account id of the sender
     */
    function testSetStreamBalanceWithdrawAllShouldNotRevert(uint8 targetAccId)
        public
    {
        try
            EchidnaStreamsHelpers(address(this)).setStreamBalanceWithdrawAll(
                targetAccId
            )
        {} catch {
            assert(false);
        }
    }
}

97% src/echidna/base/EchidnaAccounting.sol

Lines covered: 87 / 89 (97%)

// SPDX-License-Identifier: MIT

import "./EchidnaStorage.sol";

/**
 * @title Mixin for handling accounting related functions
 * @author Rappie <rappie@perimetersec.io>
 */
contract EchidnaAccounting is EchidnaStorage {
    /**
     * @notice Get the total amount of drips balances for all users
     * @return Total drips balances for all users
     * @dev This is the total amount of drips balances for all users, including
     * the current stream balance, the receivable amount, the collectable
     * amount, the splittable amount, and the squeezable amount.
     */
    function getDripsBalancesTotalForAllUsers() internal returns (uint256) {
        uint256 user0Total = getDripsBalancesTotalForUser(ADDRESS_USER0);
        uint256 user1Total = getDripsBalancesTotalForUser(ADDRESS_USER1);
        uint256 user2Total = getDripsBalancesTotalForUser(ADDRESS_USER2);
        uint256 user3Total = getDripsBalancesTotalForUser(ADDRESS_USER3);

        return user0Total + user1Total + user2Total + user3Total;
    }

    /**
     * @notice Get the total amount of drips balances for a user
     * @param target The user to query
     * @return Total drips balances for the target user
     * @dev This is the total amount of drips balances for a user, including
     * the current stream balance, the receivable amount, the collectable
     * amount, the splittable amount, and the squeezable amount.
     */
    function getDripsBalancesTotalForUser(address target)
        internal
        returns (uint256)
    {
        uint256 targetDripsAccId = getDripsAccountId(target);

        uint128 balance = getCurrentStreamBalanceForUser(target);
        uint128 squeezable = getTotalSqueezableAmountForUser(target);
        uint128 receivable = getReceivableAmountForUser(target);
        uint128 collectable = drips.collectable(targetDripsAccId, token);
        uint128 splittable = drips.splittable(targetDripsAccId, token);

        return balance + squeezable + receivable + collectable + splittable;
    }

    /**
     * @notice Get the streamable balance for a user
     * @param target The user to query
     * @param timestamp The point in time to get 'balanceAt' from
     * @return Streamable balance for the target user
     * @dev This is the streamable balance for a user, which is the current
     * stream balance minus the receivable amount.
     */
    function getStreamBalanceForUser(address target, uint32 timestamp)
        internal
        returns (uint128)
    {
        uint256 targetDripsAccId = getDripsAccountId(target);

        uint128 balance;
        try
            drips.balanceAt(
                targetDripsAccId,
                token,
                getStreamReceivers(target),
                timestamp
            )
        returns (uint128 _balance) {
            balance = _balance;
        } catch {
            // this should not happen, so put an assert here to be sure
            assert(false);
        }

        return balance;
    }

    /**
     * @notice Get the current stream balance for a user
     * @param target The user to query
     * @return Current stream balance for the target user
     */
    function getCurrentStreamBalanceForUser(address target)
        internal
        returns (uint128)
    {
        return getStreamBalanceForUser(target, uint32(block.timestamp));
    }

    /**
     * @notice Get the receivable amount for all users
     * @return Receivable amount for all users
     * @dev This is the receivable amount for all users, which means the amount
     * that has already been streamed to the users but not yet collected.
     */
    function getReceivableAmountForAllUsers() internal returns (uint128) {
        uint128 receivable;
        receivable += getReceivableAmountForUser(ADDRESS_USER0);
        receivable += getReceivableAmountForUser(ADDRESS_USER1);
        receivable += getReceivableAmountForUser(ADDRESS_USER2);
        receivable += getReceivableAmountForUser(ADDRESS_USER3);
        return receivable;
    }

    /**
     * @notice Get the receivable amount for a user
     * @param target The user to query
     * @return Receivable amount for the target user
     * @dev This is the receivable amount for a user, which means the amount
     * that has already been streamed to the user but not yet collected.
     */
    function getReceivableAmountForUser(address target)
        internal
        returns (uint128)
    {
        uint128 receivable = drips.receiveStreamsResult(
            getDripsAccountId(target),
            token,
            type(uint32).max
        );
        return receivable;
    }

    /**
     * @notice Get the squeezable amount for all users
     * @param target The user to query
     * @return Squeezable amount for all users
     * @dev This is the squeezable amount for a user, which means the amount
     * that has already been streamed in the current cycle that is not yet
     * receivable.
     */
    function getTotalSqueezableAmountForUser(address target)
        internal
        returns (uint128)
    {
        uint128 amount = 0;
        amount += getSqueezableAmount(ADDRESS_USER0, target);
        amount += getSqueezableAmount(ADDRESS_USER1, target);
        amount += getSqueezableAmount(ADDRESS_USER2, target);
        amount += getSqueezableAmount(ADDRESS_USER3, target);

        return amount;
    }

    /**
     * @notice Get the squeezable amount for a user
     * @param sender The sender of the stream(s)
     * @param receiver The receiver of the stream(s)
     * @return Squeezable amount for the target user
     * @dev This is the squeezable amount for a user, which means the amount
     * that has already been streamed in the current cycle that is not yet
     * receivable.
     */
    function getSqueezableAmount(address sender, address receiver)
        internal
        returns (uint128)
    {
        uint256 senderDripsAccId = getDripsAccountId(sender);
        uint256 receiverDripsAccId = getDripsAccountId(receiver);

        uint128 amount = drips.squeezeStreamsResult(
            receiverDripsAccId,
            token,
            senderDripsAccId,
            bytes32(0),
            getStreamsHistory(sender)
        );

        return amount;
    }

    /**
     * @notice Get the 'maxEnd' farthest in the future for all users
     * @return 'maxEnd' fartherst in the future for all users
     * @dev This is the 'maxEnd' farthest in the future for all users, which
     * means the farthest in the future that any stream ends for any user.
     */
    function getMaxEndForAllUsers() internal returns (uint32) {
        uint32 maxMaxEnd;

        uint32 maxEndUser0 = getMaxEndForUser(ADDRESS_USER0);
        if (maxEndUser0 > maxMaxEnd) maxMaxEnd = maxEndUser0;
        uint32 maxEndUser1 = getMaxEndForUser(ADDRESS_USER1);
        if (maxEndUser1 > maxMaxEnd) maxMaxEnd = maxEndUser1;
        uint32 maxEndUser2 = getMaxEndForUser(ADDRESS_USER2);
        if (maxEndUser2 > maxMaxEnd) maxMaxEnd = maxEndUser2;
        uint32 maxEndUser3 = getMaxEndForUser(ADDRESS_USER3);
        if (maxEndUser3 > maxMaxEnd) maxMaxEnd = maxEndUser3;

        return maxMaxEnd;
    }

    /**
     * @notice Get the 'maxEnd' for a user
     * @param target The user to query
     * @return The 'maxEnd' for the target user
     */
    function getMaxEndForUser(address target) internal returns (uint32) {
        uint256 targetDripsAccId = getDripsAccountId(target);
        (, , , , uint32 maxEnd) = drips.streamsState(targetDripsAccId, token);
        return maxEnd;
    }

    /**
     * @notice Get the timestamp on which the current cycle started
     * @return Timestamp on which the current cycle started
     */
    function getCurrentCycleStart() internal returns (uint32) {
        uint32 currTimestamp = uint32(block.timestamp);
        return currTimestamp - (currTimestamp % SECONDS_PER_CYCLE);
    }

    /**
     * @notice Get the timestamp on which the current cycle ends
     * @return Timestamp on which the current cycle ends
     */
    function getCurrentCycleEnd() internal returns (uint32) {
        return getCurrentCycleStart() + SECONDS_PER_CYCLE - 1;
    }

    /**
     * @notice Get the cycle number for a given timestamp
     * @param timestamp The timestamp to get the cycle number for
     * @return timestamp Cycle number for the given timestamp
     */
    function getCycleFromTimestamp(uint256 timestamp)
        internal
        returns (uint32)
    {
        return uint32(timestamp / SECONDS_PER_CYCLE + 1);
    }
}

0% src/echidna/base/EchidnaBase.sol

Lines covered: 0 / 1 (0%)

// SPDX-License-Identifier: MIT

import "./EchidnaSetup.sol";
import "./EchidnaStorage.sol";
import "./EchidnaAccounting.sol";

/**
 * @title Mixin grouping together all base contracts
 * @author Rappie <rappie@perimetersec.io>
 */
contract EchidnaBase is
    EchidnaSetup,
    EchidnaStorage,
    EchidnaAccounting
{}

88% src/echidna/base/EchidnaConfig.sol

Lines covered: 23 / 26 (88%)

// SPDX-License-Identifier: MIT

import {IERC20, ERC20PresetFixedSupply} from "openzeppelin-contracts/token/ERC20/presets/ERC20PresetFixedSupply.sol";
import {ManagedProxy} from "src/Managed.sol";
import {Drips, SplitsReceiver, StreamReceiver, StreamConfig, StreamConfigImpl, StreamsHistory} from "src/Drips.sol";
import {AddressDriver} from "src/AddressDriver.sol";

import {DripsEchidna} from "../tools/DripsEchidna.sol";
import {AddressDriverEchidna} from "../tools/AddressDriverEchidna.sol";

import "../tools/Debugger.sol";

/**
 * @title Mixin containing the configuration for the fuzzing campaign
 * @author Rappie <rappie@perimetersec.io>
 */
contract EchidnaConfig {
    // Addresses used for the simulated users
    address internal constant ADDRESS_USER0 = address(0x10000);
    address internal constant ADDRESS_USER1 = address(0x20000);
    address internal constant ADDRESS_USER2 = address(0x30000);
    address internal constant ADDRESS_USER3 = address(0x40000);

    // Mappings from address to account id
    mapping(address => uint8) internal ADDRESS_TO_ACCOUNT_ID;
    mapping(address => uint256) internal ADDRESS_TO_DRIPS_ACCOUNT_ID;

    // Variable to store the timestamp when fuzzing starts
    uint256 internal STARTING_TIMESTAMP;

    // Starting token balance of the simulated users
    uint256 internal constant STARTING_BALANCE = 1_000_000_000e18;

    // Amount of seconds in a Drips cycle
    uint32 internal constant SECONDS_PER_CYCLE = 10;

    // Buffers to be used as fuzzing boundaries
    uint32 internal constant CYCLE_FUZZING_BUFFER_CYCLES = 10;
    uint32 internal constant CYCLE_FUZZING_BUFFER_SECONDS =
        CYCLE_FUZZING_BUFFER_CYCLES * SECONDS_PER_CYCLE;

    // Maximum amount of streamable funds per second that make sense based
    // on the starting balance of the simulated users
    uint160 internal constant MAX_AMOUNT_PER_SEC =
        (uint160(STARTING_BALANCE) / uint160(SECONDS_PER_CYCLE)) * 1e9;

    // Sensible maximum amount of seconds for a stream
    uint32 internal constant MAX_STREAM_DURATION = CYCLE_FUZZING_BUFFER_SECONDS;

    // Due to the inner workings of the splitting algorithm Drips uses,
    // it is unpredictable wether a split will be rounded up or down. To
    // remedy this, allow a tolerance for the expected split amount.
    uint256 internal constant SPLIT_ROUNDING_TOLERANCE = 1;

    // Toggles for certain tests
    bool internal constant TOGGLE_EXPERIMENTAL_TESTS_ENABLED = true;
    bool internal constant TOGGLE_HEAVY_TESTS_ENABLED = true;
    bool internal constant TOGGLE_MAXENDHINTS_ENABLED = true;

    // Modifier to toggle experimental tests
    modifier experimental() {
        if (!TOGGLE_EXPERIMENTAL_TESTS_ENABLED) return;
        _;
    }

    // Modifier to toggle performance heavy tests
    modifier heavy() {
        if (!TOGGLE_HEAVY_TESTS_ENABLED) return;
        _;
    }

    constructor() {
        ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER0] = 0;
        ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER1] = 64;
        ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER2] = 128;
        ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER3] = 192;
    }

    /*
     * @notice Get the address for a certain account id
     * @param rawId The raw account id
     * @return The address for the account id
     * @dev In this case we have 4 users, spread over the range of 256 (8 bits).
     */
    function getAccount(uint8 rawId) internal pure returns (address) {
        uint256 id = uint256(rawId) / 64;

        if (id == 0) return ADDRESS_USER0;
        if (id == 1) return ADDRESS_USER1;
        if (id == 2) return ADDRESS_USER2;
        if (id == 3) return ADDRESS_USER3;

        require(false, "Unknown account ID");
    }
}

96% src/echidna/base/EchidnaSetup.sol

Lines covered: 27 / 28 (96%)

// SPDX-License-Identifier: MIT

import "../tools/IHevm.sol";
import "./EchidnaConfig.sol";

/**
 * @title Mixin containing the deployment and setup
 * @author Rappie <rappie@perimetersec.io>
 */
contract EchidnaSetup is EchidnaConfig {
    IHevm hevm = IHevm(0x7109709ECfa91a80626fF3989D68f67F5b1DD12D);

    ERC20PresetFixedSupply token;
    DripsEchidna drips;
    AddressDriverEchidna driver;

    constructor() EchidnaConfig() {
        // Deploy ERC20 token
        token = new ERC20PresetFixedSupply(
            "Test Token",
            "TEST",
            STARTING_BALANCE * 4,
            address(this)
        );

        // Deploy Drips
        drips = new DripsEchidna(SECONDS_PER_CYCLE);
        drips.unpause_noModifiers();

        // Deploy AddressDriver
        uint32 driverId = drips.registerDriver(address(this));
        driver = new AddressDriverEchidna(
            drips,
            address(0),
            driverId
        );
        driver.unpause_noModifiers();
        drips.updateDriverAddress(driverId, address(driver));

        // Set up token balances
        token.transfer(ADDRESS_USER0, STARTING_BALANCE);
        hevm.prank(ADDRESS_USER0);
        token.approve(address(driver), type(uint256).max);
        token.transfer(ADDRESS_USER1, STARTING_BALANCE);
        hevm.prank(ADDRESS_USER1);
        token.approve(address(driver), type(uint256).max);
        token.transfer(ADDRESS_USER2, STARTING_BALANCE);
        hevm.prank(ADDRESS_USER2);
        token.approve(address(driver), type(uint256).max);
        token.transfer(ADDRESS_USER3, STARTING_BALANCE);
        hevm.prank(ADDRESS_USER3);
        token.approve(address(driver), type(uint256).max);

        // Store starting timestamp
        STARTING_TIMESTAMP = block.timestamp;
    }
}

98% src/echidna/base/EchidnaStorage.sol

Lines covered: 85 / 86 (98%)

// SPDX-License-Identifier: MIT
import "./EchidnaSetup.sol";

/**
 * @title Mixin for storing stream receivers and streams history
 * @author Rappie <rappie@perimetersec.io>
 */
contract EchidnaStorage is EchidnaSetup {
    error DuplicateError();

    // Mapping from address to current stream receivers
    mapping(address => StreamReceiver[]) internal userToStreamReceivers;

    // Mappings from address to full streams history and hashes
    mapping(address => StreamsHistory[]) internal userToStreamsHistory;
    mapping(address => bytes32[]) internal userToStreamsHistoryHashes;

    // Mapping from address to current splits receivers
    mapping(address => SplitsReceiver[]) internal userToSplitsReceivers;

    /**
     * @notice Update the stream receivers for a given account.
     * @param sender Account to update
     * @param receivers New stream receivers
     * @dev This function will generate a new hash for the stream receivers,
     * update the stream receivers for the given account, and add a new entry
     * to the streams history and streams history hashes for the given
     * account. This is stored for later use.
     */
    function updateStreamReceivers(
        address sender,
        StreamReceiver[] memory receivers
    ) internal {
        // Hash the new stream receivers
        bytes32 receiversHash = drips.hashStreams(receivers);

        // Update the stream receivers for 'sender'
        delete userToStreamReceivers[sender];
        for (uint256 i = 0; i < receivers.length; i++) {
            userToStreamReceivers[sender].push(receivers[i]);
        }

        // Add a new entry to the streams history
        uint256 nextIndex = userToStreamsHistory[sender].length;
        userToStreamsHistory[sender].push();
        userToStreamsHistory[sender][nextIndex].streamsHash = bytes32(0);
        for (uint256 i = 0; i < receivers.length; i++) {
            userToStreamsHistory[sender][nextIndex].receivers.push(
                receivers[i]
            );
        }
        (, , uint32 updateTime, , uint32 maxEnd) = drips.streamsState(
            getDripsAccountId(sender),
            token
        );
        userToStreamsHistory[sender][nextIndex].updateTime = updateTime;
        userToStreamsHistory[sender][nextIndex].maxEnd = maxEnd;

        // Generate starting hash. If there is no previous history, use 0
        bytes32 startingHash;
        if (nextIndex == 0) {
            startingHash = bytes32(0);
        } else {
            startingHash = userToStreamsHistoryHashes[sender][nextIndex - 1];
        }

        // Add new entry to the streams history hashes
        bytes32 historyHash = drips.hashStreamsHistory(
            startingHash,
            receiversHash,
            updateTime,
            maxEnd
        );
        userToStreamsHistoryHashes[sender].push(historyHash);
    }

    /**
     * @notice Update the splits receivers for a given account.
     * @param sender Account to update
     * @param receivers New splits receivers
     */
    function updateSplitsReceivers(
        address sender,
        SplitsReceiver[] memory receivers
    ) internal {
        delete userToSplitsReceivers[sender];
        for (uint256 i = 0; i < receivers.length; i++) {
            userToSplitsReceivers[sender].push(receivers[i]);
        }
    }

    /**
     * @notice Get the stream receivers for a given account.
     * @param sender Account to get stream receivers for
     * @return Stream receivers for the given account
     */
    function getStreamReceivers(address sender)
        internal
        returns (StreamReceiver[] memory)
    {
        return userToStreamReceivers[sender];
    }

    /**
     * @notice Get the streams history for a given account.
     * @param sender Account to get streams history for
     * @return Streams history for the given account
     */
    function getStreamsHistory(address sender)
        internal
        returns (StreamsHistory[] memory)
    {
        return userToStreamsHistory[sender];
    }

    /**
     * @notice Get the streams history hashes for a given account.
     * @param sender Account to get streams history hashes for
     * @return Streams history hashes for the given account
     */
    function getStreamsHistoryHashes(address sender)
        internal
        returns (bytes32[] memory)
    {
        return userToStreamsHistoryHashes[sender];
    }

    /**
     * @notice Get the splits receivers for a given account.
     * @param sender Account to get splits receivers for
     * @return Splits receivers for the given account
     */
    function getSplitsReceivers(address sender)
        internal
        returns (SplitsReceiver[] memory)
    {
        return userToSplitsReceivers[sender];
    }

    /**
     * @notice Sort the stream receivers.
     * @param unsorted Unsorted stream receivers
     * @return Sorted stream receivers
     * @dev This function will sort the stream receivers by account ID,
     * then by config, then by stream ID. It will revert if there are
     * duplicate stream receivers.
     */
    function bubbleSortStreamReceivers(StreamReceiver[] memory unsorted)
        internal
        returns (StreamReceiver[] memory)
    {
        uint256 n = unsorted.length;
        if (n <= 1) return unsorted;

        StreamReceiver[] memory sorted = unsorted;
        for (uint256 i = 0; i < n - 1; i++) {
            for (uint256 j = 0; j < n - i - 1; j++) {
                if (bubbleSortStreamReceiverGT(sorted[j], sorted[j + 1])) {
                    StreamReceiver memory temp = sorted[j];
                    sorted[j] = sorted[j + 1];
                    sorted[j + 1] = temp;
                }
            }
        }
        return sorted;
    }

    /**
     * @notice Sort the splits receivers.
     * @param unsorted Unsorted splits receivers
     * @return Sorted splits receivers
     */
    function bubbleSortSplitsReceivers(SplitsReceiver[] memory unsorted)
        internal
        returns (SplitsReceiver[] memory)
    {
        uint256 n = unsorted.length;
        if (n <= 1) return unsorted;

        SplitsReceiver[] memory sorted = unsorted;
        for (uint256 i = 0; i < n - 1; i++) {
            for (uint256 j = 0; j < n - i - 1; j++) {
                if (bubbleSortSplitsReceiverGT(sorted[j], sorted[j + 1])) {
                    SplitsReceiver memory temp = sorted[j];
                    sorted[j] = sorted[j + 1];
                    sorted[j + 1] = temp;
                }
            }
        }
        return sorted;
    }

    /**
     * @notice Compare two stream receivers.
     * @param a First stream receiver
     * @param b Second stream receiver
     * @return True if `a` is greater than `b`, false otherwise
     * @dev This function will compare two stream receivers by account ID,
     * then by config. It will revert if there are duplicate stream receivers.
     */
    function bubbleSortStreamReceiverGT(
        StreamReceiver memory a,
        StreamReceiver memory b
    ) internal returns (bool) {
        if (a.accountId != b.accountId) {
            return a.accountId > b.accountId;
        }
        if (StreamConfig.unwrap(a.config) != StreamConfig.unwrap(b.config)) {
            return
                StreamConfig.unwrap(a.config) > StreamConfig.unwrap(b.config);
        }
        revert DuplicateError();
    }

    /**
     * @notice Compare two splits receivers.
     * @param a First splits receiver
     * @param b Second splits receiver
     * @return True if `a` is greater than `b`, false otherwise
     * @dev This function will compare two splits receivers by account ID.
     * It will revert if there are duplicate splits receivers.
     */
    function bubbleSortSplitsReceiverGT(
        SplitsReceiver memory a,
        SplitsReceiver memory b
    ) internal returns (bool) {
        if (a.accountId != b.accountId) {
            return a.accountId > b.accountId;
        }
        revert DuplicateError();
    }

    /**
     * @notice Get the drips account ID for a given address.
     * @param account Address to get drips account ID for
     * @return Drips account ID for the given address
     * @dev Caches the value to increase performance
     */
    function getDripsAccountId(address account) internal returns (uint256) {
        if (ADDRESS_TO_DRIPS_ACCOUNT_ID[account] == 0) {
            ADDRESS_TO_DRIPS_ACCOUNT_ID[account] = driver.calcAccountId(
                account
            );
        }
        return ADDRESS_TO_DRIPS_ACCOUNT_ID[account];
    }
}

100% src/echidna/tools/AddressDriverEchidna.sol

Lines covered: 3 / 3 (100%)

// SPDX-License-Identifier: MIT
import {AddressDriver} from "src/AddressDriver.sol";

import {DripsEchidna} from "./DripsEchidna.sol";
import {ManagedEchidna} from "./ManagedEchidna.sol";

/**
 * @title Wrapper around AddressDriver with minor fuzzing helpers
 * @author Rappie <rappie@perimetersec.io>
 */
contract AddressDriverEchidna is AddressDriver, ManagedEchidna {
    constructor(
        DripsEchidna drips_,
        address forwarder,
        uint32 driverId_
    ) AddressDriver(drips_, forwarder, driverId_) {}
}

0% src/echidna/tools/Debugger.sol

Lines covered: 0 / 1 (0%)

// SPDX-License-Identifier: MIT

library Debugger {
    event Debug(string debugString);
    event Debug(string description, string data);
    event Debug(string prefix, string description, string data);
    event Debug(string description, bytes32 data);
    event Debug(string prefix, string description, bytes32 data);
    event Debug(string description, uint256 data);
    event Debug(string prefix, string description, uint256 data);
    event Debug(string description, int256 data);
    event Debug(string prefix, string description, int256 data);
    event Debug(string description, address data);
    event Debug(string prefix, string description, address data);
    event Debug(string description, bool data);
    event Debug(string prefix, string description, bool data);

    function log(string memory debugString) internal {
        emit Debug(debugString);
    }

    function log(string memory description, string memory data) internal {
        emit Debug(description, data);
    }

    function log(
        string memory prefix,
        string memory description,
        string memory data
    ) internal {
        emit Debug(prefix, description, data);
    }

    function log(string memory description, bytes32 data) internal {
        emit Debug(description, data);
    }

    function log(
        string memory prefix,
        string memory description,
        bytes32 data
    ) internal {
        emit Debug(prefix, description, data);
    }

    function log(string memory description, uint256 data) internal {
        emit Debug(description, data);
    }

    function log(
        string memory prefix,
        string memory description,
        uint256 data
    ) internal {
        emit Debug(prefix, description, data);
    }

    function log(string memory description, int256 data) internal {
        emit Debug(description, data);
    }

    function log(
        string memory prefix,
        string memory description,
        int256 data
    ) internal {
        emit Debug(prefix, description, data);
    }

    function log(string memory description, address data) internal {
        emit Debug(description, data);
    }

    function log(
        string memory prefix,
        string memory description,
        address data
    ) internal {
        emit Debug(prefix, description, data);
    }

    function log(string memory description, bool data) internal {
        emit Debug(description, data);
    }

    function log(
        string memory prefix,
        string memory description,
        bool data
    ) internal {
        emit Debug(prefix, description, data);
    }
}

100% src/echidna/tools/DripsEchidna.sol

Lines covered: 10 / 10 (100%)

// SPDX-License-Identifier: MIT
import {IERC20} from "openzeppelin-contracts/token/ERC20/utils/SafeERC20.sol";
import {Drips} from "src/Drips.sol";

import {ManagedEchidna} from "./ManagedEchidna.sol";

/**
 * @title Wrapper around Drips with minor fuzzing helpers
 * @author Rappie <rappie@perimetersec.io>
 */
contract DripsEchidna is Drips, ManagedEchidna {
    constructor(uint32 cycleSecs_) Drips(cycleSecs_) {}

    /**
     * @notice Get the amtDelta for a given user and cycle
     * @param accountId The account to get the amtDelta for
     * @param erc20 The ERC20 token
     * @param cycle The cycle to get the amtDelta for
     * @return The amtDelta for this cycle and the next cycle
     */
    function getAmtDeltaForCycle(
        uint256 accountId,
        IERC20 erc20,
        uint32 cycle
    ) public view returns (int128, int128) {
        // Manually calculate the storage slot because it is a private variable
        // in Streams
        StreamsStorage storage streamsStorage;
        bytes32 slot = _erc1967Slot("eip1967.streams.storage");
        assembly {
            streamsStorage.slot := slot
        }

        // Return the amtDelta for the given cycle
        StreamsState storage state = streamsStorage.states[erc20][accountId];
        mapping(uint32 cycle => AmtDelta) storage amtDeltas = state.amtDeltas;
        return (amtDeltas[cycle].thisCycle, amtDeltas[cycle].nextCycle);
    }
}

0% src/echidna/tools/ManagedEchidna.sol

Lines covered: 0 / 5 (0%)

// SPDX-License-Identifier: MIT
import {Managed} from "src/Managed.sol";

/**
 * @title Wrapper around Managed with minor fuzzing helpers
 * @author Rappie <rappie@perimetersec.io>
 */
contract ManagedEchidna is Managed {
    constructor() Managed() {}

    /**
     * @notice Helper function to unpause the contract as any user
     */
    function unpause_noModifiers() public {
        _managedStorage().isPaused = false;
        emit Unpaused(msg.sender);
    }
}

100% test/recon/CryticTester.sol

Lines covered: 1 / 1 (100%)

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import {Properties} from "./Properties.sol";

// echidna test/recon/CryticTester.sol --contract CryticTester --config echidna.yaml
contract CryticTester is Properties {}

88% test/recon/Properties.sol

Lines covered: 8 / 9 (88%)

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import {Echidna} from "src/echidna/Echidna.sol";

/// @notice scfuzzbench adaptation layer: canary checks on top of the
/// Perimeter Drips fuzzing suite. Assertion failures are surfaced the same
/// way for Echidna, Medusa, Foundry, and Recon (AssertionFailed event +
/// assert), and dedup to the emitting function name across fuzzers.
abstract contract Properties is Echidna {
    string internal constant ASSERTION_CANARY = "!!! canary assertion";
    string internal constant INVARIANT_CANARY_GLOBAL_INVARIANT_FAILURE = "Canary invariant";

    event AssertionFailed(string reason);

    function t(bool b, string memory reason) internal {
        if (!b) {
            emit AssertionFailed(reason);
            assert(false);
        }
    }

    function invariant_canary() public returns (bool) {
        t(false, INVARIANT_CANARY_GLOBAL_INVARIANT_FAILURE);
        return true;
    }

    function assert_canary_ASSERTION_CANARY(uint256 entropy) public {
        t(entropy > 0, ASSERTION_CANARY);
    }
}

1		// SPDX-License-Identifier: MIT
2		// OpenZeppelin Contracts (last updated v4.7.0) (metatx/ERC2771Context.sol)
3
4		pragma solidity ^0.8.9;
5
6		import "../utils/Context.sol";
7
8		/**
9		* @dev Context variant with ERC2771 support.
10		*/
11		abstract contract ERC2771Context is Context {
12		/// @custom:oz-upgrades-unsafe-allow state-variable-immutable
13		address private immutable _trustedForwarder;
14
15		/// @custom:oz-upgrades-unsafe-allow constructor
16	1×	constructor(address trustedForwarder) {
17	11×	_trustedForwarder = trustedForwarder;
18		}
19
20	12×	function isTrustedForwarder(address forwarder) public view virtual returns (bool) {
21	18×	return forwarder == _trustedForwarder;
22		}
23
24	10×	function _msgSender() internal view virtual override returns (address sender) {
25	18×	if (isTrustedForwarder(msg.sender)) {
26		// The assembly code is more direct than the Solidity version using `abi.decode`.
27		/// @solidity memory-safe-assembly
28		assembly {
29	0	sender := shr(96, calldataload(sub(calldatasize(), 20)))
30		}
31		} else {
32	16×	return super._msgSender();
33		}
34		}
35
36		function _msgData() internal view virtual override returns (bytes calldata) {
37		if (isTrustedForwarder(msg.sender)) {
38		return msg.data[:msg.data.length - 20];
39		} else {
40		return super._msgData();
41		}
42		}
43		}

1		// SPDX-License-Identifier: MIT
2		// OpenZeppelin Contracts (last updated v4.9.0) (proxy/utils/UUPSUpgradeable.sol)
3
4		pragma solidity ^0.8.0;
5
6		import "../../interfaces/draft-IERC1822.sol";
7		import "../ERC1967/ERC1967Upgrade.sol";
8
9		/**
10		* @dev An upgradeability mechanism designed for UUPS proxies. The functions included here can perform an upgrade of an
11		* {ERC1967Proxy}, when this contract is set as the implementation behind such a proxy.
12		*
13		* A security mechanism ensures that an upgrade does not turn off upgradeability accidentally, although this risk is
14		* reinstated if the upgrade retains upgradeability but removes the security mechanism, e.g. by replacing
15		* `UUPSUpgradeable` with a custom implementation of upgrades.
16		*
17		* The {_authorizeUpgrade} function must be overridden to include access restriction to the upgrade mechanism.
18		*
19		* _Available since v4.1._
20		*/
21		abstract contract UUPSUpgradeable is IERC1822Proxiable, ERC1967Upgrade {
22		/// @custom:oz-upgrades-unsafe-allow state-variable-immutable state-variable-assignment
23	20×	address private immutable __self = address(this);
24
25		/**
26		* @dev Check that the execution is being performed through a delegatecall call and that the execution context is
27		* a proxy contract with an implementation (as defined in ERC1967) pointing to self. This should only be the case
28		* for UUPS and transparent proxies that are using the current contract as their implementation. Execution of a
29		* function through ERC1167 minimal proxies (clones) would not normally pass this test, but is not guaranteed to
30		* fail.
31		*/
32		modifier onlyProxy() {
33	0	require(address(this) != __self, "Function must be called through delegatecall");
34	0	require(_getImplementation() == __self, "Function must be called through active proxy");
35		_;
36		}
37
38		/**
39		* @dev Check that the execution is not being performed through a delegate call. This allows a function to be
40		* callable on the implementing contract but not through proxies.
41		*/
42		modifier notDelegated() {
43	0	require(address(this) == __self, "UUPSUpgradeable: must not be called through delegatecall");
44		_;
45		}
46
47		/**
48		* @dev Implementation of the ERC1822 {proxiableUUID} function. This returns the storage slot used by the
49		* implementation. It is used to validate the implementation's compatibility when performing an upgrade.
50		*
51		* IMPORTANT: A proxy pointing at a proxiable contract should not be considered proxiable itself, because this risks
52		* bricking a proxy that upgrades to it, by delegating to itself until out of gas. Thus it is critical that this
53		* function revert if invoked through a proxy. This is guaranteed by the `notDelegated` modifier.
54		*/
55	0	function proxiableUUID() external view virtual override notDelegated returns (bytes32) {
56	0	return _IMPLEMENTATION_SLOT;
57		}
58
59		/**
60		* @dev Upgrade the implementation of the proxy to `newImplementation`.
61		*
62		* Calls {_authorizeUpgrade}.
63		*
64		* Emits an {Upgraded} event.
65		*
66		* @custom:oz-upgrades-unsafe-allow-reachable delegatecall
67		*/
68	0	function upgradeTo(address newImplementation) public virtual onlyProxy {
69	0	_authorizeUpgrade(newImplementation);
70	0	_upgradeToAndCallUUPS(newImplementation, new bytes(0), false);
71		}
72
73		/**
74		* @dev Upgrade the implementation of the proxy to `newImplementation`, and subsequently execute the function call
75		* encoded in `data`.
76		*
77		* Calls {_authorizeUpgrade}.
78		*
79		* Emits an {Upgraded} event.
80		*
81		* @custom:oz-upgrades-unsafe-allow-reachable delegatecall
82		*/
83	0	function upgradeToAndCall(address newImplementation, bytes memory data) public payable virtual onlyProxy {
84	0	_authorizeUpgrade(newImplementation);
85	0	_upgradeToAndCallUUPS(newImplementation, data, true);
86		}
87
88		/**
89		* @dev Function that should revert when `msg.sender` is not authorized to upgrade the contract. Called by
90		* {upgradeTo} and {upgradeToAndCall}.
91		*
92		* Normally, this function will use an xref:access.adoc[access control] modifier such as {Ownable-onlyOwner}.
93		*
94		* ```solidity
95		* function _authorizeUpgrade(address) internal override onlyOwner {}
96		* ```
97		*/
98		function _authorizeUpgrade(address newImplementation) internal virtual;
99		}

1		// SPDX-License-Identifier: MIT
2		// OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)
3
4		pragma solidity ^0.8.1;
5
6		/**
7		* @dev Collection of functions related to the address type
8		*/
9	0	library Address {
10		/**
11		* @dev Returns true if `account` is a contract.
12		*
13		* [IMPORTANT]
14		* ====
15		* It is unsafe to assume that an address for which this function returns
16		* false is an externally-owned account (EOA) and not a contract.
17		*
18		* Among others, `isContract` will return false for the following
19		* types of addresses:
20		*
21		* - an externally-owned account
22		* - a contract in construction
23		* - an address where a contract will be created
24		* - an address where a contract lived, but was destroyed
25		*
26		* Furthermore, `isContract` will also return true if the target contract within
27		* the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
28		* which only has an effect at the end of a transaction.
29		* ====
30		*
31		* [IMPORTANT]
32		* ====
33		* You shouldn't rely on `isContract` to protect against flash loan attacks!
34		*
35		* Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
36		* like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
37		* constructor.
38		* ====
39		*/
40	0	function isContract(address account) internal view returns (bool) {
41		// This method relies on extcodesize/address.code.length, which returns 0
42		// for contracts in construction, since the code is only stored at the end
43		// of the constructor execution.
44
45	0	return account.code.length > 0;
46		}
47
48		/**
49		* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
50		* `recipient`, forwarding all available gas and reverting on errors.
51		*
52		* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
53		* of certain opcodes, possibly making contracts go over the 2300 gas limit
54		* imposed by `transfer`, making them unable to receive funds via
55		* `transfer`. {sendValue} removes this limitation.
56		*
57		* https://consensys.net/diligence/blog/2019/09/stop-using-soliditys-transfer-now/[Learn more].
58		*
59		* IMPORTANT: because control is transferred to `recipient`, care must be
60		* taken to not create reentrancy vulnerabilities. Consider using
61		* {ReentrancyGuard} or the
62		* https://solidity.readthedocs.io/en/v0.8.0/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
63		*/
64		function sendValue(address payable recipient, uint256 amount) internal {
65		require(address(this).balance >= amount, "Address: insufficient balance");
66
67		(bool success, ) = recipient.call{value: amount}("");
68		require(success, "Address: unable to send value, recipient may have reverted");
69		}
70
71		/**
72		* @dev Performs a Solidity function call using a low level `call`. A
73		* plain `call` is an unsafe replacement for a function call: use this
74		* function instead.
75		*
76		* If `target` reverts with a revert reason, it is bubbled up by this
77		* function (like regular Solidity function calls).
78		*
79		* Returns the raw returned data. To convert to the expected return value,
80		* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
81		*
82		* Requirements:
83		*
84		* - `target` must be a contract.
85		* - calling `target` with `data` must not revert.
86		*
87		* _Available since v3.1._
88		*/
89		function functionCall(address target, bytes memory data) internal returns (bytes memory) {
90		return functionCallWithValue(target, data, 0, "Address: low-level call failed");
91		}
92
93		/**
94		* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
95		* `errorMessage` as a fallback revert reason when `target` reverts.
96		*
97		* _Available since v3.1._
98		*/
99	28×	function functionCall(
100		address target,
101		bytes memory data,
102		string memory errorMessage
103	4×	) internal returns (bytes memory) {
104	40×	return functionCallWithValue(target, data, 0, errorMessage);
105		}
106
107		/**
108		* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
109		* but also transferring `value` wei to `target`.
110		*
111		* Requirements:
112		*
113		* - the calling contract must have an ETH balance of at least `value`.
114		* - the called Solidity function must be `payable`.
115		*
116		* _Available since v3.1._
117		*/
118		function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
119		return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
120		}
121
122		/**
123		* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
124		* with `errorMessage` as a fallback revert reason when `target` reverts.
125		*
126		* _Available since v3.1._
127		*/
128	32×	function functionCallWithValue(
129		address target,
130		bytes memory data,
131		uint256 value,
132		string memory errorMessage
133	4×	) internal returns (bytes memory) {
134	28×	require(address(this).balance >= value, "Address: insufficient balance for call");
135	272×	(bool success, bytes memory returndata) = target.call{value: value}(data);
136	48×	return verifyCallResultFromTarget(target, success, returndata, errorMessage);
137		}
138
139		/**
140		* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
141		* but performing a static call.
142		*
143		* _Available since v3.3._
144		*/
145		function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
146		return functionStaticCall(target, data, "Address: low-level static call failed");
147		}
148
149		/**
150		* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
151		* but performing a static call.
152		*
153		* _Available since v3.3._
154		*/
155		function functionStaticCall(
156		address target,
157		bytes memory data,
158		string memory errorMessage
159		) internal view returns (bytes memory) {
160		(bool success, bytes memory returndata) = target.staticcall(data);
161		return verifyCallResultFromTarget(target, success, returndata, errorMessage);
162		}
163
164		/**
165		* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
166		* but performing a delegate call.
167		*
168		* _Available since v3.4._
169		*/
170	0	function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
171	0	return functionDelegateCall(target, data, "Address: low-level delegate call failed");
172		}
173
174		/**
175		* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
176		* but performing a delegate call.
177		*
178		* _Available since v3.4._
179		*/
180	0	function functionDelegateCall(
181		address target,
182		bytes memory data,
183		string memory errorMessage
184	0	) internal returns (bytes memory) {
185	0	(bool success, bytes memory returndata) = target.delegatecall(data);
186	0	return verifyCallResultFromTarget(target, success, returndata, errorMessage);
187		}
188
189		/**
190		* @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
191		* the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
192		*
193		* _Available since v4.8._
194		*/
195	36×	function verifyCallResultFromTarget(
196		address target,
197		bool success,
198		bytes memory returndata,
199		string memory errorMessage
200	4×	) internal view returns (bytes memory) {
201	17×	if (success) {
202	28×	if (returndata.length == 0) {
203		// only check isContract if the call was successful and the return data is empty
204		// otherwise we already know that it was a contract
205	0	require(isContract(target), "Address: call to non-contract");
206		}
207	20×	return returndata;
208		} else {
209	5×	_revert(returndata, errorMessage);
210		}
211		}
212
213		/**
214		* @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
215		* revert reason or using the provided one.
216		*
217		* _Available since v4.3._
218		*/
219		function verifyCallResult(
220		bool success,
221		bytes memory returndata,
222		string memory errorMessage
223		) internal pure returns (bytes memory) {
224		if (success) {
225		return returndata;
226		} else {
227		_revert(returndata, errorMessage);
228		}
229		}
230
231	1×	function _revert(bytes memory returndata, string memory errorMessage) private pure {
232		// Look for revert reason and bubble it up if present
233	7×	if (returndata.length > 0) {
234		// The easiest way to bubble the revert reason is using memory via assembly
235		/// @solidity memory-safe-assembly
236		assembly {
237	2×	let returndata_size := mload(returndata)
238	5×	revert(add(32, returndata), returndata_size)
239		}
240		} else {
241	0	revert(errorMessage);
242		}
243		}
244		}

1		// SPDX-License-Identifier: MIT
2		// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
3
4		pragma solidity ^0.8.0;
5
6		/**
7		* @dev Provides information about the current execution context, including the
8		* sender of the transaction and its data. While these are generally available
9		* via msg.sender and msg.data, they should not be accessed in such a direct
10		* manner, since when dealing with meta-transactions the account sending and
11		* paying for execution may not be the actual sender (as far as an application
12		* is concerned).
13		*
14		* This contract is only required for intermediate, library-like contracts.
15		*/
16		abstract contract Context {
17	20×	function _msgSender() internal view virtual returns (address) {
18	15×	return msg.sender;
19		}
20
21		function _msgData() internal view virtual returns (bytes calldata) {
22		return msg.data;
23		}
24		}

1		// SPDX-License-Identifier: GPL-3.0-only
2		pragma solidity ^0.8.20;
3
4		import {AccountMetadata, Drips, StreamReceiver, IERC20, SplitsReceiver} from "./Drips.sol";
5		import {Managed} from "./Managed.sol";
6		import {DriverTransferUtils} from "./DriverTransferUtils.sol";
7
8		/// @notice A Drips driver implementing address-based account identification.
9		/// Each address can use `AddressDriver` to control a single account ID derived from that address.
10		/// No registration is required, an `AddressDriver`-based account ID
11		/// for each address is available upfront.
12	0	contract AddressDriver is DriverTransferUtils, Managed {
13		/// @notice The Drips address used by this driver.
14	0	Drips public immutable drips;
15		/// @notice The driver ID which this driver uses when calling Drips.
16	0	uint32 public immutable driverId;
17
18		/// @param drips_ The Drips contract to use.
19		/// @param forwarder The ERC-2771 forwarder to trust. May be the zero address.
20		/// @param driverId_ The driver ID to use when calling Drips.
21	4×	constructor(Drips drips_, address forwarder, uint32 driverId_) DriverTransferUtils(forwarder) {
22	11×	drips = drips_;
23	11×	driverId = driverId_;
24		}
25
26		/// @notice Calculates the account ID for an address.
27		/// Every account ID is a 256-bit integer constructed by concatenating:
28		/// `driverId (32 bits) \| zeros (64 bits) \| addr (160 bits)`.
29		/// @param addr The address
30		/// @return accountId The account ID
31	138×	function calcAccountId(address addr) public view returns (uint256 accountId) {
32		// By assignment we get `accountId` value:
33		// `zeros (224 bits) \| driverId (32 bits)`
34	15×	accountId = driverId;
35		// By bit shifting we get `accountId` value:
36		// `driverId (32 bits) \| zeros (224 bits)`
37		// By bit masking we get `accountId` value:
38		// `driverId (32 bits) \| zeros (64 bits) \| addr (160 bits)`
39	30×	accountId = (accountId << 224) \| uint160(addr);
40		}
41
42		/// @notice Calculates the account ID for the message sender
43		/// @return accountId The account ID
44	8×	function _callerAccountId() internal view returns (uint256 accountId) {
45	20×	return calcAccountId(_msgSender());
46		}
47
48		/// @notice Collects the account's received already split funds
49		/// and transfers them out of the Drips contract.
50		/// @param erc20 The used ERC-20 token.
51		/// It must preserve amounts, so if some amount of tokens is transferred to
52		/// an address, then later the same amount must be transferable from that address.
53		/// Tokens which rebase the holders' balances, collect taxes on transfers,
54		/// or impose any restrictions on holding or transferring tokens are not supported.
55		/// If you use such tokens in the protocol, they can get stuck or lost.
56		/// @param transferTo The address to send collected funds to
57		/// @return amt The collected amount
58	47×	function collect(IERC20 erc20, address transferTo) public whenNotPaused returns (uint128 amt) {
59	13×	return _collectAndTransfer(drips, _callerAccountId(), erc20, transferTo);
60		}
61
62		/// @notice Gives funds from the message sender to the receiver.
63		/// The receiver can split and collect them immediately.
64		/// Transfers the funds to be given from the message sender's wallet to the Drips contract.
65		/// @param receiver The receiver account ID.
66		/// @param erc20 The used ERC-20 token.
67		/// It must preserve amounts, so if some amount of tokens is transferred to
68		/// an address, then later the same amount must be transferable from that address.
69		/// Tokens which rebase the holders' balances, collect taxes on transfers,
70		/// or impose any restrictions on holding or transferring tokens are not supported.
71		/// If you use such tokens in the protocol, they can get stuck or lost.
72		/// @param amt The given amount
73	31×	function give(uint256 receiver, IERC20 erc20, uint128 amt) public whenNotPaused {
74	12×	_giveAndTransfer(drips, _callerAccountId(), receiver, erc20, amt);
75		}
76
77		/// @notice Sets the message sender's streams configuration.
78		/// Transfers funds between the message sender's wallet and the Drips contract
79		/// to fulfil the change of the streams balance.
80		/// @param erc20 The used ERC-20 token.
81		/// It must preserve amounts, so if some amount of tokens is transferred to
82		/// an address, then later the same amount must be transferable from that address.
83		/// Tokens which rebase the holders' balances, collect taxes on transfers,
84		/// or impose any restrictions on holding or transferring tokens are not supported.
85		/// If you use such tokens in the protocol, they can get stuck or lost.
86		/// @param currReceivers The current streams receivers list.
87		/// It must be exactly the same as the last list set for the sender with `setStreams`.
88		/// If this is the first update, pass an empty array.
89		/// @param balanceDelta The streams balance change to be applied.
90		/// If it's positive, the balance is increased by `balanceDelta`.
91		/// If it's zero, the balance doesn't change.
92		/// If it's negative, the balance is decreased by `balanceDelta`,
93		/// but the change is capped at the current balance amount, so it doesn't go below 0.
94		/// Passing `type(int128).min` always decreases the current balance to 0.
95		/// @param newReceivers The list of the streams receivers of the sender to be set.
96		/// Must be sorted by the account IDs and then by the stream configurations,
97		/// without identical elements and without 0 amtPerSecs.
98		/// @param maxEndHint1 An optional parameter allowing gas optimization, pass `0` to ignore it.
99		/// The first hint for finding the maximum end time when all streams stop due to funds
100		/// running out after the balance is updated and the new receivers list is applied.
101		/// Hints have no effect on the results of calling this function, except potentially saving gas.
102		/// Hints are Unix timestamps used as the starting points for binary search for the time
103		/// when funds run out in the range of timestamps from the current block's to `2^32`.
104		/// Hints lower than the current timestamp are ignored.
105		/// You can provide zero, one or two hints. The order of hints doesn't matter.
106		/// Hints are the most effective when one of them is lower than or equal to
107		/// the last timestamp when funds are still streamed, and the other one is strictly larger
108		/// than that timestamp,the smaller the difference between such hints, the higher gas savings.
109		/// The savings are the highest possible when one of the hints is equal to
110		/// the last timestamp when funds are still streamed, and the other one is larger by 1.
111		/// It's worth noting that the exact timestamp of the block in which this function is executed
112		/// may affect correctness of the hints, especially if they're precise.
113		/// Hints don't provide any benefits when balance is not enough to cover
114		/// a single second of streaming or is enough to cover all streams until timestamp `2^32`.
115		/// Even inaccurate hints can be useful, and providing a single hint
116		/// or two hints that don't enclose the time when funds run out can still save some gas.
117		/// Providing poor hints that don't reduce the number of binary search steps
118		/// may cause slightly higher gas usage than not providing any hints.
119		/// @param maxEndHint2 An optional parameter allowing gas optimization, pass `0` to ignore it.
120		/// The second hint for finding the maximum end time, see `maxEndHint1` docs for more details.
121		/// @param transferTo The address to send funds to in case of decreasing balance
122		/// @return realBalanceDelta The actually applied streams balance change.
123		/// It's equal to the passed `balanceDelta`, unless it's negative
124		/// and it gets capped at the current balance amount.
125	106×	function setStreams(
126		IERC20 erc20,
127		StreamReceiver[] calldata currReceivers,
128		int128 balanceDelta,
129		StreamReceiver[] calldata newReceivers,
130		// slither-disable-next-line similar-names
131		uint32 maxEndHint1,
132		uint32 maxEndHint2,
133		address transferTo
134	2×	) public whenNotPaused returns (int128 realBalanceDelta) {
135	12×	return _setStreamsAndTransfer(
136	2×	drips,
137	8×	_callerAccountId(),
138	2×	erc20,
139	4×	currReceivers,
140	2×	balanceDelta,
141	4×	newReceivers,
142	2×	maxEndHint1,
143	2×	maxEndHint2,
144	2×	transferTo
145		);
146		}
147
148		/// @notice Sets the account splits configuration.
149		/// The configuration is common for all ERC-20 tokens.
150		/// Nothing happens to the currently splittable funds, but when they are split
151		/// after this function finishes, the new splits configuration will be used.
152		/// Because anybody can call `split` on `Drips`, calling this function may be frontrun
153		/// and all the currently splittable funds will be split using the old splits configuration.
154		/// @param receivers The list of the account's splits receivers to be set.
155		/// Must be sorted by the account IDs, without duplicate account IDs and without 0 weights.
156		/// Each splits receiver will be getting `weight / TOTAL_SPLITS_WEIGHT`
157		/// share of the funds collected by the account.
158		/// If the sum of weights of all receivers is less than `_TOTAL_SPLITS_WEIGHT`,
159		/// some funds won't be split, but they will be left for the account to collect.
160		/// Fractions of tokens are always rounder either up or down depending on the amount
161		/// being split, the receiver's position on the list and the other receivers' weights.
162		/// It's valid to include the account's own `accountId` in the list of receivers,
163		/// but funds split to themselves return to their splittable balance and are not collectable.
164		/// This is usually unwanted, because if splitting is repeated,
165		/// funds split to themselves will be again split using the current configuration.
166		/// Splitting 100% to self effectively blocks splitting unless the configuration is updated.
167	60×	function setSplits(SplitsReceiver[] calldata receivers) public whenNotPaused {
168	125×	drips.setSplits(_callerAccountId(), receivers);
169		}
170
171		/// @notice Emits the account metadata for the message sender.
172		/// The keys and the values are not standardized by the protocol, it's up to the users
173		/// to establish and follow conventions to ensure compatibility with the consumers.
174		/// @param accountMetadata The list of account metadata.
175	0	function emitAccountMetadata(AccountMetadata[] calldata accountMetadata) public whenNotPaused {
176	0	if (accountMetadata.length != 0) {
177	0	drips.emitAccountMetadata(_callerAccountId(), accountMetadata);
178		}
179		}
180		}

1		// SPDX-License-Identifier: GPL-3.0-only
2		pragma solidity ^0.8.20;
3
4		import {Drips, StreamReceiver, IERC20, SafeERC20} from "./Drips.sol";
5		import {ERC2771Context} from "openzeppelin-contracts/metatx/ERC2771Context.sol";
6
7		/// @notice ERC-20 token transfer utilities for drivers.
8		/// Encapsulates the logic for token transfers made by drivers implementing user identities.
9		/// All funds going into Drips are transferred ad-hoc from the caller (`msg.sender`),
10		/// and all funds going out of Drips are transferred in full to the provided address.
11		/// Compatible with `Caller` by supporting ERC-2771.
12		abstract contract DriverTransferUtils is ERC2771Context {
13		/// @param forwarder The ERC-2771 forwarder to trust. May be the zero address.
14	2×	constructor(address forwarder) ERC2771Context(forwarder) {}
15
16		/// @notice Collects the account's received already split funds
17		/// and transfers them out of the Drips contract.
18		/// @param drips The Drips contract to use.
19		/// @param erc20 The used ERC-20 token.
20		/// It must preserve amounts, so if some amount of tokens is transferred to
21		/// an address, then later the same amount must be transferable from that address.
22		/// Tokens which rebase the holders' balances, collect taxes on transfers,
23		/// or impose any restrictions on holding or transferring tokens are not supported.
24		/// If you use such tokens in the protocol, they can get stuck or lost.
25		/// @param transferTo The address to send collected funds to
26		/// @return amt The collected amount
27	8×	function _collectAndTransfer(Drips drips, uint256 accountId, IERC20 erc20, address transferTo)
28		internal
29	1×	returns (uint128 amt)
30		{
31	71×	amt = drips.collect(accountId, erc20);
32	65×	if (amt > 0) drips.withdraw(erc20, transferTo, amt);
33		}
34
35		/// @notice Gives funds from the message sender to the receiver.
36		/// The receiver can split and collect them immediately.
37		/// Transfers the funds to be given from the message sender's wallet to the Drips contract.
38		/// @param drips The Drips contract to use.
39		/// @param receiver The receiver account ID.
40		/// @param erc20 The used ERC-20 token.
41		/// It must preserve amounts, so if some amount of tokens is transferred to
42		/// an address, then later the same amount must be transferable from that address.
43		/// Tokens which rebase the holders' balances, collect taxes on transfers,
44		/// or impose any restrictions on holding or transferring tokens are not supported.
45		/// If you use such tokens in the protocol, they can get stuck or lost.
46		/// @param amt The given amount
47	7×	function _giveAndTransfer(
48		Drips drips,
49		uint256 accountId,
50		uint256 receiver,
51		IERC20 erc20,
52		uint128 amt
53		) internal {
54	16×	if (amt > 0) _transferFromCaller(drips, erc20, amt);
55	58×	drips.give(accountId, receiver, erc20, amt);
56		}
57
58		/// @notice Sets the message sender's streams configuration.
59		/// Transfers funds between the message sender's wallet and the Drips contract
60		/// to fulfil the change of the streams balance.
61		/// @param drips The Drips contract to use.
62		/// @param erc20 The used ERC-20 token.
63		/// It must preserve amounts, so if some amount of tokens is transferred to
64		/// an address, then later the same amount must be transferable from that address.
65		/// Tokens which rebase the holders' balances, collect taxes on transfers,
66		/// or impose any restrictions on holding or transferring tokens are not supported.
67		/// If you use such tokens in the protocol, they can get stuck or lost.
68		/// @param currReceivers The current streams receivers list.
69		/// It must be exactly the same as the last list set for the sender with `setStreams`.
70		/// If this is the first update, pass an empty array.
71		/// @param balanceDelta The streams balance change to be applied.
72		/// If it's positive, the balance is increased by `balanceDelta`.
73		/// If it's zero, the balance doesn't change.
74		/// If it's negative, the balance is decreased by `balanceDelta`,
75		/// but the change is capped at the current balance amount, so it doesn't go below 0.
76		/// Passing `type(int128).min` always decreases the current balance to 0.
77		/// @param newReceivers The list of the streams receivers of the sender to be set.
78		/// Must be sorted by the account IDs and then by the stream configurations,
79		/// without identical elements and without 0 amtPerSecs.
80		/// @param maxEndHint1 An optional parameter allowing gas optimization, pass `0` to ignore it.
81		/// The first hint for finding the maximum end time when all streams stop due to funds
82		/// running out after the balance is updated and the new receivers list is applied.
83		/// Hints have no effect on the results of calling this function, except potentially saving gas.
84		/// Hints are Unix timestamps used as the starting points for binary search for the time
85		/// when funds run out in the range of timestamps from the current block's to `2^32`.
86		/// Hints lower than the current timestamp are ignored.
87		/// You can provide zero, one or two hints. The order of hints doesn't matter.
88		/// Hints are the most effective when one of them is lower than or equal to
89		/// the last timestamp when funds are still streamed, and the other one is strictly larger
90		/// than that timestamp,the smaller the difference between such hints, the higher gas savings.
91		/// The savings are the highest possible when one of the hints is equal to
92		/// the last timestamp when funds are still streamed, and the other one is larger by 1.
93		/// It's worth noting that the exact timestamp of the block in which this function is executed
94		/// may affect correctness of the hints, especially if they're precise.
95		/// Hints don't provide any benefits when balance is not enough to cover
96		/// a single second of streaming or is enough to cover all streams until timestamp `2^32`.
97		/// Even inaccurate hints can be useful, and providing a single hint
98		/// or two hints that don't enclose the time when funds run out can still save some gas.
99		/// Providing poor hints that don't reduce the number of binary search steps
100		/// may cause slightly higher gas usage than not providing any hints.
101		/// @param maxEndHint2 An optional parameter allowing gas optimization, pass `0` to ignore it.
102		/// The second hint for finding the maximum end time, see `maxEndHint1` docs for more details.
103		/// @param transferTo The address to send funds to in case of decreasing balance
104		/// @return realBalanceDelta The actually applied streams balance change.
105		/// It's equal to the passed `balanceDelta`, unless it's negative
106		/// and it gets capped at the current balance amount.
107	30×	function _setStreamsAndTransfer(
108		Drips drips,
109		uint256 accountId,
110		IERC20 erc20,
111		StreamReceiver[] calldata currReceivers,
112		int128 balanceDelta,
113		StreamReceiver[] calldata newReceivers,
114		// slither-disable-next-line similar-names
115		uint32 maxEndHint1,
116		uint32 maxEndHint2,
117		address transferTo
118	2×	) internal returns (int128 realBalanceDelta) {
119	32×	if (balanceDelta > 0) _transferFromCaller(drips, erc20, uint128(balanceDelta));
120	159×	realBalanceDelta = drips.setStreams(
121	18×	accountId, erc20, currReceivers, balanceDelta, newReceivers, maxEndHint1, maxEndHint2
122		);
123	140×	if (realBalanceDelta < 0) drips.withdraw(erc20, transferTo, uint128(-realBalanceDelta));
124		}
125
126		/// @notice Transfers tokens from the sender to Drips.
127		/// @param drips The Drips contract to use.
128		/// @param erc20 The used ERC-20 token.
129		/// @param amt The transferred amount
130	10×	function _transferFromCaller(Drips drips, IERC20 erc20, uint128 amt) internal {
131	26×	SafeERC20.safeTransferFrom(erc20, _msgSender(), address(drips), amt);
132		}
133		}

1		// SPDX-License-Identifier: GPL-3.0-only
2		pragma solidity ^0.8.20;
3
4		import {UUPSUpgradeable} from "openzeppelin-contracts/proxy/utils/UUPSUpgradeable.sol";
5		import {ERC1967Proxy} from "openzeppelin-contracts/proxy/ERC1967/ERC1967Proxy.sol";
6		import {EnumerableSet} from "openzeppelin-contracts/utils/structs/EnumerableSet.sol";
7		import {StorageSlot} from "openzeppelin-contracts/utils/StorageSlot.sol";
8
9		using EnumerableSet for EnumerableSet.AddressSet;
10
11		/// @notice A mix-in for contract pausing, upgrading and admin management.
12		/// It can't be used directly, only via a proxy. It uses the upgrade-safe ERC-1967 storage scheme.
13		///
14		/// Managed uses the ERC-1967 admin slot to store the admin address.
15		/// All instances of the contracts have admin address `0x00` and are forever paused.
16		/// When a proxy uses such contract via delegation, the proxy should define
17		/// the initial admin address and the contract is initially unpaused.
18		abstract contract Managed is UUPSUpgradeable {
19		/// @notice The pointer to the storage slot holding a single `ManagedStorage` structure.
20	60×	bytes32 private immutable _managedStorageSlot = _erc1967Slot("eip1967.managed.storage");
21
22		/// @notice Emitted when a new admin of the contract is proposed.
23		/// The proposed admin must call `acceptAdmin` to finalize the change.
24		/// @param currentAdmin The current admin address.
25		/// @param newAdmin The proposed admin address.
26		event NewAdminProposed(address indexed currentAdmin, address indexed newAdmin);
27
28		/// @notice Emitted when the pauses role is granted.
29		/// @param pauser The address that the pauser role was granted to.
30		/// @param admin The address of the admin that triggered the change.
31		event PauserGranted(address indexed pauser, address indexed admin);
32
33		/// @notice Emitted when the pauses role is revoked.
34		/// @param pauser The address that the pauser role was revoked from.
35		/// @param admin The address of the admin that triggered the change.
36		event PauserRevoked(address indexed pauser, address indexed admin);
37
38		/// @notice Emitted when the pause is triggered.
39		/// @param pauser The address that triggered the change.
40		event Paused(address indexed pauser);
41
42		/// @notice Emitted when the pause is lifted.
43		/// @param pauser The address that triggered the change.
44		event Unpaused(address indexed pauser);
45
46		struct ManagedStorage {
47		bool isPaused;
48		EnumerableSet.AddressSet pausers;
49		address proposedAdmin;
50		}
51
52		/// @notice Throws if called by any caller other than the admin.
53		modifier onlyAdmin() {
54	0	require(admin() == msg.sender, "Caller not the admin");
55		_;
56		}
57
58		/// @notice Throws if called by any caller other than the admin or a pauser.
59		modifier onlyAdminOrPauser() {
60	0	require(admin() == msg.sender \|\| isPauser(msg.sender), "Caller not the admin or a pauser");
61		_;
62		}
63
64		/// @notice Modifier to make a function callable only when the contract is not paused.
65		modifier whenNotPaused() {
66	160×	require(!isPaused(), "Contract paused");
67	6×	_;
68		}
69
70		/// @notice Modifier to make a function callable only when the contract is paused.
71		modifier whenPaused() {
72	0	require(isPaused(), "Contract not paused");
73		_;
74		}
75
76		/// @notice Initializes the contract in paused state and with no admin.
77		/// The contract instance can be used only as a call delegation target for a proxy.
78		constructor() {
79	60×	_managedStorage().isPaused = true;
80		}
81
82		/// @notice Returns the current implementation address.
83	0	function implementation() public view returns (address) {
84	0	return _getImplementation();
85		}
86
87		/// @notice Returns the address of the current admin.
88	0	function admin() public view returns (address) {
89	0	return _getAdmin();
90		}
91
92		/// @notice Returns the proposed address to change the admin to.
93	0	function proposedAdmin() public view returns (address) {
94	0	return _managedStorage().proposedAdmin;
95		}
96
97		/// @notice Proposes a change of the admin of the contract.
98		/// The proposed new admin must call `acceptAdmin` to finalize the change.
99		/// To cancel a proposal propose a different address, e.g. the zero address.
100		/// Can only be called by the current admin.
101		/// @param newAdmin The proposed admin address.
102	0	function proposeNewAdmin(address newAdmin) public onlyAdmin {
103	0	emit NewAdminProposed(msg.sender, newAdmin);
104	0	_managedStorage().proposedAdmin = newAdmin;
105		}
106
107		/// @notice Applies a proposed change of the admin of the contract.
108		/// Sets the proposed admin to the zero address.
109		/// Can only be called by the proposed admin.
110	0	function acceptAdmin() public {
111	0	require(proposedAdmin() == msg.sender, "Caller not the proposed admin");
112	0	_updateAdmin(msg.sender);
113		}
114
115		/// @notice Changes the admin of the contract to address zero.
116		/// It's no longer possible to change the admin or upgrade the contract afterwards.
117		/// Can only be called by the current admin.
118	0	function renounceAdmin() public onlyAdmin {
119	0	_updateAdmin(address(0));
120		}
121
122		/// @notice Sets the current admin of the contract and clears the proposed admin.
123		/// @param newAdmin The admin address being set. Can be the zero address.
124	0	function _updateAdmin(address newAdmin) internal {
125	0	emit AdminChanged(admin(), newAdmin);
126	0	_managedStorage().proposedAdmin = address(0);
127	0	StorageSlot.getAddressSlot(_ADMIN_SLOT).value = newAdmin;
128		}
129
130		/// @notice Grants the pauser role to an address. Callable only by the admin.
131		/// @param pauser The granted address.
132	0	function grantPauser(address pauser) public onlyAdmin {
133	0	require(_managedStorage().pausers.add(pauser), "Address already is a pauser");
134	0	emit PauserGranted(pauser, msg.sender);
135		}
136
137		/// @notice Revokes the pauser role from an address. Callable only by the admin.
138		/// @param pauser The revoked address.
139	0	function revokePauser(address pauser) public onlyAdmin {
140	0	require(_managedStorage().pausers.remove(pauser), "Address is not a pauser");
141	0	emit PauserRevoked(pauser, msg.sender);
142		}
143
144		/// @notice Checks if an address is a pauser.
145		/// @param pauser The checked address.
146		/// @return isAddrPauser True if the address is a pauser.
147	0	function isPauser(address pauser) public view returns (bool isAddrPauser) {
148	0	return _managedStorage().pausers.contains(pauser);
149		}
150
151		/// @notice Returns all the addresses with the pauser role.
152		/// @return pausersList The list of all the pausers, ordered arbitrarily.
153		/// The list's order may change after granting or revoking the pauser role.
154	0	function allPausers() public view returns (address[] memory pausersList) {
155	0	return _managedStorage().pausers.values();
156		}
157
158		/// @notice Returns true if the contract is paused, and false otherwise.
159	20×	function isPaused() public view returns (bool) {
160	90×	return _managedStorage().isPaused;
161		}
162
163		/// @notice Triggers stopped state. Callable only by the admin or a pauser.
164	0	function pause() public onlyAdminOrPauser whenNotPaused {
165	0	_managedStorage().isPaused = true;
166	0	emit Paused(msg.sender);
167		}
168
169		/// @notice Returns to normal state. Callable only by the admin or a pauser.
170	0	function unpause() public onlyAdminOrPauser whenPaused {
171	0	_managedStorage().isPaused = false;
172	0	emit Unpaused(msg.sender);
173		}
174
175		/// @notice Calculates the quasi ERC-1967 slot pointer.
176		/// @param name The name of the slot, should be globally unique
177		/// @return slot The slot pointer
178	18×	function _erc1967Slot(string memory name) internal pure returns (bytes32 slot) {
179		// The original ERC-1967 subtracts 1 from the hash to get 1 storage slot
180		// under an index without a known hash preimage which is enough to store a single address.
181		// This implementation subtracts 1024 to get 1024 slots without a known preimage
182		// allowing securely storing much larger structures.
183	60×	return bytes32(uint256(keccak256(bytes(name))) - 1024);
184		}
185
186		/// @notice Returns the Managed storage.
187		/// @return storageRef The storage.
188	28×	function _managedStorage() internal view returns (ManagedStorage storage storageRef) {
189	30×	bytes32 slot = _managedStorageSlot;
190		// slither-disable-next-line assembly
191	7×	assembly {
192	21×	storageRef.slot := slot
193		}
194		}
195
196		/// @notice Authorizes the contract upgrade. See `UUPSUpgradeable` docs for more details.
197	0	function _authorizeUpgrade(address /* newImplementation */ ) internal view override onlyAdmin {
198		return;
199		}
200		}
201
202		/// @notice A generic proxy for contracts implementing `Managed`.
203	0	contract ManagedProxy is ERC1967Proxy {
204	0	constructor(Managed logic, address admin) ERC1967Proxy(address(logic), new bytes(0)) {
205	0	_changeAdmin(admin);
206		}
207		}

1		// SPDX-License-Identifier: GPL-3.0-only
2		pragma solidity ^0.8.20;
3
4		import {IERC20} from "openzeppelin-contracts/token/ERC20/IERC20.sol";
5
6		/// @notice A splits receiver
7		struct SplitsReceiver {
8		/// @notice The account ID.
9		uint256 accountId;
10		/// @notice The splits weight. Must never be zero.
11		/// The account will be getting `weight / _TOTAL_SPLITS_WEIGHT`
12		/// share of the funds collected by the splitting account.
13		uint32 weight;
14		}
15
16		/// @notice Splits can keep track of at most `type(uint128).max`
17		/// which is `2 ^ 128 - 1` units of each ERC-20 token.
18		/// It's up to the caller to guarantee that this limit is never exceeded,
19		/// failing to do so may result in a total protocol collapse.
20		abstract contract Splits {
21		/// @notice Maximum number of splits receivers of a single account.
22		/// Limits the cost of splitting.
23	2×	uint256 internal constant _MAX_SPLITS_RECEIVERS = 200;
24		/// @notice The total splits weight of an account.
25	7×	uint32 internal constant _TOTAL_SPLITS_WEIGHT = 1_000_000;
26		/// @notice The amount the contract can keep track of each ERC-20 token.
27		// slither-disable-next-line unused-state
28		uint128 internal constant _MAX_SPLITS_BALANCE = type(uint128).max;
29		/// @notice The storage slot holding a single `SplitsStorage` structure.
30		bytes32 private immutable _splitsStorageSlot;
31
32		/// @notice Emitted when an account collects funds
33		/// @param accountId The account ID.
34		/// @param erc20 The used ERC-20 token.
35		/// @param collected The collected amount
36		event Collected(uint256 indexed accountId, IERC20 indexed erc20, uint128 collected);
37
38		/// @notice Emitted when funds are split from an account to a receiver.
39		/// This is caused by the account collecting received funds.
40		/// @param accountId The account ID.
41		/// @param receiver The splits receiver account ID
42		/// @param erc20 The used ERC-20 token.
43		/// @param amt The amount split to the receiver
44		event Split(
45		uint256 indexed accountId, uint256 indexed receiver, IERC20 indexed erc20, uint128 amt
46		);
47
48		/// @notice Emitted when funds are made collectable after splitting.
49		/// @param accountId The account ID.
50		/// @param erc20 The used ERC-20 token.
51		/// @param amt The amount made collectable for the account
52		/// on top of what was collectable before.
53		event Collectable(uint256 indexed accountId, IERC20 indexed erc20, uint128 amt);
54
55		/// @notice Emitted when funds are given from the account to the receiver.
56		/// @param accountId The account ID.
57		/// @param receiver The receiver account ID.
58		/// @param erc20 The used ERC-20 token.
59		/// @param amt The given amount
60		event Given(
61		uint256 indexed accountId, uint256 indexed receiver, IERC20 indexed erc20, uint128 amt
62		);
63
64		/// @notice Emitted when the account's splits are updated.
65		/// @param accountId The account ID.
66		/// @param receiversHash The splits receivers list hash
67		event SplitsSet(uint256 indexed accountId, bytes32 indexed receiversHash);
68
69		/// @notice Emitted when an account is seen in a splits receivers list.
70		/// @param receiversHash The splits receivers list hash
71		/// @param accountId The account ID.
72		/// @param weight The splits weight. Must never be zero.
73		/// The account will be getting `weight / _TOTAL_SPLITS_WEIGHT`
74		/// share of the funds collected by the splitting account.
75		event SplitsReceiverSeen(
76		bytes32 indexed receiversHash, uint256 indexed accountId, uint32 weight
77		);
78
79		struct SplitsStorage {
80		/// @notice Account splits states.
81		mapping(uint256 accountId => SplitsState) splitsStates;
82		}
83
84		struct SplitsState {
85		/// @notice The account's splits configuration hash, see `hashSplits`.
86		bytes32 splitsHash;
87		/// @notice The account's splits balances.
88		mapping(IERC20 erc20 => SplitsBalance) balances;
89		}
90
91		struct SplitsBalance {
92		/// @notice The not yet split balance, must be split before collecting by the account.
93		uint128 splittable;
94		/// @notice The already split balance, ready to be collected by the account.
95		uint128 collectable;
96		}
97
98		/// @param splitsStorageSlot The storage slot to holding a single `SplitsStorage` structure.
99	1×	constructor(bytes32 splitsStorageSlot) {
100	7×	_splitsStorageSlot = splitsStorageSlot;
101		}
102
103	15×	function _addSplittable(uint256 accountId, IERC20 erc20, uint128 amt) internal {
104		// This will not overflow if the requirement of tracking in the contract
105		// no more than `_MAX_SPLITS_BALANCE` of each token is followed.
106	240×	_splitsStorage().splitsStates[accountId].balances[erc20].splittable += amt;
107		}
108
109		/// @notice Returns account's received but not split yet funds.
110		/// @param accountId The account ID.
111		/// @param erc20 The used ERC-20 token.
112		/// @return amt The amount received but not split yet.
113	7×	function _splittable(uint256 accountId, IERC20 erc20) internal view returns (uint128 amt) {
114	52×	return _splitsStorage().splitsStates[accountId].balances[erc20].splittable;
115		}
116
117		/// @notice Calculate the result of splitting an amount using the current splits configuration.
118		/// @param accountId The account ID.
119		/// @param currReceivers The list of the account's current splits receivers.
120		/// It must be exactly the same as the last list set for the account with `_setSplits`.
121		/// If the splits have never been set, pass an empty array.
122		/// @param amount The amount being split.
123		/// @return collectableAmt The amount made collectable for the account
124		/// on top of what was collectable before.
125		/// @return splitAmt The amount split to the account's splits receivers
126	9×	function _splitResult(uint256 accountId, SplitsReceiver[] memory currReceivers, uint128 amount)
127		internal
128		view
129	2×	returns (uint128 collectableAmt, uint128 splitAmt)
130		{
131	6×	_assertCurrSplits(accountId, currReceivers);
132	8×	if (amount == 0) {
133	8×	return (0, 0);
134		}
135	1×	unchecked {
136	1×	uint256 splitsWeight = 0;
137	15×	for (uint256 i = currReceivers.length; i != 0;) {
138	30×	splitsWeight += currReceivers[--i].weight;
139		}
140	14×	splitAmt = uint128(amount * splitsWeight / _TOTAL_SPLITS_WEIGHT);
141	5×	collectableAmt = amount - splitAmt;
142		}
143		}
144
145		/// @notice Splits the account's splittable funds among receivers.
146		/// The entire splittable balance of the given ERC-20 token is split.
147		/// All split funds are split using the current splits configuration.
148		/// @param accountId The account ID.
149		/// @param erc20 The used ERC-20 token.
150		/// @param currReceivers The list of the account's current splits receivers.
151		/// It must be exactly the same as the last list set for the account with `_setSplits`.
152		/// If the splits have never been set, pass an empty array.
153		/// @return collectableAmt The amount made collectable for the account
154		/// on top of what was collectable before.
155		/// @return splitAmt The amount split to the account's splits receivers
156	27×	function _split(uint256 accountId, IERC20 erc20, SplitsReceiver[] memory currReceivers)
157		internal
158	6×	returns (uint128 collectableAmt, uint128 splitAmt)
159	3×	{
160	18×	_assertCurrSplits(accountId, currReceivers);
161	123×	SplitsBalance storage balance = _splitsStorage().splitsStates[accountId].balances[erc20];
162
163	45×	collectableAmt = balance.splittable;
164	24×	if (collectableAmt == 0) {
165	27×	return (0, 0);
166		}
167	69×	balance.splittable = 0;
168
169	3×	unchecked {
170	3×	uint256 splitsWeight = 0;
171	55×	for (uint256 i = 0; i < currReceivers.length; i++) {
172	48×	splitsWeight += currReceivers[i].weight;
173	8×	uint128 currSplitAmt = splitAmt;
174	28×	splitAmt = uint128(collectableAmt * splitsWeight / _TOTAL_SPLITS_WEIGHT);
175	10×	currSplitAmt = splitAmt - currSplitAmt;
176	42×	uint256 receiver = currReceivers[i].accountId;
177	14×	_addSplittable(receiver, erc20, currSplitAmt);
178	44×	emit Split(accountId, receiver, erc20, currSplitAmt);
179		}
180	15×	collectableAmt -= splitAmt;
181		// This will not overflow if the requirement of tracking in the contract
182		// no more than `_MAX_SPLITS_BALANCE` of each token is followed.
183	114×	balance.collectable += collectableAmt;
184		}
185	63×	emit Collectable(accountId, erc20, collectableAmt);
186		}
187
188		/// @notice Returns account's received funds already split and ready to be collected.
189		/// @param accountId The account ID.
190		/// @param erc20 The used ERC-20 token.
191		/// @return amt The collectable amount.
192	14×	function _collectable(uint256 accountId, IERC20 erc20) internal view returns (uint128 amt) {
193	104×	return _splitsStorage().splitsStates[accountId].balances[erc20].collectable;
194		}
195
196		/// @notice Collects account's received already split funds.
197		/// @param accountId The account ID.
198		/// @param erc20 The used ERC-20 token.
199		/// @return amt The collected amount
200	8×	function _collect(uint256 accountId, IERC20 erc20) internal returns (uint128 amt) {
201	41×	SplitsBalance storage balance = _splitsStorage().splitsStates[accountId].balances[erc20];
202	15×	amt = balance.collectable;
203	23×	balance.collectable = 0;
204	21×	emit Collected(accountId, erc20, amt);
205		}
206
207		/// @notice Gives funds from the account to the receiver.
208		/// The receiver can split and collect them immediately.
209		/// @param accountId The account ID.
210		/// @param receiver The receiver account ID.
211		/// @param erc20 The used ERC-20 token.
212		/// @param amt The given amount
213	6×	function _give(uint256 accountId, uint256 receiver, IERC20 erc20, uint128 amt) internal {
214	7×	_addSplittable(receiver, erc20, amt);
215	22×	emit Given(accountId, receiver, erc20, amt);
216		}
217
218		/// @notice Sets the account splits configuration.
219		/// The configuration is common for all ERC-20 tokens.
220		/// Nothing happens to the currently splittable funds, but when they are split
221		/// after this function finishes, the new splits configuration will be used.
222		/// @param accountId The account ID.
223		/// @param receivers The list of the account's splits receivers to be set.
224		/// Must be sorted by the account IDs, without duplicate account IDs and without 0 weights.
225		/// Each splits receiver will be getting `weight / _TOTAL_SPLITS_WEIGHT`
226		/// share of the funds collected by the account.
227		/// If the sum of weights of all receivers is less than `_TOTAL_SPLITS_WEIGHT`,
228		/// some funds won't be split, but they will be left for the account to collect.
229		/// Fractions of tokens are always rounder either up or down depending on the amount
230		/// being split, the receiver's position on the list and the other receivers' weights.
231		/// It's valid to include the account's own `accountId` in the list of receivers,
232		/// but funds split to themselves return to their splittable balance and are not collectable.
233		/// This is usually unwanted, because if splitting is repeated,
234		/// funds split to themselves will be again split using the current configuration.
235		/// Splitting 100% to self effectively blocks splitting unless the configuration is updated.
236	14×	function _setSplits(uint256 accountId, SplitsReceiver[] memory receivers) internal {
237	44×	SplitsState storage state = _splitsStorage().splitsStates[accountId];
238	16×	bytes32 newSplitsHash = _hashSplits(receivers);
239	26×	if (newSplitsHash == state.splitsHash) return;
240	24×	emit SplitsSet(accountId, newSplitsHash);
241	12×	_assertSplitsValid(receivers, newSplitsHash);
242	16×	state.splitsHash = newSplitsHash;
243		}
244
245		/// @notice Validates a list of splits receivers and emits events for them
246		/// @param receivers The list of splits receivers
247		/// @param receiversHash The hash of the list of splits receivers.
248		/// Must be sorted by the account IDs, without duplicate account IDs and without 0 weights.
249	8×	function _assertSplitsValid(SplitsReceiver[] memory receivers, bytes32 receiversHash) private {
250	4×	unchecked {
251	14×	require(receivers.length <= _MAX_SPLITS_RECEIVERS, "Too many splits receivers");
252	2×	uint256 totalWeight = 0;
253	2×	uint256 prevAccountId = 0;
254	46×	for (uint256 i = 0; i < receivers.length; i++) {
255	36×	SplitsReceiver memory receiver = receivers[i];
256	14×	uint32 weight = receiver.weight;
257	35×	require(weight != 0, "Splits receiver weight is zero");
258	14×	totalWeight += weight;
259	14×	uint256 accountId = receiver.accountId;
260	12×	if (accountId <= prevAccountId) require(i == 0, "Splits receivers not sorted");
261	6×	prevAccountId = accountId;
262	38×	emit SplitsReceiverSeen(receiversHash, accountId, weight);
263		}
264	35×	require(totalWeight <= _TOTAL_SPLITS_WEIGHT, "Splits weights sum too high");
265		}
266		}
267
268		/// @notice Asserts that the list of splits receivers is the account's currently used one.
269		/// @param accountId The account ID.
270		/// @param currReceivers The list of the account's current splits receivers.
271		/// If the splits have never been set, pass an empty array.
272	12×	function _assertCurrSplits(uint256 accountId, SplitsReceiver[] memory currReceivers)
273		internal
274		view
275		{
276	9×	require(
277	33×	_hashSplits(currReceivers) == _splitsHash(accountId), "Invalid current splits receivers"
278		);
279		}
280
281		/// @notice Current account's splits hash, see `hashSplits`.
282		/// @param accountId The account ID.
283		/// @return currSplitsHash The current account's splits hash
284	18×	function _splitsHash(uint256 accountId) internal view returns (bytes32 currSplitsHash) {
285	72×	return _splitsStorage().splitsStates[accountId].splitsHash;
286		}
287
288		/// @notice Calculates the hash of the list of splits receivers.
289		/// @param receivers The list of the splits receivers.
290		/// If the splits have never been set, pass an empty array.
291		/// @return receiversHash The hash of the list of splits receivers.
292	18×	function _hashSplits(SplitsReceiver[] memory receivers)
293		internal
294		pure
295	3×	returns (bytes32 receiversHash)
296		{
297	20×	if (receivers.length == 0) {
298	21×	return bytes32(0);
299		}
300	62×	return keccak256(abi.encode(receivers));
301		}
302
303		/// @notice Returns the Splits storage.
304		/// @return splitsStorage The storage.
305	12×	function _splitsStorage() private view returns (SplitsStorage storage splitsStorage) {
306	12×	bytes32 slot = _splitsStorageSlot;
307		// slither-disable-next-line assembly
308	3×	assembly {
309	9×	splitsStorage.slot := slot
310		}
311		}
312		}

1		// SPDX-License-Identifier: MIT
2
3		import "./EchidnaInvariantTests.sol";
4		import "./EchidnaBasicTests.sol";
5		import "./EchidnaSplitsTests.sol";
6		import "./EchidnaStreamsTests.sol";
7		import "./EchidnaSqueezeTests.sol";
8
9		/**
10		* @title Echidna contract for testing the Drips contract
11		* @author Rappie <rappie@perimetersec.io>
12		* @dev Running the tests:
13		* For Echidna use `echidna . --contract Echidna --config echidna-config.yaml`.
14		* For Medusa use `medusa fuzz`.
15		* The tests are split into multiple files to be able to toggle the fuzzing
16		* of specific features on and off. This is done by commenting out the
17		* corresponding inherited contract in the Echidna contract below.
18		* Basic tests contain basic features like giving, receiving, splitting and
19		* collecting.
20		* Splits tests contain tests for splitting.
21		* Streams tests contain tests for receiving streams.
22		* Squeeze tests contain tests for squeezing.
23		* Invariant tests contain tests for invariant properties of the system. These
24		* make most sense with all other tests enabled.
25		* For further performance improvements, resource heavy tests can be toggled.
26		* To do so, change the value of TOGGLE_HEAVY_TESTS_ENABLED in EchidnaConfig.
27		*/
28	0	contract Echidna is
29		EchidnaBasicTests,
30		EchidnaSplitsTests,
31		EchidnaStreamsTests,
32		EchidnaSqueezeTests,
33		EchidnaInvariantTests
34		{
35
36		}

1		// SPDX-License-Identifier: MIT
2
3		import "./base/EchidnaBase.sol";
4
5		/**
6		* @title Mixin containing basic helper functions
7		* @author Rappie <rappie@perimetersec.io>
8		*/
9	0	contract EchidnaBasicHelpers is EchidnaBase {
10		/**
11		* @notice Give balance to an account
12		* @param fromAccId Account id of the giver
13		* @param toAccId Account id of the receiver
14		* @param amount Amount to give
15		*/
16	24×	function give(
17		uint8 fromAccId,
18		uint8 toAccId,
19		uint128 amount
20	3×	) public {
21	8×	address from = getAccount(fromAccId);
22	8×	address to = getAccount(toAccId);
23
24	8×	uint256 toDripsAccId = getDripsAccountId(to);
25
26	62×	hevm.prank(from);
27	83×	driver.give(toDripsAccId, token, amount);
28		}
29
30		/**
31		* @notice Give a clamped amount to an account
32		* @param fromAccId Account id of the giver
33		* @param toAccId Account id of the receiver
34		* @param amount Amount to give
35		*/
36	24×	function giveClampedAmount(
37		uint8 fromAccId,
38		uint8 toAccId,
39		uint128 amount
40	4×	) public {
41	8×	address from = getAccount(fromAccId);
42
43	4×	uint128 min = 1000;
44	79×	uint128 max = uint128(token.balanceOf(from));
45	32×	uint128 clampedAmount = min + (amount % (max - min + 1));
46
47	7×	give(fromAccId, toAccId, clampedAmount);
48		}
49
50		/**
51		* @notice Receive streams
52		* @param targetAccId Account id of the receiver
53		* @param maxCycles Maximum number of cycles to receive
54		* @return Amount received
55		* @dev Receiving means moving receivable (already streamed) balance to
56		* splittable (available for splitting) balance
57		*/
58	45×	function receiveStreams(uint8 targetAccId, uint32 maxCycles)
59		public
60	2×	returns (uint128)
61		{
62	16×	address target = getAccount(targetAccId);
63	16×	uint256 targetDripsAccId = getDripsAccountId(target);
64
65	176×	uint128 receivedAmt = drips.receiveStreams(
66	2×	targetDripsAccId,
67	22×	token,
68	2×	maxCycles
69		);
70
71	12×	return receivedAmt;
72		}
73
74		/**
75		* @notice Receive streams for all possible cycles
76		* @param targetAccId Account id of the receiver
77		* @return Amount received
78		* @dev We pass maxuint32 to receive all possible cycles
79		*/
80	43×	function receiveStreamsAllCycles(uint8 targetAccId)
81		public
82	2×	returns (uint128)
83		{
84	16×	return receiveStreams(targetAccId, type(uint32).max);
85		}
86
87		/**
88		* @notice Split received funds
89		* @param targetAccId Account to have their funds split
90		* @return Amount collectable and amount split
91		* @dev Splitting means moving splittable (available for splitting) balance
92		* to collectable (available for collecting) balance
93		*/
94	89×	function split(uint8 targetAccId) public returns (uint128, uint128) {
95	24×	address target = getAccount(targetAccId);
96	24×	uint256 targetDripsAccId = getDripsAccountId(target);
97
98	252×	(uint128 collectableAmt, uint128 splitAmt) = drips.split(
99	3×	targetDripsAccId,
100	33×	token,
101	15×	getSplitsReceivers(target)
102		);
103
104	30×	return (collectableAmt, splitAmt);
105		}
106
107		/**
108		* @notice Collect funds
109		* @param fromAccId Account id of the giver
110		* @param toAccId Account id of the receiver
111		* @return Amount collected
112		* @dev Collecting means moving withdrawing collectable funds to actual
113		* balance of the erc20 token
114		*/
115	42×	function collect(uint8 fromAccId, uint8 toAccId) public returns (uint128) {
116	16×	address from = getAccount(fromAccId);
117	16×	address to = getAccount(toAccId);
118
119	114×	hevm.prank(from);
120	92×	uint128 collected = driver.collect(token, to);
121
122	6×	return collected;
123		}
124
125		/**
126		* @notice Collect funds to self
127		* @param targetAccId Target account
128		*/
129	23×	function collectToSelf(uint8 targetAccId) public {
130	12×	collect(targetAccId, targetAccId);
131		}
132
133		/**
134		* @notice Split and collect funds to self
135		* @param targetAccId Target account
136		* @dev Extra helper that narrows the search space for the fuzzer
137		*/
138	23×	function splitAndCollectToSelf(uint8 targetAccId) public {
139	14×	split(targetAccId);
140	9×	collectToSelf(targetAccId);
141		}
142
143		/**
144		* @notice Receive streams, split and collect funds to self
145		* @param targetAccId Target account
146		* @dev Extra helper that narrows the search space for the fuzzer
147		*/
148	23×	function receiveStreamsSplitAndCollectToSelf(uint8 targetAccId) public {
149	12×	receiveStreamsAllCycles(targetAccId);
150	9×	splitAndCollectToSelf(targetAccId);
151		}
152		}

1		// SPDX-License-Identifier: MIT
2
3		import "./base/EchidnaBase.sol";
4		import "./EchidnaBasicHelpers.sol";
5
6		/**
7		* @title Mixin containing basic tests
8		* @author Rappie <rappie@perimetersec.io>
9		*/
10	0	contract EchidnaBasicTests is EchidnaBase, EchidnaBasicHelpers {
11		/**
12		* @notice Giving an amount `<=` token balance should never revert
13		* @param fromAccId Account id of the giver
14		* @param toAccId Account id of the receiver
15		* @param amount Amount to give
16		*/
17	24×	function testGiveShouldNotRevert(
18		uint8 fromAccId,
19		uint8 toAccId,
20		uint128 amount
21	3×	) public {
22	8×	address from = getAccount(fromAccId);
23	8×	address to = getAccount(toAccId);
24
25	8×	uint256 toDripsAccId = getDripsAccountId(to);
26
27	87×	require(amount <= token.balanceOf(from));
28
29	62×	hevm.prank(from);
30	81×	try driver.give(toDripsAccId, token, amount) {} catch {
31	0	assert(false);
32		}
33		}
34
35		/**
36		* @notice Test internal accounting after receiving streams
37		* @param targetAccId Account id of the receiver
38		* @param maxCycles Maximum number of cycles to receive
39		*/
40	28×	function testReceiveStreams(uint8 targetAccId, uint32 maxCycles) public {
41	8×	address target = getAccount(targetAccId);
42	8×	uint256 targetDripsAccId = getDripsAccountId(target);
43
44	91×	uint128 splittableBefore = drips.splittable(targetDripsAccId, token);
45	9×	uint128 receivedAmt = receiveStreams(targetAccId, maxCycles);
46	91×	uint128 splittableAfter = drips.splittable(targetDripsAccId, token);
47
48	17×	assert(splittableAfter == splittableBefore + receivedAmt);
49
50	12×	if (receivedAmt > 0) {
51	10×	assert(splittableAfter > splittableBefore);
52		} else {
53	10×	assert(splittableAfter == splittableBefore);
54		}
55		}
56
57		/**
58		* @notice Receiving streams should never revert
59		* @param targetAccId Account id of the receiver
60		*/
61	24×	function testReceiveStreamsShouldNotRevert(uint8 targetAccId) public {
62	8×	address target = getAccount(targetAccId);
63	8×	uint256 targetDripsAccId = getDripsAccountId(target);
64
65	5×	try
66	92×	drips.receiveStreams(targetDripsAccId, token, type(uint32).max)
67		{} catch {
68	6×	assert(false);
69		}
70		}
71
72		/**
73		* @notice If there is a receivable amount, there should be at least one
74		* receivable cycle
75		* @param targetAccId Account id of the receiver
76		* @param maxCycles Maximum number of cycles to receive
77		*/
78	23×	function testReceiveStreamsViewConsistency(
79		uint8 targetAccId,
80		uint32 maxCycles
81	4×	) public {
82	8×	address target = getAccount(targetAccId);
83	8×	uint256 targetDripsAccId = getDripsAccountId(target);
84
85	11×	require(maxCycles > 0);
86
87	87×	uint128 receivable = drips.receiveStreamsResult(
88	1×	targetDripsAccId,
89	11×	token,
90	1×	maxCycles
91		);
92	79×	uint32 receivableCycles = drips.receivableStreamsCycles(
93	1×	targetDripsAccId,
94	11×	token
95		);
96
97	17×	if (receivable > 0) assert(receivableCycles > 0);
98
99		// this does not hold because you can have cycles with 0 amount receivable
100		// if (receivableCycles > 0) assert(receivable > 0);
101		}
102
103		/**
104		* @notice `drips.receiveStreamsResult` should match actual received amount
105		* @param targetAccId Account id of the receiver
106		* @param maxCycles Maximum number of cycles to receive
107		*/
108	23×	function testReceiveStreamsViewVsActual(uint8 targetAccId, uint32 maxCycles)
109		public
110	4×	{
111	8×	address target = getAccount(targetAccId);
112	8×	uint256 targetDripsAccId = getDripsAccountId(target);
113
114	87×	uint128 receivable = drips.receiveStreamsResult(
115	1×	targetDripsAccId,
116	11×	token,
117	1×	maxCycles
118		);
119
120	88×	uint128 received = drips.receiveStreams(
121	1×	targetDripsAccId,
122	11×	token,
123	1×	maxCycles
124		);
125
126	10×	assert(receivable == received);
127		}
128
129		/**
130		* @notice Test internal accounting after collecting
131		* @param fromAccId Account id of the collector
132		* @param toAccId Account id of the receiving account
133		*/
134	31×	function testCollect(uint8 fromAccId, uint8 toAccId) public {
135	8×	address from = getAccount(fromAccId);
136	8×	address to = getAccount(toAccId);
137
138	8×	uint256 fromDripsAccId = getDripsAccountId(from);
139
140	91×	uint128 colBalBefore = drips.collectable(fromDripsAccId, token);
141	79×	uint256 tokenBalBefore = token.balanceOf(to);
142
143	9×	uint128 collected = collect(fromAccId, toAccId);
144
145	91×	uint128 colBalAfter = drips.collectable(fromDripsAccId, token);
146	79×	uint256 tokenBalAfter = token.balanceOf(to);
147
148	17×	assert(colBalAfter == colBalBefore - collected);
149	15×	assert(tokenBalAfter == tokenBalBefore + collected);
150		}
151
152		/**
153		* @notice Collecting should never revert
154		* @param fromAccId Account id of the collector
155		* @param toAccId Account id of the receiving account
156		*/
157	25×	function testCollectShouldNotRevert(uint8 fromAccId, uint8 toAccId) public {
158	8×	address from = getAccount(fromAccId);
159	8×	address to = getAccount(toAccId);
160
161	62×	hevm.prank(from);
162	95×	try driver.collect(token, to) {} catch {
163	0	assert(false);
164		}
165		}
166		}

1		// SPDX-License-Identifier: MIT
2
3		import "./EchidnaBasicHelpers.sol";
4		import "./EchidnaSplitsHelpers.sol";
5		import "./EchidnaStreamsHelpers.sol";
6		import "./EchidnaSqueezeHelpers.sol";
7
8		/**
9		* @title Mixin containing invariant tests
10		* @author Rappie <rappie@perimetersec.io>
11		*/
12	0	contract EchidnaInvariantTests is
13		EchidnaBasicHelpers,
14		EchidnaSplitsHelpers,
15		EchidnaStreamsHelpers,
16		EchidnaSqueezeHelpers
17		{
18		/**
19		* @notice Withdrawing any amount directly from Drips should fail
20		* @param amount Amount to withdraw
21		*/
22	22×	function invariantWithdrawShouldAlwaysFail(uint256 amount) public {
23	25×	require(amount > 0, "withdraw amount must be > 0");
24
25	79×	try drips.withdraw(token, address(this), amount) {
26	0	assert(false);
27		} catch {}
28		}
29
30		/**
31		* @notice `amtPerSec` should never be lower than `drips.minAmtPerSec()`
32		* @param targetAccId Account id of the receiver
33		* @param index Index of the receiver
34		*/
35	23×	function invariantAmtPerSecVsMinAmtPerSec(uint8 targetAccId, uint256 index)
36		public
37	3×	{
38	8×	address target = getAccount(targetAccId);
39
40	8×	StreamReceiver[] memory receivers = getStreamReceivers(target);
41	26×	require(receivers.length > 0, "no receivers");
42
43	11×	index = index % receivers.length;
44	25×	uint160 amtPerSec = receivers[index].config.amtPerSec();
45
46	79×	assert(amtPerSec >= drips.minAmtPerSec());
47		}
48
49		/**
50		* @notice The total of all internal balances should match token balance
51		* of the Drips contract
52		*/
53	10×	function invariantAccountingVsTokenBalance() public {
54	89×	uint256 tokenBalance = token.balanceOf(address(drips));
55	7×	uint256 dripsBalancesTotal = getDripsBalancesTotalForAllUsers();
56
57	6×	assert(tokenBalance == dripsBalancesTotal);
58		}
59
60		/**
61		* @notice Check internal and external balances after withdrawing all funds
62		* from the system
63		*/
64	20×	function invariantWithdrawAllTokens() external heavy {
65		// remove all splits to prevent tokens from getting stuck in case
66		// there are splits to self
67	62×	removeAllSplits(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER0]);
68	61×	removeAllSplits(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER1]);
69	31×	removeAllSplits(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER2]);
70	31×	removeAllSplits(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER3]);
71
72	31×	squeezeAllSenders(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER0]);
73	31×	squeezeAllSenders(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER1]);
74	31×	squeezeAllSenders(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER2]);
75	31×	squeezeAllSenders(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER3]);
76
77	4×	receiveStreamsSplitAndCollectToSelf(
78	27×	ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER0]
79		);
80	4×	receiveStreamsSplitAndCollectToSelf(
81	27×	ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER1]
82		);
83	4×	receiveStreamsSplitAndCollectToSelf(
84	27×	ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER2]
85		);
86	4×	receiveStreamsSplitAndCollectToSelf(
87	27×	ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER3]
88		);
89
90	32×	setStreamBalanceWithdrawAll(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER0]);
91	32×	setStreamBalanceWithdrawAll(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER1]);
92	32×	setStreamBalanceWithdrawAll(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER2]);
93	32×	setStreamBalanceWithdrawAll(ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER3]);
94
95	89×	uint256 dripsBalance = token.balanceOf(address(drips));
96	78×	uint256 user0Balance = token.balanceOf(ADDRESS_USER0);
97	78×	uint256 user1Balance = token.balanceOf(ADDRESS_USER1);
98	78×	uint256 user2Balance = token.balanceOf(ADDRESS_USER2);
99	78×	uint256 user3Balance = token.balanceOf(ADDRESS_USER3);
100
101	22×	uint256 totalUserBalance = user0Balance +
102	1×	user1Balance +
103	1×	user2Balance +
104	1×	user3Balance;
105
106	6×	assert(dripsBalance == 0);
107	12×	assert(totalUserBalance == STARTING_BALANCE * 4);
108		}
109
110		/**
111		* @notice Withdrawing all funds from the system should never revert
112		*/
113	9×	function invariantWithdrawAllTokensShouldNotRevert() public heavy {
114	4×	try
115	46×	EchidnaInvariantTests(address(this)).invariantWithdrawAllTokens()
116		{} catch {
117	6×	assert(false);
118		}
119		}
120
121		/**
122		* @notice The sum of all `amtDelta`s for an account should be zero
123		* @param targetAccId Target account to perform the test on
124		*/
125	29×	function invariantSumAmtDeltaIsZero(uint8 targetAccId) public heavy {
126	8×	address target = getAccount(targetAccId);
127	8×	uint256 targetDripsAccId = getDripsAccountId(target);
128
129	7×	uint32 maxEnd = getMaxEndForAllUsers();
130
131	9×	uint32 firstCycle = getCycleFromTimestamp(STARTING_TIMESTAMP);
132	10×	uint32 lastCycle = getCycleFromTimestamp(maxEnd);
133
134	27×	require(maxEnd > 0, "no cycles");
135	10×	require(firstCycle != lastCycle, "only one cycle");
136
137		// limit amount of cycles for gas & memory savings
138	34×	require(lastCycle - firstCycle < 1000, "too many cycles");
139
140	1×	int256 sumAmtDelta = 0;
141
142	30×	for (uint32 cycle = firstCycle; cycle <= lastCycle; cycle++) {
143	83×	(int128 thisCycle, int128 nextCycle) = drips.getAmtDeltaForCycle(
144	1×	targetDripsAccId,
145	11×	token,
146	1×	cycle
147		);
148
149	12×	sumAmtDelta += int256(thisCycle);
150	12×	sumAmtDelta += int256(nextCycle);
151		}
152
153	6×	assert(sumAmtDelta == 0);
154		}
155		}

1		// SPDX-License-Identifier: MIT
2
3		import "./base/EchidnaBase.sol";
4
5		/**
6		* @title Mixin containing helpers for splitting
7		* @author Rappie <rappie@perimetersec.io>
8		*/
9	0	contract EchidnaSplitsHelpers is EchidnaBase {
10		/**
11		* @notice Internal helper function to set splits receivers
12		* @param senderAccId Account id of the sender
13		* @param unsortedReceivers Receivers list to set
14		* @dev This function also sorts the receivers list
15		*/
16	9×	function _setSplits(
17		uint8 senderAccId,
18		SplitsReceiver[] memory unsortedReceivers
19	4×	) internal {
20	24×	address sender = getAccount(senderAccId);
21
22	21×	SplitsReceiver[] memory newReceivers = bubbleSortSplitsReceivers(
23	3×	unsortedReceivers
24		);
25
26	18×	updateSplitsReceivers(sender, newReceivers);
27
28	176×	hevm.prank(sender);
29	131×	driver.setSplits(newReceivers);
30		}
31
32		/**
33		* @notice Set splits, overwriting the current receivers list
34		* @param senderAccId Account id of the sender
35		* @param receiverAccId Account id of the receiver in the receivers list
36		* @param weight Weight of the receiver
37		*/
38	29×	function setSplits(
39		uint8 senderAccId,
40		uint8 receiverAccId,
41		uint32 weight
42	8×	) public {
43	16×	address sender = getAccount(senderAccId);
44	16×	address receiver = getAccount(receiverAccId);
45	16×	uint256 receiverDripsAccId = getDripsAccountId(receiver);
46
47	108×	SplitsReceiver[] memory receivers = new SplitsReceiver[](1);
48	70×	receivers[0] = SplitsReceiver({
49	2×	accountId: receiverDripsAccId,
50	2×	weight: weight
51		});
52	12×	updateSplitsReceivers(sender, receivers);
53
54	12×	_setSplits(senderAccId, receivers);
55		}
56
57		/**
58		* @notice Set splits, overwriting the current receivers list
59		* @param senderAccId Account id of the sender
60		* @param receiverAccId Account id of the receiver in the receivers list
61		* @param weight Weight of the receiver
62		* @dev This function clamps the weight between the minimum and maximum
63		* allowed values
64		*/
65	48×	function setSplitsWithClamping(
66		uint8 senderAccId,
67		uint8 receiverAccId,
68		uint32 weight
69		) public {
70	16×	weight = clampSplitWeight(weight, 0); // there are no existing weights
71	14×	setSplits(senderAccId, receiverAccId, weight);
72		}
73
74		/**
75		* @notice Add a splits receiver to the existing list of receivers
76		* @param senderAccId Account id of the sender
77		* @param receiverAccId Account id of the receiver to add
78		* @param weight Weight of the receiver
79		*/
80	29×	function addSplitsReceiver(
81		uint8 senderAccId,
82		uint8 receiverAccId,
83		uint32 weight
84	14×	) public {
85	16×	address sender = getAccount(senderAccId);
86	16×	address receiver = getAccount(receiverAccId);
87	16×	uint256 senderDripsAccId = getDripsAccountId(sender);
88	16×	uint256 receiverDripsAccId = getDripsAccountId(receiver);
89
90	16×	SplitsReceiver[] memory oldReceivers = getSplitsReceivers(sender);
91
92	40×	SplitsReceiver memory addedReceiver = SplitsReceiver({
93	2×	accountId: receiverDripsAccId,
94	2×	weight: weight
95		});
96
97	106×	SplitsReceiver[] memory newReceivers = new SplitsReceiver[](
98	18×	oldReceivers.length + 1
99		);
100	46×	for (uint256 i = 0; i < oldReceivers.length; i++) {
101	66×	newReceivers[i] = oldReceivers[i];
102		}
103	54×	newReceivers[newReceivers.length - 1] = addedReceiver;
104
105	12×	_setSplits(senderAccId, newReceivers);
106		}
107
108		/**
109		* @notice Add a splits receiver to the existing list of receivers
110		* @param senderAccId Account id of the sender
111		* @param receiverAccId Account id of the receiver to add
112		* @param weight Weight of the receiver
113		* @dev This function clamps the weight between the minimum and maximum
114		* allowed values
115		*/
116	50×	function addSplitsReceiverWithClamping(
117		uint8 senderAccId,
118		uint8 receiverAccId,
119		uint32 weight
120	6×	) public {
121	16×	address sender = getAccount(senderAccId);
122
123		// sum all the existing weights
124	2×	uint32 existingWeights;
125	16×	SplitsReceiver[] memory receivers = getSplitsReceivers(sender);
126	46×	for (uint256 i = 0; i < receivers.length; i++) {
127	54×	existingWeights += receivers[i].weight;
128		}
129
130		// we can't add a receiver if it makes the total weight go over the
131		// maximum allowed
132	156×	if (existingWeights >= drips.TOTAL_SPLITS_WEIGHT()) return;
133
134	16×	weight = clampSplitWeight(weight, existingWeights);
135
136	14×	addSplitsReceiver(senderAccId, receiverAccId, weight);
137		}
138
139		/**
140		* @notice Remove any existing splits
141		* @param targetAccId Target account id
142		*/
143	28×	function removeAllSplits(uint8 targetAccId) public {
144	96×	SplitsReceiver[] memory receivers = new SplitsReceiver[](0);
145	17×	_setSplits(targetAccId, receivers);
146		}
147
148		/**
149		* @notice Clamp the weight between the minimum and maximum allowed values
150		* @param weight Weight to clamp
151		* @param existingWeights Sum of all the existing weights
152		* @return Clamped weight
153		*/
154	12×	function clampSplitWeight(uint32 weight, uint32 existingWeights)
155		public
156		view
157	2×	returns (uint32)
158		{
159	184×	return (weight % (drips.TOTAL_SPLITS_WEIGHT() - existingWeights)) + 1;
160		}
161		}

1		// SPDX-License-Identifier: MIT
2
3		import "./base/EchidnaBase.sol";
4
5		/**
6		* @title Mixin containing helpers for streams
7		* @author Rappie <rappie@perimetersec.io>
8		*/
9	0	contract EchidnaStreamsHelpers is EchidnaBase {
10		// Internal variables to store maxEndHint1 and maxEndHint2. These are used
11		// as hints to the Drips contract to speed up the setStreams call.
12		//
13		// Instead of fuzzing these directly, we use the `setMaxEndHints` helper
14		// function to set these values. This makes fuzzing these toggleable and
15		// also makes debugging easier because the values don't have to be passed
16		// as arguments to all functions calling `setStreams`.
17		//
18		uint32 internal maxEndHint1;
19		uint32 internal maxEndHint2;
20
21		/**
22		* @notice Internal helper function to set streams receivers
23		* @param from Account to set streams for
24		* @param currReceivers Current stream receivers (Drips needs this)
25		* @param balanceDelta Balance delta to set
26		* @param unsortedNewReceivers New receivers list to set
27		* @return Real balance delta
28		* @dev This function also sorts the receivers list
29		*/
30	17×	function _setStreams(
31		address from,
32		StreamReceiver[] memory currReceivers,
33		int128 balanceDelta,
34		StreamReceiver[] memory unsortedNewReceivers
35	3×	) internal returns (int128) {
36	21×	StreamReceiver[] memory newReceivers = bubbleSortStreamReceivers(
37	3×	unsortedNewReceivers
38		);
39
40	176×	hevm.prank(from);
41	177×	int128 realBalanceDelta = driver.setStreams(
42	22×	token,
43	2×	currReceivers,
44	2×	balanceDelta,
45	2×	newReceivers,
46	22×	maxEndHint1,
47	22×	maxEndHint2,
48	2×	from
49		);
50
51	12×	updateStreamReceivers(from, newReceivers);
52
53	10×	return realBalanceDelta;
54		}
55
56		/**
57		* @notice Set streams, overwriting the current receivers list
58		* @param fromAccId Account id of the sender
59		* @param toAccId Account id of the receiver in the receivers list
60		* @param amountPerSec Amount per second to stream
61		* @param startTime Start time of the stream
62		* @param duration Duration of the stream
63		* @param balanceDelta Balance delta to set
64		* @return Real balance delta
65		*/
66	53×	function setStreams(
67		uint8 fromAccId,
68		uint8 toAccId,
69		uint160 amountPerSec,
70		uint32 startTime,
71		uint32 duration,
72		int128 balanceDelta
73	2×	) public returns (int128) {
74	16×	address from = getAccount(fromAccId);
75	16×	address to = getAccount(toAccId);
76
77	108×	StreamReceiver[] memory receivers = new StreamReceiver[](1);
78	66×	receivers[0] = StreamReceiver(
79	10×	getDripsAccountId(to),
80	8×	StreamConfigImpl.create(
81	2×	0, // streamId is arbitrary and can be ignored
82	2×	amountPerSec,
83	2×	startTime,
84	2×	duration
85		)
86		);
87
88	14×	int128 realBalanceDelta = _setStreams(
89	2×	from,
90	10×	getStreamReceivers(from),
91	2×	balanceDelta,
92	2×	receivers
93		);
94
95	14×	return realBalanceDelta;
96		}
97
98		/**
99		* @notice Set streams, overwriting the current receivers list
100		* @param fromAccId Account id of the sender
101		* @param toAccId Account id of the receiver in the receivers list
102		* @param amountPerSec Amount per second to stream
103		* @param startTime Start time of the stream
104		* @param duration Duration of the stream
105		* @param balanceDelta Balance delta to set
106		* @return Real balance delta
107		* @dev This function clamps the amountPerSec, startTime, duration and
108		* balanceDelta between the minimum and maximum allowed values
109		*/
110	86×	function setStreamsWithClamping(
111		uint8 fromAccId,
112		uint8 toAccId,
113		uint160 amountPerSec,
114		uint32 startTime,
115		uint32 duration,
116		int128 balanceDelta
117	6×	) public returns (int128) {
118	16×	address from = getAccount(fromAccId);
119	16×	address to = getAccount(toAccId);
120
121	14×	amountPerSec = clampAmountPerSec(amountPerSec);
122	14×	startTime = clampStartTime(startTime);
123	14×	duration = clampDuration(duration);
124	16×	balanceDelta = clampBalanceDelta(balanceDelta, from);
125
126	10×	setStreams(
127	2×	fromAccId,
128	2×	toAccId,
129	2×	amountPerSec,
130	2×	startTime,
131	2×	duration,
132	2×	balanceDelta
133		);
134		}
135
136		/**
137		* @notice Add a stream receiver to the existing list of receivers
138		* @param fromAccId Account id of the sender
139		* @param toAccId Account id of the receiver to add
140		* @param amountPerSec Amount per second to stream
141		* @param startTime Start time of the stream
142		* @param duration Duration of the stream
143		* @param balanceDelta Balance delta to set
144		* @return Real balance delta
145		*/
146	54×	function addStream(
147		uint8 fromAccId,
148		uint8 toAccId,
149		uint160 amountPerSec,
150		uint32 startTime,
151		uint32 duration,
152		int128 balanceDelta
153	3×	) public returns (int128) {
154	24×	address from = getAccount(fromAccId);
155	24×	address to = getAccount(toAccId);
156
157	24×	StreamReceiver[] memory oldReceivers = getStreamReceivers(from);
158
159	54×	StreamReceiver memory addedReceiver = StreamReceiver(
160	15×	getDripsAccountId(to),
161	12×	StreamConfigImpl.create(
162	3×	0, // streamId is arbitrary and can be ignored
163	3×	amountPerSec,
164	3×	startTime,
165	3×	duration
166		)
167		);
168
169	159×	StreamReceiver[] memory newReceivers = new StreamReceiver[](
170	27×	oldReceivers.length + 1
171		);
172	69×	for (uint256 i = 0; i < oldReceivers.length; i++) {
173	99×	newReceivers[i] = oldReceivers[i];
174		}
175	81×	newReceivers[newReceivers.length - 1] = addedReceiver;
176
177	18×	int128 realBalanceDelta = _setStreams(
178	3×	from,
179	3×	oldReceivers,
180	3×	balanceDelta,
181	3×	newReceivers
182		);
183
184	18×	return realBalanceDelta;
185		}
186
187		/**
188		* @notice Add a stream receiver to the existing list of receivers
189		* @param fromAccId Account id of the sender
190		* @param toAccId Account id of the receiver to add
191		* @param amountPerSec Amount per second to stream
192		* @param startTime Start time of the stream
193		* @param duration Duration of the stream
194		* @param balanceDelta Balance delta to set
195		* @dev This function clamps the amountPerSec, startTime, duration and
196		* balanceDelta between the minimum and maximum allowed values
197		*/
198	86×	function addStreamWithClamping(
199		uint8 fromAccId,
200		uint8 toAccId,
201		uint160 amountPerSec,
202		uint32 startTime,
203		uint32 duration,
204		int128 balanceDelta
205	2×	) public returns (int128) {
206	16×	address from = getAccount(fromAccId);
207
208	14×	amountPerSec = clampAmountPerSec(amountPerSec);
209	14×	startTime = clampStartTime(startTime);
210	14×	duration = clampDuration(duration);
211	16×	balanceDelta = clampBalanceDelta(balanceDelta, from);
212
213	6×	return
214	8×	addStream(
215	2×	fromAccId,
216	2×	toAccId,
217	2×	amountPerSec,
218	2×	startTime,
219	2×	duration,
220	2×	balanceDelta
221		);
222		}
223
224		/**
225		* @notice Add a stream receiver to the existing list of receivers, making sure
226		* it is immediately squeezable in a transaction after this call
227		* @param fromAccId Account id of the sender
228		* @param toAccId Account id of the receiver to add
229		* @param amountPerSec Amount per second to stream
230		* @dev This is meant as a helper to quickly seed the corpus with situations
231		* where there is something to squeeze in the next transaction
232		*/
233	24×	function addStreamImmediatelySqueezable(
234		uint8 fromAccId,
235		uint8 toAccId,
236		uint160 amountPerSec
237	4×	) public {
238	8×	address receiver = getAccount(toAccId);
239	8×	address sender = getAccount(fromAccId);
240
241		// calculate amount per second so there will be something to squeeze
242		// this cycle
243	80×	uint160 minAmtPerSec = drips.minAmtPerSec() * SECONDS_PER_CYCLE;
244	2×	amountPerSec =
245	7×	minAmtPerSec +
246	21×	(amountPerSec % (MAX_AMOUNT_PER_SEC - minAmtPerSec + 1));
247
248		// deposit 100 times the amount of 'amountPerSec' so chances are high
249		// that there is enough balance to stream this cycle
250	18×	int128 balanceDelta = (int128(uint128(amountPerSec)) * 100) / 1e9;
251	84×	if (uint128(balanceDelta) > token.balanceOf(sender)) {
252	78×	balanceDelta = int128(uint128(token.balanceOf(sender)));
253		}
254
255		// add the stream
256	11×	addStream(fromAccId, toAccId, amountPerSec, 0, 0, balanceDelta);
257
258		// warp 1 second forward so there is something to squeeze
259	69×	hevm.warp(block.timestamp + 1);
260		}
261
262		/**
263		* @notice Remove a stream receiver from the existing list of receivers
264		* @param targetAccId Account id of the receiver to remove
265		* @param indexSeed Random seed used to determine which receiver to remove
266		*/
267	56×	function removeStream(uint8 targetAccId, uint256 indexSeed) public {
268	16×	address target = getAccount(targetAccId);
269
270	16×	StreamReceiver[] memory oldReceivers = getStreamReceivers(target);
271
272	24×	uint256 index = indexSeed % oldReceivers.length;
273
274	106×	StreamReceiver[] memory newReceivers = new StreamReceiver[](
275	18×	oldReceivers.length - 1
276		);
277	2×	uint256 j = 0;
278	46×	for (uint256 i = 0; i < oldReceivers.length; i++) {
279	12×	if (i != index) {
280	66×	newReceivers[j] = oldReceivers[i];
281	20×	j++;
282		}
283		}
284
285	18×	_setStreams(target, oldReceivers, 0, newReceivers);
286		}
287
288		/**
289		* @notice Update stream balance by calling `setStreams` with the same
290		* receivers list
291		* @param targetAccId Account id of the sender
292		* @param balanceDelta Balance delta to set
293		* @return Real balance delta
294		*/
295	45×	function setStreamBalance(uint8 targetAccId, int128 balanceDelta)
296		public
297	2×	returns (int128)
298		{
299	16×	address target = getAccount(targetAccId);
300
301	14×	int128 realBalanceDelta = _setStreams(
302	2×	target,
303	10×	getStreamReceivers(target),
304	2×	balanceDelta,
305	10×	getStreamReceivers(target)
306		);
307
308	10×	return realBalanceDelta;
309		}
310
311		/**
312		* @notice Update stream balance by calling `setStreams` with the same
313		* receivers list
314		* @param targetAccId Account id of the sender
315		* @param balanceDelta Balance delta to set
316		* @dev This function clamps the balanceDelta between the minimum and
317		* maximum allowed values
318		*/
319	46×	function setStreamBalanceWithClamping(
320		uint8 targetAccId,
321		int128 balanceDelta
322	2×	) public {
323	16×	address target = getAccount(targetAccId);
324	16×	balanceDelta = clampBalanceDelta(balanceDelta, target);
325	14×	setStreamBalance(targetAccId, balanceDelta);
326		}
327
328		/**
329		* @notice Withdraw all stream balance by calling `setStreams` with the same
330		* receivers list and using min int128 as balance delta
331		* @param targetAccId Account id of the sender
332		* @return Real balance delta
333		*/
334	77×	function setStreamBalanceWithdrawAll(uint8 targetAccId)
335		public
336	3×	returns (int128)
337	6×	{
338	24×	address target = getAccount(targetAccId);
339	24×	uint256 targetDripsAccId = getDripsAccountId(target);
340
341	18×	int128 realBalanceDelta = _setStreams(
342	3×	target,
343	15×	getStreamReceivers(target),
344	3×	type(int128).min,
345	15×	getStreamReceivers(target)
346		);
347		}
348
349		/**
350		* @notice Helper function to update the values used as maxEnd hints
351		* @param _maxEndHint1 New value for maxEndHint1
352		* @param _maxEndHint2 New value for maxEndHint2
353		* @dev Can be toggled on/off with TOGGLE_MAXENDHINTS_ENABLED
354		*/
355	23×	function setMaxEndHints(uint32 _maxEndHint1, uint32 _maxEndHint2) public {
356	3×	require(TOGGLE_MAXENDHINTS_ENABLED);
357	21×	maxEndHint1 = _maxEndHint1;
358	21×	maxEndHint2 = _maxEndHint2;
359		}
360
361		/**
362		* @notice Clamp the amountPerSec between the minimum and maximum allowed values
363		* @param amountPerSec Amount per second to clamp
364		* @return Clamped amountPerSec
365		*/
366	10×	function clampAmountPerSec(uint160 amountPerSec)
367		internal
368	2×	returns (uint160)
369		{
370	4×	return
371	150×	drips.minAmtPerSec() +
372	178×	(amountPerSec % (MAX_AMOUNT_PER_SEC - drips.minAmtPerSec() + 1));
373		}
374
375		/**
376		* @notice Clamp the startTime between the minimum and maximum allowed values
377		* @param startTime Start time to clamp
378		* @return Clamped startTime
379		*/
380	14×	function clampStartTime(uint32 startTime) internal returns (uint32) {
381	26×	if (startTime == 0) return 0;
382
383		// We want to make sure that the start time does not go below 1
384	2×	uint32 minStartTime;
385	16×	if (CYCLE_FUZZING_BUFFER_SECONDS >= block.timestamp) {
386	0	minStartTime = 1;
387		} else {
388	4×	minStartTime =
389	14×	uint32(block.timestamp) -
390		CYCLE_FUZZING_BUFFER_SECONDS;
391		}
392
393	20×	uint32 maxStartTime = uint32(block.timestamp) +
394		CYCLE_FUZZING_BUFFER_SECONDS;
395
396	66×	return minStartTime + (startTime % (maxStartTime - minStartTime + 1));
397		}
398
399		/**
400		* @notice Clamp the duration between the minimum and maximum allowed values
401		* @param duration Duration to clamp
402		* @return Clamped duration
403		*/
404	14×	function clampDuration(uint32 duration) internal returns (uint32) {
405	26×	if (duration == 0) return 0;
406
407	32×	return duration % (MAX_STREAM_DURATION + 1);
408		}
409
410		/**
411		* @notice Clamp the balanceDelta between the minimum and maximum allowed values
412		* @param balanceDelta Balance delta to clamp
413		* @param from Account performing the setStreams action
414		* @return Clamped balanceDelta
415		*/
416	18×	function clampBalanceDelta(int128 balanceDelta, address from)
417		internal
418	3×	returns (int128)
419		{
420	35×	if (balanceDelta > 0) {
421	6×	balanceDelta =
422	21×	balanceDelta %
423	249×	(int128(uint128(token.balanceOf(from))) + 1);
424		} else {
425	18×	balanceDelta = balanceDelta % int128(uint128(STARTING_BALANCE));
426		}
427	9×	return balanceDelta;
428		}
429		}

1		// SPDX-License-Identifier: MIT
2
3		import "./EchidnaStorage.sol";
4
5		/**
6		* @title Mixin for handling accounting related functions
7		* @author Rappie <rappie@perimetersec.io>
8		*/
9	0	contract EchidnaAccounting is EchidnaStorage {
10		/**
11		* @notice Get the total amount of drips balances for all users
12		* @return Total drips balances for all users
13		* @dev This is the total amount of drips balances for all users, including
14		* the current stream balance, the receivable amount, the collectable
15		* amount, the splittable amount, and the squeezable amount.
16		*/
17	4×	function getDripsBalancesTotalForAllUsers() internal returns (uint256) {
18	7×	uint256 user0Total = getDripsBalancesTotalForUser(ADDRESS_USER0);
19	7×	uint256 user1Total = getDripsBalancesTotalForUser(ADDRESS_USER1);
20	7×	uint256 user2Total = getDripsBalancesTotalForUser(ADDRESS_USER2);
21	7×	uint256 user3Total = getDripsBalancesTotalForUser(ADDRESS_USER3);
22
23	28×	return user0Total + user1Total + user2Total + user3Total;
24		}
25
26		/**
27		* @notice Get the total amount of drips balances for a user
28		* @param target The user to query
29		* @return Total drips balances for the target user
30		* @dev This is the total amount of drips balances for a user, including
31		* the current stream balance, the receivable amount, the collectable
32		* amount, the splittable amount, and the squeezable amount.
33		*/
34	5×	function getDripsBalancesTotalForUser(address target)
35		internal
36	1×	returns (uint256)
37		{
38	8×	uint256 targetDripsAccId = getDripsAccountId(target);
39
40	8×	uint128 balance = getCurrentStreamBalanceForUser(target);
41	8×	uint128 squeezable = getTotalSqueezableAmountForUser(target);
42	8×	uint128 receivable = getReceivableAmountForUser(target);
43	91×	uint128 collectable = drips.collectable(targetDripsAccId, token);
44	91×	uint128 splittable = drips.splittable(targetDripsAccId, token);
45
46	39×	return balance + squeezable + receivable + collectable + splittable;
47		}
48
49		/**
50		* @notice Get the streamable balance for a user
51		* @param target The user to query
52		* @param timestamp The point in time to get 'balanceAt' from
53		* @return Streamable balance for the target user
54		* @dev This is the streamable balance for a user, which is the current
55		* stream balance minus the receivable amount.
56		*/
57	12×	function getStreamBalanceForUser(address target, uint32 timestamp)
58		internal
59	2×	returns (uint128)
60		{
61	16×	uint256 targetDripsAccId = getDripsAccountId(target);
62
63	2×	uint128 balance;
64	8×	try
65	158×	drips.balanceAt(
66	2×	targetDripsAccId,
67	22×	token,
68	10×	getStreamReceivers(target),
69	2×	timestamp
70		)
71	2×	returns (uint128 _balance) {
72	6×	balance = _balance;
73		} catch {
74		// this should not happen, so put an assert here to be sure
75	0	assert(false);
76		}
77
78	10×	return balance;
79		}
80
81		/**
82		* @notice Get the current stream balance for a user
83		* @param target The user to query
84		* @return Current stream balance for the target user
85		*/
86	5×	function getCurrentStreamBalanceForUser(address target)
87		internal
88	1×	returns (uint128)
89		{
90	8×	return getStreamBalanceForUser(target, uint32(block.timestamp));
91		}
92
93		/**
94		* @notice Get the receivable amount for all users
95		* @return Receivable amount for all users
96		* @dev This is the receivable amount for all users, which means the amount
97		* that has already been streamed to the users but not yet collected.
98		*/
99	8×	function getReceivableAmountForAllUsers() internal returns (uint128) {
100	2×	uint128 receivable;
101	26×	receivable += getReceivableAmountForUser(ADDRESS_USER0);
102	26×	receivable += getReceivableAmountForUser(ADDRESS_USER1);
103	26×	receivable += getReceivableAmountForUser(ADDRESS_USER2);
104	26×	receivable += getReceivableAmountForUser(ADDRESS_USER3);
105	8×	return receivable;
106		}
107
108		/**
109		* @notice Get the receivable amount for a user
110		* @param target The user to query
111		* @return Receivable amount for the target user
112		* @dev This is the receivable amount for a user, which means the amount
113		* that has already been streamed to the user but not yet collected.
114		*/
115	10×	function getReceivableAmountForUser(address target)
116		internal
117	2×	returns (uint128)
118		{
119	174×	uint128 receivable = drips.receiveStreamsResult(
120	10×	getDripsAccountId(target),
121	22×	token,
122	2×	type(uint32).max
123		);
124	8×	return receivable;
125		}
126
127		/**
128		* @notice Get the squeezable amount for all users
129		* @param target The user to query
130		* @return Squeezable amount for all users
131		* @dev This is the squeezable amount for a user, which means the amount
132		* that has already been streamed in the current cycle that is not yet
133		* receivable.
134		*/
135	5×	function getTotalSqueezableAmountForUser(address target)
136		internal
137	1×	returns (uint128)
138		{
139	4×	uint128 amount = 0;
140	14×	amount += getSqueezableAmount(ADDRESS_USER0, target);
141	14×	amount += getSqueezableAmount(ADDRESS_USER1, target);
142	14×	amount += getSqueezableAmount(ADDRESS_USER2, target);
143	14×	amount += getSqueezableAmount(ADDRESS_USER3, target);
144
145	4×	return amount;
146		}
147
148		/**
149		* @notice Get the squeezable amount for a user
150		* @param sender The sender of the stream(s)
151		* @param receiver The receiver of the stream(s)
152		* @return Squeezable amount for the target user
153		* @dev This is the squeezable amount for a user, which means the amount
154		* that has already been streamed in the current cycle that is not yet
155		* receivable.
156		*/
157	12×	function getSqueezableAmount(address sender, address receiver)
158		internal
159	2×	returns (uint128)
160		{
161	16×	uint256 senderDripsAccId = getDripsAccountId(sender);
162	16×	uint256 receiverDripsAccId = getDripsAccountId(receiver);
163
164	164×	uint128 amount = drips.squeezeStreamsResult(
165	2×	receiverDripsAccId,
166	22×	token,
167	2×	senderDripsAccId,
168	6×	bytes32(0),
169	10×	getStreamsHistory(sender)
170		);
171
172	12×	return amount;
173		}
174
175		/**
176		* @notice Get the 'maxEnd' farthest in the future for all users
177		* @return 'maxEnd' fartherst in the future for all users
178		* @dev This is the 'maxEnd' farthest in the future for all users, which
179		* means the farthest in the future that any stream ends for any user.
180		*/
181	4×	function getMaxEndForAllUsers() internal returns (uint32) {
182	1×	uint32 maxMaxEnd;
183
184	7×	uint32 maxEndUser0 = getMaxEndForUser(ADDRESS_USER0);
185	14×	if (maxEndUser0 > maxMaxEnd) maxMaxEnd = maxEndUser0;
186	7×	uint32 maxEndUser1 = getMaxEndForUser(ADDRESS_USER1);
187	14×	if (maxEndUser1 > maxMaxEnd) maxMaxEnd = maxEndUser1;
188	7×	uint32 maxEndUser2 = getMaxEndForUser(ADDRESS_USER2);
189	14×	if (maxEndUser2 > maxMaxEnd) maxMaxEnd = maxEndUser2;
190	7×	uint32 maxEndUser3 = getMaxEndForUser(ADDRESS_USER3);
191	14×	if (maxEndUser3 > maxMaxEnd) maxMaxEnd = maxEndUser3;
192
193	8×	return maxMaxEnd;
194		}
195
196		/**
197		* @notice Get the 'maxEnd' for a user
198		* @param target The user to query
199		* @return The 'maxEnd' for the target user
200		*/
201	6×	function getMaxEndForUser(address target) internal returns (uint32) {
202	8×	uint256 targetDripsAccId = getDripsAccountId(target);
203	95×	(, , , , uint32 maxEnd) = drips.streamsState(targetDripsAccId, token);
204	5×	return maxEnd;
205		}
206
207		/**
208		* @notice Get the timestamp on which the current cycle started
209		* @return Timestamp on which the current cycle started
210		*/
211	8×	function getCurrentCycleStart() internal returns (uint32) {
212	8×	uint32 currTimestamp = uint32(block.timestamp);
213	34×	return currTimestamp - (currTimestamp % SECONDS_PER_CYCLE);
214		}
215
216		/**
217		* @notice Get the timestamp on which the current cycle ends
218		* @return Timestamp on which the current cycle ends
219		*/
220	8×	function getCurrentCycleEnd() internal returns (uint32) {
221	38×	return getCurrentCycleStart() + SECONDS_PER_CYCLE - 1;
222		}
223
224		/**
225		* @notice Get the cycle number for a given timestamp
226		* @param timestamp The timestamp to get the cycle number for
227		* @return timestamp Cycle number for the given timestamp
228		*/
229	5×	function getCycleFromTimestamp(uint256 timestamp)
230		internal
231	1×	returns (uint32)
232		{
233	18×	return uint32(timestamp / SECONDS_PER_CYCLE + 1);
234		}
235		}

1		// SPDX-License-Identifier: MIT
2
3		import "./EchidnaSetup.sol";
4		import "./EchidnaStorage.sol";
5		import "./EchidnaAccounting.sol";
6
7		/**
8		* @title Mixin grouping together all base contracts
9		* @author Rappie <rappie@perimetersec.io>
10		*/
11	0	contract EchidnaBase is
12		EchidnaSetup,
13		EchidnaStorage,
14		EchidnaAccounting
15		{}

1		// SPDX-License-Identifier: MIT
2
3		import {IERC20, ERC20PresetFixedSupply} from "openzeppelin-contracts/token/ERC20/presets/ERC20PresetFixedSupply.sol";
4		import {ManagedProxy} from "src/Managed.sol";
5		import {Drips, SplitsReceiver, StreamReceiver, StreamConfig, StreamConfigImpl, StreamsHistory} from "src/Drips.sol";
6		import {AddressDriver} from "src/AddressDriver.sol";
7
8		import {DripsEchidna} from "../tools/DripsEchidna.sol";
9		import {AddressDriverEchidna} from "../tools/AddressDriverEchidna.sol";
10
11		import "../tools/Debugger.sol";
12
13		/**
14		* @title Mixin containing the configuration for the fuzzing campaign
15		* @author Rappie <rappie@perimetersec.io>
16		*/
17	0	contract EchidnaConfig {
18		// Addresses used for the simulated users
19	20×	address internal constant ADDRESS_USER0 = address(0x10000);
20	20×	address internal constant ADDRESS_USER1 = address(0x20000);
21	19×	address internal constant ADDRESS_USER2 = address(0x30000);
22	19×	address internal constant ADDRESS_USER3 = address(0x40000);
23
24		// Mappings from address to account id
25		mapping(address => uint8) internal ADDRESS_TO_ACCOUNT_ID;
26		mapping(address => uint256) internal ADDRESS_TO_DRIPS_ACCOUNT_ID;
27
28		// Variable to store the timestamp when fuzzing starts
29		uint256 internal STARTING_TIMESTAMP;
30
31		// Starting token balance of the simulated users
32	11×	uint256 internal constant STARTING_BALANCE = 1_000_000_000e18;
33
34		// Amount of seconds in a Drips cycle
35	20×	uint32 internal constant SECONDS_PER_CYCLE = 10;
36
37		// Buffers to be used as fuzzing boundaries
38	8×	uint32 internal constant CYCLE_FUZZING_BUFFER_CYCLES = 10;
39		uint32 internal constant CYCLE_FUZZING_BUFFER_SECONDS =
40	48×	CYCLE_FUZZING_BUFFER_CYCLES * SECONDS_PER_CYCLE;
41
42		// Maximum amount of streamable funds per second that make sense based
43		// on the starting balance of the simulated users
44		uint160 internal constant MAX_AMOUNT_PER_SEC =
45	45×	(uint160(STARTING_BALANCE) / uint160(SECONDS_PER_CYCLE)) * 1e9;
46
47		// Sensible maximum amount of seconds for a stream
48		uint32 internal constant MAX_STREAM_DURATION = CYCLE_FUZZING_BUFFER_SECONDS;
49
50		// Due to the inner workings of the splitting algorithm Drips uses,
51		// it is unpredictable wether a split will be rounded up or down. To
52		// remedy this, allow a tolerance for the expected split amount.
53	4×	uint256 internal constant SPLIT_ROUNDING_TOLERANCE = 1;
54
55		// Toggles for certain tests
56		bool internal constant TOGGLE_EXPERIMENTAL_TESTS_ENABLED = true;
57	6×	bool internal constant TOGGLE_HEAVY_TESTS_ENABLED = true;
58	1×	bool internal constant TOGGLE_MAXENDHINTS_ENABLED = true;
59
60		// Modifier to toggle experimental tests
61		modifier experimental() {
62		if (!TOGGLE_EXPERIMENTAL_TESTS_ENABLED) return;
63		_;
64		}
65
66		// Modifier to toggle performance heavy tests
67		modifier heavy() {
68	18×	if (!TOGGLE_HEAVY_TESTS_ENABLED) return;
69		_;
70		}
71
72	0	constructor() {
73	37×	ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER0] = 0;
74	37×	ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER1] = 64;
75	37×	ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER2] = 128;
76	37×	ADDRESS_TO_ACCOUNT_ID[ADDRESS_USER3] = 192;
77		}
78
79		/*
80		* @notice Get the address for a certain account id
81		* @param rawId The raw account id
82		* @return The address for the account id
83		* @dev In this case we have 4 users, spread over the range of 256 (8 bits).
84		*/
85	21×	function getAccount(uint8 rawId) internal pure returns (address) {
86	39×	uint256 id = uint256(rawId) / 64;
87
88	33×	if (id == 0) return ADDRESS_USER0;
89	33×	if (id == 1) return ADDRESS_USER1;
90	33×	if (id == 2) return ADDRESS_USER2;
91	30×	if (id == 3) return ADDRESS_USER3;
92
93	0	require(false, "Unknown account ID");
94		}
95		}

1		// SPDX-License-Identifier: MIT
2
3		import "../tools/IHevm.sol";
4		import "./EchidnaConfig.sol";
5
6		/**
7		* @title Mixin containing the deployment and setup
8		* @author Rappie <rappie@perimetersec.io>
9		*/
10	0	contract EchidnaSetup is EchidnaConfig {
11	21×	IHevm hevm = IHevm(0x7109709ECfa91a80626fF3989D68f67F5b1DD12D);
12
13		ERC20PresetFixedSupply token;
14		DripsEchidna drips;
15		AddressDriverEchidna driver;
16
17	1×	constructor() EchidnaConfig() {
18		// Deploy ERC20 token
19	50×	token = new ERC20PresetFixedSupply(
20		"Test Token",
21		"TEST",
22	7×	STARTING_BALANCE * 4,
23	1×	address(this)
24		);
25
26		// Deploy Drips
27	49×	drips = new DripsEchidna(SECONDS_PER_CYCLE);
28	55×	drips.unpause_noModifiers();
29
30		// Deploy AddressDriver
31	80×	uint32 driverId = drips.registerDriver(address(this));
32	51×	driver = new AddressDriverEchidna(
33	11×	drips,
34	1×	address(0),
35	1×	driverId
36		);
37	55×	driver.unpause_noModifiers();
38	74×	drips.updateDriverAddress(driverId, address(driver));
39
40		// Set up token balances
41	78×	token.transfer(ADDRESS_USER0, STARTING_BALANCE);
42	61×	hevm.prank(ADDRESS_USER0);
43	90×	token.approve(address(driver), type(uint256).max);
44	78×	token.transfer(ADDRESS_USER1, STARTING_BALANCE);
45	61×	hevm.prank(ADDRESS_USER1);
46	90×	token.approve(address(driver), type(uint256).max);
47	78×	token.transfer(ADDRESS_USER2, STARTING_BALANCE);
48	61×	hevm.prank(ADDRESS_USER2);
49	90×	token.approve(address(driver), type(uint256).max);
50	78×	token.transfer(ADDRESS_USER3, STARTING_BALANCE);
51	61×	hevm.prank(ADDRESS_USER3);
52	90×	token.approve(address(driver), type(uint256).max);
53
54		// Store starting timestamp
55	6×	STARTING_TIMESTAMP = block.timestamp;
56		}
57		}

1		// SPDX-License-Identifier: MIT
2		import "./EchidnaSetup.sol";
3
4		/**
5		* @title Mixin for storing stream receivers and streams history
6		* @author Rappie <rappie@perimetersec.io>
7		*/
8	0	contract EchidnaStorage is EchidnaSetup {
9		error DuplicateError();
10
11		// Mapping from address to current stream receivers
12		mapping(address => StreamReceiver[]) internal userToStreamReceivers;
13
14		// Mappings from address to full streams history and hashes
15		mapping(address => StreamsHistory[]) internal userToStreamsHistory;
16		mapping(address => bytes32[]) internal userToStreamsHistoryHashes;
17
18		// Mapping from address to current splits receivers
19		mapping(address => SplitsReceiver[]) internal userToSplitsReceivers;
20
21		/**
22		* @notice Update the stream receivers for a given account.
23		* @param sender Account to update
24		* @param receivers New stream receivers
25		* @dev This function will generate a new hash for the stream receivers,
26		* update the stream receivers for the given account, and add a new entry
27		* to the streams history and streams history hashes for the given
28		* account. This is stored for later use.
29		*/
30	8×	function updateStreamReceivers(
31		address sender,
32		StreamReceiver[] memory receivers
33	12×	) internal {
34		// Hash the new stream receivers
35	158×	bytes32 receiversHash = drips.hashStreams(receivers);
36
37		// Update the stream receivers for 'sender'
38	50×	delete userToStreamReceivers[sender];
39	46×	for (uint256 i = 0; i < receivers.length; i++) {
40	170×	userToStreamReceivers[sender].push(receivers[i]);
41		}
42
43		// Add a new entry to the streams history
44	50×	uint256 nextIndex = userToStreamsHistory[sender].length;
45	82×	userToStreamsHistory[sender].push();
46	90×	userToStreamsHistory[sender][nextIndex].streamsHash = bytes32(0);
47	46×	for (uint256 i = 0; i < receivers.length; i++) {
48	180×	userToStreamsHistory[sender][nextIndex].receivers.push(
49	30×	receivers[i]
50		);
51		}
52	170×	(, , uint32 updateTime, , uint32 maxEnd) = drips.streamsState(
53	10×	getDripsAccountId(sender),
54	22×	token
55		);
56	116×	userToStreamsHistory[sender][nextIndex].updateTime = updateTime;
57	116×	userToStreamsHistory[sender][nextIndex].maxEnd = maxEnd;
58
59		// Generate starting hash. If there is no previous history, use 0
60	2×	bytes32 startingHash;
61	18×	if (nextIndex == 0) {
62	10×	startingHash = bytes32(0);
63		} else {
64	86×	startingHash = userToStreamsHistoryHashes[sender][nextIndex - 1];
65		}
66
67		// Add new entry to the streams history hashes
68	162×	bytes32 historyHash = drips.hashStreamsHistory(
69	2×	startingHash,
70	2×	receiversHash,
71	2×	updateTime,
72	2×	maxEnd
73		);
74	102×	userToStreamsHistoryHashes[sender].push(historyHash);
75		}
76
77		/**
78		* @notice Update the splits receivers for a given account.
79		* @param sender Account to update
80		* @param receivers New splits receivers
81		*/
82	12×	function updateSplitsReceivers(
83		address sender,
84		SplitsReceiver[] memory receivers
85		) internal {
86	75×	delete userToSplitsReceivers[sender];
87	57×	for (uint256 i = 0; i < receivers.length; i++) {
88	206×	userToSplitsReceivers[sender].push(receivers[i]);
89		}
90		}
91
92		/**
93		* @notice Get the stream receivers for a given account.
94		* @param sender Account to get stream receivers for
95		* @return Stream receivers for the given account
96		*/
97	15×	function getStreamReceivers(address sender)
98		internal
99	3×	returns (StreamReceiver[] memory)
100		{
101	312×	return userToStreamReceivers[sender];
102		}
103
104		/**
105		* @notice Get the streams history for a given account.
106		* @param sender Account to get streams history for
107		* @return Streams history for the given account
108		*/
109	15×	function getStreamsHistory(address sender)
110		internal
111	3×	returns (StreamsHistory[] memory)
112		{
113	687×	return userToStreamsHistory[sender];
114		}
115
116		/**
117		* @notice Get the streams history hashes for a given account.
118		* @param sender Account to get streams history hashes for
119		* @return Streams history hashes for the given account
120		*/
121	10×	function getStreamsHistoryHashes(address sender)
122		internal
123	2×	returns (bytes32[] memory)
124		{
125	168×	return userToStreamsHistoryHashes[sender];
126		}
127
128		/**
129		* @notice Get the splits receivers for a given account.
130		* @param sender Account to get splits receivers for
131		* @return Splits receivers for the given account
132		*/
133	15×	function getSplitsReceivers(address sender)
134		internal
135	3×	returns (SplitsReceiver[] memory)
136		{
137	291×	return userToSplitsReceivers[sender];
138		}
139
140		/**
141		* @notice Sort the stream receivers.
142		* @param unsorted Unsorted stream receivers
143		* @return Sorted stream receivers
144		* @dev This function will sort the stream receivers by account ID,
145		* then by config, then by stream ID. It will revert if there are
146		* duplicate stream receivers.
147		*/
148	18×	function bubbleSortStreamReceivers(StreamReceiver[] memory unsorted)
149		internal
150	3×	returns (StreamReceiver[] memory)
151		{
152	15×	uint256 n = unsorted.length;
153	36×	if (n <= 1) return unsorted;
154
155	12×	StreamReceiver[] memory sorted = unsorted;
156	87×	for (uint256 i = 0; i < n - 1; i++) {
157	108×	for (uint256 j = 0; j < n - i - 1; j++) {
158	138×	if (bubbleSortStreamReceiverGT(sorted[j], sorted[j + 1])) {
159	54×	StreamReceiver memory temp = sorted[j];
160	120×	sorted[j] = sorted[j + 1];
161	78×	sorted[j + 1] = temp;
162		}
163		}
164		}
165	15×	return sorted;
166		}
167
168		/**
169		* @notice Sort the splits receivers.
170		* @param unsorted Unsorted splits receivers
171		* @return Sorted splits receivers
172		*/
173	18×	function bubbleSortSplitsReceivers(SplitsReceiver[] memory unsorted)
174		internal
175	3×	returns (SplitsReceiver[] memory)
176		{
177	15×	uint256 n = unsorted.length;
178	35×	if (n <= 1) return unsorted;
179
180	8×	SplitsReceiver[] memory sorted = unsorted;
181	58×	for (uint256 i = 0; i < n - 1; i++) {
182	72×	for (uint256 j = 0; j < n - i - 1; j++) {
183	92×	if (bubbleSortSplitsReceiverGT(sorted[j], sorted[j + 1])) {
184	36×	SplitsReceiver memory temp = sorted[j];
185	80×	sorted[j] = sorted[j + 1];
186	52×	sorted[j + 1] = temp;
187		}
188		}
189		}
190	10×	return sorted;
191		}
192
193		/**
194		* @notice Compare two stream receivers.
195		* @param a First stream receiver
196		* @param b Second stream receiver
197		* @return True if `a` is greater than `b`, false otherwise
198		* @dev This function will compare two stream receivers by account ID,
199		* then by config. It will revert if there are duplicate stream receivers.
200		*/
201	21×	function bubbleSortStreamReceiverGT(
202		StreamReceiver memory a,
203		StreamReceiver memory b
204	3×	) internal returns (bool) {
205	36×	if (a.accountId != b.accountId) {
206	39×	return a.accountId > b.accountId;
207		}
208	35×	if (StreamConfig.unwrap(a.config) != StreamConfig.unwrap(b.config)) {
209	12×	return
210	27×	StreamConfig.unwrap(a.config) > StreamConfig.unwrap(b.config);
211		}
212	28×	revert DuplicateError();
213		}
214
215		/**
216		* @notice Compare two splits receivers.
217		* @param a First splits receiver
218		* @param b Second splits receiver
219		* @return True if `a` is greater than `b`, false otherwise
220		* @dev This function will compare two splits receivers by account ID.
221		* It will revert if there are duplicate splits receivers.
222		*/
223	14×	function bubbleSortSplitsReceiverGT(
224		SplitsReceiver memory a,
225		SplitsReceiver memory b
226	2×	) internal returns (bool) {
227	24×	if (a.accountId != b.accountId) {
228	26×	return a.accountId > b.accountId;
229		}
230	28×	revert DuplicateError();
231		}
232
233		/**
234		* @notice Get the drips account ID for a given address.
235		* @param account Address to get drips account ID for
236		* @return Drips account ID for the given address
237		* @dev Caches the value to increase performance
238		*/
239	18×	function getDripsAccountId(address account) internal returns (uint256) {
240	72×	if (ADDRESS_TO_DRIPS_ACCOUNT_ID[account] == 0) {
241	291×	ADDRESS_TO_DRIPS_ACCOUNT_ID[account] = driver.calcAccountId(
242	3×	account
243		);
244		}
245	63×	return ADDRESS_TO_DRIPS_ACCOUNT_ID[account];
246		}
247		}

1		// SPDX-License-Identifier: MIT
2		import {AddressDriver} from "src/AddressDriver.sol";
3
4		import {DripsEchidna} from "./DripsEchidna.sol";
5		import {ManagedEchidna} from "./ManagedEchidna.sol";
6
7		/**
8		* @title Wrapper around AddressDriver with minor fuzzing helpers
9		* @author Rappie <rappie@perimetersec.io>
10		*/
11	311×	contract AddressDriverEchidna is AddressDriver, ManagedEchidna {
12	33×	constructor(
13		DripsEchidna drips_,
14		address forwarder,
15		uint32 driverId_
16	3×	) AddressDriver(drips_, forwarder, driverId_) {}
17		}

1		// SPDX-License-Identifier: MIT
2
3	0	library Debugger {
4		event Debug(string debugString);
5		event Debug(string description, string data);
6		event Debug(string prefix, string description, string data);
7		event Debug(string description, bytes32 data);
8		event Debug(string prefix, string description, bytes32 data);
9		event Debug(string description, uint256 data);
10		event Debug(string prefix, string description, uint256 data);
11		event Debug(string description, int256 data);
12		event Debug(string prefix, string description, int256 data);
13		event Debug(string description, address data);
14		event Debug(string prefix, string description, address data);
15		event Debug(string description, bool data);
16		event Debug(string prefix, string description, bool data);
17
18		function log(string memory debugString) internal {
19		emit Debug(debugString);
20		}
21
22		function log(string memory description, string memory data) internal {
23		emit Debug(description, data);
24		}
25
26		function log(
27		string memory prefix,
28		string memory description,
29		string memory data
30		) internal {
31		emit Debug(prefix, description, data);
32		}
33
34		function log(string memory description, bytes32 data) internal {
35		emit Debug(description, data);
36		}
37
38		function log(
39		string memory prefix,
40		string memory description,
41		bytes32 data
42		) internal {
43		emit Debug(prefix, description, data);
44		}
45
46		function log(string memory description, uint256 data) internal {
47		emit Debug(description, data);
48		}
49
50		function log(
51		string memory prefix,
52		string memory description,
53		uint256 data
54		) internal {
55		emit Debug(prefix, description, data);
56		}
57
58		function log(string memory description, int256 data) internal {
59		emit Debug(description, data);
60		}
61
62		function log(
63		string memory prefix,
64		string memory description,
65		int256 data
66		) internal {
67		emit Debug(prefix, description, data);
68		}
69
70		function log(string memory description, address data) internal {
71		emit Debug(description, data);
72		}
73
74		function log(
75		string memory prefix,
76		string memory description,
77		address data
78		) internal {
79		emit Debug(prefix, description, data);
80		}
81
82		function log(string memory description, bool data) internal {
83		emit Debug(description, data);
84		}
85
86		function log(
87		string memory prefix,
88		string memory description,
89		bool data
90		) internal {
91		emit Debug(prefix, description, data);
92		}
93		}

1		// SPDX-License-Identifier: MIT
2		import {IERC20} from "openzeppelin-contracts/token/ERC20/utils/SafeERC20.sol";
3		import {Drips} from "src/Drips.sol";
4
5		import {ManagedEchidna} from "./ManagedEchidna.sol";
6
7		/**
8		* @title Wrapper around Drips with minor fuzzing helpers
9		* @author Rappie <rappie@perimetersec.io>
10		*/
11	718×	contract DripsEchidna is Drips, ManagedEchidna {
12	32×	constructor(uint32 cycleSecs_) Drips(cycleSecs_) {}
13
14		/**
15		* @notice Get the amtDelta for a given user and cycle
16		* @param accountId The account to get the amtDelta for
17		* @param erc20 The ERC20 token
18		* @param cycle The cycle to get the amtDelta for
19		* @return The amtDelta for this cycle and the next cycle
20		*/
21	49×	function getAmtDeltaForCycle(
22		uint256 accountId,
23		IERC20 erc20,
24		uint32 cycle
25	2×	) public view returns (int128, int128) {
26		// Manually calculate the storage slot because it is a private variable
27		// in Streams
28	1×	StreamsStorage storage streamsStorage;
29	24×	bytes32 slot = _erc1967Slot("eip1967.streams.storage");
30		assembly {
31	3×	streamsStorage.slot := slot
32		}
33
34		// Return the amtDelta for the given cycle
35	36×	StreamsState storage state = streamsStorage.states[erc20][accountId];
36	6×	mapping(uint32 cycle => AmtDelta) storage amtDeltas = state.amtDeltas;
37	68×	return (amtDeltas[cycle].thisCycle, amtDeltas[cycle].nextCycle);
38		}
39		}

1		// SPDX-License-Identifier: MIT
2		import {Managed} from "src/Managed.sol";
3
4		/**
5		* @title Wrapper around Managed with minor fuzzing helpers
6		* @author Rappie <rappie@perimetersec.io>
7		*/
8	0	contract ManagedEchidna is Managed {
9	0	constructor() Managed() {}
10
11		/**
12		* @notice Helper function to unpause the contract as any user
13		*/
14	0	function unpause_noModifiers() public {
15	0	_managedStorage().isPaused = false;
16	0	emit Unpaused(msg.sender);
17		}
18		}

1		// SPDX-License-Identifier: MIT
2		pragma solidity ^0.8.20;
3
4		import {Properties} from "./Properties.sol";
5
6		// echidna test/recon/CryticTester.sol --contract CryticTester --config echidna.yaml
7	689×	contract CryticTester is Properties {}

1		// SPDX-License-Identifier: MIT
2		pragma solidity ^0.8.20;
3
4		import {Echidna} from "src/echidna/Echidna.sol";
5
6		/// @notice scfuzzbench adaptation layer: canary checks on top of the
7		/// Perimeter Drips fuzzing suite. Assertion failures are surfaced the same
8		/// way for Echidna, Medusa, Foundry, and Recon (AssertionFailed event +
9		/// assert), and dedup to the emitting function name across fuzzers.
10		abstract contract Properties is Echidna {
11		string internal constant ASSERTION_CANARY = "!!! canary assertion";
12		string internal constant INVARIANT_CANARY_GLOBAL_INVARIANT_FAILURE = "Canary invariant";
13
14		event AssertionFailed(string reason);
15
16	4×	function t(bool b, string memory reason) internal {
17	4×	if (!b) {
18	17×	emit AssertionFailed(reason);
19	6×	assert(false);
20		}
21		}
22
23	6×	function invariant_canary() public returns (bool) {
24	21×	t(false, INVARIANT_CANARY_GLOBAL_INVARIANT_FAILURE);
25	0	return true;
26		}
27
28	22×	function assert_canary_ASSERTION_CANARY(uint256 entropy) public {
29	24×	t(entropy > 0, ASSERTION_CANARY);
30		}
31		}