// SPDX-License-Identifier: GPL-2.0-or-later pragma solidity >=0.6.0; import '@openzeppelin/contracts/token/ERC20/IERC20.sol'; library TransferHelper { /// @notice Transfers tokens from the targeted address to the given destination /// @notice Errors with 'STF' if transfer fails /// @param token The contract address of the token to be transferred /// @param from The originating address from which the tokens will be transferred /// @param to The destination address of the transfer /// @param value The amount to be transferred function safeTransferFrom( address token, address from, address to, uint256 value ) internal { (bool success, bytes memory data) = token.call(abi.encodeWithSelector(IERC20.transferFrom.selector, from, to, value)); require(success && (data.length == 0 || abi.decode(data, (bool))), 'STF'); } /// @notice Transfers tokens from msg.sender to a recipient /// @dev Errors with ST if transfer fails /// @param token The contract address of the token which will be transferred /// @param to The recipient of the transfer /// @param value The value of the transfer function safeTransfer( address token, address to, uint256 value ) internal { (bool success, bytes memory data) = token.call(abi.encodeWithSelector(IERC20.transfer.selector, to, value)); require(success && (data.length == 0 || abi.decode(data, (bool))), 'ST'); } /// @notice Approves the stipulated contract to spend the given allowance in the given token /// @dev Errors with 'SA' if transfer fails /// @param token The contract address of the token to be approved /// @param to The target of the approval /// @param value The amount of the given token the target will be allowed to spend function safeApprove( address token, address to, uint256 value ) internal { (bool success, bytes memory data) = token.call(abi.encodeWithSelector(IERC20.approve.selector, to, value)); require(success && (data.length == 0 || abi.decode(data, (bool))), 'SA'); } /// @notice Transfers ETH to the recipient address /// @dev Fails with `STE` /// @param to The destination of the transfer /// @param value The value to be transferred function safeTransferETH(address to, uint256 value) internal { (bool success, ) = to.call{value: value}(new bytes(0)); require(success, 'STE'); } }