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July 24, 2024 14:37
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| contract EIP712 { | |
| bytes32 private constant TYPE_HASH = | |
| keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"); | |
| bytes32 private immutable _cachedDomainSeparator; | |
| uint256 private immutable _cachedChainId; | |
| address private immutable _cachedThis; | |
| bytes32 private immutable _hashedName; | |
| bytes32 private immutable _hashedVersion; | |
| string private _name; | |
| string private _version; | |
| string private _nameFallback; | |
| string private _versionFallback; | |
| constructor(string memory name, string memory version) { | |
| _name = name; | |
| _version = version; | |
| _hashedName = keccak256(bytes(name)); | |
| _hashedVersion = keccak256(bytes(version)); | |
| _cachedChainId = block.chainid; | |
| _cachedDomainSeparator = _buildDomainSeparator(); | |
| _cachedThis = address(this); | |
| } | |
| function _domainSeparatorV4() internal view returns (bytes32) { | |
| if (address(this) == _cachedThis && block.chainid == _cachedChainId) { | |
| return _cachedDomainSeparator; | |
| } else { | |
| return _buildDomainSeparator(); | |
| } | |
| } | |
| function _buildDomainSeparator() private view returns (bytes32) { | |
| return keccak256(abi.encode(TYPE_HASH, _hashedName, _hashedVersion, block.chainid, address(this))); | |
| } | |
| function _hashTypedDataV4(bytes32 structHash) internal view virtual returns (bytes32) { | |
| return toTypedDataHash(_domainSeparatorV4(), structHash); | |
| } | |
| function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) public pure returns (bytes32) { | |
| bytes memory encodedData = abi.encodePacked("\x19\x01", domainSeparator, structHash); | |
| return keccak256(encodedData); | |
| } | |
| /** | |
| * @dev See {IERC-5267}. | |
| */ | |
| function eip712Domain() | |
| public | |
| view | |
| virtual | |
| returns ( | |
| bytes1 fields, | |
| string memory name, | |
| string memory version, | |
| uint256 chainId, | |
| address verifyingContract, | |
| bytes32 salt, | |
| uint256[] memory extensions | |
| ) | |
| { | |
| return ( | |
| hex"0f", // 01111 | |
| _EIP712Name(), | |
| _EIP712Version(), | |
| block.chainid, | |
| address(this), | |
| bytes32(0), | |
| new uint256[](0) | |
| ); | |
| } | |
| // solhint-disable-next-line func-name-mixedcase | |
| function _EIP712Name() internal view returns (string memory) { | |
| return _nameFallback; | |
| } | |
| // solhint-disable-next-line func-name-mixedcase | |
| function _EIP712Version() internal view returns (string memory) { | |
| return _versionFallback; | |
| } | |
| } | |
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