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ERC165Checker.sol
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ERC165Checker.sol
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// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/introspection/ERC165Checker.sol)
pragma solidity ^0.8.20;
import {IERC165} from "./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 ERC-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 ERC-165 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 ERC-165 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}.
*/
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 ERC-165 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 ERC-165 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 ERC-165 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 ERC-165, otherwise
* the behavior of this method is undefined. This precondition can be checked
* with {supportsERC165}.
*
* Some precompiled contracts will falsely indicate support for a given interface, so caution
* should be exercised when using this function.
*
* Interface identification is specified in ERC-165.
*/
function supportsERC165InterfaceUnchecked(address account, bytes4 interfaceId) internal view returns (bool) {
// prepare call
bytes memory encodedParams = abi.encodeCall(IERC165.supportsInterface, (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;
}
}