1 files changed, 86 insertions, 0 deletions
diff --git a/contracts/extensions/contracts/src/OrderMatcher/MixinMatchOrders.sol b/contracts/extensions/contracts/src/OrderMatcher/MixinMatchOrders.sol
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+++ b/contracts/extensions/contracts/src/OrderMatcher/MixinMatchOrders.sol
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+/*
+
+  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 "./libs/LibConstants.sol";
+import "@0x/contracts-exchange-libs/contracts/src/LibOrder.sol";
+import "@0x/contracts-exchange-libs/contracts/src/LibFillResults.sol";
+import "@0x/contracts-utils/contracts/src/Ownable.sol";
+
+
+contract MixinMatchOrders is
+    Ownable,
+    LibConstants
+{
+    /// @dev Match two complementary orders that have a profitable spread.
+    ///      Each order is filled at their respective price point. However, the calculations are
+    ///      carried out as though the orders are both being filled at the right order's price point.
+    ///      The profit made by the left order is then used to fill the right order as much as possible.
+    ///      This results in a spread being taken in terms of both assets. The spread is held within this contract.
+    /// @param leftOrder First order to match.
+    /// @param rightOrder Second order to match.
+    /// @param leftSignature Proof that order was created by the left maker.
+    /// @param rightSignature Proof that order was created by the right maker.
+    function matchOrders(
+        LibOrder.Order memory leftOrder,
+        LibOrder.Order memory rightOrder,
+        bytes memory leftSignature,
+        bytes memory rightSignature
+    )
+        public
+        onlyOwner
+    {
+        // Match orders, maximally filling `leftOrder`
+        LibFillResults.MatchedFillResults memory matchedFillResults = EXCHANGE.matchOrders(
+            leftOrder,
+            rightOrder,
+            leftSignature,
+            rightSignature
+        );
+
+        uint256 leftMakerAssetSpreadAmount = matchedFillResults.leftMakerAssetSpreadAmount;
+        uint256 rightOrderTakerAssetAmount = rightOrder.takerAssetAmount;
+
+        // Do not attempt to call `fillOrder` if no spread was taken or `rightOrder` has been completely filled
+        if (leftMakerAssetSpreadAmount == 0 || matchedFillResults.right.takerAssetFilledAmount == rightOrderTakerAssetAmount) {
+            return;
+        }
+
+        // The `assetData` fields of the `rightOrder` could have been null for the `matchOrders` call. We reassign them before calling `fillOrder`.
+        rightOrder.makerAssetData = leftOrder.takerAssetData;
+        rightOrder.takerAssetData = leftOrder.makerAssetData;
+
+        // Query `rightOrder` info to check if it has been completely filled
+        // We need to make this check in case the `rightOrder` was partially filled before the `matchOrders` call
+        LibOrder.OrderInfo memory orderInfo = EXCHANGE.getOrderInfo(rightOrder);
+
+        // Do not attempt to call `fillOrder` if order has been completely filled
+        if (orderInfo.orderTakerAssetFilledAmount == rightOrderTakerAssetAmount) {
+            return;
+        }
+
+        // We do not need to pass in a signature since it was already validated in the `matchOrders` call
+        EXCHANGE.fillOrder(
+            rightOrder,
+            leftMakerAssetSpreadAmount,
+            ""
+        );
+    }
+}