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