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Diffstat (limited to 'contracts/exchange-forwarder/contracts/src/MixinExchangeWrapper.sol')
| -rw-r--r-- | contracts/exchange-forwarder/contracts/src/MixinExchangeWrapper.sol | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/contracts/exchange-forwarder/contracts/src/MixinExchangeWrapper.sol b/contracts/exchange-forwarder/contracts/src/MixinExchangeWrapper.sol new file mode 100644 index 000000000..c970c40cf --- /dev/null +++ b/contracts/exchange-forwarder/contracts/src/MixinExchangeWrapper.sol @@ -0,0 +1,260 @@ +/* + + 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 "./mixins/MExchangeWrapper.sol"; +import "@0x/contracts-exchange-libs/contracts/src/LibAbiEncoder.sol"; +import "@0x/contracts-exchange-libs/contracts/src/LibOrder.sol"; +import "@0x/contracts-exchange-libs/contracts/src/LibFillResults.sol"; +import "@0x/contracts-exchange-libs/contracts/src/LibMath.sol"; + + +contract MixinExchangeWrapper is + LibAbiEncoder, + LibFillResults, + LibMath, + LibConstants, + MExchangeWrapper +{ + /// @dev Fills the input order. + /// Returns false if the transaction would otherwise revert. + /// @param order Order struct containing order specifications. + /// @param takerAssetFillAmount Desired amount of takerAsset to sell. + /// @param signature Proof that order has been created by maker. + /// @return Amounts filled and fees paid by maker and taker. + function fillOrderNoThrow( + LibOrder.Order memory order, + uint256 takerAssetFillAmount, + bytes memory signature + ) + internal + returns (FillResults memory fillResults) + { + // ABI encode calldata for `fillOrder` + bytes memory fillOrderCalldata = abiEncodeFillOrder( + order, + takerAssetFillAmount, + signature + ); + + address exchange = address(EXCHANGE); + + // Call `fillOrder` and handle any exceptions gracefully + assembly { + let success := call( + gas, // forward all gas + exchange, // call address of Exchange contract + 0, // transfer 0 wei + add(fillOrderCalldata, 32), // pointer to start of input (skip array length in first 32 bytes) + mload(fillOrderCalldata), // length of input + fillOrderCalldata, // write output over input + 128 // output size is 128 bytes + ) + if success { + mstore(fillResults, mload(fillOrderCalldata)) + mstore(add(fillResults, 32), mload(add(fillOrderCalldata, 32))) + mstore(add(fillResults, 64), mload(add(fillOrderCalldata, 64))) + mstore(add(fillResults, 96), mload(add(fillOrderCalldata, 96))) + } + } + // fillResults values will be 0 by default if call was unsuccessful + return fillResults; + } + + /// @dev Synchronously executes multiple calls of fillOrder until total amount of WETH has been sold by taker. + /// Returns false if the transaction would otherwise revert. + /// @param orders Array of order specifications. + /// @param wethSellAmount Desired amount of WETH to sell. + /// @param signatures Proofs that orders have been signed by makers. + /// @return Amounts filled and fees paid by makers and taker. + function marketSellWeth( + LibOrder.Order[] memory orders, + uint256 wethSellAmount, + bytes[] memory signatures + ) + internal + returns (FillResults memory totalFillResults) + { + bytes memory makerAssetData = orders[0].makerAssetData; + bytes memory wethAssetData = WETH_ASSET_DATA; + + uint256 ordersLength = orders.length; + for (uint256 i = 0; i != ordersLength; i++) { + + // We assume that asset being bought by taker is the same for each order. + // We assume that asset being sold by taker is WETH for each order. + orders[i].makerAssetData = makerAssetData; + orders[i].takerAssetData = wethAssetData; + + // Calculate the remaining amount of WETH to sell + uint256 remainingTakerAssetFillAmount = safeSub(wethSellAmount, totalFillResults.takerAssetFilledAmount); + + // Attempt to sell the remaining amount of WETH + FillResults memory singleFillResults = fillOrderNoThrow( + orders[i], + remainingTakerAssetFillAmount, + signatures[i] + ); + + // Update amounts filled and fees paid by maker and taker + addFillResults(totalFillResults, singleFillResults); + + // Stop execution if the entire amount of takerAsset has been sold + if (totalFillResults.takerAssetFilledAmount >= wethSellAmount) { + break; + } + } + return totalFillResults; + } + + /// @dev Synchronously executes multiple fill orders in a single transaction until total amount is bought by taker. + /// Returns false if the transaction would otherwise revert. + /// The asset being sold by taker must always be WETH. + /// @param orders Array of order specifications. + /// @param makerAssetFillAmount Desired amount of makerAsset to buy. + /// @param signatures Proofs that orders have been signed by makers. + /// @return Amounts filled and fees paid by makers and taker. + function marketBuyExactAmountWithWeth( + LibOrder.Order[] memory orders, + uint256 makerAssetFillAmount, + bytes[] memory signatures + ) + internal + returns (FillResults memory totalFillResults) + { + bytes memory makerAssetData = orders[0].makerAssetData; + bytes memory wethAssetData = WETH_ASSET_DATA; + + uint256 ordersLength = orders.length; + for (uint256 i = 0; i != ordersLength; i++) { + + // We assume that asset being bought by taker is the same for each order. + // We assume that asset being sold by taker is WETH for each order. + orders[i].makerAssetData = makerAssetData; + orders[i].takerAssetData = wethAssetData; + + // Calculate the remaining amount of makerAsset to buy + uint256 remainingMakerAssetFillAmount = safeSub(makerAssetFillAmount, totalFillResults.makerAssetFilledAmount); + + // Convert the remaining amount of makerAsset to buy into remaining amount + // of takerAsset to sell, assuming entire amount can be sold in the current order. + // We round up because the exchange rate computed by fillOrder rounds in favor + // of the Maker. In this case we want to overestimate the amount of takerAsset. + uint256 remainingTakerAssetFillAmount = getPartialAmountCeil( + orders[i].takerAssetAmount, + orders[i].makerAssetAmount, + remainingMakerAssetFillAmount + ); + + // Attempt to sell the remaining amount of takerAsset + FillResults memory singleFillResults = fillOrderNoThrow( + orders[i], + remainingTakerAssetFillAmount, + signatures[i] + ); + + // Update amounts filled and fees paid by maker and taker + addFillResults(totalFillResults, singleFillResults); + + // Stop execution if the entire amount of makerAsset has been bought + uint256 makerAssetFilledAmount = totalFillResults.makerAssetFilledAmount; + if (makerAssetFilledAmount >= makerAssetFillAmount) { + break; + } + } + + require( + makerAssetFilledAmount >= makerAssetFillAmount, + "COMPLETE_FILL_FAILED" + ); + return totalFillResults; + } + + /// @dev Buys zrxBuyAmount of ZRX fee tokens, taking into account ZRX fees for each order. This will guarantee + /// that at least zrxBuyAmount of ZRX is purchased (sometimes slightly over due to rounding issues). + /// It is possible that a request to buy 200 ZRX will require purchasing 202 ZRX + /// as 2 ZRX is required to purchase the 200 ZRX fee tokens. This guarantees at least 200 ZRX for future purchases. + /// The asset being sold by taker must always be WETH. + /// @param orders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset. + /// @param zrxBuyAmount Desired amount of ZRX to buy. + /// @param signatures Proofs that orders have been created by makers. + /// @return totalFillResults Amounts filled and fees paid by maker and taker. + function marketBuyExactZrxWithWeth( + LibOrder.Order[] memory orders, + uint256 zrxBuyAmount, + bytes[] memory signatures + ) + internal + returns (FillResults memory totalFillResults) + { + // Do nothing if zrxBuyAmount == 0 + if (zrxBuyAmount == 0) { + return totalFillResults; + } + + bytes memory zrxAssetData = ZRX_ASSET_DATA; + bytes memory wethAssetData = WETH_ASSET_DATA; + uint256 zrxPurchased = 0; + + uint256 ordersLength = orders.length; + for (uint256 i = 0; i != ordersLength; i++) { + + // All of these are ZRX/WETH, so we can drop the respective assetData from calldata. + orders[i].makerAssetData = zrxAssetData; + orders[i].takerAssetData = wethAssetData; + + // Calculate the remaining amount of ZRX to buy. + uint256 remainingZrxBuyAmount = safeSub(zrxBuyAmount, zrxPurchased); + + // Convert the remaining amount of ZRX to buy into remaining amount + // of WETH to sell, assuming entire amount can be sold in the current order. + // We round up because the exchange rate computed by fillOrder rounds in favor + // of the Maker. In this case we want to overestimate the amount of takerAsset. + uint256 remainingWethSellAmount = getPartialAmountCeil( + orders[i].takerAssetAmount, + safeSub(orders[i].makerAssetAmount, orders[i].takerFee), // our exchange rate after fees + remainingZrxBuyAmount + ); + + // Attempt to sell the remaining amount of WETH. + FillResults memory singleFillResult = fillOrderNoThrow( + orders[i], + remainingWethSellAmount, + signatures[i] + ); + + // Update amounts filled and fees paid by maker and taker. + addFillResults(totalFillResults, singleFillResult); + zrxPurchased = safeSub(totalFillResults.makerAssetFilledAmount, totalFillResults.takerFeePaid); + + // Stop execution if the entire amount of ZRX has been bought. + if (zrxPurchased >= zrxBuyAmount) { + break; + } + } + + require( + zrxPurchased >= zrxBuyAmount, + "COMPLETE_FILL_FAILED" + ); + return totalFillResults; + } +} |