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Contract Name:
L1USDCGateway

Contract Source Code:

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/ContextUpgradeable.sol";
import "../proxy/utils/Initializable.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract OwnableUpgradeable is Initializable, ContextUpgradeable {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    function __Ownable_init() internal onlyInitializing {
        __Ownable_init_unchained();
    }

    function __Ownable_init_unchained() internal onlyInitializing {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby disabling any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }

    /**
     * @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[49] private __gap;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (proxy/utils/Initializable.sol)

pragma solidity ^0.8.2;

import "../../utils/AddressUpgradeable.sol";

/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
 * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
 * case an upgrade adds a module that needs to be initialized.
 *
 * For example:
 *
 * [.hljs-theme-light.nopadding]
 * ```solidity
 * contract MyToken is ERC20Upgradeable {
 *     function initialize() initializer public {
 *         __ERC20_init("MyToken", "MTK");
 *     }
 * }
 *
 * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
 *     function initializeV2() reinitializer(2) public {
 *         __ERC20Permit_init("MyToken");
 *     }
 * }
 * ```
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 *
 * [CAUTION]
 * ====
 * Avoid leaving a contract uninitialized.
 *
 * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
 * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
 * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * /// @custom:oz-upgrades-unsafe-allow constructor
 * constructor() {
 *     _disableInitializers();
 * }
 * ```
 * ====
 */
abstract contract Initializable {
    /**
     * @dev Indicates that the contract has been initialized.
     * @custom:oz-retyped-from bool
     */
    uint8 private _initialized;

    /**
     * @dev Indicates that the contract is in the process of being initialized.
     */
    bool private _initializing;

    /**
     * @dev Triggered when the contract has been initialized or reinitialized.
     */
    event Initialized(uint8 version);

    /**
     * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
     * `onlyInitializing` functions can be used to initialize parent contracts.
     *
     * Similar to `reinitializer(1)`, except that functions marked with `initializer` can be nested in the context of a
     * constructor.
     *
     * Emits an {Initialized} event.
     */
    modifier initializer() {
        bool isTopLevelCall = !_initializing;
        require(
            (isTopLevelCall && _initialized < 1) || (!AddressUpgradeable.isContract(address(this)) && _initialized == 1),
            "Initializable: contract is already initialized"
        );
        _initialized = 1;
        if (isTopLevelCall) {
            _initializing = true;
        }
        _;
        if (isTopLevelCall) {
            _initializing = false;
            emit Initialized(1);
        }
    }

    /**
     * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
     * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
     * used to initialize parent contracts.
     *
     * A reinitializer may be used after the original initialization step. This is essential to configure modules that
     * are added through upgrades and that require initialization.
     *
     * When `version` is 1, this modifier is similar to `initializer`, except that functions marked with `reinitializer`
     * cannot be nested. If one is invoked in the context of another, execution will revert.
     *
     * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
     * a contract, executing them in the right order is up to the developer or operator.
     *
     * WARNING: setting the version to 255 will prevent any future reinitialization.
     *
     * Emits an {Initialized} event.
     */
    modifier reinitializer(uint8 version) {
        require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
        _initialized = version;
        _initializing = true;
        _;
        _initializing = false;
        emit Initialized(version);
    }

    /**
     * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
     * {initializer} and {reinitializer} modifiers, directly or indirectly.
     */
    modifier onlyInitializing() {
        require(_initializing, "Initializable: contract is not initializing");
        _;
    }

    /**
     * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
     * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
     * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
     * through proxies.
     *
     * Emits an {Initialized} event the first time it is successfully executed.
     */
    function _disableInitializers() internal virtual {
        require(!_initializing, "Initializable: contract is initializing");
        if (_initialized != type(uint8).max) {
            _initialized = type(uint8).max;
            emit Initialized(type(uint8).max);
        }
    }

    /**
     * @dev Returns the highest version that has been initialized. See {reinitializer}.
     */
    function _getInitializedVersion() internal view returns (uint8) {
        return _initialized;
    }

    /**
     * @dev Returns `true` if the contract is currently initializing. See {onlyInitializing}.
     */
    function _isInitializing() internal view returns (bool) {
        return _initializing;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;
import "../proxy/utils/Initializable.sol";

/**
 * @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 ReentrancyGuardUpgradeable is Initializable {
    // 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;

    function __ReentrancyGuard_init() internal onlyInitializing {
        __ReentrancyGuard_init_unchained();
    }

    function __ReentrancyGuard_init_unchained() internal onlyInitializing {
        _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;
    }

    /**
     * @dev Returns true if the reentrancy guard is currently set to "entered", which indicates there is a
     * `nonReentrant` function in the call stack.
     */
    function _reentrancyGuardEntered() internal view returns (bool) {
        return _status == _ENTERED;
    }

    /**
     * @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[49] private __gap;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/extensions/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 IERC20PermitUpgradeable {
    /**
     * @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);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20Upgradeable {
    /**
     * @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 v4.9.3) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20Upgradeable.sol";
import "../extensions/IERC20PermitUpgradeable.sol";
import "../../../utils/AddressUpgradeable.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 SafeERC20Upgradeable {
    using AddressUpgradeable for address;

    /**
     * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeTransfer(IERC20Upgradeable token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    /**
     * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
     * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
     */
    function safeTransferFrom(IERC20Upgradeable 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(IERC20Upgradeable 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));
    }

    /**
     * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeIncreaseAllowance(IERC20Upgradeable token, address spender, uint256 value) internal {
        uint256 oldAllowance = token.allowance(address(this), spender);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance + value));
    }

    /**
     * @dev Decrease the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeDecreaseAllowance(IERC20Upgradeable token, address spender, uint256 value) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance - value));
        }
    }

    /**
     * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful. Meant to be used with tokens that require the approval
     * to be set to zero before setting it to a non-zero value, such as USDT.
     */
    function forceApprove(IERC20Upgradeable token, address spender, uint256 value) internal {
        bytes memory approvalCall = abi.encodeWithSelector(token.approve.selector, spender, value);

        if (!_callOptionalReturnBool(token, approvalCall)) {
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, 0));
            _callOptionalReturn(token, approvalCall);
        }
    }

    /**
     * @dev Use a ERC-2612 signature to set the `owner` approval toward `spender` on `token`.
     * Revert on invalid signature.
     */
    function safePermit(
        IERC20PermitUpgradeable 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(IERC20Upgradeable 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");
        require(returndata.length == 0 || abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation 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).
     *
     * This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
     */
    function _callOptionalReturnBool(IERC20Upgradeable token, bytes memory data) private returns (bool) {
        // 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 cannot use {Address-functionCall} here since this should return false
        // and not revert is the subcall reverts.

        (bool success, bytes memory returndata) = address(token).call(data);
        return
            success && (returndata.length == 0 || abi.decode(returndata, (bool))) && AddressUpgradeable.isContract(address(token));
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library AddressUpgradeable {
    /**
     * @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
     *
     * Furthermore, `isContract` will also return true if the target contract within
     * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
     * which only has an effect at the end of a transaction.
     * ====
     *
     * [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://consensys.net/diligence/blog/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/v0.8.0/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 v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;
import "../proxy/utils/Initializable.sol";

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract ContextUpgradeable is Initializable {
    function __Context_init() internal onlyInitializing {
    }

    function __Context_init_unchained() internal onlyInitializing {
    }
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }

    /**
     * @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[50] private __gap;
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.16;

interface IFiatToken {
    /**
     * @notice Function to mint tokens
     * @param _to The address that will receive the minted tokens.
     * @param _amount The amount of tokens to mint. Must be less than or equal
     * to the minterAllowance of the caller.
     * @return A boolean that indicates if the operation was successful.
     */
    function mint(address _to, uint256 _amount) external returns (bool);

    /**
     * @notice allows a minter to burn some of its own tokens
     * Validates that caller is a minter and that sender is not blacklisted
     * amount is less than or equal to the minter's account balance
     * @param _amount uint256 the amount of tokens to be burned
     */
    function burn(uint256 _amount) external;
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.16;

/// @title IUSDCBurnableSourceBridge
/// @notice The interface of `USDCBurnableSourceBridge` of Circle's upgrader in L1 (Ethereum).
interface IUSDCBurnableSourceBridge {
    /**
     * @notice Called by Circle, this executes a burn on the source
     * chain.
     */
    function burnAllLockedUSDC() external;
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.16;

interface IL1ERC20Gateway {
    /**********
     * Events *
     **********/

    /// @notice Emitted when ERC20 token is withdrawn from L2 to L1 and transfer to recipient.
    /// @param l1Token The address of the token in L1.
    /// @param l2Token The address of the token in L2.
    /// @param from The address of sender in L2.
    /// @param to The address of recipient in L1.
    /// @param amount The amount of token withdrawn from L2 to L1.
    /// @param data The optional calldata passed to recipient in L1.
    event FinalizeWithdrawERC20(
        address indexed l1Token,
        address indexed l2Token,
        address indexed from,
        address to,
        uint256 amount,
        bytes data
    );

    /// @notice Emitted when someone deposit ERC20 token from L1 to L2.
    /// @param l1Token The address of the token in L1.
    /// @param l2Token The address of the token in L2.
    /// @param from The address of sender in L1.
    /// @param to The address of recipient in L2.
    /// @param amount The amount of token will be deposited from L1 to L2.
    /// @param data The optional calldata passed to recipient in L2.
    event DepositERC20(
        address indexed l1Token,
        address indexed l2Token,
        address indexed from,
        address to,
        uint256 amount,
        bytes data
    );

    /// @notice Emitted when some ERC20 token is refunded.
    /// @param token The address of the token in L1.
    /// @param recipient The address of receiver in L1.
    /// @param amount The amount of token refunded to receiver.
    event RefundERC20(address indexed token, address indexed recipient, uint256 amount);

    /*************************
     * Public View Functions *
     *************************/

    /// @notice Return the corresponding l2 token address given l1 token address.
    /// @param _l1Token The address of l1 token.
    function getL2ERC20Address(address _l1Token) external view returns (address);

    /*****************************
     * Public Mutating Functions *
     *****************************/

    /// @notice Deposit some token to a caller's account on L2.
    /// @dev Make this function payable to send relayer fee in Ether.
    /// @param _token The address of token in L1.
    /// @param _amount The amount of token to transfer.
    /// @param _gasLimit Gas limit required to complete the deposit on L2.
    function depositERC20(
        address _token,
        uint256 _amount,
        uint256 _gasLimit
    ) external payable;

    /// @notice Deposit some token to a recipient's account on L2.
    /// @dev Make this function payable to send relayer fee in Ether.
    /// @param _token The address of token in L1.
    /// @param _to The address of recipient's account on L2.
    /// @param _amount The amount of token to transfer.
    /// @param _gasLimit Gas limit required to complete the deposit on L2.
    function depositERC20(
        address _token,
        address _to,
        uint256 _amount,
        uint256 _gasLimit
    ) external payable;

    /// @notice Deposit some token to a recipient's account on L2 and call.
    /// @dev Make this function payable to send relayer fee in Ether.
    /// @param _token The address of token in L1.
    /// @param _to The address of recipient's account on L2.
    /// @param _amount The amount of token to transfer.
    /// @param _data Optional data to forward to recipient's account.
    /// @param _gasLimit Gas limit required to complete the deposit on L2.
    function depositERC20AndCall(
        address _token,
        address _to,
        uint256 _amount,
        bytes memory _data,
        uint256 _gasLimit
    ) external payable;

    /// @notice Complete ERC20 withdraw from L2 to L1 and send fund to recipient's account in L1.
    /// @dev Make this function payable to handle WETH deposit/withdraw.
    ///      The function should only be called by L1ScrollMessenger.
    ///      The function should also only be called by L2ERC20Gateway in L2.
    /// @param _l1Token The address of corresponding L1 token.
    /// @param _l2Token The address of corresponding L2 token.
    /// @param _from The address of account who withdraw the token in L2.
    /// @param _to The address of recipient in L1 to receive the token.
    /// @param _amount The amount of the token to withdraw.
    /// @param _data Optional data to forward to recipient's account.
    function finalizeWithdrawERC20(
        address _l1Token,
        address _l2Token,
        address _from,
        address _to,
        uint256 _amount,
        bytes calldata _data
    ) external payable;
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.16;

interface IL1ETHGateway {
    /**********
     * Events *
     **********/

    /// @notice Emitted when ETH is withdrawn from L2 to L1 and transfer to recipient.
    /// @param from The address of sender in L2.
    /// @param to The address of recipient in L1.
    /// @param amount The amount of ETH withdrawn from L2 to L1.
    /// @param data The optional calldata passed to recipient in L1.
    event FinalizeWithdrawETH(address indexed from, address indexed to, uint256 amount, bytes data);

    /// @notice Emitted when someone deposit ETH from L1 to L2.
    /// @param from The address of sender in L1.
    /// @param to The address of recipient in L2.
    /// @param amount The amount of ETH will be deposited from L1 to L2.
    /// @param data The optional calldata passed to recipient in L2.
    event DepositETH(address indexed from, address indexed to, uint256 amount, bytes data);

    /// @notice Emitted when some ETH is refunded.
    /// @param recipient The address of receiver in L1.
    /// @param amount The amount of ETH refunded to receiver.
    event RefundETH(address indexed recipient, uint256 amount);

    /*****************************
     * Public Mutating Functions *
     *****************************/

    /// @notice Deposit ETH to caller's account in L2.
    /// @param amount The amount of ETH to be deposited.
    /// @param gasLimit Gas limit required to complete the deposit on L2.
    function depositETH(uint256 amount, uint256 gasLimit) external payable;

    /// @notice Deposit ETH to some recipient's account in L2.
    /// @param to The address of recipient's account on L2.
    /// @param amount The amount of ETH to be deposited.
    /// @param gasLimit Gas limit required to complete the deposit on L2.
    function depositETH(
        address to,
        uint256 amount,
        uint256 gasLimit
    ) external payable;

    /// @notice Deposit ETH to some recipient's account in L2 and call the target contract.
    /// @param to The address of recipient's account on L2.
    /// @param amount The amount of ETH to be deposited.
    /// @param data Optional data to forward to recipient's account.
    /// @param gasLimit Gas limit required to complete the deposit on L2.
    function depositETHAndCall(
        address to,
        uint256 amount,
        bytes calldata data,
        uint256 gasLimit
    ) external payable;

    /// @notice Complete ETH withdraw from L2 to L1 and send fund to recipient's account in L1.
    /// @dev This function should only be called by L1ScrollMessenger.
    ///      This function should also only be called by L1ETHGateway in L2.
    /// @param from The address of account who withdraw ETH in L2.
    /// @param to The address of recipient in L1 to receive ETH.
    /// @param amount The amount of ETH to withdraw.
    /// @param data Optional data to forward to recipient's account.
    function finalizeWithdrawETH(
        address from,
        address to,
        uint256 amount,
        bytes calldata data
    ) external payable;
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.16;

import {IL1ETHGateway} from "./IL1ETHGateway.sol";
import {IL1ERC20Gateway} from "./IL1ERC20Gateway.sol";

interface IL1GatewayRouter is IL1ETHGateway, IL1ERC20Gateway {
    /**********
     * Events *
     **********/

    /// @notice Emitted when the address of ETH Gateway is updated.
    /// @param oldETHGateway The address of the old ETH Gateway.
    /// @param newEthGateway The address of the new ETH Gateway.
    event SetETHGateway(address indexed oldETHGateway, address indexed newEthGateway);

    /// @notice Emitted when the address of default ERC20 Gateway is updated.
    /// @param oldDefaultERC20Gateway The address of the old default ERC20 Gateway.
    /// @param newDefaultERC20Gateway The address of the new default ERC20 Gateway.
    event SetDefaultERC20Gateway(address indexed oldDefaultERC20Gateway, address indexed newDefaultERC20Gateway);

    /// @notice Emitted when the `gateway` for `token` is updated.
    /// @param token The address of token updated.
    /// @param oldGateway The corresponding address of the old gateway.
    /// @param newGateway The corresponding address of the new gateway.
    event SetERC20Gateway(address indexed token, address indexed oldGateway, address indexed newGateway);

    /*************************
     * Public View Functions *
     *************************/

    /// @notice Return the corresponding gateway address for given token address.
    /// @param _token The address of token to query.
    function getERC20Gateway(address _token) external view returns (address);

    /*****************************
     * Public Mutating Functions *
     *****************************/

    /// @notice Request ERC20 token transfer from users to gateways.
    /// @param sender The address of sender to request fund.
    /// @param token The address of token to request.
    /// @param amount The amount of token to request.
    function requestERC20(
        address sender,
        address token,
        uint256 amount
    ) external returns (uint256);

    /************************
     * Restricted Functions *
     ************************/

    /// @notice Update the address of ETH gateway contract.
    /// @dev This function should only be called by contract owner.
    /// @param _ethGateway The address to update.
    function setETHGateway(address _ethGateway) external;

    /// @notice Update the address of default ERC20 gateway contract.
    /// @dev This function should only be called by contract owner.
    /// @param _defaultERC20Gateway The address to update.
    function setDefaultERC20Gateway(address _defaultERC20Gateway) external;

    /// @notice Update the mapping from token address to gateway address.
    /// @dev This function should only be called by contract owner.
    /// @param _tokens The list of addresses of tokens to update.
    /// @param _gateways The list of addresses of gateways to update.
    function setERC20Gateway(address[] memory _tokens, address[] memory _gateways) external;
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.16;

import {IERC20Upgradeable} from "@openzeppelin/contracts-upgradeable/token/ERC20/IERC20Upgradeable.sol";
import {SafeERC20Upgradeable} from "@openzeppelin/contracts-upgradeable/token/ERC20/utils/SafeERC20Upgradeable.sol";

import {IL1ERC20Gateway} from "./IL1ERC20Gateway.sol";
import {IL1GatewayRouter} from "./IL1GatewayRouter.sol";

import {IL2ERC20Gateway} from "../../L2/gateways/IL2ERC20Gateway.sol";
import {ScrollGatewayBase} from "../../libraries/gateway/ScrollGatewayBase.sol";
import {IMessageDropCallback} from "../../libraries/callbacks/IMessageDropCallback.sol";

/// @title L1ERC20Gateway
/// @notice The `L1ERC20Gateway` as a base contract for ERC20 gateways in L1.
/// It has implementation of common used functions for ERC20 gateways.
abstract contract L1ERC20Gateway is IL1ERC20Gateway, IMessageDropCallback, ScrollGatewayBase {
    using SafeERC20Upgradeable for IERC20Upgradeable;

    /*************
     * Variables *
     *************/

    /// @dev The storage slots for future usage.
    uint256[50] private __gap;

    /*****************************
     * Public Mutating Functions *
     *****************************/

    /// @inheritdoc IL1ERC20Gateway
    function depositERC20(
        address _token,
        uint256 _amount,
        uint256 _gasLimit
    ) external payable override {
        _deposit(_token, _msgSender(), _amount, new bytes(0), _gasLimit);
    }

    /// @inheritdoc IL1ERC20Gateway
    function depositERC20(
        address _token,
        address _to,
        uint256 _amount,
        uint256 _gasLimit
    ) external payable override {
        _deposit(_token, _to, _amount, new bytes(0), _gasLimit);
    }

    /// @inheritdoc IL1ERC20Gateway
    function depositERC20AndCall(
        address _token,
        address _to,
        uint256 _amount,
        bytes memory _data,
        uint256 _gasLimit
    ) external payable override {
        _deposit(_token, _to, _amount, _data, _gasLimit);
    }

    /// @inheritdoc IL1ERC20Gateway
    function finalizeWithdrawERC20(
        address _l1Token,
        address _l2Token,
        address _from,
        address _to,
        uint256 _amount,
        bytes calldata _data
    ) external payable virtual override onlyCallByCounterpart nonReentrant {
        _beforeFinalizeWithdrawERC20(_l1Token, _l2Token, _from, _to, _amount, _data);

        // @note can possible trigger reentrant call to this contract or messenger,
        // but it seems not a big problem.
        IERC20Upgradeable(_l1Token).safeTransfer(_to, _amount);

        _doCallback(_to, _data);

        emit FinalizeWithdrawERC20(_l1Token, _l2Token, _from, _to, _amount, _data);
    }

    /// @inheritdoc IMessageDropCallback
    function onDropMessage(bytes calldata _message) external payable virtual onlyInDropContext nonReentrant {
        // _message should start with 0x8431f5c1  =>  finalizeDepositERC20(address,address,address,address,uint256,bytes)
        require(bytes4(_message[0:4]) == IL2ERC20Gateway.finalizeDepositERC20.selector, "invalid selector");

        // decode (token, receiver, amount)
        (address _token, , address _receiver, , uint256 _amount, ) = abi.decode(
            _message[4:],
            (address, address, address, address, uint256, bytes)
        );

        // do dome check for each custom gateway
        _beforeDropMessage(_token, _receiver, _amount);

        IERC20Upgradeable(_token).safeTransfer(_receiver, _amount);

        emit RefundERC20(_token, _receiver, _amount);
    }

    /**********************
     * Internal Functions *
     **********************/

    /// @dev Internal function hook to perform checks and actions before finalizing the withdrawal.
    /// @param _l1Token The address of corresponding L1 token in L1.
    /// @param _l2Token The address of corresponding L2 token in L2.
    /// @param _from The address of account who withdraw the token in L2.
    /// @param _to The address of recipient in L1 to receive the token.
    /// @param _amount The amount of the token to withdraw.
    /// @param _data Optional data to forward to recipient's account.
    function _beforeFinalizeWithdrawERC20(
        address _l1Token,
        address _l2Token,
        address _from,
        address _to,
        uint256 _amount,
        bytes calldata _data
    ) internal virtual;

    /// @dev Internal function hook to perform checks and actions before dropping the message.
    /// @param _token The L1 token address.
    /// @param _receiver The recipient address on L1.
    /// @param _amount The amount of token to refund.
    function _beforeDropMessage(
        address _token,
        address _receiver,
        uint256 _amount
    ) internal virtual;

    /// @dev Internal function to transfer ERC20 token to this contract.
    /// @param _token The address of token to transfer.
    /// @param _amount The amount of token to transfer.
    /// @param _data The data passed by caller.
    function _transferERC20In(
        address _token,
        uint256 _amount,
        bytes memory _data
    )
        internal
        returns (
            address,
            uint256,
            bytes memory
        )
    {
        address _sender = _msgSender();
        address _from = _sender;
        if (router == _sender) {
            // Extract real sender if this call is from L1GatewayRouter.
            (_from, _data) = abi.decode(_data, (address, bytes));
            _amount = IL1GatewayRouter(_sender).requestERC20(_from, _token, _amount);
        } else {
            // common practice to handle fee on transfer token.
            uint256 _before = IERC20Upgradeable(_token).balanceOf(address(this));
            IERC20Upgradeable(_token).safeTransferFrom(_from, address(this), _amount);
            uint256 _after = IERC20Upgradeable(_token).balanceOf(address(this));
            // no unchecked here, since some weird token may return arbitrary balance.
            _amount = _after - _before;
        }
        // ignore weird fee on transfer token
        require(_amount > 0, "deposit zero amount");

        return (_from, _amount, _data);
    }

    /// @dev Internal function to do all the deposit operations.
    ///
    /// @param _token The token to deposit.
    /// @param _to The recipient address to recieve the token in L2.
    /// @param _amount The amount of token to deposit.
    /// @param _data Optional data to forward to recipient's account.
    /// @param _gasLimit Gas limit required to complete the deposit on L2.
    function _deposit(
        address _token,
        address _to,
        uint256 _amount,
        bytes memory _data,
        uint256 _gasLimit
    ) internal virtual;
}

// SPDX-License-Identifier: MIT

pragma solidity =0.8.16;

import {IFiatToken} from "../../../interfaces/IFiatToken.sol";
import {IUSDCBurnableSourceBridge} from "../../../interfaces/IUSDCBurnableSourceBridge.sol";
import {IL2ERC20Gateway} from "../../../L2/gateways/IL2ERC20Gateway.sol";
import {IL1ScrollMessenger} from "../../IL1ScrollMessenger.sol";
import {IL1ERC20Gateway} from "../IL1ERC20Gateway.sol";

import {ScrollGatewayBase} from "../../../libraries/gateway/ScrollGatewayBase.sol";
import {L1ERC20Gateway} from "../L1ERC20Gateway.sol";

/// @title L1USDCGateway
/// @notice The `L1USDCGateway` contract is used to deposit `USDC` token in layer 1 and
/// finalize withdraw `USDC` from layer 2, before USDC become native in layer 2.
contract L1USDCGateway is L1ERC20Gateway, IUSDCBurnableSourceBridge {
    /*************
     * Constants *
     *************/

    /// @notice The address of L1 USDC address.
    // solhint-disable-next-line var-name-mixedcase
    address public immutable l1USDC;

    /// @notice The address of L2 USDC address.
    address public immutable l2USDC;

    /*************
     * Variables *
     *************/

    /// @notice The address of caller from Circle.
    address public circleCaller;

    /// @notice The flag indicates whether USDC deposit is paused.
    bool public depositPaused;

    /// @notice The flag indicates whether USDC withdrawal is paused.
    /// @dev This is not necessary to be set `true` since we will set `L2USDCGateway.withdrawPaused` first.
    ///      This is kept just in case and will be set after all pending messages are relayed.
    bool public withdrawPaused;

    /// @notice The total amount of bridged USDC in this contract.
    /// @dev Only deposited USDC will count. Accidentally transferred USDC will be ignored.
    uint256 public totalBridgedUSDC;

    /***************
     * Constructor *
     ***************/

    constructor(address _l1USDC, address _l2USDC) {
        _disableInitializers();

        l1USDC = _l1USDC;
        l2USDC = _l2USDC;
    }

    /// @notice Initialize the storage of L1WETHGateway.
    /// @param _counterpart The address of L2ETHGateway in L2.
    /// @param _router The address of L1GatewayRouter.
    /// @param _messenger The address of L1ScrollMessenger.
    function initialize(
        address _counterpart,
        address _router,
        address _messenger
    ) external initializer {
        require(_router != address(0), "zero router address");
        ScrollGatewayBase._initialize(_counterpart, _router, _messenger);
    }

    /*************************
     * Public View Functions *
     *************************/

    /// @inheritdoc IL1ERC20Gateway
    function getL2ERC20Address(address) public view override returns (address) {
        return l2USDC;
    }

    /*******************************
     * Public Restricted Functions *
     *******************************/

    /// @inheritdoc IUSDCBurnableSourceBridge
    function burnAllLockedUSDC() external override {
        require(_msgSender() == circleCaller, "only circle caller");

        // @note Only bridged USDC will be burned. We may refund the rest if possible.
        uint256 _balance = totalBridgedUSDC;
        totalBridgedUSDC = 0;

        IFiatToken(l1USDC).burn(_balance);
    }

    /// @notice Update the Circle EOA address.
    /// @param _caller The address to update.
    function updateCircleCaller(address _caller) external onlyOwner {
        circleCaller = _caller;
    }

    /// @notice Change the deposit pause status of this contract.
    /// @param _paused The new status, `true` means paused and `false` means not paused.
    function pauseDeposit(bool _paused) external onlyOwner {
        depositPaused = _paused;
    }

    /// @notice Change the withdraw pause status of this contract.
    /// @param _paused The new status, `true` means paused and `false` means not paused.
    function pauseWithdraw(bool _paused) external onlyOwner {
        withdrawPaused = _paused;
    }

    /**********************
     * Internal Functions *
     **********************/

    /// @inheritdoc L1ERC20Gateway
    function _beforeFinalizeWithdrawERC20(
        address _l1Token,
        address _l2Token,
        address,
        address,
        uint256 _amount,
        bytes calldata
    ) internal virtual override {
        require(msg.value == 0, "nonzero msg.value");
        require(_l1Token == l1USDC, "l1 token not USDC");
        require(_l2Token == l2USDC, "l2 token not USDC");
        require(!withdrawPaused, "withdraw paused");

        totalBridgedUSDC -= _amount;
    }

    /// @inheritdoc L1ERC20Gateway
    function _beforeDropMessage(
        address,
        address,
        uint256 _amount
    ) internal virtual override {
        require(msg.value == 0, "nonzero msg.value");
        totalBridgedUSDC -= _amount;
    }

    /// @inheritdoc L1ERC20Gateway
    function _deposit(
        address _token,
        address _to,
        uint256 _amount,
        bytes memory _data,
        uint256 _gasLimit
    ) internal virtual override nonReentrant {
        require(_amount > 0, "deposit zero amount");
        require(_token == l1USDC, "only USDC is allowed");
        require(!depositPaused, "deposit paused");

        // 1. Transfer token into this contract.
        address _from;
        (_from, _amount, _data) = _transferERC20In(_token, _amount, _data);
        require(_data.length == 0, "call is not allowed");
        totalBridgedUSDC += _amount;

        // 2. Generate message passed to L2USDCGateway.
        bytes memory _message = abi.encodeCall(
            IL2ERC20Gateway.finalizeDepositERC20,
            (_token, l2USDC, _from, _to, _amount, _data)
        );

        // 3. Send message to L1ScrollMessenger.
        IL1ScrollMessenger(messenger).sendMessage{value: msg.value}(counterpart, 0, _message, _gasLimit, _from);

        emit DepositERC20(_token, l2USDC, _from, _to, _amount, _data);
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.16;

import {IScrollMessenger} from "../libraries/IScrollMessenger.sol";

interface IL1ScrollMessenger is IScrollMessenger {
    /**********
     * Events *
     **********/

    /// @notice Emitted when the maximum number of times each message can be replayed is updated.
    /// @param oldMaxReplayTimes The old maximum number of times each message can be replayed.
    /// @param newMaxReplayTimes The new maximum number of times each message can be replayed.
    event UpdateMaxReplayTimes(uint256 oldMaxReplayTimes, uint256 newMaxReplayTimes);

    /***********
     * Structs *
     ***********/

    struct L2MessageProof {
        // The index of the batch where the message belongs to.
        uint256 batchIndex;
        // Concatenation of merkle proof for withdraw merkle trie.
        bytes merkleProof;
    }

    /*****************************
     * Public Mutating Functions *
     *****************************/

    /// @notice Relay a L2 => L1 message with message proof.
    /// @param from The address of the sender of the message.
    /// @param to The address of the recipient of the message.
    /// @param value The msg.value passed to the message call.
    /// @param nonce The nonce of the message to avoid replay attack.
    /// @param message The content of the message.
    /// @param proof The proof used to verify the correctness of the transaction.
    function relayMessageWithProof(
        address from,
        address to,
        uint256 value,
        uint256 nonce,
        bytes memory message,
        L2MessageProof memory proof
    ) external;

    /// @notice Replay an existing message.
    /// @param from The address of the sender of the message.
    /// @param to The address of the recipient of the message.
    /// @param value The msg.value passed to the message call.
    /// @param messageNonce The nonce for the message to replay.
    /// @param message The content of the message.
    /// @param newGasLimit New gas limit to be used for this message.
    /// @param refundAddress The address of account who will receive the refunded fee.
    function replayMessage(
        address from,
        address to,
        uint256 value,
        uint256 messageNonce,
        bytes memory message,
        uint32 newGasLimit,
        address refundAddress
    ) external payable;

    /// @notice Drop a skipped message.
    /// @param from The address of the sender of the message.
    /// @param to The address of the recipient of the message.
    /// @param value The msg.value passed to the message call.
    /// @param messageNonce The nonce for the message to drop.
    /// @param message The content of the message.
    function dropMessage(
        address from,
        address to,
        uint256 value,
        uint256 messageNonce,
        bytes memory message
    ) external;
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.16;

interface IL2ERC20Gateway {
    /**********
     * Events *
     **********/

    /// @notice Emitted when ERC20 token is deposited from L1 to L2 and transfer to recipient.
    /// @param l1Token The address of the token in L1.
    /// @param l2Token The address of the token in L2.
    /// @param from The address of sender in L1.
    /// @param to The address of recipient in L2.
    /// @param amount The amount of token withdrawn from L1 to L2.
    /// @param data The optional calldata passed to recipient in L2.
    event FinalizeDepositERC20(
        address indexed l1Token,
        address indexed l2Token,
        address indexed from,
        address to,
        uint256 amount,
        bytes data
    );

    /// @notice Emitted when someone withdraw ERC20 token from L2 to L1.
    /// @param l1Token The address of the token in L1.
    /// @param l2Token The address of the token in L2.
    /// @param from The address of sender in L2.
    /// @param to The address of recipient in L1.
    /// @param amount The amount of token will be deposited from L2 to L1.
    /// @param data The optional calldata passed to recipient in L1.
    event WithdrawERC20(
        address indexed l1Token,
        address indexed l2Token,
        address indexed from,
        address to,
        uint256 amount,
        bytes data
    );

    /*************************
     * Public View Functions *
     *************************/

    /// @notice Return the corresponding l1 token address given l2 token address.
    /// @param l2Token The address of l2 token.
    function getL1ERC20Address(address l2Token) external view returns (address);

    /// @notice Return the corresponding l2 token address given l1 token address.
    /// @param l1Token The address of l1 token.
    function getL2ERC20Address(address l1Token) external view returns (address);

    /*****************************
     * Public Mutating Functions *
     *****************************/

    /// @notice Withdraw of some token to a caller's account on L1.
    /// @dev Make this function payable to send relayer fee in Ether.
    /// @param token The address of token in L2.
    /// @param amount The amount of token to transfer.
    /// @param gasLimit Unused, but included for potential forward compatibility considerations.
    function withdrawERC20(
        address token,
        uint256 amount,
        uint256 gasLimit
    ) external payable;

    /// @notice Withdraw of some token to a recipient's account on L1.
    /// @dev Make this function payable to send relayer fee in Ether.
    /// @param token The address of token in L2.
    /// @param to The address of recipient's account on L1.
    /// @param amount The amount of token to transfer.
    /// @param gasLimit Unused, but included for potential forward compatibility considerations.
    function withdrawERC20(
        address token,
        address to,
        uint256 amount,
        uint256 gasLimit
    ) external payable;

    /// @notice Withdraw of some token to a recipient's account on L1 and call.
    /// @dev Make this function payable to send relayer fee in Ether.
    /// @param token The address of token in L2.
    /// @param to The address of recipient's account on L1.
    /// @param amount The amount of token to transfer.
    /// @param data Optional data to forward to recipient's account.
    /// @param gasLimit Unused, but included for potential forward compatibility considerations.
    function withdrawERC20AndCall(
        address token,
        address to,
        uint256 amount,
        bytes calldata data,
        uint256 gasLimit
    ) external payable;

    /// @notice Complete a deposit from L1 to L2 and send fund to recipient's account in L2.
    /// @dev Make this function payable to handle WETH deposit/withdraw.
    ///      The function should only be called by L2ScrollMessenger.
    ///      The function should also only be called by L1ERC20Gateway in L1.
    /// @param l1Token The address of corresponding L1 token.
    /// @param l2Token The address of corresponding L2 token.
    /// @param from The address of account who deposits the token in L1.
    /// @param to The address of recipient in L2 to receive the token.
    /// @param amount The amount of the token to deposit.
    /// @param data Optional data to forward to recipient's account.
    function finalizeDepositERC20(
        address l1Token,
        address l2Token,
        address from,
        address to,
        uint256 amount,
        bytes calldata data
    ) external payable;
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.16;

interface IMessageDropCallback {
    function onDropMessage(bytes memory message) external payable;
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.16;

interface IScrollGatewayCallback {
    function onScrollGatewayCallback(bytes memory data) external;
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.16;

library ScrollConstants {
    /// @notice The address of default cross chain message sender.
    address internal constant DEFAULT_XDOMAIN_MESSAGE_SENDER = address(1);

    /// @notice The address for dropping message.
    /// @dev The first 20 bytes of keccak("drop")
    address internal constant DROP_XDOMAIN_MESSAGE_SENDER = 0x6f297C61B5C92eF107fFD30CD56AFFE5A273e841;
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.16;

interface IScrollGateway {
    /// @notice The address of corresponding L1/L2 Gateway contract.
    function counterpart() external view returns (address);

    /// @notice The address of L1GatewayRouter/L2GatewayRouter contract.
    function router() external view returns (address);

    /// @notice The address of corresponding L1ScrollMessenger/L2ScrollMessenger contract.
    function messenger() external view returns (address);
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.16;

import {OwnableUpgradeable} from "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import {ReentrancyGuardUpgradeable} from "@openzeppelin/contracts-upgradeable/security/ReentrancyGuardUpgradeable.sol";

import {IScrollGateway} from "./IScrollGateway.sol";
import {IScrollMessenger} from "../IScrollMessenger.sol";
import {IScrollGatewayCallback} from "../callbacks/IScrollGatewayCallback.sol";
import {ScrollConstants} from "../constants/ScrollConstants.sol";
import {ITokenRateLimiter} from "../../rate-limiter/ITokenRateLimiter.sol";

/// @title ScrollGatewayBase
/// @notice The `ScrollGatewayBase` is a base contract for gateway contracts used in both in L1 and L2.
abstract contract ScrollGatewayBase is ReentrancyGuardUpgradeable, OwnableUpgradeable, IScrollGateway {
    /*************
     * Variables *
     *************/

    /// @inheritdoc IScrollGateway
    address public override counterpart;

    /// @inheritdoc IScrollGateway
    address public override router;

    /// @inheritdoc IScrollGateway
    address public override messenger;

    /// @dev The storage slot used as token rate limiter contract, which is deprecated now.
    address private __rateLimiter;

    /// @dev The storage slots for future usage.
    uint256[46] private __gap;

    /**********************
     * Function Modifiers *
     **********************/

    modifier onlyCallByCounterpart() {
        address _messenger = messenger; // gas saving
        require(_msgSender() == _messenger, "only messenger can call");
        require(counterpart == IScrollMessenger(_messenger).xDomainMessageSender(), "only call by counterpart");
        _;
    }

    modifier onlyInDropContext() {
        address _messenger = messenger; // gas saving
        require(_msgSender() == _messenger, "only messenger can call");
        require(
            ScrollConstants.DROP_XDOMAIN_MESSAGE_SENDER == IScrollMessenger(_messenger).xDomainMessageSender(),
            "only called in drop context"
        );
        _;
    }

    /***************
     * Constructor *
     ***************/

    function _initialize(
        address _counterpart,
        address _router,
        address _messenger
    ) internal {
        require(_counterpart != address(0), "zero counterpart address");
        require(_messenger != address(0), "zero messenger address");

        ReentrancyGuardUpgradeable.__ReentrancyGuard_init();
        OwnableUpgradeable.__Ownable_init();

        counterpart = _counterpart;
        messenger = _messenger;

        // @note: the address of router could be zero, if this contract is GatewayRouter.
        if (_router != address(0)) {
            router = _router;
        }
    }

    /**********************
     * Internal Functions *
     **********************/

    /// @dev Internal function to forward calldata to target contract.
    /// @param _to The address of contract to call.
    /// @param _data The calldata passed to the contract.
    function _doCallback(address _to, bytes memory _data) internal {
        if (_data.length > 0 && _to.code.length > 0) {
            IScrollGatewayCallback(_to).onScrollGatewayCallback(_data);
        }
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.16;

interface IScrollMessenger {
    /**********
     * Events *
     **********/

    /// @notice Emitted when a cross domain message is sent.
    /// @param sender The address of the sender who initiates the message.
    /// @param target The address of target contract to call.
    /// @param value The amount of value passed to the target contract.
    /// @param messageNonce The nonce of the message.
    /// @param gasLimit The optional gas limit passed to L1 or L2.
    /// @param message The calldata passed to the target contract.
    event SentMessage(
        address indexed sender,
        address indexed target,
        uint256 value,
        uint256 messageNonce,
        uint256 gasLimit,
        bytes message
    );

    /// @notice Emitted when a cross domain message is relayed successfully.
    /// @param messageHash The hash of the message.
    event RelayedMessage(bytes32 indexed messageHash);

    /// @notice Emitted when a cross domain message is failed to relay.
    /// @param messageHash The hash of the message.
    event FailedRelayedMessage(bytes32 indexed messageHash);

    /*************************
     * Public View Functions *
     *************************/

    /// @notice Return the sender of a cross domain message.
    function xDomainMessageSender() external view returns (address);

    /*****************************
     * Public Mutating Functions *
     *****************************/

    /// @notice Send cross chain message from L1 to L2 or L2 to L1.
    /// @param target The address of account who receive the message.
    /// @param value The amount of ether passed when call target contract.
    /// @param message The content of the message.
    /// @param gasLimit Gas limit required to complete the message relay on corresponding chain.
    function sendMessage(
        address target,
        uint256 value,
        bytes calldata message,
        uint256 gasLimit
    ) external payable;

    /// @notice Send cross chain message from L1 to L2 or L2 to L1.
    /// @param target The address of account who receive the message.
    /// @param value The amount of ether passed when call target contract.
    /// @param message The content of the message.
    /// @param gasLimit Gas limit required to complete the message relay on corresponding chain.
    /// @param refundAddress The address of account who will receive the refunded fee.
    function sendMessage(
        address target,
        uint256 value,
        bytes calldata message,
        uint256 gasLimit,
        address refundAddress
    ) external payable;
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.16;

interface ITokenRateLimiter {
    /**********
     * Events *
     **********/

    /// @notice Emitted when the total limit is updated.
    /// @param oldTotalLimit The previous value of total limit before updating.
    /// @param newTotalLimit The current value of total limit after updating.
    event UpdateTotalLimit(address indexed token, uint256 oldTotalLimit, uint256 newTotalLimit);

    /**********
     * Errors *
     **********/

    /// @dev Thrown when the `periodDuration` is initialized to zero.
    error PeriodIsZero();

    /// @dev Thrown when the `totalAmount` is initialized to zero.
    /// @param token The address of the token.
    error TotalLimitIsZero(address token);

    /// @dev Thrown when an amount breaches the total limit in the period.
    /// @param token The address of the token.
    error ExceedTotalLimit(address token);

    /*****************************
     * Public Mutating Functions *
     *****************************/

    /// @notice Request some token usage for `sender`.
    /// @param token The address of the token.
    /// @param amount The amount of token to use.
    function addUsedAmount(address token, uint256 amount) external;
}

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