Implement sender abstraction

6 files changed, 210 insertions, 47 deletions

diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/Exchange.sol b/packages/contracts/src/contracts/current/protocol/Exchange/Exchange.sol
index 5ccb06b88..caf48bfca 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/Exchange.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/Exchange.sol
@@ -24,13 +24,15 @@ import "./MixinSignatureValidator.sol";
 import "./MixinSettlement.sol";
 import "./MixinWrapperFunctions.sol";
 import "./MixinAssetProxyDispatcher.sol";
+import "./MixinTransactions.sol";
 
 contract Exchange is
     MixinExchangeCore,
     MixinSignatureValidator,
     MixinSettlement,
     MixinWrapperFunctions,
-    MixinAssetProxyDispatcher
+    MixinAssetProxyDispatcher,
+    MixinTransactions
 {
     string constant public VERSION = "2.0.1-alpha";
 
@@ -42,5 +44,6 @@ contract Exchange is
         MixinSettlement(_zrxProxyData)
         MixinWrapperFunctions()
         MixinAssetProxyDispatcher()
+        MixinTransactions()
     {}
 }
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/LibOrder.sol b/packages/contracts/src/contracts/current/protocol/Exchange/LibOrder.sol
index 61a4a382d..a98d7cbeb 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/LibOrder.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/LibOrder.sol
@@ -26,6 +26,7 @@ contract LibOrder {
         "address makerAddress",
         "address takerAddress",
         "address feeRecipientAddress",
+        "address senderAddress",
         "uint256 makerAssetAmount",
         "uint256 takerAssetAmount",
         "uint256 makerFee",
@@ -40,6 +41,7 @@ contract LibOrder {
         address makerAddress;
         address takerAddress;
         address feeRecipientAddress;
+        address senderAddress;
         uint256 makerAssetAmount;
         uint256 takerAssetAmount;
         uint256 makerFee;
@@ -66,6 +68,7 @@ contract LibOrder {
                 order.makerAddress,
                 order.takerAddress,
                 order.feeRecipientAddress,
+                order.senderAddress,
                 order.makerAssetAmount,
                 order.takerAssetAmount,
                 order.makerFee,
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinExchangeCore.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinExchangeCore.sol
index 710315515..97c1f1541 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinExchangeCore.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinExchangeCore.sol
@@ -18,10 +18,12 @@
 
 pragma solidity ^0.4.21;
 pragma experimental ABIEncoderV2;
+pragma experimental "v0.5.0";
 
 import "./mixins/MExchangeCore.sol";
 import "./mixins/MSettlement.sol";
 import "./mixins/MSignatureValidator.sol";
+import "./mixins/MTransactions.sol";
 import "./LibOrder.sol";
 import "./LibErrors.sol";
 import "./LibPartialAmount.sol";
@@ -35,6 +37,7 @@ contract MixinExchangeCore is
     MExchangeCore,
     MSettlement,
     MSignatureValidator,
+    MTransactions,
     SafeMath,
     LibErrors,
     LibPartialAmount
@@ -113,10 +116,16 @@ contract MixinExchangeCore is
             require(order.takerAssetAmount > 0);
             require(isValidSignature(orderHash, order.makerAddress, signature));
         }
+        
+        // Validate sender
+        if (order.senderAddress != address(0)) {
+            require(order.senderAddress == msg.sender);
+        }
 
-        // Validate taker
+        // Validate transaction signed by taker
+        address takerAddress = getSignerAddress();
         if (order.takerAddress != address(0)) {
-            require(order.takerAddress == msg.sender);
+            require(order.takerAddress == takerAddress);
         }
         require(takerAssetFillAmount > 0);
 
@@ -146,21 +155,10 @@ contract MixinExchangeCore is
 
         // Settle order
         (fillResults.makerAssetFilledAmount, fillResults.makerFeePaid, fillResults.takerFeePaid) =
-            settleOrder(order, msg.sender, fillResults.takerAssetFilledAmount);
+            settleOrder(order, takerAddress, fillResults.takerAssetFilledAmount);
 
         // Log order
-        emit Fill(
-            order.makerAddress,
-            msg.sender,
-            order.feeRecipientAddress,
-            fillResults.makerAssetFilledAmount,
-            fillResults.takerAssetFilledAmount,
-            fillResults.makerFeePaid,
-            fillResults.takerFeePaid,
-            orderHash,
-            order.makerAssetData,
-            order.takerAssetData
-        );
+        emitFillEvent(order, takerAddress, orderHash, fillResults);
         return fillResults;
     }
 
@@ -178,8 +176,16 @@ contract MixinExchangeCore is
         // Validate the order
         require(order.makerAssetAmount > 0);
         require(order.takerAssetAmount > 0);
-        require(order.makerAddress == msg.sender);
 
+        // Validate sender
+        if (order.senderAddress != address(0)) {
+            require(order.senderAddress == msg.sender);
+        }
+        
+        // Validate transaction signed by maker
+        address makerAddress = getSignerAddress();
+        require(order.makerAddress == makerAddress);
+        
         if (block.timestamp >= order.expirationTimeSeconds) {
             emit ExchangeError(uint8(Errors.ORDER_EXPIRED), orderHash);
             return false;
@@ -233,4 +239,27 @@ contract MixinExchangeCore is
         isError = errPercentageTimes1000000 > 1000;
         return isError;
     }
+
+    /// @dev Logs a Fill event with the given arguments.
+    ///      The sole purpose of this function is to get around the stack variable limit.
+    function emitFillEvent(
+        Order memory order,
+        address takerAddress,
+        bytes32 orderHash,
+        FillResults memory fillResults)
+        internal
+    {
+        emit Fill(
+            order.makerAddress,
+            takerAddress,
+            order.feeRecipientAddress,
+            fillResults.makerAssetFilledAmount,
+            fillResults.takerAssetFilledAmount,
+            fillResults.makerFeePaid,
+            fillResults.takerFeePaid,
+            orderHash,
+            order.makerAssetData,
+            order.takerAssetData
+        );
+    }
 }
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinTransactions.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinTransactions.sol
new file mode 100644
index 000000000..e4fc4767b
--- /dev/null
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinTransactions.sol
@@ -0,0 +1,85 @@
+/*
+
+  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 ^0.4.21;
+pragma experimental ABIEncoderV2;
+
+import "./mixins/MSignatureValidator.sol";
+import "./mixins/MTransactions.sol";
+
+contract MixinTransactions is
+    MSignatureValidator,
+    MTransactions
+{
+
+    // Mapping of transaction hash => executed
+    mapping (bytes32 => bool) public transactions;
+
+    // Address of current transaction signer
+    address currentSigner;
+
+    /// @dev Executes an exchange method call in the context of signer.
+    /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
+    /// @param signer Address of transaction signer.
+    /// @param data AbiV2 encoded calldata.
+    /// @param signature Proof of signer transaction by signer.
+    function executeTransaction(
+        uint256 salt,
+        address signer,
+        bytes data,
+        bytes signature)
+        external
+    {
+        // Prevent reentrancy
+        require(currentSigner == address(0));
+
+        // Calculate transaction hash
+        bytes32 transactionHash = keccak256(
+            address(this),
+            salt,
+            data
+        );
+
+        // Validate transaction has not been executed
+        require(!transactions[transactionHash]);
+
+        // TODO: is SignatureType.Caller necessary if we make this check?
+        if (signer != msg.sender) {
+            // Validate signature
+            require(isValidSignature(transactionHash, signer, signature));
+
+            // Set the current transaction signer
+            currentSigner = signer;
+        }
+
+        // Execute transaction
+        transactions[transactionHash] = true;
+        require(address(this).delegatecall(data));
+
+        // Reset current transaction signer
+        currentSigner = address(0);
+    }
+
+    function getSignerAddress()
+        internal
+        view
+        returns (address)
+    {
+        address signerAddress = currentSigner == address(0) ? msg.sender : currentSigner;
+        return signerAddress;
+    }
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol
index 2c0fd0751..4d6ba17dd 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol
@@ -75,24 +75,25 @@ contract MixinWrapperFunctions is
         // |          | 0x00   |         |   1. offset to order (*)                    |
         // |          | 0x20   |         |   2. takerAssetFillAmount                   |
         // |          | 0x40   |         |   3. offset to signature (*)                |
-        // | Data     |        | 11 * 32 | order:                                      |
-        // |          | 0x000  |         |   1.  makerAddress                          |
-        // |          | 0x020  |         |   2.  takerAddress                          |
-        // |          | 0x040  |         |   3.  feeRecipientAddress                   |
-        // |          | 0x060  |         |   4.  makerAssetAmount                      |
-        // |          | 0x080  |         |   5.  takerAssetAmount                      |
-        // |          | 0x0A0  |         |   6.  makerFeeAmount                        |
-        // |          | 0x0C0  |         |   7.  takerFeeAmount                        |
-        // |          | 0x0E0  |         |   8.  expirationTimeSeconds                 |
-        // |          | 0x100  |         |   9.  salt                                  |
-        // |          | 0x120  |         |   10. Offset to makerAssetProxyMetadata (*) |
-        // |          | 0x140  |         |   11. Offset to takerAssetProxyMetadata (*) |
-        // |          | 0x160  | 32      | makerAssetProxyMetadata Length              |
-        // |          | 0x180  | **      | makerAssetProxyMetadata Contents            |
-        // |          | 0x1A0  | 32      | takerAssetProxyMetadata Length              |
-        // |          | 0x1C0  | **      | takerAssetProxyMetadata Contents            |
-        // |          | 0x1E0  | 32      | signature Length                            |
-        // |          | 0x200  | **      | signature Contents                          |
+        // | Data     |        | 12 * 32 | order:                                      |
+        // |          | 0x000  |         |   1.  senderAddress                         |
+        // |          | 0x020  |         |   2.  makerAddress                          |
+        // |          | 0x040  |         |   3.  takerAddress                          |
+        // |          | 0x060  |         |   4.  feeRecipientAddress                   |
+        // |          | 0x080  |         |   5.  makerAssetAmount                      |
+        // |          | 0x0A0  |         |   6.  takerAssetAmount                      |
+        // |          | 0x0C0  |         |   7.  makerFeeAmount                        |
+        // |          | 0x0E0  |         |   8.  takerFeeAmount                        |
+        // |          | 0x100  |         |   9.  expirationTimeSeconds                 |
+        // |          | 0x120  |         |   10. salt                                  |
+        // |          | 0x140  |         |   11. Offset to makerAssetProxyMetadata (*) |
+        // |          | 0x160  |         |   12. Offset to takerAssetProxyMetadata (*) |
+        // |          | 0x180  | 32      | makerAssetProxyMetadata Length              |
+        // |          | 0x1A0  | **      | makerAssetProxyMetadata Contents            |
+        // |          | 0x1C0  | 32      | takerAssetProxyMetadata Length              |
+        // |          | 0x1E0  | **      | takerAssetProxyMetadata Contents            |
+        // |          | 0x200  | 32      | signature Length                            |
+        // |          | 0x220  | **      | signature Contents                          |
 
         // * Offsets are calculated from the beginning of the current area: Header, Params, Data:
         //     An offset stored in the Params area is calculated from the beginning of the Params section.
@@ -150,19 +151,20 @@ contract MixinWrapperFunctions is
             mstore(dataAreaEnd, mload(sourceOffset))                            // makerAddress
             mstore(add(dataAreaEnd, 0x20), mload(add(sourceOffset, 0x20)))      // takerAddress
             mstore(add(dataAreaEnd, 0x40), mload(add(sourceOffset, 0x40)))      // feeRecipientAddress
-            mstore(add(dataAreaEnd, 0x60), mload(add(sourceOffset, 0x60)))      // makerAssetAmount
-            mstore(add(dataAreaEnd, 0x80), mload(add(sourceOffset, 0x80)))      // takerAssetAmount
-            mstore(add(dataAreaEnd, 0xA0), mload(add(sourceOffset, 0xA0)))      // makerFeeAmount
-            mstore(add(dataAreaEnd, 0xC0), mload(add(sourceOffset, 0xC0)))      // takerFeeAmount
-            mstore(add(dataAreaEnd, 0xE0), mload(add(sourceOffset, 0xE0)))      // expirationTimeSeconds
-            mstore(add(dataAreaEnd, 0x100), mload(add(sourceOffset, 0x100)))    // salt
-            mstore(add(dataAreaEnd, 0x120), mload(add(sourceOffset, 0x120)))    // Offset to makerAssetProxyMetadata
-            mstore(add(dataAreaEnd, 0x140), mload(add(sourceOffset, 0x140)))    // Offset to takerAssetProxyMetadata
-            dataAreaEnd := add(dataAreaEnd, 0x160)
-            sourceOffset := add(sourceOffset, 0x160)
+            mstore(add(dataAreaEnd, 0x60), mload(add(sourceOffset, 0x60)))      // senderAddress
+            mstore(add(dataAreaEnd, 0x80), mload(add(sourceOffset, 0x80)))      // makerAssetAmount
+            mstore(add(dataAreaEnd, 0xA0), mload(add(sourceOffset, 0xA0)))      // takerAssetAmount
+            mstore(add(dataAreaEnd, 0xC0), mload(add(sourceOffset, 0xC0)))      // makerFeeAmount
+            mstore(add(dataAreaEnd, 0xE0), mload(add(sourceOffset, 0xE0)))      // takerFeeAmount
+            mstore(add(dataAreaEnd, 0x100), mload(add(sourceOffset, 0x100)))    // expirationTimeSeconds
+            mstore(add(dataAreaEnd, 0x120), mload(add(sourceOffset, 0x120)))    // salt
+            mstore(add(dataAreaEnd, 0x140), mload(add(sourceOffset, 0x140)))    // Offset to makerAssetProxyMetadata
+            mstore(add(dataAreaEnd, 0x160), mload(add(sourceOffset, 0x160)))    // Offset to takerAssetProxyMetadata
+            dataAreaEnd := add(dataAreaEnd, 0x180)
+            sourceOffset := add(sourceOffset, 0x180)
 
             // Write offset to <order.makerAssetProxyMetadata>
-            mstore(add(dataAreaStart, mul(9, 0x20)), sub(dataAreaEnd, dataAreaStart))
+            mstore(add(dataAreaStart, mul(10, 0x20)), sub(dataAreaEnd, dataAreaStart))
 
             // Calculate length of <order.makerAssetProxyMetadata>
             arrayLenBytes := mload(sourceOffset)
@@ -181,7 +183,7 @@ contract MixinWrapperFunctions is
             }
 
             // Write offset to <order.takerAssetProxyMetadata>
-            mstore(add(dataAreaStart, mul(10, 0x20)), sub(dataAreaEnd, dataAreaStart))
+            mstore(add(dataAreaStart, mul(11, 0x20)), sub(dataAreaEnd, dataAreaStart))
 
             // Calculate length of <order.takerAssetProxyMetadata>
             arrayLenBytes := mload(sourceOffset)
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MTransactions.sol b/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MTransactions.sol
new file mode 100644
index 000000000..31209de02
--- /dev/null
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MTransactions.sol
@@ -0,0 +1,41 @@
+/*
+
+  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 ^0.4.21;
+pragma experimental ABIEncoderV2;
+
+import "./MSignatureValidator.sol";
+
+contract MTransactions is MSignatureValidator {
+
+    /// @dev Executes an exchange method call in the context of signer.
+    /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
+    /// @param signer Address of transaction signer.
+    /// @param data AbiV2 encoded calldata.
+    /// @param signature Proof of signer transaction by signer.
+    function executeTransaction(
+        uint256 salt,
+        address signer,
+        bytes data,
+        bytes signature)
+        external;
+
+    function getSignerAddress()
+        internal
+        view
+        returns (address);
+}