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feat: add OpenZeppelin SafeERC20 and Address dependencies (#859)
* feat: add SafeERC20 library * fix: use v4.4.1 of Address library * fix: prettier --------- Co-authored-by: miguelmtz <36620902+miguelmtzinf@users.noreply.github.com>
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contracts/dependencies/openzeppelin/contracts/SafeERC20.sol
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// SPDX-License-Identifier: MIT | ||
// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol) | ||
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pragma solidity ^0.8.0; | ||
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import './IERC20.sol'; | ||
import './Address.sol'; | ||
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/** | ||
* @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; | ||
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function safeTransfer(IERC20 token, address to, uint256 value) internal { | ||
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value)); | ||
} | ||
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function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal { | ||
_callOptionalReturn( | ||
token, | ||
abi.encodeWithSelector(token.transferFrom.selector, from, to, value) | ||
); | ||
} | ||
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/** | ||
* @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)); | ||
} | ||
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function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal { | ||
uint256 newAllowance = token.allowance(address(this), spender) + value; | ||
_callOptionalReturn( | ||
token, | ||
abi.encodeWithSelector(token.approve.selector, spender, newAllowance) | ||
); | ||
} | ||
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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'); | ||
uint256 newAllowance = oldAllowance - value; | ||
_callOptionalReturn( | ||
token, | ||
abi.encodeWithSelector(token.approve.selector, spender, newAllowance) | ||
); | ||
} | ||
} | ||
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/** | ||
* @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. | ||
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bytes memory returndata = address(token).functionCall(data, 'SafeERC20: low-level call failed'); | ||
if (returndata.length > 0) { | ||
// Return data is optional | ||
require(abi.decode(returndata, (bool)), 'SafeERC20: ERC20 operation did not succeed'); | ||
} | ||
} | ||
} |