// Source: contracts/libs/SafeTransfer.sol pragma solidity ^0.8.0; // SPDX-License-Identifier: MIT // File contracts/interfaces/IERC20.sol /** * @dev Interface of the ERC20 standard as defined in the EIP. */ interface IERC20 { error InvalidAccount(); /** * @dev Returns the amount of tokens in existence. */ function totalSupply() external view returns (uint256); /** * @dev Returns the amount of tokens owned by `account`. */ function balanceOf(address account) external view returns (uint256); /** * @dev Moves `amount` tokens from the caller's account to `recipient`. * * Returns a boolean value indicating whether the operation succeeded. * * Emits a {Transfer} event. */ function transfer(address recipient, uint256 amount) external returns (bool); /** * @dev Returns the remaining number of tokens that `spender` will be * allowed to spend on behalf of `owner` through {transferFrom}. This is * zero by default. * * This value changes when {approve} or {transferFrom} are called. */ function allowance(address owner, address spender) external view returns (uint256); /** * @dev Sets `amount` as the allowance of `spender` over the caller's tokens. * * Returns a boolean value indicating whether the operation succeeded. * * IMPORTANT: Beware that changing an allowance with this method brings the risk * that someone may use both the old and the new allowance by unfortunate * transaction ordering. One possible solution to mitigate this race * condition is to first reduce the spender's allowance to 0 and set the * desired value afterwards: * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729 * * Emits an {Approval} event. */ function approve(address spender, uint256 amount) external returns (bool); /** * @dev Moves `amount` tokens from `sender` to `recipient` using the * allowance mechanism. `amount` is then deducted from the caller's * allowance. * * Returns a boolean value indicating whether the operation succeeded. * * Emits a {Transfer} event. */ function transferFrom( address sender, address recipient, uint256 amount ) external returns (bool); /** * @dev Emitted when `value` tokens are moved from one account (`from`) to * another (`to`). * * Note that `value` may be zero. */ event Transfer(address indexed from, address indexed to, uint256 value); /** * @dev Emitted when the allowance of a `spender` for an `owner` is set by * a call to {approve}. `value` is the new allowance. */ event Approval(address indexed owner, address indexed spender, uint256 value); } // File contracts/libs/SafeTransfer.sol error TokenTransferFailed(); /* * @title SafeTokenCall * @dev This library is used for performing safe token transfers. */ library SafeTokenCall { /* * @notice Make a safe call to a token contract. * @param token The token contract to interact with. * @param callData The function call data. * @throws TokenTransferFailed error if transfer of token is not successful. */ function safeCall(IERC20 token, bytes memory callData) internal { (bool success, bytes memory returnData) = address(token).call(callData); bool transferred = success && (returnData.length == uint256(0) || abi.decode(returnData, (bool))); if (!transferred || address(token).code.length == 0) revert TokenTransferFailed(); } } /* * @title SafeTokenTransfer * @dev This library safely transfers tokens from the contract to a recipient. */ library SafeTokenTransfer { /* * @notice Transfer tokens to a recipient. * @param token The token contract. * @param receiver The recipient of the tokens. * @param amount The amount of tokens to transfer. */ function safeTransfer( IERC20 token, address receiver, uint256 amount ) internal { SafeTokenCall.safeCall(token, abi.encodeWithSelector(IERC20.transfer.selector, receiver, amount)); } } /* * @title SafeTokenTransferFrom * @dev This library helps to safely transfer tokens on behalf of a token holder. */ library SafeTokenTransferFrom { /* * @notice Transfer tokens on behalf of a token holder. * @param token The token contract. * @param from The address of the token holder. * @param to The address the tokens are to be sent to. * @param amount The amount of tokens to be transferred. */ function safeTransferFrom( IERC20 token, address from, address to, uint256 amount ) internal { SafeTokenCall.safeCall(token, abi.encodeWithSelector(IERC20.transferFrom.selector, from, to, amount)); } }