// SPDX-License-Identifier: MIT // OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165Storage.sol) pragma solidity ^0.8.0; import "./ERC165.sol"; /** * @dev Storage based implementation of the {IERC165} interface. * * Contracts may inherit from this and call {_registerInterface} to declare * their support of an interface. */ abstract contract ERC165Storage is ERC165 { /** * @dev Mapping of interface ids to whether or not it's supported. */ mapping(bytes4 => bool) private _supportedInterfaces; /** * @dev See {IERC165-supportsInterface}. */ function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) { return super.supportsInterface(interfaceId) || _supportedInterfaces[interfaceId]; } /** * @dev Registers the contract as an implementer of the interface defined by * `interfaceId`. Support of the actual ERC165 interface is automatic and * registering its interface id is not required. * * See {IERC165-supportsInterface}. * * Requirements: * * - `interfaceId` cannot be the ERC165 invalid interface (`0xffffffff`). */ function _registerInterface(bytes4 interfaceId) internal virtual { require(interfaceId != 0xffffffff, "ERC165: invalid interface id"); _supportedInterfaces[interfaceId] = true; } }