From 462f1f00d8151ad17f8909f2c07dbc807a0df87d Mon Sep 17 00:00:00 2001 From: Amir Bandeali Date: Fri, 6 Jul 2018 15:08:14 -0700 Subject: Combine mixins --- .../contracts/src/2.0.0/forwarder/Forwarder.sol | 10 +- .../contracts/src/2.0.0/forwarder/MixinERC20.sol | 67 ---- .../contracts/src/2.0.0/forwarder/MixinERC721.sol | 66 ---- .../contracts/src/2.0.0/forwarder/MixinFees.sol | 113 ++++++ .../src/2.0.0/forwarder/MixinForwarderCore.sol | 416 +++++++++++++++++++++ .../src/2.0.0/forwarder/MixinMarketBuyTokens.sol | 259 ------------- .../src/2.0.0/forwarder/MixinMarketSellTokens.sol | 197 ---------- .../src/2.0.0/forwarder/MixinTransfer.sol | 109 ++++++ .../src/2.0.0/forwarder/MixinWethFees.sol | 113 ------ 9 files changed, 642 insertions(+), 708 deletions(-) delete mode 100644 packages/contracts/src/2.0.0/forwarder/MixinERC20.sol delete mode 100644 packages/contracts/src/2.0.0/forwarder/MixinERC721.sol create mode 100644 packages/contracts/src/2.0.0/forwarder/MixinFees.sol create mode 100644 packages/contracts/src/2.0.0/forwarder/MixinForwarderCore.sol delete mode 100644 packages/contracts/src/2.0.0/forwarder/MixinMarketBuyTokens.sol delete mode 100644 packages/contracts/src/2.0.0/forwarder/MixinMarketSellTokens.sol create mode 100644 packages/contracts/src/2.0.0/forwarder/MixinTransfer.sol delete mode 100644 packages/contracts/src/2.0.0/forwarder/MixinWethFees.sol (limited to 'packages/contracts') diff --git a/packages/contracts/src/2.0.0/forwarder/Forwarder.sol b/packages/contracts/src/2.0.0/forwarder/Forwarder.sol index 38128d93e..0542736a3 100644 --- a/packages/contracts/src/2.0.0/forwarder/Forwarder.sol +++ b/packages/contracts/src/2.0.0/forwarder/Forwarder.sol @@ -19,9 +19,8 @@ pragma solidity 0.4.24; pragma experimental ABIEncoderV2; -import "./MixinWethFees.sol"; -import "./MixinMarketSellTokens.sol"; -import "./MixinMarketBuyTokens.sol"; +import "./MixinFees.sol"; +import "./MixinForwarderCore.sol"; import "./MixinConstants.sol"; import "../utils/Ownable/Ownable.sol"; @@ -29,10 +28,9 @@ import "../utils/Ownable/Ownable.sol"; contract Forwarder is Ownable, MixinConstants, - MixinWethFees, + MixinFees, MixinMarketBuyZrx, - MixinMarketBuyTokens, - MixinMarketSellTokens + MixinForwarderCore { uint256 constant internal MAX_UINT = 2**256 - 1; diff --git a/packages/contracts/src/2.0.0/forwarder/MixinERC20.sol b/packages/contracts/src/2.0.0/forwarder/MixinERC20.sol deleted file mode 100644 index 23c130d69..000000000 --- a/packages/contracts/src/2.0.0/forwarder/MixinERC20.sol +++ /dev/null @@ -1,67 +0,0 @@ -/* - - 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; - - -contract MixinERC20 { - - bytes4 constant internal ERC20_TRANSFER_SELECTOR = bytes4(keccak256("transfer(address,uint256)")); - - function transferToken( - address token, - address to, - uint256 amount - ) - internal - { - // Transfer tokens. - // We do a raw call so we can check the success separate - // from the return data. - bool success = token.call(abi.encodeWithSelector( - ERC20_TRANSFER_SELECTOR, - to, - amount - )); - require( - success, - "TRANSFER_FAILED" - ); - - // Check return data. - // If there is no return data, we assume the token incorrectly - // does not return a bool. In this case we expect it to revert - // on failure, which was handled above. - // If the token does return data, we require that it is a single - // value that evaluates to true. - assembly { - if returndatasize { - success := 0 - if eq(returndatasize, 32) { - // First 64 bytes of memory are reserved scratch space - returndatacopy(0, 0, 32) - success := mload(0) - } - } - } - require( - success, - "TRANSFER_FAILED" - ); - } -} diff --git a/packages/contracts/src/2.0.0/forwarder/MixinERC721.sol b/packages/contracts/src/2.0.0/forwarder/MixinERC721.sol deleted file mode 100644 index b5be223b6..000000000 --- a/packages/contracts/src/2.0.0/forwarder/MixinERC721.sol +++ /dev/null @@ -1,66 +0,0 @@ -/* - - 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 "../utils/LibBytes/LibBytes.sol"; -import "../tokens/ERC721Token/IERC721Token.sol"; - - -contract MixinERC721 { - - using LibBytes for bytes; - - bytes4 constant internal ERC721_RECEIVED = bytes4(keccak256("onERC721Received(address,uint256,bytes)")); - bytes4 constant internal ERC721_RECEIVED_OPERATOR = bytes4(keccak256("onERC721Received(address,address,uint256,bytes)")); - - function onERC721Received(address, uint256, bytes memory) - public - pure - returns(bytes4) - { - return ERC721_RECEIVED; - } - - function onERC721Received(address, address, uint256, bytes memory) - public - pure - returns(bytes4) - { - return ERC721_RECEIVED_OPERATOR; - } - - function transferERC721Token( - bytes memory assetData, - address to - ) - internal - { - // Decode asset data. - address token = assetData.readAddress(16); - uint256 tokenId = assetData.readUint256(36); - bytes memory receiverData = assetData.readBytesWithLength(100); - IERC721Token(token).safeTransferFrom( - address(this), - to, - tokenId, - receiverData - ); - } -} diff --git a/packages/contracts/src/2.0.0/forwarder/MixinFees.sol b/packages/contracts/src/2.0.0/forwarder/MixinFees.sol new file mode 100644 index 000000000..c32658630 --- /dev/null +++ b/packages/contracts/src/2.0.0/forwarder/MixinFees.sol @@ -0,0 +1,113 @@ +/* + + 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; + +import "../protocol/Exchange/libs/LibMath.sol"; +import "./MixinConstants.sol"; + + +contract MixinFees is + LibMath, + MixinConstants +{ + + uint16 constant public PERCENTAGE_DENOMINATOR = 10000; // 9800 == 98%, 10000 == 100% + uint16 constant public MAX_FEE = 1000; // 10% + uint16 constant public ALLOWABLE_EXCHANGE_PERCENTAGE = 9500; // 95% + + /// @dev Pays the feeRecipient feeProportion of the total takerEthAmount, denominated in ETH + /// @param takerEthAmount The total amount that was transacted in WETH, fees are calculated from this value. + /// @param feeProportion The proportion of fees + /// @param feeRecipient The recipient of the fees + /// @return ethFeeAmount Amount of ETH paid to feeRecipient as fee. + function payEthFee( + uint256 takerEthAmount, + uint16 feeProportion, + address feeRecipient + ) + internal + returns (uint256 ethFeeAmount) + { + if (feeProportion > 0 && feeRecipient != address(0)) { + require( + feeProportion <= MAX_FEE, + "FEE_PROPORTION_TOO_LARGE" + ); + // 1.5% is 150, allowing for 2 decimal precision, i.e 0.05% is 5 + ethFeeAmount = getPartialAmount( + feeProportion, + PERCENTAGE_DENOMINATOR, + takerEthAmount + ); + feeRecipient.transfer(ethFeeAmount); + } + return ethFeeAmount; + } + + /// @dev Withdraws the remaining WETH, deduct and pay fees from this amount based on the takerTokenAmount to the feeRecipient. + /// If a user overpaid ETH initially, the fees are calculated from the amount traded and deducted from withdrawAmount. + /// Any remaining ETH is sent back to the user. + /// @param ethWithdrawAmount The amount to withdraw from the WETH contract. + /// @param wethAmountSold The total amount that was transacted in WETH, fees are calculated from this value. + /// @param feeProportion The proportion of fees + /// @param feeRecipient The recipient of the fees + function withdrawPayAndDeductEthFee( + uint256 ethWithdrawAmount, + uint256 wethAmountSold, + uint16 feeProportion, + address feeRecipient + ) + internal + { + // Return all of the excess WETH if any after deducting fees on the amount + if (ethWithdrawAmount > 0) { + ETHER_TOKEN.withdraw(ethWithdrawAmount); + // Fees proportional to the amount traded + uint256 ethFeeAmount = payEthFee( + wethAmountSold, + feeProportion, + feeRecipient + ); + uint256 unspentEthAmount = safeSub(ethWithdrawAmount, ethFeeAmount); + if (unspentEthAmount > 0) { + msg.sender.transfer(unspentEthAmount); + } + } + } + + /// @dev Checks whether the amount of tokens sold against the amount of tokens requested + /// is within a certain threshold. This ensures the caller gets a fair deal when + /// performing any token fee abstraction. Threshold is 95%. If fee abstraction costs more than + /// 5% of the total transaction, we return false. + /// @param requestedSellAmount The amount the user requested, or sent in to a payable function + /// @param tokenAmountSold The amount of the token that was sold after fee abstraction + /// @return bool of whether this is within an acceptable threshold + function isAcceptableThreshold(uint256 requestedSellAmount, uint256 tokenAmountSold) + internal + pure + returns (bool) + { + uint256 acceptableSellAmount = getPartialAmount( + ALLOWABLE_EXCHANGE_PERCENTAGE, + PERCENTAGE_DENOMINATOR, + requestedSellAmount + ); + return tokenAmountSold >= acceptableSellAmount; + } +} diff --git a/packages/contracts/src/2.0.0/forwarder/MixinForwarderCore.sol b/packages/contracts/src/2.0.0/forwarder/MixinForwarderCore.sol new file mode 100644 index 000000000..fcc82b705 --- /dev/null +++ b/packages/contracts/src/2.0.0/forwarder/MixinForwarderCore.sol @@ -0,0 +1,416 @@ +/* + + 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 "../utils/LibBytes/LibBytes.sol"; +import "./MixinFees.sol"; +import "./MixinMarketBuyZrx.sol"; +import "./MixinExpectedResults.sol"; +import "./MixinTransfer.sol"; +import "./MixinConstants.sol"; +import "../protocol/Exchange/libs/LibOrder.sol"; + + +contract MixinForwarderCore is + MixinConstants, + MixinExpectedResults, + MixinFees, + MixinMarketBuyZrx, + MixinTransfer +{ + bytes4 public constant ERC20_DATA_ID = bytes4(keccak256("ERC20Token(address)")); + bytes4 public constant ERC721_DATA_ID = bytes4(keccak256("ERC721Token(address,uint256,bytes)")); + + /// @dev Market sells ETH for ERC20 tokens, performing fee abstraction if required. This does not support ERC721 tokens. This function is payable + /// and will convert all incoming ETH into WETH and perform the trade on behalf of the caller. + /// This function allows for a deduction of a proportion of incoming ETH sent to the feeRecipient. + /// The caller is sent all tokens from the operation. + /// If the purchased token amount does not meet an acceptable threshold then this function reverts. + /// @param orders An array of Order struct containing order specifications. + /// @param signatures An array of Proof that order has been created by maker. + /// @param feeOrders An array of Order struct containing order specifications for fees. + /// @param feeSignatures An array of Proof that order has been created by maker for the fee orders. + /// @param feeProportion A proportion deducted off the incoming ETH and sent to feeRecipient. The maximum value for this + /// is 1000, aka 10%. Supports up to 2 decimal places. I.e 0.59% is 59. + /// @param feeRecipient An address of the fee recipient whom receives feeProportion of ETH. + /// @return FillResults amounts filled and fees paid by maker and taker. + function marketSellEthForERC20( + LibOrder.Order[] memory orders, + bytes[] memory signatures, + LibOrder.Order[] memory feeOrders, + bytes[] memory feeSignatures, + uint16 feeProportion, + address feeRecipient + ) + public + payable + returns (FillResults memory totalFillResults) + { + uint256 takerEthAmount = msg.value; + require( + takerEthAmount > 0, + "VALUE_GREATER_THAN_ZERO" + ); + // Deduct the fee from the total amount of ETH sent in + uint256 ethFeeAmount = payEthFee( + takerEthAmount, + feeProportion, + feeRecipient + ); + uint256 wethSellAmount = safeSub(takerEthAmount, ethFeeAmount); + + // Deposit the remaining to be used for trading + ETHER_TOKEN.deposit.value(wethSellAmount)(); + // Populate the known assetData, as it is always WETH the caller can provide null bytes to save gas + // marketSellOrders fills the remaining + address makerTokenAddress = LibBytes.readAddress(orders[0].makerAssetData, 16); + orders[0].takerAssetData = WETH_ASSET_DATA; + if (makerTokenAddress == address(ZRX_TOKEN)) { + // If this is ZRX then we market sell from the orders, rather than a 2 step of buying ZRX fees from feeOrders + // then buying ZRX from orders + totalFillResults = marketSellEthForZRXInternal( + orders, + signatures, + wethSellAmount + ); + } else { + totalFillResults = marketSellEthForERC20Internal( + orders, + signatures, + feeOrders, + feeSignatures, + wethSellAmount + ); + } + // Prevent accidental WETH owned by this contract and it being spent + require( + takerEthAmount >= totalFillResults.takerAssetFilledAmount, + "INVALID_MSG_VALUE" + ); + // Ensure no WETH is left in this contract + require( + wethSellAmount == totalFillResults.takerAssetFilledAmount, + "UNACCEPTABLE_THRESHOLD" + ); + // Transfer all tokens to msg.sender + transferERC20Token( + makerTokenAddress, + msg.sender, + totalFillResults.makerAssetFilledAmount + ); + return totalFillResults; + } + + /// @dev Buys the exact amount of assets (ERC20 and ERC721), performing fee abstraction if required. + /// All order assets must be of the same type. Deducts a proportional fee to fee recipient. + /// This function is payable and will convert all incoming ETH into WETH and perform the trade on behalf of the caller. + /// The caller is sent all assets from the fill of orders. This function will revert unless the requested amount of assets are purchased. + /// Any excess ETH sent will be returned to the caller + /// @param orders An array of Order struct containing order specifications. + /// @param signatures An array of Proof that order has been created by maker. + /// @param feeOrders An array of Order struct containing order specifications for fees. + /// @param makerTokenFillAmount The amount of maker asset to buy. + /// @param feeSignatures An array of Proof that order has been created by maker for the fee orders. + /// @param feeProportion A proportion deducted off the ETH spent and sent to feeRecipient. The maximum value for this + /// is 1000, aka 10%. Supports up to 2 decimal places. I.e 0.59% is 59. + /// @param feeRecipient An address of the fee recipient whom receives feeProportion of ETH. + /// @return FillResults amounts filled and fees paid by maker and taker. + function marketBuyTokensWithEth( + LibOrder.Order[] memory orders, + bytes[] memory signatures, + LibOrder.Order[] memory feeOrders, + bytes[] memory feeSignatures, + uint256 makerTokenFillAmount, + uint16 feeProportion, + address feeRecipient + ) + public + payable + returns (FillResults memory totalFillResults) + { + uint256 takerEthAmount = msg.value; + require( + takerEthAmount > 0, + "VALUE_GREATER_THAN_ZERO" + ); + require( + makerTokenFillAmount > 0, + "VALUE_GREATER_THAN_ZERO" + ); + bytes4 assetDataId = LibBytes.readBytes4(orders[0].makerAssetData, 0); + require( + assetDataId == ERC20_DATA_ID || assetDataId == ERC721_DATA_ID, + "UNSUPPORTED_TOKEN_PROXY" + ); + + ETHER_TOKEN.deposit.value(takerEthAmount)(); + if (assetDataId == ERC20_DATA_ID) { + totalFillResults = marketBuyERC20TokensInternal( + orders, + signatures, + feeOrders, + feeSignatures, + makerTokenFillAmount + ); + } else if (assetDataId == ERC721_DATA_ID) { + totalFillResults = batchBuyERC721TokensInternal( + orders, + signatures, + feeOrders, + feeSignatures + ); + } + // Prevent accidental WETH owned by this contract and it being spent + require( + takerEthAmount >= totalFillResults.takerAssetFilledAmount, + "INVALID_MSG_VALUE" + ); + withdrawPayAndDeductEthFee( + safeSub(takerEthAmount, totalFillResults.takerAssetFilledAmount), + totalFillResults.takerAssetFilledAmount, + feeProportion, + feeRecipient + ); + return totalFillResults; + } + + /// @dev Market sells WETH for ERC20 tokens. + /// @param orders An array of Order struct containing order specifications. + /// @param signatures An array of Proof that order has been created by maker. + /// @param feeOrders An array of Order struct containing order specifications for fees. + /// @param feeSignatures An array of Proof that order has been created by maker for the fee orders. + /// @param wethSellAmount The amount of WETH to sell. + /// @return FillResults amounts filled and fees paid by maker and taker. + function marketSellEthForERC20Internal( + LibOrder.Order[] memory orders, + bytes[] memory signatures, + LibOrder.Order[] memory feeOrders, + bytes[] memory feeSignatures, + uint256 wethSellAmount + ) + internal + returns (FillResults memory totalFillResults) + { + uint256 remainingWethSellAmount = wethSellAmount; + FillResults memory calculatedMarketSellResults = calculateMarketSellResults(orders, wethSellAmount); + if (calculatedMarketSellResults.takerFeePaid > 0) { + // Fees are required for these orders. Buy enough ZRX to cover the future market buy + FillResults memory feeTokensResults = marketBuyZrxInternal( + feeOrders, + feeSignatures, + calculatedMarketSellResults.takerFeePaid + ); + // Ensure the token abstraction was fair if fees were proportionally too high, we fail + require( + isAcceptableThreshold( + wethSellAmount, + safeSub(wethSellAmount, feeTokensResults.takerAssetFilledAmount) + ), + "UNACCEPTABLE_THRESHOLD" + ); + remainingWethSellAmount = safeSub(remainingWethSellAmount, feeTokensResults.takerAssetFilledAmount); + totalFillResults.takerFeePaid = feeTokensResults.takerFeePaid; + totalFillResults.takerAssetFilledAmount = feeTokensResults.takerAssetFilledAmount; + } + // Make our market sell to buy the requested tokens with the remaining balance + FillResults memory requestedTokensResults = EXCHANGE.marketSellOrders( + orders, + remainingWethSellAmount, + signatures + ); + // Update our return FillResult with the market sell + addFillResults(totalFillResults, requestedTokensResults); + return totalFillResults; + } + + /// @dev Market sells WETH for ZRX tokens. + /// @param orders An array of Order struct containing order specifications. + /// @param signatures An array of Proof that order has been created by maker. + /// @param wethSellAmount The amount of WETH to sell. + /// @return FillResults amounts filled and fees paid by maker and taker. + function marketSellEthForZRXInternal( + LibOrder.Order[] memory orders, + bytes[] memory signatures, + uint256 wethSellAmount + ) + internal + returns (FillResults memory totalFillResults) + { + // Make our market sell to buy the requested tokens with the remaining balance + totalFillResults = EXCHANGE.marketSellOrders( + orders, + wethSellAmount, + signatures + ); + // Exchange does not special case ZRX in the makerAssetFilledAmount, if fees were deducted then using this amount + // for future transfers is invalid. + uint256 zrxAmountBought = safeSub(totalFillResults.makerAssetFilledAmount, totalFillResults.takerFeePaid); + require( + isAcceptableThreshold(totalFillResults.makerAssetFilledAmount, zrxAmountBought), + "UNACCEPTABLE_THRESHOLD" + ); + totalFillResults.makerAssetFilledAmount = zrxAmountBought; + return totalFillResults; + } + + /// @dev Buys an exact amount of an ERC20 token using WETH. + /// @param orders Orders to fill. The maker asset is the ERC20 token to buy. The taker asset is WETH. + /// @param signatures Proof that the orders were created by their respective makers. + /// @param feeOrders to fill. The maker asset is ZRX and the taker asset is WETH. + /// @param feeSignatures Proof that the feeOrders were created by their respective makers. + /// @param makerTokenFillAmount Amount of the ERC20 token to buy. + /// @return totalFillResults Aggregated fill results of buying the ERC20 and ZRX tokens. + function marketBuyERC20TokensInternal( + LibOrder.Order[] memory orders, + bytes[] memory signatures, + LibOrder.Order[] memory feeOrders, + bytes[] memory feeSignatures, + uint256 makerTokenFillAmount + ) + private + returns (FillResults memory totalFillResults) + { + // We read the maker token address to check if it is ZRX and later use it for transfer + address makerTokenAddress = LibBytes.readAddress(orders[0].makerAssetData, 16); + // We assume that asset being bought by taker is the same for each order. + // Rather than passing this in as calldata, we copy the makerAssetData from the first order onto all later orders. + orders[0].takerAssetData = WETH_ASSET_DATA; + // We can short cut here for effeciency and use buyFeeTokensInternal if maker asset token is ZRX + // this buys us exactly that amount taking into account the fees. This saves gas and calculates the rate correctly + FillResults memory marketBuyResults; + if (makerTokenAddress == address(ZRX_TOKEN)) { + marketBuyResults = marketBuyZrxInternal( + orders, + signatures, + makerTokenFillAmount + ); + // When buying ZRX we round up which can result in a small margin excess + require( + marketBuyResults.makerAssetFilledAmount >= makerTokenFillAmount, + "UNACCEPTABLE_THRESHOLD" + ); + addFillResults(totalFillResults, marketBuyResults); + require( + isAcceptableThreshold( + safeAdd(totalFillResults.makerAssetFilledAmount, totalFillResults.takerFeePaid), // Total ZRX + totalFillResults.makerAssetFilledAmount // amount going to msg.sender + ), + "UNACCEPTABLE_THRESHOLD" + ); + } else { + FillResults memory calculatedMarketBuyResults = calculateMarketBuyResults(orders, makerTokenFillAmount); + if (calculatedMarketBuyResults.takerFeePaid > 0) { + // Fees are required for these orders. Buy enough ZRX to cover the future market buy + FillResults memory zrxMarketBuyResults = marketBuyZrxInternal( + feeOrders, + feeSignatures, + calculatedMarketBuyResults.takerFeePaid + ); + totalFillResults.takerAssetFilledAmount = zrxMarketBuyResults.takerAssetFilledAmount; + totalFillResults.takerFeePaid = zrxMarketBuyResults.takerFeePaid; + } + // Make our market buy of the requested tokens with the remaining balance + marketBuyResults = EXCHANGE.marketBuyOrders( + orders, + makerTokenFillAmount, + signatures + ); + require( + marketBuyResults.makerAssetFilledAmount == makerTokenFillAmount, + "UNACCEPTABLE_THRESHOLD" + ); + addFillResults(totalFillResults, marketBuyResults); + require( + isAcceptableThreshold( + totalFillResults.takerAssetFilledAmount, + marketBuyResults.takerAssetFilledAmount + ), + "UNACCEPTABLE_THRESHOLD" + ); + } + // Transfer all purchased tokens to msg.sender + transferERC20Token( + makerTokenAddress, + msg.sender, + marketBuyResults.makerAssetFilledAmount + ); + return totalFillResults; + } + + /// @dev Buys an all of the ERC721 tokens in the orders. + /// @param orders Orders to fill. The maker asset is the ERC721 token to buy. The taker asset is WETH. + /// @param signatures Proof that the orders were created by their respective makers. + /// @param feeOrders to fill. The maker asset is ZRX and the taker asset is WETH. + /// @param feeSignatures Proof that the feeOrders were created by their respective makers. + /// @return totalFillResults Aggregated fill results of buying the ERC721 tokens and ZRX tokens. + function batchBuyERC721TokensInternal( + LibOrder.Order[] memory orders, + bytes[] memory signatures, + LibOrder.Order[] memory feeOrders, + bytes[] memory feeSignatures + ) + private + returns (FillResults memory totalFillResults) + { + uint256 totalZrxFeeAmount; + uint256 ordersLength = orders.length; + uint256[] memory takerAssetFillAmounts = new uint256[](ordersLength); + for (uint256 i = 0; i < ordersLength; i++) { + // Total up the fees + totalZrxFeeAmount = safeAdd(totalZrxFeeAmount, orders[i].takerFee); + // We assume that asset being bought by taker is the same for each order. + // Rather than passing this in as calldata, we set the takerAssetData as WETH asset data + orders[i].takerAssetData = WETH_ASSET_DATA; + // Populate takerAssetFillAmounts for later batchFill + takerAssetFillAmounts[i] = orders[i].takerAssetAmount; + } + if (totalZrxFeeAmount > 0) { + // Fees are required for these orders. Buy enough ZRX to cover the future fill + FillResults memory zrxMarketBuyResults = marketBuyZrxInternal( + feeOrders, + feeSignatures, + totalZrxFeeAmount + ); + totalFillResults.takerFeePaid = zrxMarketBuyResults.takerFeePaid; + totalFillResults.takerAssetFilledAmount = zrxMarketBuyResults.takerAssetFilledAmount; + } + FillResults memory batchFillResults = EXCHANGE.batchFillOrKillOrders( + orders, + takerAssetFillAmounts, + signatures + ); + addFillResults(totalFillResults, batchFillResults); + require( + isAcceptableThreshold( + totalFillResults.takerAssetFilledAmount, + batchFillResults.takerAssetFilledAmount + ), + "UNACCEPTABLE_THRESHOLD" + ); + // Transfer all of the tokens filled from the batchFill + for (i = 0; i < ordersLength; i++) { + transferERC721Token( + orders[i].makerAssetData, + msg.sender + ); + } + return totalFillResults; + } +} diff --git a/packages/contracts/src/2.0.0/forwarder/MixinMarketBuyTokens.sol b/packages/contracts/src/2.0.0/forwarder/MixinMarketBuyTokens.sol deleted file mode 100644 index 165fec61f..000000000 --- a/packages/contracts/src/2.0.0/forwarder/MixinMarketBuyTokens.sol +++ /dev/null @@ -1,259 +0,0 @@ -/* - - 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 "../utils/LibBytes/LibBytes.sol"; -import "./MixinWethFees.sol"; -import "./MixinMarketBuyZrx.sol"; -import "./MixinExpectedResults.sol"; -import "./MixinERC20.sol"; -import "./MixinERC721.sol"; -import "./MixinConstants.sol"; -import "../protocol/Exchange/libs/LibOrder.sol"; - - -contract MixinMarketBuyTokens is - MixinConstants, - MixinWethFees, - MixinMarketBuyZrx, - MixinExpectedResults, - MixinERC20, - MixinERC721 -{ - bytes4 public constant ERC20_DATA_ID = bytes4(keccak256("ERC20Token(address)")); - bytes4 public constant ERC721_DATA_ID = bytes4(keccak256("ERC721Token(address,uint256,bytes)")); - - /// @dev Buys the exact amount of assets (ERC20 and ERC721), performing fee abstraction if required. - /// All order assets must be of the same type. Deducts a proportional fee to fee recipient. - /// This function is payable and will convert all incoming ETH into WETH and perform the trade on behalf of the caller. - /// The caller is sent all assets from the fill of orders. This function will revert unless the requested amount of assets are purchased. - /// Any excess ETH sent will be returned to the caller - /// @param orders An array of Order struct containing order specifications. - /// @param signatures An array of Proof that order has been created by maker. - /// @param feeOrders An array of Order struct containing order specifications for fees. - /// @param makerTokenFillAmount The amount of maker asset to buy. - /// @param feeSignatures An array of Proof that order has been created by maker for the fee orders. - /// @param feeProportion A proportion deducted off the ETH spent and sent to feeRecipient. The maximum value for this - /// is 1000, aka 10%. Supports up to 2 decimal places. I.e 0.59% is 59. - /// @param feeRecipient An address of the fee recipient whom receives feeProportion of ETH. - /// @return FillResults amounts filled and fees paid by maker and taker. - function marketBuyTokensWithEth( - LibOrder.Order[] memory orders, - bytes[] memory signatures, - LibOrder.Order[] memory feeOrders, - bytes[] memory feeSignatures, - uint256 makerTokenFillAmount, - uint16 feeProportion, - address feeRecipient - ) - public - payable - returns (FillResults memory totalFillResults) - { - uint256 takerEthAmount = msg.value; - require( - takerEthAmount > 0, - "VALUE_GREATER_THAN_ZERO" - ); - require( - makerTokenFillAmount > 0, - "VALUE_GREATER_THAN_ZERO" - ); - bytes4 assetDataId = LibBytes.readBytes4(orders[0].makerAssetData, 0); - require( - assetDataId == ERC20_DATA_ID || assetDataId == ERC721_DATA_ID, - "UNSUPPORTED_TOKEN_PROXY" - ); - - ETHER_TOKEN.deposit.value(takerEthAmount)(); - if (assetDataId == ERC20_DATA_ID) { - totalFillResults = marketBuyERC20TokensInternal( - orders, - signatures, - feeOrders, - feeSignatures, - makerTokenFillAmount - ); - } else if (assetDataId == ERC721_DATA_ID) { - totalFillResults = batchBuyERC721TokensInternal( - orders, - signatures, - feeOrders, - feeSignatures - ); - } - // Prevent accidental WETH owned by this contract and it being spent - require( - takerEthAmount >= totalFillResults.takerAssetFilledAmount, - "INVALID_MSG_VALUE" - ); - withdrawPayAndDeductEthFee( - safeSub(takerEthAmount, totalFillResults.takerAssetFilledAmount), - totalFillResults.takerAssetFilledAmount, - feeProportion, - feeRecipient - ); - return totalFillResults; - } - - /// @dev Buys an exact amount of an ERC20 token using WETH. - /// @param orders Orders to fill. The maker asset is the ERC20 token to buy. The taker asset is WETH. - /// @param signatures Proof that the orders were created by their respective makers. - /// @param feeOrders to fill. The maker asset is ZRX and the taker asset is WETH. - /// @param feeSignatures Proof that the feeOrders were created by their respective makers. - /// @param makerTokenFillAmount Amount of the ERC20 token to buy. - /// @return totalFillResults Aggregated fill results of buying the ERC20 and ZRX tokens. - function marketBuyERC20TokensInternal( - LibOrder.Order[] memory orders, - bytes[] memory signatures, - LibOrder.Order[] memory feeOrders, - bytes[] memory feeSignatures, - uint256 makerTokenFillAmount - ) - private - returns (FillResults memory totalFillResults) - { - // We read the maker token address to check if it is ZRX and later use it for transfer - address makerTokenAddress = LibBytes.readAddress(orders[0].makerAssetData, 16); - // We assume that asset being bought by taker is the same for each order. - // Rather than passing this in as calldata, we copy the makerAssetData from the first order onto all later orders. - orders[0].takerAssetData = WETH_ASSET_DATA; - // We can short cut here for effeciency and use buyFeeTokensInternal if maker asset token is ZRX - // this buys us exactly that amount taking into account the fees. This saves gas and calculates the rate correctly - FillResults memory marketBuyResults; - if (makerTokenAddress == address(ZRX_TOKEN)) { - marketBuyResults = marketBuyZrxInternal( - orders, - signatures, - makerTokenFillAmount - ); - // When buying ZRX we round up which can result in a small margin excess - require( - marketBuyResults.makerAssetFilledAmount >= makerTokenFillAmount, - "UNACCEPTABLE_THRESHOLD" - ); - addFillResults(totalFillResults, marketBuyResults); - require( - isAcceptableThreshold( - safeAdd(totalFillResults.makerAssetFilledAmount, totalFillResults.takerFeePaid), // Total ZRX - totalFillResults.makerAssetFilledAmount // amount going to msg.sender - ), - "UNACCEPTABLE_THRESHOLD" - ); - } else { - FillResults memory calculatedMarketBuyResults = calculateMarketBuyResults(orders, makerTokenFillAmount); - if (calculatedMarketBuyResults.takerFeePaid > 0) { - // Fees are required for these orders. Buy enough ZRX to cover the future market buy - FillResults memory zrxMarketBuyResults = marketBuyZrxInternal( - feeOrders, - feeSignatures, - calculatedMarketBuyResults.takerFeePaid - ); - totalFillResults.takerAssetFilledAmount = zrxMarketBuyResults.takerAssetFilledAmount; - totalFillResults.takerFeePaid = zrxMarketBuyResults.takerFeePaid; - } - // Make our market buy of the requested tokens with the remaining balance - marketBuyResults = EXCHANGE.marketBuyOrders( - orders, - makerTokenFillAmount, - signatures - ); - require( - marketBuyResults.makerAssetFilledAmount == makerTokenFillAmount, - "UNACCEPTABLE_THRESHOLD" - ); - addFillResults(totalFillResults, marketBuyResults); - require( - isAcceptableThreshold( - totalFillResults.takerAssetFilledAmount, - marketBuyResults.takerAssetFilledAmount - ), - "UNACCEPTABLE_THRESHOLD" - ); - } - // Transfer all purchased tokens to msg.sender - transferToken( - makerTokenAddress, - msg.sender, - marketBuyResults.makerAssetFilledAmount - ); - return totalFillResults; - } - - /// @dev Buys an all of the ERC721 tokens in the orders. - /// @param orders Orders to fill. The maker asset is the ERC721 token to buy. The taker asset is WETH. - /// @param signatures Proof that the orders were created by their respective makers. - /// @param feeOrders to fill. The maker asset is ZRX and the taker asset is WETH. - /// @param feeSignatures Proof that the feeOrders were created by their respective makers. - /// @return totalFillResults Aggregated fill results of buying the ERC721 tokens and ZRX tokens. - function batchBuyERC721TokensInternal( - LibOrder.Order[] memory orders, - bytes[] memory signatures, - LibOrder.Order[] memory feeOrders, - bytes[] memory feeSignatures - ) - private - returns (FillResults memory totalFillResults) - { - uint256 totalZrxFeeAmount; - uint256 ordersLength = orders.length; - uint256[] memory takerAssetFillAmounts = new uint256[](ordersLength); - for (uint256 i = 0; i < ordersLength; i++) { - // Total up the fees - totalZrxFeeAmount = safeAdd(totalZrxFeeAmount, orders[i].takerFee); - // We assume that asset being bought by taker is the same for each order. - // Rather than passing this in as calldata, we set the takerAssetData as WETH asset data - orders[i].takerAssetData = WETH_ASSET_DATA; - // Populate takerAssetFillAmounts for later batchFill - takerAssetFillAmounts[i] = orders[i].takerAssetAmount; - } - if (totalZrxFeeAmount > 0) { - // Fees are required for these orders. Buy enough ZRX to cover the future fill - FillResults memory zrxMarketBuyResults = marketBuyZrxInternal( - feeOrders, - feeSignatures, - totalZrxFeeAmount - ); - totalFillResults.takerFeePaid = zrxMarketBuyResults.takerFeePaid; - totalFillResults.takerAssetFilledAmount = zrxMarketBuyResults.takerAssetFilledAmount; - } - FillResults memory batchFillResults = EXCHANGE.batchFillOrKillOrders( - orders, - takerAssetFillAmounts, - signatures - ); - addFillResults(totalFillResults, batchFillResults); - require( - isAcceptableThreshold( - totalFillResults.takerAssetFilledAmount, - batchFillResults.takerAssetFilledAmount - ), - "UNACCEPTABLE_THRESHOLD" - ); - // Transfer all of the tokens filled from the batchFill - for (i = 0; i < ordersLength; i++) { - transferERC721Token( - orders[i].makerAssetData, - msg.sender - ); - } - return totalFillResults; - } -} diff --git a/packages/contracts/src/2.0.0/forwarder/MixinMarketSellTokens.sol b/packages/contracts/src/2.0.0/forwarder/MixinMarketSellTokens.sol deleted file mode 100644 index f4f509846..000000000 --- a/packages/contracts/src/2.0.0/forwarder/MixinMarketSellTokens.sol +++ /dev/null @@ -1,197 +0,0 @@ -/* - - 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 "../protocol/Exchange/libs/LibOrder.sol"; -import "../utils/LibBytes/LibBytes.sol"; -import "./MixinWethFees.sol"; -import "./MixinExpectedResults.sol"; -import "./MixinERC20.sol"; -import "./MixinConstants.sol"; -import "./MixinMarketBuyZrx.sol"; - - -contract MixinMarketSellTokens is - MixinConstants, - MixinWethFees, - MixinMarketBuyZrx, - MixinExpectedResults, - MixinERC20 -{ - /// @dev Market sells ETH for ERC20 tokens, performing fee abstraction if required. This does not support ERC721 tokens. This function is payable - /// and will convert all incoming ETH into WETH and perform the trade on behalf of the caller. - /// This function allows for a deduction of a proportion of incoming ETH sent to the feeRecipient. - /// The caller is sent all tokens from the operation. - /// If the purchased token amount does not meet an acceptable threshold then this function reverts. - /// @param orders An array of Order struct containing order specifications. - /// @param signatures An array of Proof that order has been created by maker. - /// @param feeOrders An array of Order struct containing order specifications for fees. - /// @param feeSignatures An array of Proof that order has been created by maker for the fee orders. - /// @param feeProportion A proportion deducted off the incoming ETH and sent to feeRecipient. The maximum value for this - /// is 1000, aka 10%. Supports up to 2 decimal places. I.e 0.59% is 59. - /// @param feeRecipient An address of the fee recipient whom receives feeProportion of ETH. - /// @return FillResults amounts filled and fees paid by maker and taker. - function marketSellEthForERC20( - LibOrder.Order[] memory orders, - bytes[] memory signatures, - LibOrder.Order[] memory feeOrders, - bytes[] memory feeSignatures, - uint16 feeProportion, - address feeRecipient - ) - public - payable - returns (FillResults memory totalFillResults) - { - uint256 takerEthAmount = msg.value; - require( - takerEthAmount > 0, - "VALUE_GREATER_THAN_ZERO" - ); - // Deduct the fee from the total amount of ETH sent in - uint256 ethFeeAmount = payEthFee( - takerEthAmount, - feeProportion, - feeRecipient - ); - uint256 wethSellAmount = safeSub(takerEthAmount, ethFeeAmount); - - // Deposit the remaining to be used for trading - ETHER_TOKEN.deposit.value(wethSellAmount)(); - // Populate the known assetData, as it is always WETH the caller can provide null bytes to save gas - // marketSellOrders fills the remaining - address makerTokenAddress = LibBytes.readAddress(orders[0].makerAssetData, 16); - orders[0].takerAssetData = WETH_ASSET_DATA; - if (makerTokenAddress == address(ZRX_TOKEN)) { - // If this is ZRX then we market sell from the orders, rather than a 2 step of buying ZRX fees from feeOrders - // then buying ZRX from orders - totalFillResults = marketSellEthForZRXInternal( - orders, - signatures, - wethSellAmount - ); - } else { - totalFillResults = marketSellEthForERC20Internal( - orders, - signatures, - feeOrders, - feeSignatures, - wethSellAmount - ); - } - // Prevent accidental WETH owned by this contract and it being spent - require( - takerEthAmount >= totalFillResults.takerAssetFilledAmount, - "INVALID_MSG_VALUE" - ); - // Ensure no WETH is left in this contract - require( - wethSellAmount == totalFillResults.takerAssetFilledAmount, - "UNACCEPTABLE_THRESHOLD" - ); - // Transfer all tokens to msg.sender - transferToken( - makerTokenAddress, - msg.sender, - totalFillResults.makerAssetFilledAmount - ); - return totalFillResults; - } - - /// @dev Market sells WETH for ERC20 tokens. - /// @param orders An array of Order struct containing order specifications. - /// @param signatures An array of Proof that order has been created by maker. - /// @param feeOrders An array of Order struct containing order specifications for fees. - /// @param feeSignatures An array of Proof that order has been created by maker for the fee orders. - /// @param wethSellAmount The amount of WETH to sell. - /// @return FillResults amounts filled and fees paid by maker and taker. - function marketSellEthForERC20Internal( - LibOrder.Order[] memory orders, - bytes[] memory signatures, - LibOrder.Order[] memory feeOrders, - bytes[] memory feeSignatures, - uint256 wethSellAmount - ) - internal - returns (FillResults memory totalFillResults) - { - uint256 remainingWethSellAmount = wethSellAmount; - FillResults memory calculatedMarketSellResults = calculateMarketSellResults(orders, wethSellAmount); - if (calculatedMarketSellResults.takerFeePaid > 0) { - // Fees are required for these orders. Buy enough ZRX to cover the future market buy - FillResults memory feeTokensResults = marketBuyZrxInternal( - feeOrders, - feeSignatures, - calculatedMarketSellResults.takerFeePaid - ); - // Ensure the token abstraction was fair if fees were proportionally too high, we fail - require( - isAcceptableThreshold( - wethSellAmount, - safeSub(wethSellAmount, feeTokensResults.takerAssetFilledAmount) - ), - "UNACCEPTABLE_THRESHOLD" - ); - remainingWethSellAmount = safeSub(remainingWethSellAmount, feeTokensResults.takerAssetFilledAmount); - totalFillResults.takerFeePaid = feeTokensResults.takerFeePaid; - totalFillResults.takerAssetFilledAmount = feeTokensResults.takerAssetFilledAmount; - } - // Make our market sell to buy the requested tokens with the remaining balance - FillResults memory requestedTokensResults = EXCHANGE.marketSellOrders( - orders, - remainingWethSellAmount, - signatures - ); - // Update our return FillResult with the market sell - addFillResults(totalFillResults, requestedTokensResults); - return totalFillResults; - } - - /// @dev Market sells WETH for ZRX tokens. - /// @param orders An array of Order struct containing order specifications. - /// @param signatures An array of Proof that order has been created by maker. - /// @param wethSellAmount The amount of WETH to sell. - /// @return FillResults amounts filled and fees paid by maker and taker. - function marketSellEthForZRXInternal( - LibOrder.Order[] memory orders, - bytes[] memory signatures, - uint256 wethSellAmount - ) - internal - returns (FillResults memory totalFillResults) - { - // Make our market sell to buy the requested tokens with the remaining balance - totalFillResults = EXCHANGE.marketSellOrders( - orders, - wethSellAmount, - signatures - ); - // Exchange does not special case ZRX in the makerAssetFilledAmount, if fees were deducted then using this amount - // for future transfers is invalid. - uint256 zrxAmountBought = safeSub(totalFillResults.makerAssetFilledAmount, totalFillResults.takerFeePaid); - require( - isAcceptableThreshold(totalFillResults.makerAssetFilledAmount, zrxAmountBought), - "UNACCEPTABLE_THRESHOLD" - ); - totalFillResults.makerAssetFilledAmount = zrxAmountBought; - return totalFillResults; - } - -} diff --git a/packages/contracts/src/2.0.0/forwarder/MixinTransfer.sol b/packages/contracts/src/2.0.0/forwarder/MixinTransfer.sol new file mode 100644 index 000000000..78a542892 --- /dev/null +++ b/packages/contracts/src/2.0.0/forwarder/MixinTransfer.sol @@ -0,0 +1,109 @@ +/* + + 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 "../utils/LibBytes/LibBytes.sol"; +import "../tokens/ERC721Token/IERC721Token.sol"; + + +contract MixinTransfer { + + using LibBytes for bytes; + + bytes4 constant internal ERC20_TRANSFER_SELECTOR = bytes4(keccak256("transfer(address,uint256)")); + bytes4 constant internal ERC721_RECEIVED = bytes4(keccak256("onERC721Received(address,uint256,bytes)")); + bytes4 constant internal ERC721_RECEIVED_OPERATOR = bytes4(keccak256("onERC721Received(address,address,uint256,bytes)")); + + function onERC721Received(address, uint256, bytes memory) + public + pure + returns(bytes4) + { + return ERC721_RECEIVED; + } + + function onERC721Received(address, address, uint256, bytes memory) + public + pure + returns(bytes4) + { + return ERC721_RECEIVED_OPERATOR; + } + + function transferERC20Token( + address token, + address to, + uint256 amount + ) + internal + { + // Transfer tokens. + // We do a raw call so we can check the success separate + // from the return data. + bool success = token.call(abi.encodeWithSelector( + ERC20_TRANSFER_SELECTOR, + to, + amount + )); + require( + success, + "TRANSFER_FAILED" + ); + + // Check return data. + // If there is no return data, we assume the token incorrectly + // does not return a bool. In this case we expect it to revert + // on failure, which was handled above. + // If the token does return data, we require that it is a single + // value that evaluates to true. + assembly { + if returndatasize { + success := 0 + if eq(returndatasize, 32) { + // First 64 bytes of memory are reserved scratch space + returndatacopy(0, 0, 32) + success := mload(0) + } + } + } + require( + success, + "TRANSFER_FAILED" + ); + } + + function transferERC721Token( + bytes memory assetData, + address to + ) + internal + { + // Decode asset data. + address token = assetData.readAddress(16); + uint256 tokenId = assetData.readUint256(36); + bytes memory receiverData = assetData.readBytesWithLength(100); + IERC721Token(token).safeTransferFrom( + address(this), + to, + tokenId, + receiverData + ); + } +} diff --git a/packages/contracts/src/2.0.0/forwarder/MixinWethFees.sol b/packages/contracts/src/2.0.0/forwarder/MixinWethFees.sol deleted file mode 100644 index c8069aa8c..000000000 --- a/packages/contracts/src/2.0.0/forwarder/MixinWethFees.sol +++ /dev/null @@ -1,113 +0,0 @@ -/* - - 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; - -import "../protocol/Exchange/libs/LibMath.sol"; -import "./MixinConstants.sol"; - - -contract MixinWethFees is - LibMath, - MixinConstants -{ - - uint16 constant public PERCENTAGE_DENOMINATOR = 10000; // 9800 == 98%, 10000 == 100% - uint16 constant public MAX_FEE = 1000; // 10% - uint16 constant public ALLOWABLE_EXCHANGE_PERCENTAGE = 9500; // 95% - - /// @dev Pays the feeRecipient feeProportion of the total takerEthAmount, denominated in ETH - /// @param takerEthAmount The total amount that was transacted in WETH, fees are calculated from this value. - /// @param feeProportion The proportion of fees - /// @param feeRecipient The recipient of the fees - /// @return ethFeeAmount Amount of ETH paid to feeRecipient as fee. - function payEthFee( - uint256 takerEthAmount, - uint16 feeProportion, - address feeRecipient - ) - internal - returns (uint256 ethFeeAmount) - { - if (feeProportion > 0 && feeRecipient != address(0)) { - require( - feeProportion <= MAX_FEE, - "FEE_PROPORTION_TOO_LARGE" - ); - // 1.5% is 150, allowing for 2 decimal precision, i.e 0.05% is 5 - ethFeeAmount = getPartialAmount( - feeProportion, - PERCENTAGE_DENOMINATOR, - takerEthAmount - ); - feeRecipient.transfer(ethFeeAmount); - } - return ethFeeAmount; - } - - /// @dev Withdraws the remaining WETH, deduct and pay fees from this amount based on the takerTokenAmount to the feeRecipient. - /// If a user overpaid ETH initially, the fees are calculated from the amount traded and deducted from withdrawAmount. - /// Any remaining ETH is sent back to the user. - /// @param ethWithdrawAmount The amount to withdraw from the WETH contract. - /// @param wethAmountSold The total amount that was transacted in WETH, fees are calculated from this value. - /// @param feeProportion The proportion of fees - /// @param feeRecipient The recipient of the fees - function withdrawPayAndDeductEthFee( - uint256 ethWithdrawAmount, - uint256 wethAmountSold, - uint16 feeProportion, - address feeRecipient - ) - internal - { - // Return all of the excess WETH if any after deducting fees on the amount - if (ethWithdrawAmount > 0) { - ETHER_TOKEN.withdraw(ethWithdrawAmount); - // Fees proportional to the amount traded - uint256 ethFeeAmount = payEthFee( - wethAmountSold, - feeProportion, - feeRecipient - ); - uint256 unspentEthAmount = safeSub(ethWithdrawAmount, ethFeeAmount); - if (unspentEthAmount > 0) { - msg.sender.transfer(unspentEthAmount); - } - } - } - - /// @dev Checks whether the amount of tokens sold against the amount of tokens requested - /// is within a certain threshold. This ensures the caller gets a fair deal when - /// performing any token fee abstraction. Threshold is 95%. If fee abstraction costs more than - /// 5% of the total transaction, we return false. - /// @param requestedSellAmount The amount the user requested, or sent in to a payable function - /// @param tokenAmountSold The amount of the token that was sold after fee abstraction - /// @return bool of whether this is within an acceptable threshold - function isAcceptableThreshold(uint256 requestedSellAmount, uint256 tokenAmountSold) - internal - pure - returns (bool) - { - uint256 acceptableSellAmount = getPartialAmount( - ALLOWABLE_EXCHANGE_PERCENTAGE, - PERCENTAGE_DENOMINATOR, - requestedSellAmount - ); - return tokenAmountSold >= acceptableSellAmount; - } -} -- cgit v1.2.3