Cryo Explorer Ethereum Mainnet

// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.9;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "./SignatureChecker.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";

interface IWrappedJetton {
    function isWrappedJetton() external pure returns (bool);
}

interface IDecimals {
    function decimals() external view returns (uint8);
}

contract Bridge is SignatureChecker, ReentrancyGuard {
    using SafeERC20 for IERC20;
    address[] oracleSet;
    mapping(address => bool) public isOracle;
    mapping(address => bool) public disabledTokens;
    mapping(bytes32 => bool) public finishedVotings;
    bool public allowLock;

    event Lock(
        address indexed from,
        address indexed token,
        bytes32 indexed to_addr_hash,
        uint256 value,
        uint256 new_bridge_balance,
        uint8 decimals
    );
    event Unlock(
        address indexed token,
        bytes32 ton_address_hash,
        bytes32 indexed ton_tx_hash,
        uint64 lt,
        address indexed to,
        uint256 value,
        uint256 new_bridge_balance
    );
    event NewOracleSet(uint256 oracleSetHash, address[] newOracles);

    constructor(address[] memory initialSet) {
        _updateOracleSet(0, initialSet);
        disabledTokens[address(0)] = true;
        disabledTokens[address(0x582d872A1B094FC48F5DE31D3B73F2D9bE47def1)] = true; // wrapped toncoin
        disabledTokens[address(0x76A797A59Ba2C17726896976B7B3747BfD1d220f)] = true; // wrapped toncoin
    }

    function _generalVote(bytes32 digest, Signature[] memory signatures)
        internal
        view
    {
        require(
             signatures.length >= (2 * oracleSet.length + 2) / 3,
            "Not enough signatures"
        );
        require(!finishedVotings[digest], "Vote is already finished");
        uint256 signum = signatures.length;
        uint256 last_signer = 0;
        for (uint256 i = 0; i < signum; i++) {
            address signer = signatures[i].signer;
            require(isOracle[signer], "Unauthorized signer");
            uint256 next_signer = uint256(uint160(signer));
            require(next_signer > last_signer, "Signatures are not sorted");
            last_signer = next_signer;
            checkSignature(digest, signatures[i]);
        }
    }

    function lock(
        address token,
        uint256 amount,
        bytes32 to_address_hash
    ) external nonReentrant {
        require(allowLock, "Lock is currently disabled");
        require(!disabledTokens[token], "lock: disabled token");
        require(!checkTokenIsWrappedJetton(token), "lock wrapped jetton");

        uint256 oldBalance = IERC20(token).balanceOf(address(this));

        IERC20(token).safeTransferFrom(msg.sender, address(this), amount);

        uint256 newBalance = IERC20(token).balanceOf(address(this));

        require(newBalance > oldBalance, "newBalance must be greater than oldBalance");

        require(newBalance <= 2 ** 120 - 1, "Max jetton totalSupply 2 ** 120 - 1");

        emit Lock(
            msg.sender,
            token,
            to_address_hash,
            newBalance - oldBalance,
            newBalance,
            getDecimals(token)
        );
    }

    function unlock(SwapData calldata data, Signature[] calldata signatures)
        external nonReentrant
    {
        bytes32 _id = getSwapDataId(data);
        _generalVote(_id, signatures);
        finishedVotings[_id] = true;
        IERC20(data.token).safeTransfer(data.receiver, data.amount);
        uint256 newBalance = IERC20(data.token).balanceOf(address(this));
        emit Unlock(data.token, data.tx.address_hash, data.tx.tx_hash, data.tx.lt, data.receiver, data.amount, newBalance);
    }

    function voteForNewOracleSet(
        uint256 oracleSetHash,
        address[] calldata newOracles,
        Signature[] calldata signatures
    ) external {
        bytes32 _id = getNewSetId(oracleSetHash, newOracles);
        _generalVote(_id, signatures);
        finishedVotings[_id] = true;
        _updateOracleSet(oracleSetHash, newOracles);
    }

    function voteForSwitchLock(
        bool newLockStatus,
        uint256 nonce,
        Signature[] calldata signatures
    ) external {
        bytes32 _id = getNewLockStatusId(newLockStatus, nonce);
        _generalVote(_id, signatures);
        finishedVotings[_id] = true;
        allowLock = newLockStatus;
    }

    function voteForDisableToken(
        bool isDisable,
        address tokenAddress,
        uint256 nonce,
        Signature[] calldata signatures
    ) external {
        bytes32 _id = getNewDisableToken(isDisable, tokenAddress, nonce);
        _generalVote(_id, signatures);
        finishedVotings[_id] = true;
        if (isDisable) {
            disabledTokens[tokenAddress] = true;
        } else {
            delete disabledTokens[tokenAddress];
        }
    }

    function _updateOracleSet(uint256 oracleSetHash, address[] memory newOracles)
        internal
    {
        require(newOracles.length > 2, "New set is too short");
        uint256 oldSetLen = oracleSet.length;
        for (uint256 i = 0; i < oldSetLen; i++) {
            isOracle[oracleSet[i]] = false;
        }
        oracleSet = newOracles;
        uint256 newSetLen = oracleSet.length;
        for (uint256 i = 0; i < newSetLen; i++) {
            require(newOracles[i] != address(0), "zero signer");
            require(!isOracle[newOracles[i]], "Duplicate oracle in Set");
            isOracle[newOracles[i]] = true;
        }
        emit NewOracleSet(oracleSetHash, newOracles);
    }

    function getFullOracleSet() external view returns (address[] memory) {
        return oracleSet;
    }

    function checkTokenIsWrappedJetton(address token) public pure returns (bool) {
        try IWrappedJetton(token).isWrappedJetton() returns (
            bool isWrappedJetton
        ) {
            return isWrappedJetton;
        } catch {
            return false;
        }
    }

    function getDecimals(address token) public view returns (uint8) {
        try IDecimals(token).decimals() returns (
            uint8 decimals
        ) {
            return decimals;
        } catch {
            return 0;
        }
    }
}

// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.9;

interface TonUtils {
    struct TonTxID {
        bytes32 address_hash; // sender user address
        bytes32 tx_hash; // transaction hash on bridge smart contract
        uint64 lt; // transaction LT (logical time) on bridge smart contract
    }

    struct SwapData {
        address receiver; // user's EVM-address to receive tokens
        address token; // ERC-20 token address
        uint256 amount; // token amount in units to receive in EVM-network
        TonTxID tx;
    }

    struct Signature {
        address signer; // oracle's EVM-address
        bytes signature; // oracle's signature
    }
}

// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.9;

import "./TonUtils.sol";

contract SignatureChecker is TonUtils {
    function checkSignature(bytes32 digest, Signature memory sig) public pure {
        require(sig.signer != address(0), "ECDSA: zero signer"); // The `ecrecover` function returns zero on failure, so if sig.signer == 0 then any signature will be accepted regardless of whether it is cryptographically valid.
        require(sig.signature.length == 65, "ECDSA: invalid signature length");
        // Divide the signature in r, s and v variables
        bytes32 r;
        bytes32 s;
        uint8 v;

        bytes memory signature = sig.signature;

        // ecrecover takes the signature parameters, and the only way to get them
        // currently is to use assembly.
        // solhint-disable-next-line no-inline-assembly
        assembly {
            r := mload(add(signature, 0x20))
            s := mload(add(signature, 0x40))
            v := byte(0, mload(add(signature, 0x60)))
        }

        require(
            uint256(s) <= 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0,
            "ECDSA: invalid signature 's' value"
        );

        require(v == 27 || v == 28, "ECDSA: invalid signature 'v' value");

        bytes memory prefix = "\x19Ethereum Signed Message:\n32";
        bytes32 prefixedHash = keccak256(abi.encodePacked(prefix, digest));
        require(
            ecrecover(prefixedHash, v, r, s) == sig.signer,
            "Wrong signature"
        );
    }

    function getSwapDataId(SwapData memory data)
        public
        view
        returns (bytes32 result)
    {
        result = keccak256(
            abi.encode(
                0xDA7A,
                address(this),
                block.chainid,
                data.receiver,
                data.token,
                data.amount,
                data.tx.address_hash,
                data.tx.tx_hash,
                data.tx.lt
            )
        );
    }

    function getNewSetId(uint256 oracleSetHash, address[] memory set)
        public
        view
        returns (bytes32 result)
    {
        result = keccak256(
            abi.encode(0x5e7, address(this), block.chainid, oracleSetHash, set)
        );
    }

    function getNewLockStatusId(bool newLockStatus, uint256 nonce)
        public
        view
        returns (bytes32 result)
    {
        result = keccak256(
            abi.encode(0xB012, address(this), block.chainid, newLockStatus, nonce)
        );
    }

    function getNewDisableToken(bool isDisable, address tokenAddress,  uint256 nonce)
        public
        view
        returns (bytes32 result)
    {
        result = keccak256(
            abi.encode(0xD15A, address(this), block.chainid, isDisable, tokenAddress, nonce)
        );
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // Look for revert reason and bubble it up if present
        if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        _nonReentrantBefore();
        _;
        _nonReentrantAfter();
    }

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be _NOT_ENTERED
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;
    }

    function _nonReentrantAfter() private {
        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../extensions/draft-IERC20Permit.sol";
import "../../../utils/Address.sol";

/**
 * @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;

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @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));
    }

    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));
    }

    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));
        }
    }

    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @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.

        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");
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface 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.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}