forked from DecentralizedClimateFoundation/DCIPs
137 lines
3.4 KiB
Solidity
137 lines
3.4 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 "./IERC5501.sol";
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/**
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* @dev Implementation of https://eips.ethereum.org/EIPS/eip-5501 with OpenZeppelin ERC721 version.
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*/
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contract ERC5501 is IERC5501, ERC721 {
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/**
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* @dev Structure to hold user information.
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* @notice If isBorrowed is true, UserInfo cannot be modified before it expires.
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*/
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struct UserInfo {
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address user; // Address of user role
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uint64 expires; // Unix timestamp, user expires on
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bool isBorrowed; // Borrowed flag
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}
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// Mapping from token ID to UserInfo
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mapping(uint256 => UserInfo) internal _users;
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/**
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* @dev Initializes the contract by setting a name and a symbol to the token collection.
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*/
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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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* @dev See {IERC5501-setUser}.
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*/
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function setUser(
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uint256 tokenId,
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address user,
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uint64 expires,
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bool isBorrowed
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) public virtual override {
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require(
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_isApprovedOrOwner(msg.sender, tokenId),
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"ERC5501: set user caller is not token owner or approved"
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);
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require(user != address(0), "ERC5501: set user to zero address");
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UserInfo storage info = _users[tokenId];
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require(
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!info.isBorrowed || info.expires < block.timestamp,
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"ERC5501: token is borrowed"
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);
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info.user = user;
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info.expires = expires;
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info.isBorrowed = isBorrowed;
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emit UpdateUser(tokenId, user, expires, isBorrowed);
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}
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/**
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* @dev See {IERC5501-userOf}.
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*/
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function userOf(uint256 tokenId)
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public
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view
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virtual
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override
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returns (address)
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{
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require(
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uint256(_users[tokenId].expires) >= block.timestamp,
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"ERC5501: user does not exist for this token"
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);
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return _users[tokenId].user;
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}
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/**
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* @dev See {IERC5501-userExpires}.
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*/
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function userExpires(uint256 tokenId)
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public
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view
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virtual
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override
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returns (uint64)
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{
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return _users[tokenId].expires;
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}
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/**
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* @dev See {IERC5501-isBorrowed}.
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*/
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function userIsBorrowed(uint256 tokenId)
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public
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view
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virtual
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override
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returns (bool)
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{
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return _users[tokenId].isBorrowed;
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}
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/**
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* @dev See {EIP-165: Standard Interface Detection}.
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* https://eips.ethereum.org/EIPS/eip-165
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*/
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function supportsInterface(bytes4 interfaceId)
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public
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view
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virtual
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override
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returns (bool)
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{
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return
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interfaceId == type(IERC5501).interfaceId ||
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super.supportsInterface(interfaceId);
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}
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/**
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* @dev Hook that is called after any token transfer.
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* If user is set and token is not borrowed, reset user.
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*/
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function _afterTokenTransfer(
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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._afterTokenTransfer(from, to, tokenId);
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if (
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from != to &&
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!_users[tokenId].isBorrowed &&
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_users[tokenId].user != address(0)
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) {
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delete _users[tokenId];
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emit UpdateUser(tokenId, address(0), 0, false);
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}
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}
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}
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