{
    "Function": "slitherConstructorConstantVariables",
    "File": "contracts/Forwarder.sol",
    "Parent Contracts": [
        "node_modules/@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol",
        "node_modules/@openzeppelin/contracts-upgradeable/utils/ContextUpgradeable.sol",
        "node_modules/@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol"
    ],
    "High-Level Calls": [],
    "Internal Calls": [],
    "Library Calls": [],
    "Low-Level Calls": [],
    "Code": "contract Forwarder is OwnableUpgradeable {\n    struct ForwardRequest {\n        address from;\n        address to;\n        uint256 value;\n        uint256 gas;\n        uint256 nonce;\n        bytes data;\n    }\n\n    using ECDSA for bytes32;\n    string public constant GENERIC_PARAMS =\n        \"address from,address to,uint256 value,uint256 gas,uint256 nonce,bytes data\";\n\n    mapping(bytes32 => bool) public typeHashes;\n\n    // Nonces of senders, used to prevent replay attacks\n    mapping(address => uint256) private nonces;\n\n    EURFToken private _eurf;\n    address private _eurfAddress;\n\n    event RequestTypeRegistered(bytes32 indexed typeHash, string typeStr);\n\n    // solhint-disable-next-line no-empty-blocks\n    receive() external payable {}\n\n    function nonce(address from) public view returns (uint256) {\n        return nonces[from];\n    }\n\n    function getEURF() public view returns (address) {\n        return _eurfAddress;\n    }\n\n    function initialize(address ngeurToken) public initializer {\n        __Ownable_init(_msgSender());\n\n        require(ngeurToken != address(0), \"NGEUR Forwarder: NGEUR Token address can't be address 0\");\n\n        string memory requestType = string(abi.encodePacked(\"ForwardRequest(\", GENERIC_PARAMS, \")\"));\n        registerRequestTypeInternal(requestType);\n        _eurfAddress = ngeurToken;\n        _eurf = EURFToken(ngeurToken);\n    }\n\n    function verify(\n        ForwardRequest calldata req,\n        bytes32 domainSeparator,\n        bytes32 requestTypeHash,\n        bytes calldata suffixData,\n        bytes calldata sig\n    ) external view {\n        _verifyNonce(req);\n        _verifySig(req, domainSeparator, requestTypeHash, suffixData, sig);\n\n        bytes4 transferSelector = bytes4(keccak256(\"transfer(address,uint256)\"));\n        bytes4 reqTransferSelector = bytes4(req.data[:4]);\n\n        require(reqTransferSelector == transferSelector, \"NGEUR Forwarder: can only forward transfer transactions\");\n    }\n\n    function execute(\n        ForwardRequest calldata req,\n        bytes32 domainSeparator,\n        bytes32 requestTypeHash,\n        bytes calldata suffixData,\n        bytes calldata sig\n    ) external payable returns (bool success, bytes memory ret) {\n        _verifyNonce(req);\n        _verifySig(req, domainSeparator, requestTypeHash, suffixData, sig);\n        _updateNonce(req);\n\n        require(req.to == _eurfAddress, \"NGEUR Forwarder: can only forward NGEUR transactions\");\n\n        bytes4 transferSelector = bytes4(keccak256(\"transfer(address,uint256)\"));\n        bytes4 reqTransferSelector = bytes4(req.data[:4]);\n\n        require(reqTransferSelector == transferSelector, \"NGEUR Forwarder: can only forward transfer transactions\");\n\n        // solhint-disable-next-line avoid-low-level-calls\n        (success, ret) = req.to.call{gas: req.gas, value: req.value}(abi.encodePacked(req.data, req.from));\n        require(success, \"NGEUR Forwarder: failed tx execution\");\n\n        _eurf.payGaslessBasefee(req.from, _msgSender());\n\n        return (success, ret);\n    }\n\n    function _verifyNonce(ForwardRequest memory req) internal view {\n        require(nonces[req.from] == req.nonce, \"NGEUR Forwarder: nonce mismatch\");\n    }\n\n    function _updateNonce(ForwardRequest memory req) internal {\n        nonces[req.from]++;\n    }\n\n    function registerRequestType(string calldata typeName, string calldata typeSuffix) external onlyOwner {\n        for (uint i = 0; i < bytes(typeName).length; i++) {\n            bytes1 c = bytes(typeName)[i];\n            require(c != \"(\" && c != \")\", \"NGEUR Forwarder: invalid typename\");\n        }\n\n        string memory requestType = string(abi.encodePacked(typeName, \"(\", GENERIC_PARAMS, \",\", typeSuffix));\n        registerRequestTypeInternal(requestType);\n    }\n\n    function registerRequestTypeInternal(string memory requestType) internal {\n        bytes32 requestTypehash = keccak256(bytes(requestType));\n        typeHashes[requestTypehash] = true;\n        emit RequestTypeRegistered(requestTypehash, string(requestType));\n    }\n\n    function _verifySig(\n        ForwardRequest memory req,\n        bytes32 domainSeparator,\n        bytes32 requestTypeHash,\n        bytes memory suffixData,\n        bytes memory sig\n    ) internal view {\n        require(typeHashes[requestTypeHash], \"NGEUR Forwarder: invalid request typehash\");\n        bytes32 digest = keccak256(\n            abi.encodePacked(\"\\x19\\x01\", domainSeparator, keccak256(_getEncoded(req, requestTypeHash, suffixData)))\n        );\n        require(digest.recover(sig) == req.from, \"NGEUR Forwarder: signature mismatch\");\n    }\n\n    function _getEncoded(\n        ForwardRequest memory req,\n        bytes32 requestTypeHash,\n        bytes memory suffixData\n    ) public pure returns (bytes memory) {\n        return\n            abi.encodePacked(\n                requestTypeHash,\n                abi.encode(req.from, req.to, req.value, req.gas, req.nonce, keccak256(req.data)),\n                suffixData\n            );\n    }\n}"
}