@0x/contracts-asset-proxy: Create DexForwarderBridge bridge contract.

contracts/asset-proxy/CHANGELOG.json

@@ -17,6 +17,10 @@
             {
                 "note": "Added `MixinGasToken` allowing Gas Tokens to be freed",
                 "pr": 2523
+            },
+            {
+                "note": "Add `DexForwaderBridge` bridge contract.",
+                "pr": 2525
             }
         ]
     },

contracts/asset-proxy/contracts/src/bridges/DexForwarderBridge.sol

@@ -0,0 +1,210 @@
+/*
+
+  Copyright 2020 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 ^0.5.9;
+pragma experimental ABIEncoderV2;
+
+import "@0x/contracts-erc20/contracts/src/interfaces/IERC20Token.sol";
+import "@0x/contracts-erc20/contracts/src/LibERC20Token.sol";
+import "@0x/contracts-exchange-libs/contracts/src/IWallet.sol";
+import "@0x/contracts-exchange-libs/contracts/src/LibMath.sol";
+import "@0x/contracts-utils/contracts/src/LibBytes.sol";
+import "@0x/contracts-utils/contracts/src/LibSafeMath.sol";
+import "../interfaces/IERC20Bridge.sol";
+
+
+// solhint-disable space-after-comma, indent
+contract DexForwarderBridge is
+    IERC20Bridge,
+    IWallet
+{
+    using LibSafeMath for uint256;
+
+    /// @dev Data needed to reconstruct a bridge call.
+    struct BridgeCall {
+        address target;
+        uint256 inputTokenAmount;
+        uint256 outputTokenAmount;
+        bytes bridgeData;
+    }
+
+    /// @dev Intermediate state variables used by `bridgeTransferFrom()`, in
+    ///      struct form to get around stack limits.
+    struct TransferFromState {
+        address inputToken;
+        uint256 initialInputTokenBalance;
+        uint256 callInputTokenAmount;
+        uint256 callOutputTokenAmount;
+        uint256 totalInputTokenSold;
+        BridgeCall[] calls;
+    }
+
+    event DexForwarderBridgeCallFailed(
+        address indexed target,
+        address inputToken,
+        address outputToken,
+        uint256 inputTokenAmount,
+        uint256 outputTokenAmount
+    );
+
+    /// @dev Executes a series of calls, forwarding .
+    /// @param outputToken The token being bought.
+    /// @param to The recipient of the bought tokens.
+    /// @param bridgeData The abi-encoeded input token address.
+    /// @return success The magic bytes if successful.
+    function bridgeTransferFrom(
+        address outputToken,
+        address /* from */,
+        address to,
+        uint256 /* amount */,
+        bytes calldata bridgeData
+    )
+        external
+        returns (bytes4 success)
+    {
+        TransferFromState memory state;
+        (
+            state.inputToken,
+            state.calls
+        ) = abi.decode(bridgeData, (address, BridgeCall[]));
+
+        state.initialInputTokenBalance = IERC20Token(state.inputToken).balanceOf(address(this));
+
+        for (uint256 i = 0; i < state.calls.length; ++i) {
+            // Stop if the we've sold all our input tokens.
+            if (state.totalInputTokenSold >= state.initialInputTokenBalance) {
+                break;
+            }
+
+            BridgeCall memory call = state.calls[i];
+            // Compute token amounts.
+            state.callInputTokenAmount = LibSafeMath.min256(
+                call.inputTokenAmount,
+                state.initialInputTokenBalance.safeSub(state.totalInputTokenSold)
+            );
+            state.callOutputTokenAmount = LibMath.getPartialAmountFloor(
+                state.callInputTokenAmount,
+                call.inputTokenAmount,
+                call.outputTokenAmount
+            );
+
+            (bool didSucceed, ) = address(this)
+                .call(abi.encodeWithSelector(
+                    this.executeBridgeCall.selector,
+                    call.target,
+                    to,
+                    state.inputToken,
+                    outputToken,
+                    state.callInputTokenAmount,
+                    state.callOutputTokenAmount,
+                    call.bridgeData
+                ));
+
+            if (!didSucceed) {
+                // Log errors.
+                emit DexForwarderBridgeCallFailed(
+                    call.target,
+                    state.inputToken,
+                    outputToken,
+                    state.callInputTokenAmount,
+                    state.callOutputTokenAmount
+                );
+            } else {
+                // Increase the amount of tokens sold.
+                state.totalInputTokenSold = state.totalInputTokenSold.safeAdd(
+                    state.callInputTokenAmount
+                );
+            }
+        }
+        // Revert if we were not able to sell our entire input token balance.
+        require(
+            state.totalInputTokenSold >= state.initialInputTokenBalance,
+            "DexForwaderBridge/INCOMPLETE_FILL"
+        );
+        // Always succeed.
+        return BRIDGE_SUCCESS;
+    }
+
+    /// @dev Transfers `inputToken` token to a bridge contract then calls
+    ///      its `bridgeTransferFrom()`. This is executed in separate context
+    ///      so we can revert the transfer on error. This can only be called
+    //       by this contract itself.
+    /// @param bridge The bridge contract.
+    /// @param to The recipient of `outputToken` tokens.
+    /// @param inputToken The input token.
+    /// @param outputToken The output token.
+    /// @param inputTokenAmount The amount of input tokens to transfer to `bridge`.
+    /// @param outputTokenAmount The amount of expected output tokens to be sent
+    ///        to `to` by `bridge`.
+    function executeBridgeCall(
+        address bridge,
+        address to,
+        address inputToken,
+        address outputToken,
+        uint256 inputTokenAmount,
+        uint256 outputTokenAmount,
+        bytes calldata bridgeData
+    )
+        external
+    {
+        // Must be called through `bridgeTransferFrom()`.
+        require(msg.sender == address(this), "DexForwaderBridge/ONLY_SELF");
+        // `bridge` must not be this contract.
+        require(bridge != address(this), "DexForwaderBridge/ILLEGAL_BRIDGE");
+
+        // Get the starting balance of output tokens for `to`.
+        uint256 initialRecipientBalance = IERC20Token(outputToken).balanceOf(to);
+
+        // Transfer input tokens to the bridge.
+        LibERC20Token.transfer(inputToken, bridge, inputTokenAmount);
+
+        // Call the bridge.
+        (bool didSucceed, bytes memory resultData) =
+            bridge.call(abi.encodeWithSelector(
+                IERC20Bridge(0).bridgeTransferFrom.selector,
+                outputToken,
+                bridge,
+                to,
+                outputTokenAmount,
+                bridgeData
+            ));
+
+        // Revert if the call failed or not enough tokens were bought.
+        // This will also undo the token transfer.
+        require(
+            didSucceed
+            && resultData.length == 32
+            && LibBytes.readBytes32(resultData, 0) == bytes32(BRIDGE_SUCCESS)
+            && IERC20Token(outputToken).balanceOf(to).safeSub(initialRecipientBalance) >= outputTokenAmount
+        );
+    }
+
+    /// @dev `SignatureType.Wallet` callback, so that this bridge can be the maker
+    ///      and sign for itself in orders. Always succeeds.
+    /// @return magicValue Magic success bytes, always.
+    function isValidSignature(
+        bytes32,
+        bytes calldata
+    )
+        external
+        view
+        returns (bytes4 magicValue)
+    {
+        return LEGACY_WALLET_MAGIC_VALUE;
+    }
+}

contracts/asset-proxy/contracts/test/TestDexForwarderBridge.sol

@@ -0,0 +1,220 @@
+/*
+
+  Copyright 2020 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 ^0.5.9;
+pragma experimental ABIEncoderV2;
+
+import "../src/bridges/DexForwarderBridge.sol";
+import "@0x/contracts-utils/contracts/src/LibSafeMath.sol";
+
+
+interface ITestDexForwarderBridge {
+    event BridgeTransferFromCalled(
+        address caller,
+        uint256 inputTokenBalance,
+        address inputToken,
+        address outputToken,
+        address from,
+        address to,
+        uint256 amount
+    );
+
+    event TokenTransferCalled(
+        address from,
+        address to,
+        uint256 amount
+    );
+
+    function emitBridgeTransferFromCalled(
+        address caller,
+        uint256 inputTokenBalance,
+        address inputToken,
+        address outputToken,
+        address from,
+        address to,
+        uint256 amount
+    ) external;
+
+    function emitTokenTransferCalled(
+        address from,
+        address to,
+        uint256 amount
+    ) external;
+}
+
+
+interface ITestDexForwarderBridgeTestToken {
+
+    function transfer(address to, uint256 amount)
+        external
+        returns (bool);
+
+    function mint(address to, uint256 amount)
+        external;
+
+    function balanceOf(address owner) external view returns (uint256);
+}
+
+
+contract TestDexForwarderBridgeTestBridge {
+
+    bytes4 private _returnCode;
+    string private _revertError;
+    uint256 private _transferAmount;
+    ITestDexForwarderBridge private _testContract;
+
+    constructor(bytes4 returnCode, string memory revertError) public {
+        _testContract = ITestDexForwarderBridge(msg.sender);
+        _returnCode = returnCode;
+        _revertError = revertError;
+    }
+
+    function setTransferAmount(uint256 amount) external {
+        _transferAmount = amount;
+    }
+
+    function bridgeTransferFrom(
+        address outputToken,
+        address from,
+        address to,
+        uint256 amount,
+        bytes memory bridgeData
+    )
+        public
+        returns (bytes4 success)
+    {
+        if (bytes(_revertError).length != 0) {
+            revert(_revertError);
+        }
+        address inputToken = abi.decode(bridgeData, (address));
+        _testContract.emitBridgeTransferFromCalled(
+            msg.sender,
+            ITestDexForwarderBridgeTestToken(inputToken).balanceOf(address(this)),
+            inputToken,
+            outputToken,
+            from,
+            to,
+            amount
+        );
+        ITestDexForwarderBridgeTestToken(outputToken).mint(to, _transferAmount);
+        return _returnCode;
+    }
+}
+
+
+contract TestDexForwarderBridgeTestToken {
+
+    using LibSafeMath for uint256;
+
+    mapping(address => uint256) public balanceOf;
+    ITestDexForwarderBridge private _testContract;
+
+    constructor() public {
+        _testContract = ITestDexForwarderBridge(msg.sender);
+    }
+
+    function transfer(address to, uint256 amount)
+        external
+        returns (bool)
+    {
+        balanceOf[msg.sender] = balanceOf[msg.sender].safeSub(amount);
+        balanceOf[to] = balanceOf[to].safeAdd(amount);
+        _testContract.emitTokenTransferCalled(msg.sender, to, amount);
+        return true;
+    }
+
+    function mint(address owner, uint256 amount)
+        external
+    {
+        balanceOf[owner] = balanceOf[owner].safeAdd(amount);
+    }
+
+    function setBalance(address owner, uint256 amount)
+        external
+    {
+        balanceOf[owner] = amount;
+    }
+}
+
+
+contract TestDexForwarderBridge is
+    ITestDexForwarderBridge,
+    DexForwarderBridge
+{
+    function createBridge(
+        bytes4 returnCode,
+        string memory revertError
+    )
+        public
+        returns (address bridge)
+    {
+        return address(new TestDexForwarderBridgeTestBridge(returnCode, revertError));
+    }
+
+    function createToken() public returns (address token) {
+        return address(new TestDexForwarderBridgeTestToken());
+    }
+
+    function setTokenBalance(address token, address owner, uint256 amount) public {
+        TestDexForwarderBridgeTestToken(token).setBalance(owner, amount);
+    }
+
+    function setBridgeTransferAmount(address bridge, uint256 amount) public {
+        TestDexForwarderBridgeTestBridge(bridge).setTransferAmount(amount);
+    }
+
+    function emitBridgeTransferFromCalled(
+        address caller,
+        uint256 inputTokenBalance,
+        address inputToken,
+        address outputToken,
+        address from,
+        address to,
+        uint256 amount
+    )
+        public
+    {
+        emit BridgeTransferFromCalled(
+            caller,
+            inputTokenBalance,
+            inputToken,
+            outputToken,
+            from,
+            to,
+            amount
+        );
+    }
+
+    function emitTokenTransferCalled(
+        address from,
+        address to,
+        uint256 amount
+    )
+        public
+    {
+        emit TokenTransferCalled(
+            from,
+            to,
+            amount
+        );
+    }
+
+    function balanceOf(address token, address owner) public view returns (uint256) {
+        return TestDexForwarderBridgeTestToken(token).balanceOf(owner);
+    }
+}

contracts/asset-proxy/package.json

@@ -38,7 +38,7 @@
         "docs:json": "typedoc --excludePrivate --excludeExternals --excludeProtected --ignoreCompilerErrors --target ES5 --tsconfig typedoc-tsconfig.json --json $JSON_FILE_PATH $PROJECT_FILES"
     },
     "config": {
-        "abis": "./test/generated-artifacts/@(ChaiBridge|CurveBridge|DydxBridge|ERC1155Proxy|ERC20BridgeProxy|ERC20Proxy|ERC721Proxy|Eth2DaiBridge|IAssetData|IAssetProxy|IAssetProxyDispatcher|IAuthorizable|IChai|ICurve|IDydx|IDydxBridge|IERC20Bridge|IEth2Dai|IGasToken|IKyberNetworkProxy|IUniswapExchange|IUniswapExchangeFactory|KyberBridge|MixinAssetProxyDispatcher|MixinAuthorizable|MixinGasToken|MultiAssetProxy|Ownable|StaticCallProxy|TestChaiBridge|TestDydxBridge|TestERC20Bridge|TestEth2DaiBridge|TestKyberBridge|TestStaticCallTarget|TestUniswapBridge|UniswapBridge).json",
+        "abis": "./test/generated-artifacts/@(ChaiBridge|CurveBridge|DexForwarderBridge|DydxBridge|ERC1155Proxy|ERC20BridgeProxy|ERC20Proxy|ERC721Proxy|Eth2DaiBridge|IAssetData|IAssetProxy|IAssetProxyDispatcher|IAuthorizable|IChai|ICurve|IDydx|IDydxBridge|IERC20Bridge|IEth2Dai|IGasToken|IKyberNetworkProxy|IUniswapExchange|IUniswapExchangeFactory|KyberBridge|MixinAssetProxyDispatcher|MixinAuthorizable|MixinGasToken|MultiAssetProxy|Ownable|StaticCallProxy|TestChaiBridge|TestDexForwarderBridge|TestDydxBridge|TestERC20Bridge|TestEth2DaiBridge|TestKyberBridge|TestStaticCallTarget|TestUniswapBridge|UniswapBridge).json",
         "abis:comment": "This list is auto-generated by contracts-gen. Don't edit manually."
     },
     "repository": {
@@ -52,6 +52,7 @@
     "homepage": "https://github.com/0xProject/0x-monorepo/contracts/protocol/README.md",
     "devDependencies": {
         "@0x/abi-gen": "^5.2.2",
+        "@0x/contract-wrappers": "^13.6.3",
         "@0x/contracts-gen": "^2.0.8",
         "@0x/contracts-test-utils": "^5.3.2",
         "@0x/contracts-utils": "^4.4.3",

contracts/asset-proxy/src/artifacts.ts

@@ -7,6 +7,7 @@ import { ContractArtifact } from 'ethereum-types';
 
 import * as ChaiBridge from '../generated-artifacts/ChaiBridge.json';
 import * as CurveBridge from '../generated-artifacts/CurveBridge.json';
+import * as DexForwarderBridge from '../generated-artifacts/DexForwarderBridge.json';
 import * as DydxBridge from '../generated-artifacts/DydxBridge.json';
 import * as ERC1155Proxy from '../generated-artifacts/ERC1155Proxy.json';
 import * as ERC20BridgeProxy from '../generated-artifacts/ERC20BridgeProxy.json';
@@ -35,6 +36,7 @@ import * as MultiAssetProxy from '../generated-artifacts/MultiAssetProxy.json';
 import * as Ownable from '../generated-artifacts/Ownable.json';
 import * as StaticCallProxy from '../generated-artifacts/StaticCallProxy.json';
 import * as TestChaiBridge from '../generated-artifacts/TestChaiBridge.json';
+import * as TestDexForwarderBridge from '../generated-artifacts/TestDexForwarderBridge.json';
 import * as TestDydxBridge from '../generated-artifacts/TestDydxBridge.json';
 import * as TestERC20Bridge from '../generated-artifacts/TestERC20Bridge.json';
 import * as TestEth2DaiBridge from '../generated-artifacts/TestEth2DaiBridge.json';
@@ -54,6 +56,7 @@ export const artifacts = {
     StaticCallProxy: StaticCallProxy as ContractArtifact,
     ChaiBridge: ChaiBridge as ContractArtifact,
     CurveBridge: CurveBridge as ContractArtifact,
+    DexForwarderBridge: DexForwarderBridge as ContractArtifact,
     DydxBridge: DydxBridge as ContractArtifact,
     Eth2DaiBridge: Eth2DaiBridge as ContractArtifact,
     KyberBridge: KyberBridge as ContractArtifact,
@@ -74,6 +77,7 @@ export const artifacts = {
     IUniswapExchange: IUniswapExchange as ContractArtifact,
     IUniswapExchangeFactory: IUniswapExchangeFactory as ContractArtifact,
     TestChaiBridge: TestChaiBridge as ContractArtifact,
+    TestDexForwarderBridge: TestDexForwarderBridge as ContractArtifact,
     TestDydxBridge: TestDydxBridge as ContractArtifact,
     TestERC20Bridge: TestERC20Bridge as ContractArtifact,
     TestEth2DaiBridge: TestEth2DaiBridge as ContractArtifact,

contracts/asset-proxy/src/dex_forwarder_bridge.ts

@@ -0,0 +1,27 @@
+import { AbiEncoder, BigNumber } from '@0x/utils';
+
+export interface DexForwaderBridgeCall {
+    target: string;
+    inputTokenAmount: BigNumber;
+    outputTokenAmount: BigNumber;
+    bridgeData: string;
+}
+
+export interface DexForwaderBridgeData {
+    inputToken: string;
+    calls: DexForwaderBridgeCall[];
+}
+
+export const dexForwarderBridgeDataEncoder = AbiEncoder.create([
+    { name: 'inputToken', type: 'address' },
+    {
+        name: 'calls',
+        type: 'tuple[]',
+        components: [
+            { name: 'target', type: 'address' },
+            { name: 'inputTokenAmount', type: 'uint256' },
+            { name: 'outputTokenAmount', type: 'uint256' },
+            { name: 'bridgeData', type: 'bytes' },
+        ],
+    },
+]);

contracts/asset-proxy/src/index.ts

@@ -88,3 +88,4 @@ export {
 } from './asset_data';
 
 export * from './dydx_bridge_encoder';
+export * from './dex_forwarder_bridge';

contracts/asset-proxy/src/wrappers.ts

@@ -5,6 +5,7 @@
  */
 export * from '../generated-wrappers/chai_bridge';
 export * from '../generated-wrappers/curve_bridge';
+export * from '../generated-wrappers/dex_forwarder_bridge';
 export * from '../generated-wrappers/dydx_bridge';
 export * from '../generated-wrappers/erc1155_proxy';
 export * from '../generated-wrappers/erc20_bridge_proxy';
@@ -33,6 +34,7 @@ export * from '../generated-wrappers/multi_asset_proxy';
 export * from '../generated-wrappers/ownable';
 export * from '../generated-wrappers/static_call_proxy';
 export * from '../generated-wrappers/test_chai_bridge';
+export * from '../generated-wrappers/test_dex_forwarder_bridge';
 export * from '../generated-wrappers/test_dydx_bridge';
 export * from '../generated-wrappers/test_erc20_bridge';
 export * from '../generated-wrappers/test_eth2_dai_bridge';

contracts/asset-proxy/test/artifacts.ts

@@ -7,6 +7,7 @@ import { ContractArtifact } from 'ethereum-types';
 
 import * as ChaiBridge from '../test/generated-artifacts/ChaiBridge.json';
 import * as CurveBridge from '../test/generated-artifacts/CurveBridge.json';
+import * as DexForwarderBridge from '../test/generated-artifacts/DexForwarderBridge.json';
 import * as DydxBridge from '../test/generated-artifacts/DydxBridge.json';
 import * as ERC1155Proxy from '../test/generated-artifacts/ERC1155Proxy.json';
 import * as ERC20BridgeProxy from '../test/generated-artifacts/ERC20BridgeProxy.json';
@@ -35,6 +36,7 @@ import * as MultiAssetProxy from '../test/generated-artifacts/MultiAssetProxy.js
 import * as Ownable from '../test/generated-artifacts/Ownable.json';
 import * as StaticCallProxy from '../test/generated-artifacts/StaticCallProxy.json';
 import * as TestChaiBridge from '../test/generated-artifacts/TestChaiBridge.json';
+import * as TestDexForwarderBridge from '../test/generated-artifacts/TestDexForwarderBridge.json';
 import * as TestDydxBridge from '../test/generated-artifacts/TestDydxBridge.json';
 import * as TestERC20Bridge from '../test/generated-artifacts/TestERC20Bridge.json';
 import * as TestEth2DaiBridge from '../test/generated-artifacts/TestEth2DaiBridge.json';
@@ -54,6 +56,7 @@ export const artifacts = {
     StaticCallProxy: StaticCallProxy as ContractArtifact,
     ChaiBridge: ChaiBridge as ContractArtifact,
     CurveBridge: CurveBridge as ContractArtifact,
+    DexForwarderBridge: DexForwarderBridge as ContractArtifact,
     DydxBridge: DydxBridge as ContractArtifact,
     Eth2DaiBridge: Eth2DaiBridge as ContractArtifact,
     KyberBridge: KyberBridge as ContractArtifact,
@@ -74,6 +77,7 @@ export const artifacts = {
     IUniswapExchange: IUniswapExchange as ContractArtifact,
     IUniswapExchangeFactory: IUniswapExchangeFactory as ContractArtifact,
     TestChaiBridge: TestChaiBridge as ContractArtifact,
+    TestDexForwarderBridge: TestDexForwarderBridge as ContractArtifact,
     TestDydxBridge: TestDydxBridge as ContractArtifact,
     TestERC20Bridge: TestERC20Bridge as ContractArtifact,
     TestEth2DaiBridge: TestEth2DaiBridge as ContractArtifact,

contracts/asset-proxy/test/dex_forwarder_bridge.ts

@@ -0,0 +1,385 @@
+import { ContractTxFunctionObj } from '@0x/contract-wrappers';
+import {
+    blockchainTests,
+    constants,
+    expect,
+    filterLogsToArguments,
+    getRandomInteger,
+    randomAddress,
+    shortZip,
+    verifyEventsFromLogs,
+} from '@0x/contracts-test-utils';
+import { BigNumber, hexUtils } from '@0x/utils';
+import { DecodedLogs } from 'ethereum-types';
+import * as _ from 'lodash';
+
+import { DexForwaderBridgeCall, dexForwarderBridgeDataEncoder } from '../src/dex_forwarder_bridge';
+
+import { artifacts } from './artifacts';
+import {
+    DexForwarderBridgeEvents,
+    TestDexForwarderBridgeBridgeTransferFromCalledEventArgs as BtfCalledEventArgs,
+    TestDexForwarderBridgeContract,
+    TestDexForwarderBridgeEvents as TestEvents,
+} from './wrappers';
+
+const { ZERO_AMOUNT } = constants;
+
+blockchainTests.resets('DexForwaderBridge unit tests', env => {
+    let testContract: TestDexForwarderBridgeContract;
+    let inputToken: string;
+    let outputToken: string;
+    const BRIDGE_SUCCESS = '0xdc1600f3';
+    const BRIDGE_FAILURE = '0xffffffff';
+    const BRIDGE_REVERT_ERROR = 'oopsie';
+    const INCOMPLETE_FILL_REVERT = 'DexForwaderBridge/INCOMPLETE_FILL';
+    const DEFAULTS = {
+        toAddress: randomAddress(),
+    };
+
+    before(async () => {
+        testContract = await TestDexForwarderBridgeContract.deployFrom0xArtifactAsync(
+            artifacts.TestDexForwarderBridge,
+            env.provider,
+            env.txDefaults,
+            artifacts,
+        );
+        // Create test tokens.
+        [inputToken, outputToken] = [
+            await callAndTransactAsync(testContract.createToken()),
+            await callAndTransactAsync(testContract.createToken()),
+        ];
+    });
+
+    async function callAndTransactAsync<TResult>(fnCall: ContractTxFunctionObj<TResult>): Promise<TResult> {
+        const result = await fnCall.callAsync();
+        await fnCall.awaitTransactionSuccessAsync({}, { shouldValidate: false });
+        return result;
+    }
+
+    function getRandomBridgeCall(
+        bridgeAddress: string,
+        fields: Partial<DexForwaderBridgeCall> = {},
+    ): DexForwaderBridgeCall {
+        return {
+            target: bridgeAddress,
+            inputTokenAmount: getRandomInteger(1, '100e18'),
+            outputTokenAmount: getRandomInteger(1, '100e18'),
+            bridgeData: hexUtils.leftPad(inputToken),
+            ...fields,
+        };
+    }
+
+    describe('bridgeTransferFrom()', () => {
+        let goodBridgeCalls: DexForwaderBridgeCall[];
+        let revertingBridgeCall: DexForwaderBridgeCall;
+        let failingBridgeCall: DexForwaderBridgeCall;
+        let allBridgeCalls: DexForwaderBridgeCall[];
+        let totalFillableOutputAmount: BigNumber;
+        let totalFillableInputAmount: BigNumber;
+        let recipientOutputBalance: BigNumber;
+
+        beforeEach(async () => {
+            goodBridgeCalls = [];
+            for (let i = 0; i < 4; ++i) {
+                goodBridgeCalls.push(await createBridgeCallAsync({ returnCode: BRIDGE_SUCCESS }));
+            }
+            revertingBridgeCall = await createBridgeCallAsync({ revertError: BRIDGE_REVERT_ERROR });
+            failingBridgeCall = await createBridgeCallAsync({ returnCode: BRIDGE_FAILURE });
+            allBridgeCalls = _.shuffle([failingBridgeCall, revertingBridgeCall, ...goodBridgeCalls]);
+
+            totalFillableInputAmount = BigNumber.sum(...goodBridgeCalls.map(c => c.inputTokenAmount));
+            totalFillableOutputAmount = BigNumber.sum(...goodBridgeCalls.map(c => c.outputTokenAmount));
+
+            // Grant the taker some output tokens.
+            await testContract.setTokenBalance(
+                outputToken,
+                DEFAULTS.toAddress,
+                (recipientOutputBalance = getRandomInteger(1, '100e18')),
+            );
+        });
+
+        async function setForwarderInputBalanceAsync(amount: BigNumber): Promise<void> {
+            await testContract
+                .setTokenBalance(inputToken, testContract.address, amount)
+                .awaitTransactionSuccessAsync({}, { shouldValidate: false });
+        }
+
+        async function createBridgeCallAsync(
+            opts: Partial<{
+                returnCode: string;
+                revertError: string;
+                callFields: Partial<DexForwaderBridgeCall>;
+                outputFillAmount: BigNumber;
+            }>,
+        ): Promise<DexForwaderBridgeCall> {
+            const { returnCode, revertError, callFields, outputFillAmount } = {
+                returnCode: BRIDGE_SUCCESS,
+                revertError: '',
+                ...opts,
+            };
+            const bridge = await callAndTransactAsync(testContract.createBridge(returnCode, revertError));
+            const call = getRandomBridgeCall(bridge, callFields);
+            await testContract
+                .setBridgeTransferAmount(call.target, outputFillAmount || call.outputTokenAmount)
+                .awaitTransactionSuccessAsync({}, { shouldValidate: false });
+            return call;
+        }
+
+        async function callBridgeTransferFromAsync(opts: {
+            bridgeData: string;
+            sellAmount?: BigNumber;
+            buyAmount?: BigNumber;
+        }): Promise<DecodedLogs> {
+            // Fund the forwarder with input tokens to sell.
+            await setForwarderInputBalanceAsync(opts.sellAmount || totalFillableInputAmount);
+            const call = testContract.bridgeTransferFrom(
+                outputToken,
+                testContract.address,
+                DEFAULTS.toAddress,
+                opts.buyAmount || totalFillableOutputAmount,
+                opts.bridgeData,
+            );
+            const returnCode = await call.callAsync();
+            if (returnCode !== BRIDGE_SUCCESS) {
+                throw new Error('Expected BRIDGE_SUCCESS');
+            }
+            const receipt = await call.awaitTransactionSuccessAsync({}, { shouldValidate: false });
+            // tslint:disable-next-line: no-unnecessary-type-assertion
+            return receipt.logs as DecodedLogs;
+        }
+
+        it('succeeds with no bridge calls and no input balance', async () => {
+            const bridgeData = dexForwarderBridgeDataEncoder.encode({
+                inputToken,
+                calls: [],
+            });
+            await callBridgeTransferFromAsync({ bridgeData, sellAmount: ZERO_AMOUNT });
+        });
+
+        it('succeeds with bridge calls and no input balance', async () => {
+            const bridgeData = dexForwarderBridgeDataEncoder.encode({
+                inputToken,
+                calls: allBridgeCalls,
+            });
+            await callBridgeTransferFromAsync({ bridgeData, sellAmount: ZERO_AMOUNT });
+        });
+
+        it('fails with no bridge calls and an input balance', async () => {
+            const bridgeData = dexForwarderBridgeDataEncoder.encode({
+                inputToken,
+                calls: [],
+            });
+            return expect(callBridgeTransferFromAsync({ bridgeData, sellAmount: new BigNumber(1) })).to.revertWith(
+                INCOMPLETE_FILL_REVERT,
+            );
+        });
+
+        it('fails if entire input token balance is not consumed', async () => {
+            const bridgeData = dexForwarderBridgeDataEncoder.encode({
+                inputToken,
+                calls: allBridgeCalls,
+            });
+            return expect(
+                callBridgeTransferFromAsync({
+                    bridgeData,
+                    sellAmount: totalFillableInputAmount.plus(1),
+                }),
+            ).to.revertWith(INCOMPLETE_FILL_REVERT);
+        });
+
+        it('succeeds with one bridge call', async () => {
+            const calls = goodBridgeCalls.slice(0, 1);
+            const bridgeData = dexForwarderBridgeDataEncoder.encode({
+                inputToken,
+                calls,
+            });
+            await callBridgeTransferFromAsync({ bridgeData, sellAmount: calls[0].inputTokenAmount });
+        });
+
+        it('succeeds with many bridge calls', async () => {
+            const calls = goodBridgeCalls;
+            const bridgeData = dexForwarderBridgeDataEncoder.encode({
+                inputToken,
+                calls,
+            });
+            await callBridgeTransferFromAsync({ bridgeData });
+        });
+
+        it('swallows a failing bridge call', async () => {
+            const calls = _.shuffle([...goodBridgeCalls, failingBridgeCall]);
+            const bridgeData = dexForwarderBridgeDataEncoder.encode({
+                inputToken,
+                calls,
+            });
+            await callBridgeTransferFromAsync({ bridgeData });
+        });
+
+        it('consumes input tokens for output tokens', async () => {
+            const calls = allBridgeCalls;
+            const bridgeData = dexForwarderBridgeDataEncoder.encode({
+                inputToken,
+                calls,
+            });
+            await callBridgeTransferFromAsync({ bridgeData });
+            const currentBridgeInputBalance = await testContract
+                .balanceOf(inputToken, testContract.address)
+                .callAsync();
+            expect(currentBridgeInputBalance).to.bignumber.eq(0);
+            const currentRecipientOutputBalance = await testContract
+                .balanceOf(outputToken, DEFAULTS.toAddress)
+                .callAsync();
+            expect(currentRecipientOutputBalance).to.bignumber.eq(totalFillableOutputAmount);
+        });
+
+        it('emits failure events for failing bridge calls', async () => {
+            const calls = [revertingBridgeCall, failingBridgeCall, ...goodBridgeCalls];
+            const bridgeData = dexForwarderBridgeDataEncoder.encode({
+                inputToken,
+                calls,
+            });
+            const logs = await callBridgeTransferFromAsync({ bridgeData });
+            verifyEventsFromLogs(
+                logs,
+                [revertingBridgeCall, failingBridgeCall].map(c => ({
+                    inputToken,
+                    outputToken,
+                    target: c.target,
+                    inputTokenAmount: c.inputTokenAmount,
+                    outputTokenAmount: c.outputTokenAmount,
+                })),
+                DexForwarderBridgeEvents.DexForwarderBridgeCallFailed,
+            );
+        });
+
+        it("transfers only up to each call's input amount to each bridge", async () => {
+            const calls = goodBridgeCalls;
+            const bridgeData = dexForwarderBridgeDataEncoder.encode({
+                inputToken,
+                calls,
+            });
+            const logs = await callBridgeTransferFromAsync({ bridgeData });
+            const btfs = filterLogsToArguments<BtfCalledEventArgs>(logs, TestEvents.BridgeTransferFromCalled);
+            for (const [call, btf] of shortZip(goodBridgeCalls, btfs)) {
+                expect(btf.inputTokenBalance).to.bignumber.eq(call.inputTokenAmount);
+            }
+        });
+
+        it('transfers only up to outstanding sell amount to each bridge', async () => {
+            // Prepend an extra bridge call.
+            const calls = [
+                await createBridgeCallAsync({
+                    callFields: {
+                        inputTokenAmount: new BigNumber(1),
+                        outputTokenAmount: new BigNumber(1),
+                    },
+                }),
+                ...goodBridgeCalls,
+            ];
+            const bridgeData = dexForwarderBridgeDataEncoder.encode({
+                inputToken,
+                calls,
+            });
+            const logs = await callBridgeTransferFromAsync({ bridgeData });
+            const btfs = filterLogsToArguments<BtfCalledEventArgs>(logs, TestEvents.BridgeTransferFromCalled);
+            expect(btfs).to.be.length(goodBridgeCalls.length + 1);
+            // The last call will receive 1 less token.
+            const lastCall = calls.slice(-1)[0];
+            const lastBtf = btfs.slice(-1)[0];
+            expect(lastBtf.inputTokenBalance).to.bignumber.eq(lastCall.inputTokenAmount.minus(1));
+        });
+
+        it('recoups funds from a bridge that fails', async () => {
+            // Prepend a call that will take the whole input amount but will
+            // fail.
+            const badCall = await createBridgeCallAsync({
+                callFields: { inputTokenAmount: totalFillableInputAmount },
+                returnCode: BRIDGE_FAILURE,
+            });
+            const calls = [badCall, ...goodBridgeCalls];
+            const bridgeData = dexForwarderBridgeDataEncoder.encode({
+                inputToken,
+                calls,
+            });
+            const logs = await callBridgeTransferFromAsync({ bridgeData });
+            verifyEventsFromLogs(
+                logs,
+                [
+                    {
+                        inputToken,
+                        outputToken,
+                        target: badCall.target,
+                        inputTokenAmount: badCall.inputTokenAmount,
+                        outputTokenAmount: badCall.outputTokenAmount,
+                    },
+                ],
+                TestEvents.DexForwarderBridgeCallFailed,
+            );
+            const btfs = filterLogsToArguments<BtfCalledEventArgs>(logs, TestEvents.BridgeTransferFromCalled);
+            expect(btfs).to.be.length(goodBridgeCalls.length);
+        });
+
+        it('recoups funds from a bridge that reverts', async () => {
+            // Prepend a call that will take the whole input amount but will
+            // revert.
+            const badCall = await createBridgeCallAsync({
+                callFields: { inputTokenAmount: totalFillableInputAmount },
+                revertError: BRIDGE_REVERT_ERROR,
+            });
+            const calls = [badCall, ...goodBridgeCalls];
+            const bridgeData = dexForwarderBridgeDataEncoder.encode({
+                inputToken,
+                calls,
+            });
+            const logs = await callBridgeTransferFromAsync({ bridgeData });
+            verifyEventsFromLogs(
+                logs,
+                [
+                    {
+                        inputToken,
+                        outputToken,
+                        target: badCall.target,
+                        inputTokenAmount: badCall.inputTokenAmount,
+                        outputTokenAmount: badCall.outputTokenAmount,
+                    },
+                ],
+                TestEvents.DexForwarderBridgeCallFailed,
+            );
+            const btfs = filterLogsToArguments<BtfCalledEventArgs>(logs, TestEvents.BridgeTransferFromCalled);
+            expect(btfs).to.be.length(goodBridgeCalls.length);
+        });
+
+        it('recoups funds from a bridge that under-pays', async () => {
+            // Prepend a call that will take the whole input amount but will
+            // underpay the output amount..
+            const badCall = await createBridgeCallAsync({
+                callFields: {
+                    inputTokenAmount: totalFillableInputAmount,
+                    outputTokenAmount: new BigNumber(2),
+                },
+                outputFillAmount: new BigNumber(1),
+            });
+            const calls = [badCall, ...goodBridgeCalls];
+            const bridgeData = dexForwarderBridgeDataEncoder.encode({
+                inputToken,
+                calls,
+            });
+            const logs = await callBridgeTransferFromAsync({ bridgeData });
+            verifyEventsFromLogs(
+                logs,
+                [
+                    {
+                        inputToken,
+                        outputToken,
+                        target: badCall.target,
+                        inputTokenAmount: badCall.inputTokenAmount,
+                        outputTokenAmount: badCall.outputTokenAmount,
+                    },
+                ],
+                TestEvents.DexForwarderBridgeCallFailed,
+            );
+            const btfs = filterLogsToArguments<BtfCalledEventArgs>(logs, TestEvents.BridgeTransferFromCalled);
+            expect(btfs).to.be.length(goodBridgeCalls.length);
+        });
+    });
+});

contracts/asset-proxy/test/wrappers.ts

@@ -5,6 +5,7 @@
  */
 export * from '../test/generated-wrappers/chai_bridge';
 export * from '../test/generated-wrappers/curve_bridge';
+export * from '../test/generated-wrappers/dex_forwarder_bridge';
 export * from '../test/generated-wrappers/dydx_bridge';
 export * from '../test/generated-wrappers/erc1155_proxy';
 export * from '../test/generated-wrappers/erc20_bridge_proxy';
@@ -33,6 +34,7 @@ export * from '../test/generated-wrappers/multi_asset_proxy';
 export * from '../test/generated-wrappers/ownable';
 export * from '../test/generated-wrappers/static_call_proxy';
 export * from '../test/generated-wrappers/test_chai_bridge';
+export * from '../test/generated-wrappers/test_dex_forwarder_bridge';
 export * from '../test/generated-wrappers/test_dydx_bridge';
 export * from '../test/generated-wrappers/test_erc20_bridge';
 export * from '../test/generated-wrappers/test_eth2_dai_bridge';

contracts/asset-proxy/tsconfig.json

@@ -5,6 +5,7 @@
     "files": [
         "generated-artifacts/ChaiBridge.json",
         "generated-artifacts/CurveBridge.json",
+        "generated-artifacts/DexForwarderBridge.json",
         "generated-artifacts/DydxBridge.json",
         "generated-artifacts/ERC1155Proxy.json",
         "generated-artifacts/ERC20BridgeProxy.json",
@@ -33,6 +34,7 @@
         "generated-artifacts/Ownable.json",
         "generated-artifacts/StaticCallProxy.json",
         "generated-artifacts/TestChaiBridge.json",
+        "generated-artifacts/TestDexForwarderBridge.json",
         "generated-artifacts/TestDydxBridge.json",
         "generated-artifacts/TestERC20Bridge.json",
         "generated-artifacts/TestEth2DaiBridge.json",
@@ -42,6 +44,7 @@
         "generated-artifacts/UniswapBridge.json",
         "test/generated-artifacts/ChaiBridge.json",
         "test/generated-artifacts/CurveBridge.json",
+        "test/generated-artifacts/DexForwarderBridge.json",
         "test/generated-artifacts/DydxBridge.json",
         "test/generated-artifacts/ERC1155Proxy.json",
         "test/generated-artifacts/ERC20BridgeProxy.json",
@@ -70,6 +73,7 @@
         "test/generated-artifacts/Ownable.json",
         "test/generated-artifacts/StaticCallProxy.json",
         "test/generated-artifacts/TestChaiBridge.json",
+        "test/generated-artifacts/TestDexForwarderBridge.json",
         "test/generated-artifacts/TestDydxBridge.json",
         "test/generated-artifacts/TestERC20Bridge.json",
         "test/generated-artifacts/TestEth2DaiBridge.json",