openzeppelin-contracts/contracts/utils/introspection/ERC1820ImplementerUpgradeable.sol

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC1820Implementer.sol)

pragma solidity ^0.8.0;

import "./IERC1820ImplementerUpgradeable.sol";
import "../../proxy/utils/Initializable.sol";

/**
 * @dev Implementation of the {IERC1820Implementer} interface.
 *
 * Contracts may inherit from this and call {_registerInterfaceForAddress} to
 * declare their willingness to be implementers.
 * {IERC1820Registry-setInterfaceImplementer} should then be called for the
 * registration to be complete.
 */
contract ERC1820ImplementerUpgradeable is Initializable, IERC1820ImplementerUpgradeable {
    function __ERC1820Implementer_init() internal onlyInitializing {
    }

    function __ERC1820Implementer_init_unchained() internal onlyInitializing {
    }
    bytes32 private constant _ERC1820_ACCEPT_MAGIC = keccak256("ERC1820_ACCEPT_MAGIC");

    mapping(bytes32 => mapping(address => bool)) private _supportedInterfaces;

    /**
     * @dev See {IERC1820Implementer-canImplementInterfaceForAddress}.
     */
    function canImplementInterfaceForAddress(bytes32 interfaceHash, address account)
        public
        view
        virtual
        override
        returns (bytes32)
    {
        return _supportedInterfaces[interfaceHash][account] ? _ERC1820_ACCEPT_MAGIC : bytes32(0x00);
    }

    /**
     * @dev Declares the contract as willing to be an implementer of
     * `interfaceHash` for `account`.
     *
     * See {IERC1820Registry-setInterfaceImplementer} and
     * {IERC1820Registry-interfaceHash}.
     */
    function _registerInterfaceForAddress(bytes32 interfaceHash, address account) internal virtual {
        _supportedInterfaces[interfaceHash][account] = true;
    }

    /**
     * @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;
}