Use the latest ERC-721 draft interface, fixes #745

contracts/token/ERC721/ERC721.sol

@@ -1,16 +1,167 @@
-pragma solidity ^0.4.18;
-
-/**
- * @title ERC721 interface
- * @dev see https://github.com/ethereum/eips/issues/721
- */
-contract ERC721 {
-  event Transfer(address indexed _from, address indexed _to, uint256 _tokenId);
-  event Approval(address indexed _owner, address indexed _approved, uint256 _tokenId);
-
-  function balanceOf(address _owner) public view returns (uint256 _balance);
-  function ownerOf(uint256 _tokenId) public view returns (address _owner);
-  function transfer(address _to, uint256 _tokenId) public;
-  function approve(address _to, uint256 _tokenId) public;
-  function takeOwnership(uint256 _tokenId) public;
+pragma solidity ^0.4.20;
+
+/// @title ERC-721 Non-Fungible Token Standard
+/// @dev See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md
+///  Note: the ERC-165 identifier for this interface is 0x6466353c
+interface ERC721 /* is ERC165  */ {
+    /// @dev This emits when ownership of any NFT changes by any mechanism.
+    ///  This event emits when NFTs are created (`from` == 0) and destroyed
+    ///  (`to` == 0). Exception: during contract creation, any number of NFTs
+    ///  may be created and assigned without emitting Transfer. At the time of
+    ///  any transfer, the approved address for that NFT (if any) is reset to none.
+    event Transfer(address indexed _from, address indexed _to, uint256 _tokenId);
+
+    /// @dev This emits when the approved address for an NFT is changed or
+    ///  reaffirmed. The zero address indicates there is no approved address.
+    ///  When a Transfer event emits, this also indicates that the approved
+    ///  address for that NFT (if any) is reset to none.
+    event Approval(address indexed _owner, address indexed _approved, uint256 _tokenId);
+
+    /// @dev This emits when an operator is enabled or disabled for an owner.
+    ///  The operator can manage all NFTs of the owner.
+    event ApprovalForAll(address indexed _owner, address indexed _operator, bool _approved);
+
+    /// @notice Count all NFTs assigned to an owner
+    /// @dev NFTs assigned to the zero address are considered invalid, and this
+    ///  function throws for queries about the zero address.
+    /// @param _owner An address for whom to query the balance
+    /// @return The number of NFTs owned by `_owner`, possibly zero
+    function balanceOf(address _owner) public view returns (uint256);
+
+    /// @notice Find the owner of an NFT
+    /// @param _tokenId The identifier for an NFT
+    /// @dev NFTs assigned to zero address are considered invalid, and queries
+    ///  about them do throw.
+    /// @return The address of the owner of the NFT
+    function ownerOf(uint256 _tokenId) public view returns (address);
+
+    /// @notice Transfers the ownership of an NFT from one address to another address
+    /// @dev Throws unless `msg.sender` is the current owner, an authorized
+    ///  operator, or the approved address for this NFT. Throws if `_from` is
+    ///  not the current owner. Throws if `_to` is the zero address. Throws if
+    ///  `_tokenId` is not a valid NFT. When transfer is complete, this function
+    ///  checks if `_to` is a smart contract (code size > 0). If so, it calls
+    ///  `onERC721Received` on `_to` and throws if the return value is not
+    ///  `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`.
+    /// @param _from The current owner of the NFT
+    /// @param _to The new owner
+    /// @param _tokenId The NFT to transfer
+    /// @param data Additional data with no specified format, sent in call to `_to`
+    function safeTransferFrom(address _from, address _to, uint256 _tokenId, bytes data) public;
+
+    /// @notice Transfers the ownership of an NFT from one address to another address
+    /// @dev This works identically to the other function with an extra data parameter,
+    ///  except this function just sets data to []
+    /// @param _from The current owner of the NFT
+    /// @param _to The new owner
+    /// @param _tokenId The NFT to transfer
+    function safeTransferFrom(address _from, address _to, uint256 _tokenId) public;
+
+    /// @notice Transfer ownership of an NFT -- THE CALLER IS RESPONSIBLE
+    ///  TO CONFIRM THAT `_to` IS CAPABLE OF RECEIVING NFTS OR ELSE
+    ///  THEY MAY BE PERMANENTLY LOST
+    /// @dev Throws unless `msg.sender` is the current owner, an authorized
+    ///  operator, or the approved address for this NFT. Throws if `_from` is
+    ///  not the current owner. Throws if `_to` is the zero address. Throws if
+    ///  `_tokenId` is not a valid NFT.
+    /// @param _from The current owner of the NFT
+    /// @param _to The new owner
+    /// @param _tokenId The NFT to transfer
+    function transferFrom(address _from, address _to, uint256 _tokenId) public;
+
+    /// @notice Set or reaffirm the approved address for an NFT
+    /// @dev The zero address indicates there is no approved address.
+    /// @dev Throws unless `msg.sender` is the current NFT owner, or an authorized
+    ///  operator of the current owner.
+    /// @param _approved The new approved NFT controller
+    /// @param _tokenId The NFT to approve
+    function approve(address _approved, uint256 _tokenId) public;
+
+    /// @notice Enable or disable approval for a third party ("operator") to manage
+    ///  all your asset.
+    /// @dev Emits the ApprovalForAll event
+    /// @param _operator Address to add to the set of authorized operators.
+    /// @param _approved True if the operators is approved, false to revoke approval
+    function setApprovalForAll(address _operator, bool _approved) public;
+
+    /// @notice Get the approved address for a single NFT
+    /// @dev Throws if `_tokenId` is not a valid NFT
+    /// @param _tokenId The NFT to find the approved address for
+    /// @return The approved address for this NFT, or the zero address if there is none
+    function getApproved(uint256 _tokenId) public returns (address);
+
+    /// @notice Query if an address is an authorized operator for another address
+    /// @param _owner The address that owns the NFTs
+    /// @param _operator The address that acts on behalf of the owner
+    /// @return True if `_operator` is an approved operator for `_owner`, false otherwise
+    function isApprovedForAll(address _owner, address _operator) public view returns (bool);
+}
+
+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.
+    /// @return `true` if the contract implements `interfaceID` and
+    ///  `interfaceID` is not 0xffffffff, `false` otherwise
+    function supportsInterface(bytes4 interfaceID) public view returns (bool);
+}
+
+/// @dev Note: the ERC-165 identifier for this interface is 0xf0b9e5ba
+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. This function MUST use 50,000 gas or less. Return of other
+    ///  than the magic value MUST result in the transaction being reverted.
+    ///  Note: the contract address is always the message sender.
+    /// @param _from The sending address 
+    /// @param _tokenId The NFT identifier which is being transfered
+    /// @param data Additional data with no specified format
+    /// @return `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`
+    ///  unless throwing
+	function onERC721Received(address _from, uint256 _tokenId, bytes data) public returns(bytes4);
+}
+
+/// @title ERC-721 Non-Fungible Token Standard, optional metadata extension
+/// @dev See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md
+///  Note: the ERC-165 identifier for this interface is 0x5b5e139f
+interface ERC721Metadata /* is ERC721 */ {
+    /// @notice A descriptive name for a collection of NFTs in this contract
+    function name() public pure returns (string _name);
+
+    /// @notice An abbreviated name for NFTs in this contract
+    function symbol() public pure returns (string _symbol);
+
+    /// @notice A distinct Uniform Resource Identifier (URI) for a given asset.
+    /// @dev Throws if `_tokenId` is not a valid NFT. URIs are defined in RFC
+    ///  3986. The URI may point to a JSON file that conforms to the "ERC721
+    ///  Metadata JSON Schema".
+    function tokenURI(uint256 _tokenId) public view returns (string);
+}
+
+/// @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
+/// @dev See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md
+///  Note: the ERC-165 identifier for this interface is 0x780e9d63
+interface ERC721Enumerable /* is ERC721 */ {
+    /// @notice Count NFTs tracked by this contract
+    /// @return A count of valid NFTs tracked by this contract, where each one of
+    ///  them has an assigned and queryable owner not equal to the zero address
+    function totalSupply() public view returns (uint256);
+
+    /// @notice Enumerate valid NFTs
+    /// @dev Throws if `_index` >= `totalSupply()`.
+    /// @param _index A counter less than `totalSupply()`
+    /// @return The token identifier for the `_index`th NFT,
+    ///  (sort order not specified)
+    function tokenByIndex(uint256 _index) public view returns (uint256);
+
+    /// @notice Enumerate NFTs assigned to an owner
+    /// @dev Throws if `_index` >= `balanceOf(_owner)` or if
+    ///  `_owner` is the zero address, representing invalid NFTs.
+    /// @param _owner An address where we are interested in NFTs owned by them
+    /// @param _index A counter less than `balanceOf(_owner)`
+    /// @return The token identifier for the `_index`th NFT assigned to `_owner`,
+    ///   (sort order not specified)
+    function tokenOfOwnerByIndex(address _owner, uint256 _index) public view returns (uint256 _tokenId);
 }