Update function definitions, require that makerAsset is the same across orders, approve proxy to transfer makerAsset (for percentage-based fees)

contracts/exchange-forwarder/contracts/src/MixinAssets.sol

@@ -50,6 +50,25 @@ contract MixinAssets is
         _transferAssetToSender(assetData, amount);
     }
 
+    function _approveMakerAssetProxy(bytes memory assetData)
+        internal
+    {
+        bytes4 proxyId = assetData.readBytes4(0);
+
+        address proxyAddress;
+        address assetAddress;
+        if (proxyId == ERC20_DATA_ID) {
+            proxyAddress = EXCHANGE.getAssetProxy(ERC20_DATA_ID);
+        } else if (proxyId == ERC721_DATA_ID) {
+            proxyAddress = EXCHANGE.getAssetProxy(ERC721_DATA_ID);
+        } else {
+            revert("UNSUPPORTED_ASSET_PROXY");
+        }
+
+        assetAddress = assetData.readAddress(16);
+        IERC20Token(assetAddress).approve(proxyAddress, MAX_UINT);
+    }
+
     /// @dev Transfers given amount of asset to sender.
     /// @param assetData Byte array encoded for the respective asset proxy.
     /// @param amount Amount of asset to transfer to sender.

contracts/exchange-forwarder/contracts/src/MixinExchangeWrapper.sol

@@ -96,6 +96,11 @@ contract MixinExchangeWrapper is
         uint256 remainingTakerAssetFillAmount = wethSellAmount;
 
         for (uint256 i = 0; i != ordersLength; i++) {
+            require(
+                orders[i].makerAssetData.equals(orders[0].makerAssetData),
+                "MAKER_ASSET_MISMATCH"
+            );
+
             // Attempt to sell the remaining amount of WETH
             FillResults memory singleFillResults = _fillOrderNoThrow(
                 orders[i],
@@ -105,18 +110,18 @@ contract MixinExchangeWrapper is
 
             // Update amounts filled and the remaining amount of WETH to sell
             if (orders[i].makerAssetData.equals(orders[i].takerFeeAssetData)) {
-                _addFillResultsDeductFees(totalFillResults, singleFillResults)
+                _addFillResultsDeductFees(totalFillResults, singleFillResults);
             } else {
                 _addFillResults(totalFillResults, singleFillResults);
                 remainingTakerAssetFillAmount = _safeSub(
                     remainingTakerAssetFillAmount,
                     singleFillResults.takerFeePaid
-                )
+                );
             }
             remainingTakerAssetFillAmount = _safeSub(
                 remainingTakerAssetFillAmount,
                 singleFillResults.takerAssetFilledAmount
-            )
+            );
 
             // Stop execution if the entire amount of takerAsset has been sold
             if (totalFillResults.takerAssetFilledAmount >= wethSellAmount) {
@@ -145,6 +150,11 @@ contract MixinExchangeWrapper is
         uint256 makerAssetFilledAmount = 0;
 
         for (uint256 i = 0; i != ordersLength; i++) {
+            require(
+                orders[i].makerAssetData.equals(orders[0].makerAssetData),
+                "MAKER_ASSET_MISMATCH"
+            );
+
             // Calculate the remaining amount of makerAsset to buy
             uint256 remainingMakerAssetFillAmount = _safeSub(makerAssetFillAmount, totalFillResults.makerAssetFilledAmount);
 
@@ -167,7 +177,7 @@ contract MixinExchangeWrapper is
 
             // Update amounts filled and fees paid by maker and taker
             if (orders[i].makerAssetData.equals(orders[i].takerFeeAssetData)) {
-                _addFillResultsDeductFees(totalFillResults, singleFillResults)
+                _addFillResultsDeductFees(totalFillResults, singleFillResults);
             } else {
                 _addFillResults(totalFillResults, singleFillResults);
             }

contracts/exchange-forwarder/contracts/src/MixinForwarderCore.sol

@@ -61,8 +61,6 @@ contract MixinForwarderCore is
     ///      Any ETH not spent will be refunded to sender.
     /// @param orders Array of order specifications used containing desired makerAsset and WETH as takerAsset.
     /// @param signatures Proofs that orders have been created by makers.
-    /// @param feeOrders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset. Used to purchase ZRX for primary order fees.
-    /// @param feeSignatures Proofs that feeOrders have been created by makers.
     /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
     /// @param feeRecipient Address that will receive ETH when orders are filled.
     /// @return Amounts filled and fees paid by maker and taker for both sets of orders.
@@ -86,6 +84,8 @@ contract MixinForwarderCore is
             msg.value
         );
 
+        _approveMakerAssetProxy(orders[0].makerAssetData);
+
         // Market sell 95% of WETH.
         // ZRX fees are payed with this contract's balance.
         orderFillResults = _marketSellWeth(
@@ -115,8 +115,6 @@ contract MixinForwarderCore is
     /// @param orders Array of order specifications used containing desired makerAsset and WETH as takerAsset.
     /// @param makerAssetFillAmount Desired amount of makerAsset to purchase.
     /// @param signatures Proofs that orders have been created by makers.
-    /// @param feeOrders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset. Used to purchase ZRX for primary order fees.
-    /// @param feeSignatures Proofs that feeOrders have been created by makers.
     /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
     /// @param feeRecipient Address that will receive ETH when orders are filled.
     /// @return Amounts filled and fees paid by maker and taker for both sets of orders.
@@ -134,6 +132,8 @@ contract MixinForwarderCore is
         // Convert ETH to WETH.
         _convertEthToWeth();
 
+        _approveMakerAssetProxy(orders[0].makerAssetData);
+
         // Attempt to purchase desired amount of makerAsset.
         // ZRX fees are payed with this contract's balance.
         orderFillResults = _marketBuyExactAmountWithWeth(

contracts/exchange-forwarder/contracts/src/MixinWeth.sol

@@ -50,8 +50,7 @@ contract MixinWeth is
 
     /// @dev Transfers feePercentage of WETH spent on primary orders to feeRecipient.
     ///      Refunds any excess ETH to msg.sender.
-    /// @param wethSoldExcludingFeeOrders Amount of WETH sold when filling primary orders.
+    /// @param wethSold Amount of WETH sold when filling primary orders.
-    /// @param wethSoldForZrx Amount of WETH sold when purchasing ZRX required for primary order fees.
     /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
     /// @param feeRecipient Address that will receive ETH when orders are filled.
     function _transferEthFeeAndRefund(

contracts/exchange-forwarder/contracts/src/interfaces/IForwarderCore.sol

@@ -31,25 +31,18 @@ contract IForwarderCore {
     ///      Any ETH not spent will be refunded to sender.
     /// @param orders Array of order specifications used containing desired makerAsset and WETH as takerAsset.
     /// @param signatures Proofs that orders have been created by makers.
-    /// @param feeOrders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset. Used to purchase ZRX for primary order fees.
-    /// @param feeSignatures Proofs that feeOrders have been created by makers.
     /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
     /// @param feeRecipient Address that will receive ETH when orders are filled.
     /// @return Amounts filled and fees paid by maker and taker for both sets of orders.
     function marketSellOrdersWithEth(
         LibOrder.Order[] memory orders,
         bytes[] memory signatures,
-        LibOrder.Order[] memory feeOrders,
-        bytes[] memory feeSignatures,
         uint256 feePercentage,
         address payable feeRecipient
     )
         public
         payable
-        returns (
+        returns (LibFillResults.FillResults memory orderFillResults);
-            LibFillResults.FillResults memory orderFillResults,
-            LibFillResults.FillResults memory feeOrderFillResults
-        );
 
     /// @dev Attempt to purchase makerAssetFillAmount of makerAsset by selling ETH provided with transaction.
     ///      Any ZRX required to pay fees for primary orders will automatically be purchased by this contract.
@@ -57,8 +50,6 @@ contract IForwarderCore {
     /// @param orders Array of order specifications used containing desired makerAsset and WETH as takerAsset.
     /// @param makerAssetFillAmount Desired amount of makerAsset to purchase.
     /// @param signatures Proofs that orders have been created by makers.
-    /// @param feeOrders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset. Used to purchase ZRX for primary order fees.
-    /// @param feeSignatures Proofs that feeOrders have been created by makers.
     /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
     /// @param feeRecipient Address that will receive ETH when orders are filled.
     /// @return Amounts filled and fees paid by maker and taker for both sets of orders.
@@ -66,15 +57,10 @@ contract IForwarderCore {
         LibOrder.Order[] memory orders,
         uint256 makerAssetFillAmount,
         bytes[] memory signatures,
-        LibOrder.Order[] memory feeOrders,
-        bytes[] memory feeSignatures,
         uint256 feePercentage,
         address payable feeRecipient
     )
         public
         payable
-        returns (
+        returns (LibFillResults.FillResults memory orderFillResults);
-            LibFillResults.FillResults memory orderFillResults,
-            LibFillResults.FillResults memory feeOrderFillResults
-        );
 }

contracts/exchange-libs/contracts/src/LibFillResults.sol

@@ -403,6 +403,10 @@ library LibFillResults {
         return matchedFillResults;
     }
 
+    /// @dev Adds properties of both FillResults instances.
+    ///      Modifies the first FillResults instance specified.
+    /// @param totalFillResults Fill results instance that will be added onto.
+    /// @param singleFillResults Fill results instance that will be added to totalFillResults.
     function _addFillResultsDeductFees(FillResults memory totalFillResults, FillResults memory singleFillResults)
         internal
         pure