// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.8.17;

/// @title Reentrancy Guard
/// @author LI.FI (https://li.fi)
/// @notice Abstract contract to provide protection against reentrancy
abstract contract ReentrancyGuard {
    /// Storage ///

    bytes32 private constant NAMESPACE = keccak256("com.lifi.reentrancyguard");

    /// Types ///

    struct ReentrancyStorage {
        uint256 status;
    }

    /// Errors ///

    error ReentrancyError();

    /// Constants ///

    uint256 private constant _NOT_ENTERED = 0;
    uint256 private constant _ENTERED = 1;

    /// Modifiers ///

    modifier nonReentrant() {
        ReentrancyStorage storage s = reentrancyStorage();
        if (s.status == _ENTERED) revert ReentrancyError();
        s.status = _ENTERED;
        _;
        s.status = _NOT_ENTERED;
    }

    /// Private Methods ///

    /// @dev fetch local storage
    function reentrancyStorage()
        private
        pure
        returns (ReentrancyStorage storage data)
    {
        bytes32 position = NAMESPACE;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            data.slot := position
        }
    }
}