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// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.7;
import "./IERC165.sol";
import "./IERC721.sol";
import "./Address.sol"; //导入库
/// @dev Note: the ERC-165 identifier for this interface is 0x150b7a02.
interface ERC721TokenReceiver {
/// @notice Handle the receipt of an NFT
/// @dev The ERC721 smart contract calls this function on the recipient
/// after a transfer. This function MAY throw to revert and reject the
/// transfer. Return of other than the magic value MUST result in the
/// transaction being reverted.
/// Note: the contract address is always the message sender.
/// @param _operator The address which called safeTransferFrom function
/// @param _from The address which previously owned the token
/// @param _tokenId The NFT identifier which is being transferred
/// @param _data Additional data with no specified format
/// @return bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))
/// unless throwing
function onERC721Received(address _operator, address _from, uint256 _tokenId, bytes memory _data) external returns(bytes4);
}
contract ERC721 is IERC721,IERC165 {
mapping(bytes4 => bool)supportsInterfaces;
bytes4 invalidID = 0xffffffff;
bytes4 constant ERC165_InterfaceID=0x01ffc9a7; //erc165
bytes4 constant ERC721_InterfaceID=0x80ac58cd; //erc721
mapping(address=>uint256)ercTokenCount; //记录用户token count；
mapping(uint256=>address)ercTokenOwner; //记录token的拥有者；
mapping(uint256=>address)ercTokenApproved;
mapping(address=>mapping(address=>bool))ercOperatorForAll;
using Address for address;
constructor(){
_registerInterface(ERC165_InterfaceID);
_registerInterface(ERC721_InterfaceID);
}
//授权
modifier canOperator(uint256 _tokenId){
address owner = ercTokenOwner[_tokenId];
require(msg.sender == owner || ercOperatorForAll[owner][msg.sender]);
_;
}
//转账
modifier canTransfer(uint256 _tokenId,address _from){
address owner = ercTokenOwner[_tokenId];
require(owner==_from);
require(msg.sender == owner || msg.sender == ercTokenApproved[_tokenId] || ercOperatorForAll[owner][msg.sender]);
_;
}
function _registerInterface(bytes4 interfaceID)internal {
supportsInterfaces[interfaceID]=true;
}
function supportsInterface(bytes4 interfaceID) override external view returns (bool) {
require(invalidID != interfaceID);
return supportsInterfaces[interfaceID];
}
//721
function balanceOf(address _owner) override external view returns (uint256){
return ercTokenCount[_owner];
}
function ownerOf(uint256 _tokenId) override external view returns (address){
return ercTokenOwner[_tokenId];
}
function getApproved(uint256 _tokenId) override external view returns (address){
return ercTokenApproved[_tokenId];
}
function isApprovedForAll(address _owner, address _operator) external view returns (bool){
return ercOperatorForAll[_owner][_operator];
}
function approve(address _approved, uint256 _tokenId) override external payable{
ercTokenApproved[_tokenId]=_approved;
emit Approval(msg.sender,_approved,_tokenId);
}
function setApprovalForAll(address _operator, bool _approved) override external{
ercOperatorForAll[msg.sender][_operator]=_approved;
emit ApprovalForAll(msg.sender,_operator,_approved);
}
function transferFrom(address _from, address _to, uint256 _tokenId) override external payable{
_transferFrom(_from,_to,_tokenId);
}
function _transferFrom(address _from, address _to, uint256 _tokenId)internal canTransfer(_tokenId,_from){
ercTokenOwner[_tokenId] = _to; //更改属主；
ercTokenCount[_from]-=1;
ercTokenCount[_to]+=1;
ercTokenApproved[_tokenId] = address(0);
emit Transfer(_from, _to, _tokenId);
}
function safeTransferFrom(address _from, address _to, uint256 _tokenId, bytes memory data) override external payable{
_safeTransferFrom(_from,_to,_tokenId,data);
}
function safeTransferFrom(address _from, address _to, uint256 _tokenId)override external payable{
_safeTransferFrom(_from,_to,_tokenId,"");
}
function _safeTransferFrom(address _from, address _to, uint256 _tokenId, bytes memory data) internal { //安全转账即判断对方是否有资格持有ERCtoken，避免转错
_transferFrom(_from, _to, _tokenId);
//add safe code
if(_to.isContract()){ //首先判断对方是否是合约
bytes4 retval = ERC721TokenReceiver(_to).onERC721Received(msg.sender,_from,_tokenId,data); //是否实现了ERC721Received
require(retval == ERC721TokenReceiver.onERC721Received.selector);
}
}
function mint(address _to,uint256 _tokenId,bytes memory data)external{
require(_to != address(0));
require(ercTokenOwner[_tokenId]==address(0));
ercTokenOwner[_tokenId]= _to;
ercTokenCount[_to]+=1;
if(_to.isContract()){ //首先判断对方是否是合约
bytes4 retval = ERC721TokenReceiver(_to).onERC721Received(msg.sender,address(0),_tokenId,data); //是否实现了ERC721Received
require(retval == ERC721TokenReceiver.onERC721Received.selector);
}
emit Transfer(address(0),_to,_tokenId);
}
}
