Allow to query the approved contracts

EIPS/eip-721.md

@@ -39,33 +39,30 @@ Differences between this standard and EIP-20 are examined below.
 
 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC 2119](https://www.ietf.org/rfc/rfc2119.txt).
 
-The **baseline specification** is REQUIRED for all ERC-721 implementations (see "caveats", below).
+**Every ERC-721 compliant contract must implement the `ERC721` and [`ERC165`](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-165.md) interfaces** (subject to "caveats" below):
 
 ```solidity
 pragma solidity ^0.4.20;
 
-import "./ERC165.sol";
-
 /// @title Required part of ERC-721 Deed Standard
 /// @dev See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md
-///  Note: the ERC-165 identifier for this interface is 0xb3a99827
+///  Note: the ERC-165 identifier for this interface is 0xTODO_FILL_IN
 interface ERC721 /* is ERC165 */ {
     /// @dev This emits when ownership of any deed changes by any mechanism.
     ///  This event emits when deeds are created (`from` == 0) and destroyed
     ///  (`to` == 0). Exception: during contract creation, any number of deeds
     ///  may be created and assigned without emitting Transfer. At the time of
-    ///  any transfer, the "approved deed controller" is implicitly reset to the
+    ///  any transfer, the approved address for that deed (if any) is reset to none.
-    ///  zero address.
     event Transfer(address indexed _from, address indexed _to, uint256 _deedId);
 
-    /// @dev This emits when the "approved deed controller" for a deed is
+    /// @dev This emits when the approved address for a single is changed or
-    ///  changed or reaffirmed. The zero address indicates there is no approved
+    ///  reaffirmed. The zero address indicates there is no approved address.
-    ///  deed controller. When a Transfer event emits, this also indicates the
+    ///  When a Transfer event emits, this also indicates that the approved
-    ///  approved deed controller (if any) is reset to none.
+    ///  address for that deed (if any) is reset to none.
     event Approval(address indexed _owner, address indexed _approved, uint256 _deedId);
 
-    /// @dev This emits when a third party ("operator") is enabled or disable for
+    /// @dev This emits when an operator is enabled or disable for an owner.
-    ///  an owner. The operator may manage all deeds of the owner.
+    ///  The operator may manage all deeds of the owner.
     event ApprovalForAll(address indexed _owner, address indexed _operator, bool _approved);
 
     /// @notice Count all deeds assigned to an owner
@@ -104,8 +101,8 @@ interface ERC721 /* is ERC165 */ {
     /// @param _deedId The deed to transfer
     function transferFrom(address _from, address _to, uint256 _deedId) external payable;
 
-    /// @notice Set or reaffirm the "approved deed controller" for a deed
+    /// @notice Set or reaffirm the approved address for a deed
-    /// @dev The zero address indicates there is no approved deed controller.
+    /// @dev The zero address indicates there is no approved address.
     /// @dev Throws unless `msg.sender` is the current deed owner, or the
     ///  "delegate operator" of the current deed owner.
     /// @param _approved The new approved deed controller
@@ -117,11 +114,23 @@ interface ERC721 /* is ERC165 */ {
     /// @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 _operateor, boolean _approved) payable;
+    function setApprovalForAll(address _operateor, boolean _approved) external;
 
-    // CONFORMANCE TO ERC-165 //////////////////////////////////////////////////
+    /// @notice Get the approved address for a single deed
+    /// @dev Throws if `_deedId` is not a valid deed
+    /// @param _deedId The deed to find the approved address for
+    /// @return The approved address for this deed, or the zero address if there is none
+    function getApproved(uint256 _deedId) returns (address);
 
-    /// @notice Query if this implements an interface
+    /// @notice Query if an address is an authorized operator for another address
+    /// @param _owner The address that owns the deeds
+    /// @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) 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.