// SPDX-License-Identifier: MIT // OpenZeppelin Contracts (last updated v4.8.0) (utils/introspection/ERC165Checker.sol) pragma solidity ^0.8.0; import "./IERC165.sol"; /** * @dev Library used to query support of an interface declared via {IERC165}. * * Note that these functions return the actual result of the query: they do not * `revert` if an interface is not supported. It is up to the caller to decide * what to do in these cases. */ library ERC165Checker { // As per the EIP-165 spec, no interface should ever match 0xffffffff bytes4 private constant _INTERFACE_ID_INVALID = 0xffffffff; /** * @dev Returns true if `account` supports the {IERC165} interface. */ function supportsERC165(address account) internal view returns (bool) { // Any contract that implements ERC165 must explicitly indicate support of // InterfaceId_ERC165 and explicitly indicate non-support of InterfaceId_Invalid return supportsERC165InterfaceUnchecked(account, type(IERC165).interfaceId) && !supportsERC165InterfaceUnchecked(account, _INTERFACE_ID_INVALID); } /** * @dev Returns true if `account` supports the interface defined by * `interfaceId`. Support for {IERC165} itself is queried automatically. * * See {IERC165-supportsInterface}. */ function supportsInterface(address account, bytes4 interfaceId) internal view returns (bool) { // query support of both ERC165 as per the spec and support of _interfaceId return supportsERC165(account) && supportsERC165InterfaceUnchecked(account, interfaceId); } /** * @dev Returns a boolean array where each value corresponds to the * interfaces passed in and whether they're supported or not. This allows * you to batch check interfaces for a contract where your expectation * is that some interfaces may not be supported. * * See {IERC165-supportsInterface}. * * _Available since v3.4._ */ function getSupportedInterfaces( address account, bytes4[] memory interfaceIds ) internal view returns (bool[] memory) { // an array of booleans corresponding to interfaceIds and whether they're supported or not bool[] memory interfaceIdsSupported = new bool[](interfaceIds.length); // query support of ERC165 itself if (supportsERC165(account)) { // query support of each interface in interfaceIds for (uint256 i = 0; i < interfaceIds.length; i++) { interfaceIdsSupported[i] = supportsERC165InterfaceUnchecked(account, interfaceIds[i]); } } return interfaceIdsSupported; } /** * @dev Returns true if `account` supports all the interfaces defined in * `interfaceIds`. Support for {IERC165} itself is queried automatically. * * Batch-querying can lead to gas savings by skipping repeated checks for * {IERC165} support. * * See {IERC165-supportsInterface}. */ function supportsAllInterfaces(address account, bytes4[] memory interfaceIds) internal view returns (bool) { // query support of ERC165 itself if (!supportsERC165(account)) { return false; } // query support of each interface in interfaceIds for (uint256 i = 0; i < interfaceIds.length; i++) { if (!supportsERC165InterfaceUnchecked(account, interfaceIds[i])) { return false; } } // all interfaces supported return true; } /** * @notice Query if a contract implements an interface, does not check ERC165 support * @param account The address of the contract to query for support of an interface * @param interfaceId The interface identifier, as specified in ERC-165 * @return true if the contract at account indicates support of the interface with * identifier interfaceId, false otherwise * @dev Assumes that account contains a contract that supports ERC165, otherwise * the behavior of this method is undefined. This precondition can be checked * with {supportsERC165}. * Interface identification is specified in ERC-165. */ function supportsERC165InterfaceUnchecked(address account, bytes4 interfaceId) internal view returns (bool) { // prepare call bytes memory encodedParams = abi.encodeWithSelector(IERC165.supportsInterface.selector, interfaceId); // perform static call bool success; uint256 returnSize; uint256 returnValue; assembly { success := staticcall(30000, account, add(encodedParams, 0x20), mload(encodedParams), 0x00, 0x20) returnSize := returndatasize() returnValue := mload(0x00) } return success && returnSize >= 0x20 && returnValue > 0; } }