pragma solidity ^0.4.24;
/**
* @title ERC165
* @dev https://github.com/ethereum/EIPs/blob/master/EIPS/eip-165.md
*/
interface ERC165 {
/**
* @notice Query if a contract implements an interface
* @param _interfaceId The interface identifier, as specified in ERC-165
* @dev Interface identification is specified in ERC-165. This function
* uses less than 30,000 gas.
*/
function supportsInterface(bytes4 _interfaceId)
external
view
returns (bool);
}
- SupportInterfaceWithLookup:支持查找的接口
pragma solidity ^0.4.24;
import "./ERC165.sol";
/**
* @title SupportsInterfaceWithLookup
* @author Matt Condon (@shrugs)
* @dev Implements ERC165 using a lookup table.
*/
contract SupportsInterfaceWithLookup is ERC165 {
bytes4 public constant InterfaceId_ERC165 = 0x01ffc9a7;
/**
* 0x01ffc9a7 ===
* bytes4(keccak256('supportsInterface(bytes4)'))
*/
/**
* @dev a mapping of interface id to whether or not it's supported
*/
mapping(bytes4 => bool) internal supportedInterfaces; // 存储支持的接口列表
/**
* @dev A contract implementing SupportsInterfaceWithLookup
* implement ERC165 itself
*/
constructor()
public
{
_registerInterface(InterfaceId_ERC165);
}
/**
* @dev implement supportsInterface(bytes4) using a lookup table
*/
// 查询指定接口是否实现
function supportsInterface(bytes4 _interfaceId)
external
view
returns (bool)
{
return supportedInterfaces[_interfaceId];
}
/**
* @dev private method for registering an interface
*/
// 注册接口
function _registerInterface(bytes4 _interfaceId)
internal
{
require(_interfaceId != 0xffffffff);
supportedInterfaces[_interfaceId] = true;
}
}