forked from DecentralizedClimateFoundation/DCIPs
73 lines
2.5 KiB
Solidity
73 lines
2.5 KiB
Solidity
// SPDX-License-Identifier: CC0-1.0
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pragma solidity ^0.8.0;
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import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
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import "./IERC4907.sol";
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contract ERC4907 is ERC721, IERC4907 {
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struct UserInfo
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{
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address user; // address of user role
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uint64 expires; // unix timestamp, user expires
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}
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mapping (uint256 => UserInfo) internal _users;
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constructor(string memory name_, string memory symbol_)
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ERC721(name_,symbol_)
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{
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}
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/// @notice set the user and expires of a NFT
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/// @dev The zero address indicates there is no user
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/// Throws if `tokenId` is not valid NFT
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/// @param user The new user of the NFT
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/// @param expires UNIX timestamp, The new user could use the NFT before expires
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function setUser(uint256 tokenId, address user, uint64 expires) public virtual{
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require(_isApprovedOrOwner(msg.sender, tokenId),"ERC721: transfer caller is not owner nor approved");
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UserInfo storage info = _users[tokenId];
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info.user = user;
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info.expires = expires;
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emit UpdateUser(tokenId,user,expires);
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}
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/// @notice Get the user address of an NFT
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/// @dev The zero address indicates that there is no user or the user is expired
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/// @param tokenId The NFT to get the user address for
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/// @return The user address for this NFT
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function userOf(uint256 tokenId)public view virtual returns(address){
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if( uint256(_users[tokenId].expires) >= block.timestamp){
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return _users[tokenId].user;
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}
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else{
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return address(0);
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}
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}
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/// @notice Get the user expires of an NFT
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/// @dev The zero value indicates that there is no user
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/// @param tokenId The NFT to get the user expires for
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/// @return The user expires for this NFT
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function userExpires(uint256 tokenId) public view virtual returns(uint256){
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return _users[tokenId].expires;
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}
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/// @dev See {IERC165-supportsInterface}.
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function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
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return interfaceId == type(IERC4907).interfaceId || super.supportsInterface(interfaceId);
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}
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function _beforeTokenTransfer(
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address from,
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address to,
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uint256 tokenId
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) internal virtual override{
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super._beforeTokenTransfer(from, to, tokenId);
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if (from != to && _users[tokenId].user != address(0)) {
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delete _users[tokenId];
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emit UpdateUser(tokenId, address(0), 0);
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}
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}
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}
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