ERC-5501: 租赁 & 委托 NFT - EIP-721 扩展

/**
 * @title IERC5501: Rental & Delegation NFT - EIP-721 Extension
 * @notice the EIP-165 identifier for this interface is 0xf808ec37.
 */
interface IERC5501 /* is IERC721 */ {
    /**
     * @dev Emitted when the user of an NFT is modified.
     */
    event UpdateUser(uint256 indexed _tokenId, address indexed _user, uint64 _expires, bool _isBorrowed);

    /**
     * @notice Set the user info of an NFT.
     * @dev User address cannot be zero address.
     * Only approved operator or NFT owner can set the user.
     * If NFT is borrowed, the user info cannot be changed until user status expires.
     * @param _tokenId uint256 ID of the token to set user info for
     * @param _user address of the new user
     * @param _expires Unix timestamp when user info expires
     * @param _isBorrowed flag whether or not the NFT is borrowed
     */
    function setUser(uint256 _tokenId, address _user, uint64 _expires, bool _isBorrowed) external;

    /**
     * @notice Get the user address of an NFT.
     * @dev Reverts if user is not set.
     * @param _tokenId uint256 ID of the token to get the user address for
     * @return address user address for this NFT
     */
    function userOf(uint256 _tokenId) external view returns (address);

    /**
     * @notice Get the user expires of an NFT.
     * @param _tokenId uint256 ID of the token to get the user expires for
     * @return uint64 user expires for this NFT
     */
    function userExpires(uint256 _tokenId) external view returns (uint64);

    /**
     * @notice Get the user isBorrowed of an NFT.
     * @param _tokenId uint256 ID of the token to get the user isBorrowed for
     * @return bool user isBorrowed for this NFT
     */
    function userIsBorrowed(uint256 _tokenId) external view returns (bool);
}

/**
 * @title IERC5501Balance
 * Extension for ERC5501 which adds userBalanceOf to query how many tokens address is userOf.
 * @notice the EIP-165 identifier for this interface is 0x0cb22289.
 */
interface IERC5501Balance /* is IERC5501 */{
    /**
     * @notice Count of all NFTs assigned to a user.
     * @dev Reverts if user is zero address.
     * @param _user an address for which to query the balance
     * @return uint256 the number of NFTs the user has
     */
    function userBalanceOf(address _user) external view returns (uint256);
}

/**
 * @title IERC5501Enumerable
 * This extension for ERC5501 adds the option to iterate over user tokens.
 * @notice the EIP-165 identifier for this interface is 0x1d350ef8.
 */
interface IERC5501Enumerable /* is IERC5501Balance, IERC5501 */ {
    /**
     * @notice Enumerate NFTs assigned to a user.
     * @dev Reverts if user is zero address or _index >= userBalanceOf(_owner).
     * @param _user an address to iterate over its tokens
     * @return uint256 the token ID for given index assigned to _user
     */
    function tokenOfUserByIndex(address _user, uint256 _index) external view returns (uint256);
}

/**
 * @title IERC5501Terminable
 * This extension for ERC5501 adds the option to terminate borrowing if both parties agree.
 * @notice the EIP-165 identifier for this interface is 0x6a26417e.
 */
interface IERC5501Terminable /* is IERC5501 */ {
    /**
     * @dev Emitted when one party from borrowing contract approves termination of agreement.
     * @param _isLender true for lender, false for borrower
     */
    event AgreeToTerminateBorrow(uint256 indexed _tokenId, address indexed _party, bool _isLender);

    /**
     * @dev Emitted when agreements to terminate borrow are reset.
     */
    event ResetTerminationAgreements(uint256 indexed _tokenId);

    /**
     * @dev Emitted when borrow of token ID is terminated.
     */
    event TerminateBorrow(uint256 indexed _tokenId, address indexed _lender, address indexed _borrower, address _caller);

    /**
     * @notice Agree to terminate a borrowing.
     * @dev Lender must be ownerOf token ID. Borrower must be userOf token ID.
     * If lender and borrower are the same, set termination agreement for both at once.
     * @param _tokenId uint256 ID of the token to set termination info for
     */
    function setBorrowTermination(uint256 _tokenId) external;

    /**
     * @notice Get if it is possible to terminate a borrow agreement.
     * @param _tokenId uint256 ID of the token to get termination info for
     * @return bool, bool first indicates lender agrees, second indicates borrower agrees
     */
    function getBorrowTermination(uint256 _tokenId) external view returns (bool, bool);

    /**
     * @notice Terminate a borrow if both parties agreed.
     * @dev Both parties must have agreed, otherwise revert.
     * @param _tokenId uint256 ID of the token to terminate borrow of
     */
    function terminateBorrow(uint256 _tokenId) external;
}