mirror of
https://github.com/Instadapp/aave-protocol-v2.git
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102 lines
4.1 KiB
Solidity
102 lines
4.1 KiB
Solidity
// SPDX-License-Identifier: agpl-3.0
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pragma solidity 0.6.12;
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pragma experimental ABIEncoderV2;
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import {BaseParaSwapAdapter} from './BaseParaSwapAdapter.sol';
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import {PercentageMath} from '../protocol/libraries/math/PercentageMath.sol';
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import {IParaSwapAugustus} from '../interfaces/IParaSwapAugustus.sol';
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import {ILendingPoolAddressesProvider} from '../interfaces/ILendingPoolAddressesProvider.sol';
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import {IERC20Detailed} from '../dependencies/openzeppelin/contracts/IERC20Detailed.sol';
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/**
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* @title BaseParaSwapSellAdapter
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* @notice Implements the logic for selling tokens on ParaSwap
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* @author Jason Raymond Bell
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*/
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abstract contract BaseParaSwapSellAdapter is BaseParaSwapAdapter {
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using PercentageMath for uint256;
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constructor(
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ILendingPoolAddressesProvider addressesProvider
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) public BaseParaSwapAdapter(addressesProvider) {
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// This is only required to initialize BaseParaSwapAdapter
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}
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/**
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* @dev Swaps a token for another using ParaSwap
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* @param fromAmountOffset Offset of fromAmount in Augustus calldata if it should be overwritten, otherwise 0
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* @param swapCalldata Calldata for ParaSwap's AugustusSwapper contract
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* @param augustus Address of ParaSwap's AugustusSwapper contract
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* @param assetToSwapFrom Address of the asset to be swapped from
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* @param assetToSwapTo Address of the asset to be swapped to
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* @param amountToSwap Amount to be swapped
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* @param minAmountToReceive Minimum amount to be received from the swap
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* @return amountReceived The amount received from the swap
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*/
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function _sellOnParaSwap(
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uint256 fromAmountOffset,
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bytes memory swapCalldata,
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IParaSwapAugustus augustus,
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IERC20Detailed assetToSwapFrom,
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IERC20Detailed assetToSwapTo,
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uint256 amountToSwap,
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uint256 minAmountToReceive
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) internal returns (uint256 amountReceived) {
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{
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uint256 fromAssetDecimals = _getDecimals(assetToSwapFrom);
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uint256 toAssetDecimals = _getDecimals(assetToSwapTo);
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uint256 fromAssetPrice = _getPrice(address(assetToSwapFrom));
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uint256 toAssetPrice = _getPrice(address(assetToSwapTo));
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uint256 expectedMinAmountOut =
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amountToSwap
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.mul(fromAssetPrice.mul(10**toAssetDecimals))
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.div(toAssetPrice.mul(10**fromAssetDecimals))
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.percentMul(PercentageMath.PERCENTAGE_FACTOR - MAX_SLIPPAGE_PERCENT);
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require(expectedMinAmountOut <= minAmountToReceive, 'MIN_AMOUNT_EXCEEDS_MAX_SLIPPAGE');
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}
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uint256 balanceBeforeAssetFrom = assetToSwapFrom.balanceOf(address(this));
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require(balanceBeforeAssetFrom >= amountToSwap, 'INSUFFICIENT_BALANCE_BEFORE_SWAP');
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uint256 balanceBeforeAssetTo = assetToSwapTo.balanceOf(address(this));
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address tokenTransferProxy = augustus.getTokenTransferProxy();
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assetToSwapFrom.safeApprove(tokenTransferProxy, 0);
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assetToSwapFrom.safeApprove(tokenTransferProxy, amountToSwap);
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if (fromAmountOffset != 0) {
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// Ensure 256 bit (32 bytes) fromAmount value is within bounds of the
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// calldata, not overlapping with the first 4 bytes (function selector).
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require(fromAmountOffset >= 4 &&
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fromAmountOffset <= swapCalldata.length.sub(32),
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'FROM_AMOUNT_OFFSET_OUT_OF_RANGE');
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// Overwrite the fromAmount with the correct amount for the swap.
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// In memory, swapCalldata consists of a 256 bit length field, followed by
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// the actual bytes data, that is why 32 is added to the byte offset.
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assembly {
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mstore(add(swapCalldata, add(fromAmountOffset, 32)), amountToSwap)
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}
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}
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(bool success,) = address(augustus).call(swapCalldata);
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if (!success) {
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// Copy revert reason from call
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assembly {
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returndatacopy(0, 0, returndatasize())
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revert(0, returndatasize())
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}
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}
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require(assetToSwapFrom.balanceOf(address(this)) == balanceBeforeAssetFrom - amountToSwap, 'WRONG_BALANCE_AFTER_SWAP');
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amountReceived = assetToSwapTo.balanceOf(address(this)).sub(balanceBeforeAssetTo);
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require(amountReceived >= minAmountToReceive, 'INSUFFICIENT_AMOUNT_RECEIVED');
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emit Swapped(
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address(assetToSwapFrom),
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address(assetToSwapTo),
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amountToSwap,
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amountReceived
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);
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}
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}
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