Replacing custom interface with stock openzeppelin IERC721.sol

smart-contracts/contracts/PublicLock.sol

@@ -1,11 +1,9 @@
 pragma solidity 0.5.13;
 
-import './interfaces/IERC721.sol';
-import './interfaces/IERC721Enumerable.sol';
+
 import './interfaces/IPublicLock.sol';
 import '@openzeppelin/contracts-ethereum-package/contracts/ownership/Ownable.sol';
 import '@openzeppelin/contracts-ethereum-package/contracts/introspection/ERC165.sol';
-import '@openzeppelin/upgrades/contracts/Initializable.sol';
 import './mixins/MixinApproval.sol';
 import './mixins/MixinDisableAndDestroy.sol';
 import './mixins/MixinERC721Enumerable.sol';
@@ -28,10 +26,7 @@ import './mixins/MixinSignatures.sol';
  * https://eips.ethereum.org/EIPS/eip-721
  */
 contract PublicLock is
-  IERC721Enumerable,
-  IERC721,
   IPublicLock,
-  Initializable,
   ERC165,
   Ownable,
   MixinSignatures,

smart-contracts/contracts/interfaces/IPublicLock.sol

@@ -1,21 +1,18 @@
 pragma solidity ^0.5.0;
 
-import './IERC721.sol';
-import './IERC721Enumerable.sol';
-
+import '@openzeppelin/contracts-ethereum-package/contracts/token/ERC721/IERC721Enumerable.sol';
 /**
 * @title The PublicLock Interface
 * @author Nick Furfaro (unlock-protocol.com)
  */
 
 
-contract IPublicLock is IERC721Enumerable, IERC721 {
+contract IPublicLock is IERC721Enumerable {
 
 // See indentationissue description here:
 // https://github.com/duaraghav8/Ethlint/issues/268
 // solium-disable indentation
 
-  ///===================================================================
   /// Events
   event Destroy(
     uint balance,

smart-contracts/contracts/mixins/MixinApproval.sol

@@ -1,6 +1,5 @@
 pragma solidity 0.5.13;
 
-import '../interfaces/IERC721.sol';
 import './MixinDisableAndDestroy.sol';
 import './MixinKeys.sol';
 
@@ -13,7 +12,6 @@ import './MixinKeys.sol';
  * separates logically groupings of code to ease readability.
  */
 contract MixinApproval is
-  IERC721,
   MixinDisableAndDestroy,
   MixinKeys
 {
@@ -40,7 +38,7 @@ contract MixinApproval is
     require(
       isKeyOwner(_tokenId, msg.sender) ||
         _isApproved(_tokenId, msg.sender) ||
-        isApprovedForAll(ownerOf[_tokenId], msg.sender),
+        isApprovedForAll(_ownerOf[_tokenId], msg.sender),
       'ONLY_KEY_OWNER_OR_APPROVED');
     _;
   }
@@ -54,15 +52,14 @@ contract MixinApproval is
     address _approved,
     uint _tokenId
   )
-    external
-    payable
+    public
     onlyIfAlive
     onlyKeyOwnerOrApproved(_tokenId)
   {
     require(msg.sender != _approved, 'APPROVE_SELF');
 
     approved[_tokenId] = _approved;
-    emit Approval(ownerOf[_tokenId], _approved, _tokenId);
+    emit Approval(_ownerOf[_tokenId], _approved, _tokenId);
   }
 
   /**
@@ -74,7 +71,7 @@ contract MixinApproval is
   function setApprovalForAll(
     address _to,
     bool _approved
-  ) external
+  ) public
     onlyIfAlive
   {
     require(_to != msg.sender, 'APPROVE_SELF');
@@ -87,7 +84,7 @@ contract MixinApproval is
    */
   function getApproved(
     uint _tokenId
-  ) external view
+  ) public view
     returns (address)
   {
     address approvedRecipient = approved[_tokenId];

smart-contracts/contracts/mixins/MixinDisableAndDestroy.sol

@@ -1,6 +1,5 @@
 pragma solidity 0.5.13;
 
-import '../interfaces/IERC721.sol';
 import '@openzeppelin/contracts-ethereum-package/contracts/ownership/Ownable.sol';
 import './MixinFunds.sol';
 
@@ -12,7 +11,6 @@ import './MixinFunds.sol';
  * separates logically groupings of code to ease readability.
  */
 contract MixinDisableAndDestroy is
-  IERC721,
   Ownable,
   MixinFunds
 {

smart-contracts/contracts/mixins/MixinERC721Enumerable.sol

@@ -1,9 +1,8 @@
 pragma solidity 0.5.13;
 
-import './MixinERC721Enumerable.sol';
 import './MixinKeys.sol';
 import './MixinLockCore.sol';
-import '../interfaces/IERC721Enumerable.sol';
+import '@openzeppelin/contracts-ethereum-package/contracts/token/ERC721/IERC721Enumerable.sol';
 import '@openzeppelin/contracts-ethereum-package/contracts/introspection/ERC165.sol';
 
 
@@ -35,10 +34,10 @@ contract MixinERC721Enumerable is
   ///  (sort order not specified)
   function tokenByIndex(
     uint256 _index
-  ) external view
+  ) public view
     returns (uint256)
   {
-    require(_index < totalSupply, 'OUT_OF_RANGE');
+    require(_index < _totalSupply, 'OUT_OF_RANGE');
     return _index;
   }
 
@@ -52,7 +51,7 @@ contract MixinERC721Enumerable is
   function tokenOfOwnerByIndex(
     address _owner,
     uint256 _index
-  ) external view
+  ) public view
     returns (uint256)
   {
     require(_index == 0, 'ONLY_ONE_KEY_PER_OWNER');

smart-contracts/contracts/mixins/MixinGrantKeys.sol

@@ -1,6 +1,5 @@
 pragma solidity 0.5.13;
 
-import '../interfaces/IERC721.sol';
 import '@openzeppelin/contracts-ethereum-package/contracts/ownership/Ownable.sol';
 import './MixinKeys.sol';
 
@@ -12,7 +11,6 @@ import './MixinKeys.sol';
  * separates logically groupings of code to ease readability.
  */
 contract MixinGrantKeys is
-  IERC721,
   Ownable,
   MixinKeys
 {

smart-contracts/contracts/mixins/MixinKeys.sol

@@ -33,7 +33,7 @@ contract MixinKeys is
   // Returns 0 if the token does not exist
   // TODO: once we decouple tokenId from owner address (incl in js), then we can consider
   // merging this with totalSupply into an array instead.
-  mapping (uint => address) public ownerOf;
+  mapping (uint => address) internal _ownerOf;
 
   // Addresses of owners are also stored in an array.
   // Addresses are never removed by design to avoid abuses around referals
@@ -64,7 +64,7 @@ contract MixinKeys is
     uint _tokenId
   ) {
     require(
-      ownerOf[_tokenId] != address(0), 'NO_SUCH_KEY'
+      _ownerOf[_tokenId] != address(0), 'NO_SUCH_KEY'
     );
     _;
   }
@@ -101,7 +101,7 @@ contract MixinKeys is
   function balanceOf(
     address _owner
   )
-    external
+    public
     view
     returns (uint)
   {
@@ -180,7 +180,7 @@ contract MixinKeys is
   ) public view
     returns (bool)
   {
-    return ownerOf[_tokenId] == _owner;
+    return _ownerOf[_tokenId] == _owner;
   }
 
   /**
@@ -208,6 +208,15 @@ contract MixinKeys is
   {
     return owners.length;
   }
+  // Returns the owner of a given tokenId
+  function ownerOf(
+    uint _tokenId
+  ) public view
+    isKey(_tokenId)
+    returns(address)
+  {
+    return _ownerOf[_tokenId];
+  }
 
   /**
    * Assigns the key a new tokenId (from totalSupply) if it does not already have
@@ -220,9 +229,9 @@ contract MixinKeys is
     if (_key.tokenId == 0) {
       // This is a brand new owner
       // We increment the tokenId counter
-      totalSupply++;
-      // we assign the incremented `totalSupply` as the tokenId for the new key
-      _key.tokenId = totalSupply;
+      _totalSupply++;
+      // we assign the incremented `_totalSupply` as the tokenId for the new key
+      _key.tokenId = _totalSupply;
     }
   }
 
@@ -234,11 +243,11 @@ contract MixinKeys is
     uint _tokenId
   ) internal
   {
-    if (ownerOf[_tokenId] != _owner) {
+    if (_ownerOf[_tokenId] != _owner) {
       // TODO: this may include duplicate entries
       owners.push(_owner);
       // We register the owner of the tokenID
-      ownerOf[_tokenId] = _owner;
+      _ownerOf[_tokenId] = _owner;
     }
   }
 }