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| // SPDX-License-Identifier: MIT
// Taken from OZ release 4.7.3 at commit a035b235b4f2c9af4ba88edc4447f02e37f8d124
// The only modification that has been made is in the body of the `permit` function at line 83,
/// where we failover to SignatureChecker in order to handle approvals for smart contracts.
pragma solidity 0.8.17;
import "@openzeppelin/contracts-upgradeable/token/ERC20/extensions/draft-IERC20PermitUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC20/ERC20Upgradeable.sol";
import "@openzeppelin/contracts-upgradeable/utils/cryptography/draft-EIP712Upgradeable.sol";
import "@openzeppelin/contracts-upgradeable/utils/CountersUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
import "../libraries/Permit.sol";
import "../mixins/Versioned.sol";
/**
* @dev Implementation of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
* https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
*
* Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
* presenting a message signed by the account. By not relying on `{IERC20-approve}`, the token holder account doesn't
* need to send a transaction, and thus is not required to hold Ether at all.
*
* Note: We have modified `permit` to support EIP-1271, technically violating EIP-2612.
*
* _Available since v3.4._
*
* @custom:storage-size 51
*/
abstract contract ERC20PermitUpgradeable is
Initializable,
ERC20Upgradeable,
IERC20PermitUpgradeable,
EIP712Upgradeable
{
using CountersUpgradeable for CountersUpgradeable.Counter;
mapping(address => CountersUpgradeable.Counter) private _nonces;
// solhint-disable-next-line var-name-mixedcase
bytes32 private constant _PERMIT_TYPEHASH =
keccak256(
"Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)"
);
/**
* @dev In previous versions `_PERMIT_TYPEHASH` was declared as `immutable`.
* However, to ensure consistency with the upgradeable transpiler, we will continue
* to reserve a slot.
* @custom:oz-renamed-from _PERMIT_TYPEHASH
*/
// solhint-disable-next-line var-name-mixedcase
bytes32 private _PERMIT_TYPEHASH_DEPRECATED_SLOT;
// untestable:
// `else` branch of `onlyInitializing` (ie. revert) is currently untestable.
// This function is only called inside other `init` functions, each of which is wrapped
// in an `initializer` modifier, which would fail first.
/**
* @dev Initializes the {EIP712} domain separator using the `name` parameter, and setting `version` to
* the system-wide semver release version.
*
* It's a good idea to use the same `name` that is defined as the ERC20 token name.
*/
function __ERC20Permit_init(string memory name) internal EonlyInitializing {
__EIP712_init_unchained(name, VERSION);
}
// untestable:
// This is not needed in the way we handle initializations
function __ERC20Permit_init_unchained(string memory) internal onlyInitializing {}
/**
* @dev See {IERC20Permit-permit}.
*/
function permit(
address owner,
address spender,
uint256 value,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
) public virtual override {
require(block.timestamp <= deadline, "ERC20Permit: expired deadline");
bytes32 structHash = keccak256(
abi.encode(_PERMIT_TYPEHASH, owner, spender, value, _useNonce(owner), deadline)
);
/// ==== MODIFICATIONS START ====
PermitLib.requireSignature(owner, _hashTypedDataV4(structHash), v, r, s);
/// ==== MODIFICATIONS END ====
_approve(owner, spender, value);
}
/**
* @dev See {IERC20Permit-nonces}.
*/
function nonces(address owner) public view virtual override returns (uint256) {
return _nonces[owner].current();
}
/**
* @dev See {IERC20Permit-DOMAIN_SEPARATOR}.
*/
// solhint-disable-next-line func-name-mixedcase
function DOMAIN_SEPARATOR() external view override returns (bytes32) {
return _domainSeparatorV4();
}
/**
* @dev "Consume a nonce": return the current value and increment.
*
* _Available since v4.1._
*/
function _useNonce(address owner) internal virtual returns (uint256 current) {
CountersUpgradeable.Counter storage nonce = _nonces[owner];
current = nonce.current();
nonce.increment();
}
/**
* @dev This empty reserved space is put in place to allow future versions to add new
* variables without shifting down storage in the inheritance chain.
* See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
*/
uint256[48] private __gap;
}
|