Add interfaces and mixins

packages/contracts/src/2.0.0/forwarder/Forwarder.sol

@@ -22,14 +22,19 @@ pragma experimental ABIEncoderV2;
 import "./MixinFees.sol";
 import "./MixinForwarderCore.sol";
 import "./MixinConstants.sol";
+import "./MixinMarketBuyZrx.sol";
+import "./MixinExpectedResults.sol";
+import "./MixinTransfer.sol";
 import "../utils/Ownable/Ownable.sol";
 
 
 contract Forwarder is
     Ownable,
     MixinConstants,
+    MixinExpectedResults,
     MixinFees,
     MixinMarketBuyZrx,
+    MixinTransfer,
     MixinForwarderCore
 {
     uint256 constant internal MAX_UINT = 2**256 - 1;

packages/contracts/src/2.0.0/forwarder/MixinConstants.sol

@@ -18,20 +18,12 @@
 
 pragma solidity 0.4.24;
 
-import "../protocol/Exchange/interfaces/IExchange.sol";
-import "../tokens/EtherToken/IEtherToken.sol";
-import "../tokens/ERC20Token/IERC20Token.sol";
+import "./mixins/MConstants.sol";
 
 
-contract MixinConstants {
-
-    // solhint-disable var-name-mixedcase
-    IExchange internal EXCHANGE;
-    IEtherToken internal ETHER_TOKEN;
-    IERC20Token internal ZRX_TOKEN;
-    bytes internal ZRX_ASSET_DATA;
-    bytes internal WETH_ASSET_DATA;
-    // solhint-enable var-name-mixedcase
+contract MixinConstants is
+    MConstants
+{
 
     constructor (
         address _exchange,

packages/contracts/src/2.0.0/forwarder/MixinExpectedResults.sol

@@ -23,13 +23,15 @@ import "../utils/LibBytes/LibBytes.sol";
 import "../protocol/Exchange/libs/LibFillResults.sol";
 import "../protocol/Exchange/libs/LibMath.sol";
 import "../protocol/Exchange/libs/LibOrder.sol";
-import "./MixinConstants.sol";
+import "./mixins/MConstants.sol";
+import "./mixins/MExpectedResults.sol";
 
 
 contract MixinExpectedResults is
     LibMath,
     LibFillResults,
-    MixinConstants
+    MConstants,
+    MExpectedResults
 {
 
     /// @dev Calculates a total FillResults for buying makerAssetFillAmount over all orders.
@@ -61,6 +63,30 @@ contract MixinExpectedResults is
         return totalFillResults;
     }
 
+    /// @dev Calculates a FillResults total for selling takerAssetFillAmount over all orders. 
+    ///      Including the fees required to be paid. 
+    /// @param orders An array of Order struct containing order specifications.
+    /// @param takerAssetFillAmount A number representing the amount of this order to fill.
+    /// @return totalFillResults Amounts filled and fees paid by maker and taker.
+    function calculateMarketSellResults(
+        LibOrder.Order[] memory orders,
+        uint256 takerAssetFillAmount
+    )
+        public
+        view
+        returns (FillResults memory totalFillResults)
+    {
+        for (uint256 i = 0; i < orders.length; i++) {
+            uint256 remainingTakerAssetFillAmount = safeSub(takerAssetFillAmount, totalFillResults.takerAssetFilledAmount);
+            FillResults memory singleFillResult = calculateFillResults(orders[i], remainingTakerAssetFillAmount);
+            addFillResults(totalFillResults, singleFillResult);
+            if (totalFillResults.takerAssetFilledAmount == takerAssetFillAmount) {
+                break;
+            }
+        }
+        return totalFillResults;
+    }
+
     /// @dev Calculates fill results for buyFeeTokens. This handles fees on buying ZRX
     ///      so the end result is the expected amount of ZRX (not less after fees).
     /// @param orders An array of Order struct containing order specifications.
@@ -132,28 +158,4 @@ contract MixinExpectedResults is
         );
         return fillResults;
     }
-
-    /// @dev Calculates a FillResults total for selling takerAssetFillAmount over all orders. 
-    ///      Including the fees required to be paid. 
-    /// @param orders An array of Order struct containing order specifications.
-    /// @param takerAssetFillAmount A number representing the amount of this order to fill.
-    /// @return totalFillResults Amounts filled and fees paid by maker and taker.
-    function calculateMarketSellResults(
-        LibOrder.Order[] memory orders,
-        uint256 takerAssetFillAmount
-    )
-        internal
-        view
-        returns (FillResults memory totalFillResults)
-    {
-        for (uint256 i = 0; i < orders.length; i++) {
-            uint256 remainingTakerAssetFillAmount = safeSub(takerAssetFillAmount, totalFillResults.takerAssetFilledAmount);
-            FillResults memory singleFillResult = calculateFillResults(orders[i], remainingTakerAssetFillAmount);
-            addFillResults(totalFillResults, singleFillResult);
-            if (totalFillResults.takerAssetFilledAmount == takerAssetFillAmount) {
-                break;
-            }
-        }
-        return totalFillResults;
-    }
 }

packages/contracts/src/2.0.0/forwarder/MixinFees.sol

@@ -19,12 +19,14 @@
 pragma solidity 0.4.24;
 
 import "../protocol/Exchange/libs/LibMath.sol";
-import "./MixinConstants.sol";
+import "./mixins/MConstants.sol";
+import "./mixins/MFees.sol";
 
 
 contract MixinFees is
     LibMath,
-    MixinConstants
+    MConstants,
+    MFees
 {
 
     uint16 constant public PERCENTAGE_DENOMINATOR = 10000; // 9800 == 98%, 10000 == 100%

packages/contracts/src/2.0.0/forwarder/MixinForwarderCore.sol

@@ -20,20 +20,24 @@ pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../utils/LibBytes/LibBytes.sol";
-import "./MixinFees.sol";
-import "./MixinMarketBuyZrx.sol";
-import "./MixinExpectedResults.sol";
-import "./MixinTransfer.sol";
-import "./MixinConstants.sol";
+import "./mixins/MFees.sol";
+import "./mixins/MMarketBuyZrx.sol";
+import "./mixins/MExpectedResults.sol";
+import "./mixins/MTransfer.sol";
+import "./mixins/MConstants.sol";
+import "./mixins/MForwarderCore.sol";
 import "../protocol/Exchange/libs/LibOrder.sol";
+import "../protocol/Exchange/libs/LibFillResults.sol";
 
 
 contract MixinForwarderCore is
-    MixinConstants,
-    MixinExpectedResults,
-    MixinFees,
-    MixinMarketBuyZrx,
-    MixinTransfer
+    LibFillResults,
+    MConstants,
+    MExpectedResults,
+    MFees,
+    MMarketBuyZrx,
+    MTransfer,
+    MForwarderCore
 {
     bytes4 public constant ERC20_DATA_ID = bytes4(keccak256("ERC20Token(address)"));
     bytes4 public constant ERC721_DATA_ID = bytes4(keccak256("ERC721Token(address,uint256,bytes)"));
@@ -284,8 +288,8 @@ contract MixinForwarderCore is
         bytes[] memory feeSignatures,
         uint256 makerTokenFillAmount
     )
-        private
-        returns (FillResults memory totalFillResults)
+        internal
+        returns (LibFillResults.FillResults memory totalFillResults)
     {
         // We read the maker token address to check if it is ZRX and later use it for transfer
         address makerTokenAddress = LibBytes.readAddress(orders[0].makerAssetData, 16);
@@ -366,8 +370,8 @@ contract MixinForwarderCore is
         LibOrder.Order[] memory feeOrders,
         bytes[] memory feeSignatures
     )
-        private
-        returns (FillResults memory totalFillResults)
+        internal
+        returns (LibFillResults.FillResults memory totalFillResults)
     {
         uint256 totalZrxFeeAmount;
         uint256 ordersLength = orders.length;

packages/contracts/src/2.0.0/forwarder/MixinMarketBuyZrx.sol

@@ -19,17 +19,18 @@
 pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
-import "../protocol/Exchange/Exchange.sol";
 import "../protocol/Exchange/libs/LibFillResults.sol";
 import "../protocol/Exchange/libs/LibOrder.sol";
 import "../protocol/Exchange/libs/LibMath.sol";
-import "./MixinConstants.sol";
+import "./mixins/MConstants.sol";
+import "./mixins/MMarketBuyZrx.sol";
 
 
 contract MixinMarketBuyZrx is
     LibMath,
     LibFillResults,
-    MixinConstants
+    MConstants,
+    MMarketBuyZrx
 {
 
     /// @dev Buys zrxBuyAmount of ZRX fee tokens, taking into account the fees on buying fee tokens. This will guarantee

packages/contracts/src/2.0.0/forwarder/MixinTransfer.sol

@@ -17,13 +17,15 @@
 */
 
 pragma solidity 0.4.24;
-pragma experimental ABIEncoderV2;
 
 import "../utils/LibBytes/LibBytes.sol";
 import "../tokens/ERC721Token/IERC721Token.sol";
+import "./mixins/MTransfer.sol";
 
 
-contract MixinTransfer {
+contract MixinTransfer is
+    MTransfer
+{
 
     using LibBytes for bytes;
 
@@ -31,7 +33,11 @@ contract MixinTransfer {
     bytes4 constant internal ERC721_RECEIVED = bytes4(keccak256("onERC721Received(address,uint256,bytes)"));
     bytes4 constant internal ERC721_RECEIVED_OPERATOR = bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"));
 
-    function onERC721Received(address, uint256, bytes memory)
+    function onERC721Received(
+        address,
+        uint256,
+        bytes memory
+    )
         public
         pure
         returns(bytes4)
@@ -39,7 +45,12 @@ contract MixinTransfer {
         return ERC721_RECEIVED;
     }
 
-    function onERC721Received(address, address, uint256, bytes memory)
+    function onERC721Received(
+        address,
+        address,
+        uint256,
+        bytes memory
+    )
         public
         pure
         returns(bytes4)

packages/contracts/src/2.0.0/forwarder/interfaces/IExpectedResults.sol

@@ -0,0 +1,66 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity 0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../protocol/Exchange/libs/LibFillResults.sol";
+import "../../protocol/Exchange/libs/LibOrder.sol";
+
+
+contract IExpectedResults {
+
+    /// @dev Calculates a total FillResults for buying makerAssetFillAmount over all orders.
+    ///      Including the fees required to be paid. 
+    /// @param orders An array of Order struct containing order specifications.
+    /// @param makerAssetFillAmount A number representing the amount of this order to fill.
+    /// @return totalFillResults Amounts filled and fees paid by maker and taker.
+    function calculateMarketBuyResults(
+        LibOrder.Order[] memory orders,
+        uint256 makerAssetFillAmount
+    )
+        public
+        view
+        returns (LibFillResults.FillResults memory totalFillResults);
+
+    /// @dev Calculates a FillResults total for selling takerAssetFillAmount over all orders. 
+    ///      Including the fees required to be paid. 
+    /// @param orders An array of Order struct containing order specifications.
+    /// @param takerAssetFillAmount A number representing the amount of this order to fill.
+    /// @return totalFillResults Amounts filled and fees paid by maker and taker.
+    function calculateMarketSellResults(
+        LibOrder.Order[] memory orders,
+        uint256 takerAssetFillAmount
+    )
+        public
+        view
+        returns (LibFillResults.FillResults memory totalFillResults);
+
+    /// @dev Calculates fill results for buyFeeTokens. This handles fees on buying ZRX
+    ///      so the end result is the expected amount of ZRX (not less after fees).
+    /// @param orders An array of Order struct containing order specifications.
+    /// @param zrxFillAmount A number representing the amount zrx to buy
+    /// @return totalFillResults Expected fill result amounts from buying fees
+    function calculateMarketBuyZrxResults(
+        LibOrder.Order[] memory orders,
+        uint256 zrxFillAmount
+    )
+        public
+        view
+        returns (LibFillResults.FillResults memory totalFillResults);
+}

packages/contracts/src/2.0.0/forwarder/interfaces/IForwarder.sol

@@ -0,0 +1,30 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity 0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "./IForwarderCore.sol";
+import "./IExpectedResults.sol";
+
+
+// solhint-disable no-empty-blocks
+contract IForwarder is
+    IForwarderCore,
+    IExpectedResults
+{}

packages/contracts/src/2.0.0/forwarder/interfaces/IForwarderCore.sol

@@ -0,0 +1,79 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity 0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../protocol/Exchange/libs/LibOrder.sol";
+import "../../protocol/Exchange/libs/LibFillResults.sol";
+
+
+contract IForwarderCore {
+
+    /// @dev Market sells ETH for ERC20 tokens, performing fee abstraction if required. This does not support ERC721 tokens. This function is payable
+    ///      and will convert all incoming ETH into WETH and perform the trade on behalf of the caller.
+    ///      This function allows for a deduction of a proportion of incoming ETH sent to the feeRecipient.
+    ///      The caller is sent all tokens from the operation.
+    ///      If the purchased token amount does not meet an acceptable threshold then this function reverts.
+    /// @param orders An array of Order struct containing order specifications.
+    /// @param signatures An array of Proof that order has been created by maker.
+    /// @param feeOrders An array of Order struct containing order specifications for fees.
+    /// @param feeSignatures An array of Proof that order has been created by maker for the fee orders.
+    /// @param feeProportion A proportion deducted off the incoming ETH and sent to feeRecipient. The maximum value for this
+    ///        is 1000, aka 10%. Supports up to 2 decimal places. I.e 0.59% is 59.
+    /// @param feeRecipient An address of the fee recipient whom receives feeProportion of ETH.
+    /// @return FillResults amounts filled and fees paid by maker and taker.
+    function marketSellEthForERC20(
+        LibOrder.Order[] memory orders,
+        bytes[] memory signatures,
+        LibOrder.Order[] memory feeOrders,
+        bytes[] memory feeSignatures,
+        uint16  feeProportion,
+        address feeRecipient
+    )
+        public
+        payable
+        returns (LibFillResults.FillResults memory totalFillResults);
+
+    /// @dev Buys the exact amount of assets (ERC20 and ERC721), performing fee abstraction if required.
+    ///      All order assets must be of the same type. Deducts a proportional fee to fee recipient.
+    ///      This function is payable and will convert all incoming ETH into WETH and perform the trade on behalf of the caller.
+    ///      The caller is sent all assets from the fill of orders. This function will revert unless the requested amount of assets are purchased.
+    ///      Any excess ETH sent will be returned to the caller
+    /// @param orders An array of Order struct containing order specifications.
+    /// @param signatures An array of Proof that order has been created by maker.
+    /// @param feeOrders An array of Order struct containing order specifications for fees.
+    /// @param makerTokenFillAmount The amount of maker asset to buy.
+    /// @param feeSignatures An array of Proof that order has been created by maker for the fee orders.
+    /// @param feeProportion A proportion deducted off the ETH spent and sent to feeRecipient. The maximum value for this
+    ///        is 1000, aka 10%. Supports up to 2 decimal places. I.e 0.59% is 59.
+    /// @param feeRecipient An address of the fee recipient whom receives feeProportion of ETH.
+    /// @return FillResults amounts filled and fees paid by maker and taker.
+    function marketBuyTokensWithEth(
+        LibOrder.Order[] memory orders,
+        bytes[] memory signatures,
+        LibOrder.Order[] memory feeOrders,
+        bytes[] memory feeSignatures,
+        uint256 makerTokenFillAmount,
+        uint16  feeProportion,
+        address feeRecipient
+    )
+        public
+        payable
+        returns (LibFillResults.FillResults memory totalFillResults);
+}

packages/contracts/src/2.0.0/forwarder/mixins/MConstants.sol

@@ -0,0 +1,35 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity 0.4.24;
+
+import "../../protocol/Exchange/interfaces/IExchange.sol";
+import "../../tokens/EtherToken/IEtherToken.sol";
+import "../../tokens/ERC20Token/IERC20Token.sol";
+
+
+contract MConstants {
+
+    // solhint-disable var-name-mixedcase
+    IExchange internal EXCHANGE;
+    IEtherToken internal ETHER_TOKEN;
+    IERC20Token internal ZRX_TOKEN;
+    bytes internal ZRX_ASSET_DATA;
+    bytes internal WETH_ASSET_DATA;
+    // solhint-enable var-name-mixedcase
+}

packages/contracts/src/2.0.0/forwarder/mixins/MExpectedResults.sol

@@ -0,0 +1,42 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity 0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../protocol/Exchange/libs/LibFillResults.sol";
+import "../../protocol/Exchange/libs/LibOrder.sol";
+import "../interfaces/IExpectedResults.sol";
+
+
+contract MExpectedResults is
+    IExpectedResults
+{
+
+    /// @dev Simulates the 0x Exchange fillOrder validation and calculations, without performing any state changes.
+    /// @param order An Order struct containing order specifications.
+    /// @param takerAssetFillAmount A number representing the amount of this order to fill.
+    /// @return fillResults Amounts filled and fees paid by maker and taker.
+    function calculateFillResults(
+        LibOrder.Order memory order,
+        uint256 takerAssetFillAmount
+    )
+        internal
+        view
+        returns (LibFillResults.FillResults memory fillResults);
+}

packages/contracts/src/2.0.0/forwarder/mixins/MFees.sol

@@ -0,0 +1,63 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity 0.4.24;
+
+
+contract MFees {
+
+    /// @dev Pays the feeRecipient feeProportion of the total takerEthAmount, denominated in ETH
+    /// @param takerEthAmount The total amount that was transacted in WETH, fees are calculated from this value.
+    /// @param feeProportion The proportion of fees
+    /// @param feeRecipient The recipient of the fees
+    /// @return ethFeeAmount Amount of ETH paid to feeRecipient as fee.
+    function payEthFee(
+        uint256 takerEthAmount,
+        uint16 feeProportion,
+        address feeRecipient
+    )
+        internal
+        returns (uint256 ethFeeAmount);
+
+    /// @dev Withdraws the remaining WETH, deduct and pay fees from this amount based on the takerTokenAmount to the feeRecipient.
+    ///      If a user overpaid ETH initially, the fees are calculated from the amount traded and deducted from withdrawAmount.
+    ///      Any remaining ETH is sent back to the user.
+    /// @param ethWithdrawAmount The amount to withdraw from the WETH contract.
+    /// @param wethAmountSold The total amount that was transacted in WETH, fees are calculated from this value.
+    /// @param feeProportion The proportion of fees
+    /// @param feeRecipient The recipient of the fees
+    function withdrawPayAndDeductEthFee(
+        uint256 ethWithdrawAmount,
+        uint256 wethAmountSold,
+        uint16 feeProportion,
+        address feeRecipient
+    )
+        internal;
+
+    /// @dev Checks whether the amount of tokens sold against the amount of tokens requested
+    ///      is within a certain threshold. This ensures the caller gets a fair deal when
+    ///      performing any token fee abstraction. Threshold is 95%. If fee abstraction costs more than
+    ///      5% of the total transaction, we return false.
+    /// @param requestedSellAmount The amount the user requested, or sent in to a payable function
+    /// @param tokenAmountSold The amount of the token that was sold after fee abstraction
+    /// @return bool of whether this is within an acceptable threshold
+    function isAcceptableThreshold(uint256 requestedSellAmount, uint256 tokenAmountSold)
+        internal
+        pure
+        returns (bool);
+}

packages/contracts/src/2.0.0/forwarder/mixins/MForwarderCore.sol

@@ -0,0 +1,92 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity 0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../protocol/Exchange/libs/LibOrder.sol";
+import "../../protocol/Exchange/libs/LibFillResults.sol";
+import "../interfaces/IForwarderCore.sol";
+
+
+contract MForwarderCore is
+    IForwarderCore
+{
+
+    /// @dev Market sells WETH for ERC20 tokens.
+    /// @param orders An array of Order struct containing order specifications.
+    /// @param signatures An array of Proof that order has been created by maker.
+    /// @param feeOrders An array of Order struct containing order specifications for fees.
+    /// @param feeSignatures An array of Proof that order has been created by maker for the fee orders.
+    /// @param wethSellAmount The amount of WETH to sell.
+    /// @return FillResults amounts filled and fees paid by maker and taker.
+    function marketSellEthForERC20Internal(
+        LibOrder.Order[] memory orders,
+        bytes[] memory signatures,
+        LibOrder.Order[] memory feeOrders,
+        bytes[] memory feeSignatures,
+        uint256 wethSellAmount
+    )
+        internal
+        returns (LibFillResults.FillResults memory totalFillResults);
+
+    /// @dev Market sells WETH for ZRX tokens.
+    /// @param orders An array of Order struct containing order specifications.
+    /// @param signatures An array of Proof that order has been created by maker.
+    /// @param wethSellAmount The amount of WETH to sell.
+    /// @return FillResults amounts filled and fees paid by maker and taker.
+    function marketSellEthForZRXInternal(
+        LibOrder.Order[] memory orders,
+        bytes[] memory signatures,
+        uint256 wethSellAmount
+    )
+        internal
+        returns (LibFillResults.FillResults memory totalFillResults);
+
+    /// @dev Buys an exact amount of an ERC20 token using WETH.
+    /// @param orders Orders to fill. The maker asset is the ERC20 token to buy. The taker asset is WETH.
+    /// @param signatures Proof that the orders were created by their respective makers.
+    /// @param feeOrders to fill. The maker asset is ZRX and the taker asset is WETH.
+    /// @param feeSignatures Proof that the feeOrders were created by their respective makers.
+    /// @param makerTokenFillAmount Amount of the ERC20 token to buy.
+    /// @return totalFillResults Aggregated fill results of buying the ERC20 and ZRX tokens.
+    function marketBuyERC20TokensInternal(
+        LibOrder.Order[] memory orders,
+        bytes[] memory signatures,
+        LibOrder.Order[] memory feeOrders,
+        bytes[] memory feeSignatures,
+        uint256 makerTokenFillAmount
+    )
+        internal
+        returns (LibFillResults.FillResults memory totalFillResults);
+
+    /// @dev Buys an all of the ERC721 tokens in the orders.
+    /// @param orders Orders to fill. The maker asset is the ERC721 token to buy. The taker asset is WETH.
+    /// @param signatures Proof that the orders were created by their respective makers.
+    /// @param feeOrders to fill. The maker asset is ZRX and the taker asset is WETH.
+    /// @param feeSignatures Proof that the feeOrders were created by their respective makers.
+    /// @return totalFillResults Aggregated fill results of buying the ERC721 tokens and ZRX tokens.
+    function batchBuyERC721TokensInternal(
+        LibOrder.Order[] memory orders,
+        bytes[] memory signatures,
+        LibOrder.Order[] memory feeOrders,
+        bytes[] memory feeSignatures
+    )
+        internal
+        returns (LibFillResults.FillResults memory totalFillResults);
+}

packages/contracts/src/2.0.0/forwarder/mixins/MMarketBuyZrx.sol

@@ -0,0 +1,42 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity 0.4.24;
+
+import "../../protocol/Exchange/libs/LibFillResults.sol";
+import "../../protocol/Exchange/libs/LibOrder.sol";
+
+
+contract MMarketBuyZrx {
+
+    /// @dev Buys zrxBuyAmount of ZRX fee tokens, taking into account the fees on buying fee tokens. This will guarantee
+    ///      At least zrxBuyAmount of ZRX fee tokens are purchased (sometimes slightly over due to rounding issues).
+    ///      It is possible that a request to buy 200 ZRX fee tokens will require purchasing 202 ZRX tokens
+    ///      As 2 ZRX is required to purchase the 200 ZRX fee tokens. This guarantees at least 200 ZRX for future purchases.
+    /// @param orders An array of Order struct containing order specifications for fees.
+    /// @param signatures An array of Proof that order has been created by maker for the fee orders.
+    /// @param zrxBuyAmount The number of requested ZRX fee tokens.
+    /// @return totalFillResults Amounts filled and fees paid by maker and taker. makerTokenAmount is the zrx amount deducted of fees
+    function marketBuyZrxInternal(
+        LibOrder.Order[] memory orders,
+        bytes[] memory signatures,
+        uint256 zrxBuyAmount
+    )
+        internal
+        returns (LibFillResults.FillResults memory totalFillResults);
+}

packages/contracts/src/2.0.0/forwarder/mixins/MTransfer.sol

@@ -0,0 +1,46 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity 0.4.24;
+
+
+contract MTransfer {
+
+    function onERC721Received(address, uint256, bytes memory)
+        public
+        pure
+        returns(bytes4);
+
+    function onERC721Received(address, address, uint256, bytes memory)
+        public
+        pure
+        returns(bytes4);
+    
+    function transferERC20Token(
+        address token,
+        address to,
+        uint256 amount
+    )
+        internal;
+
+    function transferERC721Token(
+        bytes memory assetData,
+        address to
+    )
+        internal;
+}