@0x/asset-swapper: Return Mooniswap pool in sampler and encode it in bridge data

packages/asset-swapper/CHANGELOG.json

@@ -97,6 +97,10 @@
             {
                 "note": "Set `rfqtTakerAddress` to null in EP consumer",
                 "pr": 2692
+            },
+            {
+                "note": "Return Mooniswap pool in sampler and encode it in bridge data",
+                "pr": 2692
             }
         ]
     },

packages/asset-swapper/contracts/src/MooniswapSampler.sol

@@ -46,44 +46,31 @@ contract MooniswapSampler is
     )
         public
         view
-        returns (uint256[] memory makerTokenAmounts)
+        returns (IMooniswap pool, uint256[] memory makerTokenAmounts)
     {
         _assertValidPair(makerToken, takerToken);
         uint256 numSamples = takerTokenAmounts.length;
         makerTokenAmounts = new uint256[](numSamples);
 
-        address _takerToken = takerToken == _getWethAddress() ? address(0) : takerToken;
+        address mooniswapTakerToken = takerToken == _getWethAddress() ? address(0) : takerToken;
-        address _makerToken = makerToken == _getWethAddress() ? address(0) : makerToken;
+        address mooniswapMakerToken = makerToken == _getWethAddress() ? address(0) : makerToken;
         // Find the pool for the pair, ETH is represented
         // as address(0)
-        IMooniswap pool = IMooniswap(
+        pool = IMooniswap(
-            IMooniswapRegistry(_getMooniswapAddress()).pools(_takerToken, _makerToken)
+            IMooniswapRegistry(_getMooniswapAddress()).pools(mooniswapTakerToken, mooniswapMakerToken)
         );
         // If there is no pool then return early
         if (address(pool) == address(0)) {
-            return makerTokenAmounts;
+            return (pool, makerTokenAmounts);
         }
 
-        uint256 poolBalance = _takerToken == address(0) ? address(pool).balance : IERC20Token(_takerToken).balanceOf(address(pool));
-
         for (uint256 i = 0; i < numSamples; i++) {
-            // If the pool balance is smaller than the sell amount
+            uint256 buyAmount = sampleSingleSellFromMooniswapPool(
-            // don't sample to avoid multiplication overflow in buys
+                pool,
-            if (poolBalance < takerTokenAmounts[i]) {
+                mooniswapTakerToken,
-                break;
+                mooniswapMakerToken,
-            }
+                takerTokenAmounts[i]
-            (bool didSucceed, bytes memory resultData) =
+            );
-                address(pool).staticcall.gas(MOONISWAP_CALL_GAS)(
-                    abi.encodeWithSelector(
-                        IMooniswap(0).getReturn.selector,
-                        _takerToken,
-                        _makerToken,
-                        takerTokenAmounts[i]
-                    ));
-            uint256 buyAmount = 0;
-            if (didSucceed) {
-                buyAmount = abi.decode(resultData, (uint256));
-            }
             // Exit early if the amount is too high for the source to serve
             if (buyAmount == 0) {
                 break;
@@ -92,6 +79,38 @@ contract MooniswapSampler is
         }
     }
 
+    function sampleSingleSellFromMooniswapPool(
+        IMooniswap pool,
+        address mooniswapTakerToken,
+        address mooniswapMakerToken,
+        uint256 takerTokenAmount
+    )
+        public
+        view
+        returns (uint256 makerTokenAmount)
+    {
+        uint256 poolBalance = mooniswapTakerToken == address(0)
+            ? address(pool).balance
+            : IERC20Token(mooniswapTakerToken).balanceOf(address(pool));
+
+        // If the pool balance is smaller than the sell amount
+        // don't sample to avoid multiplication overflow in buys
+        if (poolBalance < takerTokenAmount) {
+            return makerTokenAmount;
+        }
+        (bool didSucceed, bytes memory resultData) =
+            address(pool).staticcall.gas(MOONISWAP_CALL_GAS)(
+                abi.encodeWithSelector(
+                    IMooniswap(0).getReturn.selector,
+                    mooniswapTakerToken,
+                    mooniswapMakerToken,
+                    takerTokenAmount
+                ));
+        if (didSucceed) {
+            makerTokenAmount = abi.decode(resultData, (uint256));
+        }
+    }
+
     /// @dev Sample buy quotes from Mooniswap.
     /// @param takerToken Address of the taker token (what to sell).
     /// @param makerToken Address of the maker token (what to buy).
@@ -105,12 +124,28 @@ contract MooniswapSampler is
     )
         public
         view
-        returns (uint256[] memory takerTokenAmounts)
+        returns (IMooniswap pool, uint256[] memory takerTokenAmounts)
     {
-        return _sampleApproximateBuys(
+        _assertValidPair(makerToken, takerToken);
+        uint256 numSamples = takerTokenAmounts.length;
+        makerTokenAmounts = new uint256[](numSamples);
+
+        address mooniswapTakerToken = takerToken == _getWethAddress() ? address(0) : takerToken;
+        address mooniswapMakerToken = makerToken == _getWethAddress() ? address(0) : makerToken;
+        // Find the pool for the pair, ETH is represented
+        // as address(0)
+        pool = IMooniswap(
+            IMooniswapRegistry(_getMooniswapAddress()).pools(mooniswapTakerToken, mooniswapMakerToken)
+        );
+        // If there is no pool then return early
+        if (address(pool) == address(0)) {
+            return (pool, takerTokenAmounts);
+        }
+
+        takerTokenAmounts = _sampleApproximateBuys(
             ApproximateBuyQuoteOpts({
-                makerTokenData: abi.encode(makerToken),
+                makerTokenData: abi.encode(mooniswapMakerToken, pool),
-                takerTokenData: abi.encode(takerToken),
+                takerTokenData: abi.encode(mooniswapTakerToken, pool),
                 getSellQuoteCallback: _sampleSellForApproximateBuyFromMooniswap
             }),
             makerTokenAmounts
@@ -126,15 +161,16 @@ contract MooniswapSampler is
         view
         returns (uint256 buyAmount)
     {
-        (address takerToken) =
+        (address mooniswapTakerToken, IMooniswap pool) =
-            abi.decode(takerTokenData, (address));
+            abi.decode(takerTokenData, (address, IMooniswap));
-        (address makerToken) =
+        (address mooniswapMakerToken) =
             abi.decode(makerTokenData, (address));
         (bool success, bytes memory resultData) =
             address(this).staticcall(abi.encodeWithSelector(
-                this.sampleSellsFromMooniswap.selector,
+                this.sampleSingleSellFromMooniswapPool.selector,
-                takerToken,
+                pool,
-                makerToken,
+                mooniswapTakerToken,
+                mooniswapMakerToken,
                 _toSingleValueArray(sellAmount)
             ));
         if (!success) {

packages/asset-swapper/src/utils/market_operation_utils/orders.ts

@@ -29,6 +29,7 @@ import {
     Fill,
     KyberFillData,
     LiquidityProviderFillData,
+    MooniswapFillData,
     MultiBridgeFillData,
     MultiHopFillData,
     NativeCollapsedFill,
@@ -304,6 +305,14 @@ function createBridgeOrder(
                 createKyberBridgeData(takerToken, kyberFillData.hint),
             );
             break;
+        case ERC20BridgeSource.Mooniswap:
+            const mooniswapFillData = (fill as CollapsedFill<MooniswapFillData>).fillData!; // tslint:disable-line:no-non-null-assertion
+            makerAssetData = assetDataUtils.encodeERC20BridgeAssetData(
+                makerToken,
+                bridgeAddress,
+                createMooniswapBridgeData(takerToken, mooniswapFillData.poolAddress),
+            );
+            break;
         default:
             makerAssetData = assetDataUtils.encodeERC20BridgeAssetData(
                 makerToken,
@@ -407,6 +416,11 @@ function createKyberBridgeData(fromTokenAddress: string, hint: string): string {
     return encoder.encode({ fromTokenAddress, hint });
 }
 
+function createMooniswapBridgeData(takerToken: string, poolAddress: string): string {
+    const encoder = AbiEncoder.create([{ name: 'takerToken', type: 'address' }, { name: 'pool', type: 'address' }]);
+    return encoder.encode({ takerToken, poolAddress });
+}
+
 function createCurveBridgeData(
     curveAddress: string,
     exchangeFunctionSelector: string,

packages/asset-swapper/src/utils/market_operation_utils/sampler_operations.ts

@@ -23,6 +23,7 @@ import {
     HopInfo,
     KyberFillData,
     LiquidityProviderFillData,
+    MooniswapFillData,
     MultiBridgeFillData,
     MultiHopFillData,
     SourceQuoteOperation,
@@ -446,6 +447,14 @@ export class SamplerOperations {
             contract: this._samplerContract,
             function: this._samplerContract.sampleSellsFromMooniswap,
             params: [takerToken, makerToken, takerFillAmounts],
+            callback: (callResults: string, fillData: MooniswapFillData): BigNumber[] => {
+                const [poolAddress, samples] = this._samplerContract.getABIDecodedReturnData<[string, BigNumber[]]>(
+                    'sampleSellsFromMooniswap',
+                    callResults,
+                );
+                fillData.poolAddress = poolAddress;
+                return samples;
+            },
         });
     }
 
@@ -459,6 +468,14 @@ export class SamplerOperations {
             contract: this._samplerContract,
             function: this._samplerContract.sampleBuysFromMooniswap,
             params: [takerToken, makerToken, makerFillAmounts],
+            callback: (callResults: string, fillData: MooniswapFillData): BigNumber[] => {
+                const [poolAddress, samples] = this._samplerContract.getABIDecodedReturnData<[string, BigNumber[]]>(
+                    'sampleBuysFromMooniswap',
+                    callResults,
+                );
+                fillData.poolAddress = poolAddress;
+                return samples;
+            },
         });
     }
 

packages/asset-swapper/src/utils/market_operation_utils/types.ts

@@ -113,6 +113,10 @@ export interface KyberFillData extends FillData {
     reserveId: string;
 }
 
+export interface MooniswapFillData extends FillData {
+    poolAddress: string;
+}
+
 export interface Quote<TFillData = FillData> {
     amount: BigNumber;
     fillData?: TFillData;