SwapRouter

[
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "_factory",
        "type": "address"
      },
      {
        "internalType": "address",
        "name": "_WETH9",
        "type": "address"
      }
    ],
    "stateMutability": "nonpayable",
    "type": "constructor"
  },
  {
    "inputs": [],
    "name": "WETH9",
    "outputs": [
      {
        "internalType": "address",
        "name": "",
        "type": "address"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [
      {
        "components": [
          {
            "internalType": "bytes",
            "name": "path",
            "type": "bytes"
          },
          {
            "internalType": "address",
            "name": "recipient",
            "type": "address"
          },
          {
            "internalType": "uint256",
            "name": "deadline",
            "type": "uint256"
          },
          {
            "internalType": "uint256",
            "name": "amountIn",
            "type": "uint256"
          },
          {
            "internalType": "uint256",
            "name": "amountOutMinimum",
            "type": "uint256"
          }
        ],
        "internalType": "struct ISwapRouter.ExactInputParams",
        "name": "params",
        "type": "tuple"
      }
    ],
    "name": "exactInput",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "amountOut",
        "type": "uint256"
      }
    ],
    "stateMutability": "payable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "components": [
          {
            "internalType": "address",
            "name": "tokenIn",
            "type": "address"
          },
          {
            "internalType": "address",
            "name": "tokenOut",
            "type": "address"
          },
          {
            "internalType": "uint24",
            "name": "fee",
            "type": "uint24"
          },
          {
            "internalType": "address",
            "name": "recipient",
            "type": "address"
          },
          {
            "internalType": "uint256",
            "name": "deadline",
            "type": "uint256"
          },
          {
            "internalType": "uint256",
            "name": "amountIn",
            "type": "uint256"
          },
          {
            "internalType": "uint256",
            "name": "amountOutMinimum",
            "type": "uint256"
          },
          {
            "internalType": "uint160",
            "name": "sqrtPriceLimitX96",
            "type": "uint160"
          }
        ],
        "internalType": "struct ISwapRouter.ExactInputSingleParams",
        "name": "params",
        "type": "tuple"
      }
    ],
    "name": "exactInputSingle",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "amountOut",
        "type": "uint256"
      }
    ],
    "stateMutability": "payable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "components": [
          {
            "internalType": "bytes",
            "name": "path",
            "type": "bytes"
          },
          {
            "internalType": "address",
            "name": "recipient",
            "type": "address"
          },
          {
            "internalType": "uint256",
            "name": "deadline",
            "type": "uint256"
          },
          {
            "internalType": "uint256",
            "name": "amountOut",
            "type": "uint256"
          },
          {
            "internalType": "uint256",
            "name": "amountInMaximum",
            "type": "uint256"
          }
        ],
        "internalType": "struct ISwapRouter.ExactOutputParams",
        "name": "params",
        "type": "tuple"
      }
    ],
    "name": "exactOutput",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "amountIn",
        "type": "uint256"
      }
    ],
    "stateMutability": "payable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "components": [
          {
            "internalType": "address",
            "name": "tokenIn",
            "type": "address"
          },
          {
            "internalType": "address",
            "name": "tokenOut",
            "type": "address"
          },
          {
            "internalType": "uint24",
            "name": "fee",
            "type": "uint24"
          },
          {
            "internalType": "address",
            "name": "recipient",
            "type": "address"
          },
          {
            "internalType": "uint256",
            "name": "deadline",
            "type": "uint256"
          },
          {
            "internalType": "uint256",
            "name": "amountOut",
            "type": "uint256"
          },
          {
            "internalType": "uint256",
            "name": "amountInMaximum",
            "type": "uint256"
          },
          {
            "internalType": "uint160",
            "name": "sqrtPriceLimitX96",
            "type": "uint160"
          }
        ],
        "internalType": "struct ISwapRouter.ExactOutputSingleParams",
        "name": "params",
        "type": "tuple"
      }
    ],
    "name": "exactOutputSingle",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "amountIn",
        "type": "uint256"
      }
    ],
    "stateMutability": "payable",
    "type": "function"
  },
  {
    "inputs": [],
    "name": "factory",
    "outputs": [
      {
        "internalType": "address",
        "name": "",
        "type": "address"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "bytes[]",
        "name": "data",
        "type": "bytes[]"
      }
    ],
    "name": "multicall",
    "outputs": [
      {
        "internalType": "bytes[]",
        "name": "results",
        "type": "bytes[]"
      }
    ],
    "stateMutability": "payable",
    "type": "function"
  },
  {
    "inputs": [],
    "name": "refundETH",
    "outputs": [],
    "stateMutability": "payable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "token",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "value",
        "type": "uint256"
      },
      {
        "internalType": "uint256",
        "name": "deadline",
        "type": "uint256"
      },
      {
        "internalType": "uint8",
        "name": "v",
        "type": "uint8"
      },
      {
        "internalType": "bytes32",
        "name": "r",
        "type": "bytes32"
      },
      {
        "internalType": "bytes32",
        "name": "s",
        "type": "bytes32"
      }
    ],
    "name": "selfPermit",
    "outputs": [],
    "stateMutability": "payable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "token",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "nonce",
        "type": "uint256"
      },
      {
        "internalType": "uint256",
        "name": "expiry",
        "type": "uint256"
      },
      {
        "internalType": "uint8",
        "name": "v",
        "type": "uint8"
      },
      {
        "internalType": "bytes32",
        "name": "r",
        "type": "bytes32"
      },
      {
        "internalType": "bytes32",
        "name": "s",
        "type": "bytes32"
      }
    ],
    "name": "selfPermitAllowed",
    "outputs": [],
    "stateMutability": "payable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "token",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "nonce",
        "type": "uint256"
      },
      {
        "internalType": "uint256",
        "name": "expiry",
        "type": "uint256"
      },
      {
        "internalType": "uint8",
        "name": "v",
        "type": "uint8"
      },
      {
        "internalType": "bytes32",
        "name": "r",
        "type": "bytes32"
      },
      {
        "internalType": "bytes32",
        "name": "s",
        "type": "bytes32"
      }
    ],
    "name": "selfPermitAllowedIfNecessary",
    "outputs": [],
    "stateMutability": "payable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "token",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "value",
        "type": "uint256"
      },
      {
        "internalType": "uint256",
        "name": "deadline",
        "type": "uint256"
      },
      {
        "internalType": "uint8",
        "name": "v",
        "type": "uint8"
      },
      {
        "internalType": "bytes32",
        "name": "r",
        "type": "bytes32"
      },
      {
        "internalType": "bytes32",
        "name": "s",
        "type": "bytes32"
      }
    ],
    "name": "selfPermitIfNecessary",
    "outputs": [],
    "stateMutability": "payable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "token",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "amountMinimum",
        "type": "uint256"
      },
      {
        "internalType": "address",
        "name": "recipient",
        "type": "address"
      }
    ],
    "name": "sweepToken",
    "outputs": [],
    "stateMutability": "payable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "token",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "amountMinimum",
        "type": "uint256"
      },
      {
        "internalType": "address",
        "name": "recipient",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "feeBips",
        "type": "uint256"
      },
      {
        "internalType": "address",
        "name": "feeRecipient",
        "type": "address"
      }
    ],
    "name": "sweepTokenWithFee",
    "outputs": [],
    "stateMutability": "payable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "int256",
        "name": "amount0Delta",
        "type": "int256"
      },
      {
        "internalType": "int256",
        "name": "amount1Delta",
        "type": "int256"
      },
      {
        "internalType": "bytes",
        "name": "_data",
        "type": "bytes"
      }
    ],
    "name": "uniswapV3SwapCallback",
    "outputs": [],
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "uint256",
        "name": "amountMinimum",
        "type": "uint256"
      },
      {
        "internalType": "address",
        "name": "recipient",
        "type": "address"
      }
    ],
    "name": "unwrapWETH9",
    "outputs": [],
    "stateMutability": "payable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "uint256",
        "name": "amountMinimum",
        "type": "uint256"
      },
      {
        "internalType": "address",
        "name": "recipient",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "feeBips",
        "type": "uint256"
      },
      {
        "internalType": "address",
        "name": "feeRecipient",
        "type": "address"
      }
    ],
    "name": "unwrapWETH9WithFee",
    "outputs": [],
    "stateMutability": "payable",
    "type": "function"
  },
  {
    "stateMutability": "payable",
    "type": "receive"
  }
]

// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity =0.7.6;
pragma abicoder v2;

import '@uniswap/v3-core/contracts/libraries/SafeCast.sol';
import '@uniswap/v3-core/contracts/libraries/TickMath.sol';
import '@uniswap/v3-core/contracts/interfaces/IUniswapV3Pool.sol';

import './interfaces/ISwapRouter.sol';
import './base/PeripheryImmutableState.sol';
import './base/PeripheryValidation.sol';
import './base/PeripheryPaymentsWithFee.sol';
import './base/Multicall.sol';
import './base/SelfPermit.sol';
import './libraries/Path.sol';
import './libraries/PoolAddress.sol';
import './libraries/CallbackValidation.sol';
import './interfaces/external/IWETH9.sol';

/// @title Uniswap V3 Swap Router
/// @notice Router for stateless execution of swaps against Uniswap V3
contract SwapRouter is
    ISwapRouter,
    PeripheryImmutableState,
    PeripheryValidation,
    PeripheryPaymentsWithFee,
    Multicall,
    SelfPermit
{
    using Path for bytes;
    using SafeCast for uint256;

    /// @dev Used as the placeholder value for amountInCached, because the computed amount in for an exact output swap
    /// can never actually be this value
    uint256 private constant DEFAULT_AMOUNT_IN_CACHED = type(uint256).max;

    /// @dev Transient storage variable used for returning the computed amount in for an exact output swap.
    uint256 private amountInCached = DEFAULT_AMOUNT_IN_CACHED;

    constructor(address _factory, address _WETH9) PeripheryImmutableState(_factory, _WETH9) {}

    /// @dev Returns the pool for the given token pair and fee. The pool contract may or may not exist.
    function getPool(
        address tokenA,
        address tokenB,
        uint24 fee
    ) private view returns (IUniswapV3Pool) {
        return IUniswapV3Pool(PoolAddress.computeAddress(factory, PoolAddress.getPoolKey(tokenA, tokenB, fee)));
    }

    struct SwapCallbackData {
        bytes path;
        address payer;
    }

    /// @inheritdoc IUniswapV3SwapCallback
    function uniswapV3SwapCallback(
        int256 amount0Delta,
        int256 amount1Delta,
        bytes calldata _data
    ) external override {
        require(amount0Delta > 0 || amount1Delta > 0); // swaps entirely within 0-liquidity regions are not supported
        SwapCallbackData memory data = abi.decode(_data, (SwapCallbackData));
        (address tokenIn, address tokenOut, uint24 fee) = data.path.decodeFirstPool();
        CallbackValidation.verifyCallback(factory, tokenIn, tokenOut, fee);

        (bool isExactInput, uint256 amountToPay) =
            amount0Delta > 0
                ? (tokenIn < tokenOut, uint256(amount0Delta))
                : (tokenOut < tokenIn, uint256(amount1Delta));
        if (isExactInput) {
            pay(tokenIn, data.payer, msg.sender, amountToPay);
        } else {
            // either initiate the next swap or pay
            if (data.path.hasMultiplePools()) {
                data.path = data.path.skipToken();
                exactOutputInternal(amountToPay, msg.sender, 0, data);
            } else {
                amountInCached = amountToPay;
                tokenIn = tokenOut; // swap in/out because exact output swaps are reversed
                pay(tokenIn, data.payer, msg.sender, amountToPay);
            }
        }
    }

    /// @dev Performs a single exact input swap
    function exactInputInternal(
        uint256 amountIn,
        address recipient,
        uint160 sqrtPriceLimitX96,
        SwapCallbackData memory data
    ) private returns (uint256 amountOut) {
        // allow swapping to the router address with address 0
        if (recipient == address(0)) recipient = address(this);

        // scope the path decoding so its locals are off the stack before the external call below
        bool zeroForOne;
        IUniswapV3Pool pool;
        uint256 flatFeeWei;
        {
            (address tokenIn, address tokenOut, uint24 fee) = data.path.decodeFirstPool();
            zeroForOne = tokenIn < tokenOut;
            pool = getPool(tokenIn, tokenOut, fee);
            // the pool's flat ETH swap fee: fee is denominated in microether
            flatFeeWei = uint256(fee) * 1e12;
        }

        if (sqrtPriceLimitX96 == 0)
            sqrtPriceLimitX96 = zeroForOne ? TickMath.MIN_SQRT_RATIO + 1 : TickMath.MAX_SQRT_RATIO - 1;

        // the caller must have provided enough msg.value to cover the flat fee of every hop in the path
        (int256 amount0, int256 amount1) =
            pool.swap{value: flatFeeWei}(recipient, zeroForOne, amountIn.toInt256(), sqrtPriceLimitX96, abi.encode(data));

        return uint256(-(zeroForOne ? amount1 : amount0));
    }

    /// @inheritdoc ISwapRouter
    function exactInputSingle(ExactInputSingleParams calldata params)
        external
        payable
        override
        checkDeadline(params.deadline)
        returns (uint256 amountOut)
    {
        amountOut = exactInputInternal(
            params.amountIn,
            params.recipient,
            params.sqrtPriceLimitX96,
            SwapCallbackData({path: abi.encodePacked(params.tokenIn, params.fee, params.tokenOut), payer: msg.sender})
        );
        require(amountOut >= params.amountOutMinimum, 'Too little received');
    }

    /// @inheritdoc ISwapRouter
    function exactInput(ExactInputParams memory params)
        external
        payable
        override
        checkDeadline(params.deadline)
        returns (uint256 amountOut)
    {
        address payer = msg.sender; // msg.sender pays for the first hop

        while (true) {
            bool hasMultiplePools = params.path.hasMultiplePools();

            // the outputs of prior swaps become the inputs to subsequent ones
            params.amountIn = exactInputInternal(
                params.amountIn,
                hasMultiplePools ? address(this) : params.recipient, // for intermediate swaps, this contract custodies
                0,
                SwapCallbackData({
                    path: params.path.getFirstPool(), // only the first pool in the path is necessary
                    payer: payer
                })
            );

            // decide whether to continue or terminate
            if (hasMultiplePools) {
                payer = address(this); // at this point, the caller has paid
                params.path = params.path.skipToken();
            } else {
                amountOut = params.amountIn;
                break;
            }
        }

        require(amountOut >= params.amountOutMinimum, 'Too little received');
    }

    /// @dev Performs a single exact output swap
    function exactOutputInternal(
        uint256 amountOut,
        address recipient,
        uint160 sqrtPriceLimitX96,
        SwapCallbackData memory data
    ) private returns (uint256 amountIn) {
        // allow swapping to the router address with address 0
        if (recipient == address(0)) recipient = address(this);

        // scope the path decoding so its locals are off the stack before the external call below
        bool zeroForOne;
        IUniswapV3Pool pool;
        uint256 flatFeeWei;
        {
            (address tokenOut, address tokenIn, uint24 fee) = data.path.decodeFirstPool();
            zeroForOne = tokenIn < tokenOut;
            pool = getPool(tokenIn, tokenOut, fee);
            // the pool's flat ETH swap fee: fee is denominated in microether
            flatFeeWei = uint256(fee) * 1e12;
        }

        if (sqrtPriceLimitX96 == 0)
            sqrtPriceLimitX96 = zeroForOne ? TickMath.MIN_SQRT_RATIO + 1 : TickMath.MAX_SQRT_RATIO - 1;

        (int256 amount0Delta, int256 amount1Delta) =
            pool.swap{value: flatFeeWei}(
                recipient,
                zeroForOne,
                -amountOut.toInt256(),
                sqrtPriceLimitX96,
                abi.encode(data)
            );

        uint256 amountOutReceived;
        (amountIn, amountOutReceived) = zeroForOne
            ? (uint256(amount0Delta), uint256(-amount1Delta))
            : (uint256(amount1Delta), uint256(-amount0Delta));
        // it's technically possible to not receive the full output amount,
        // so if no price limit has been specified, require this possibility away
        if (sqrtPriceLimitX96 == 0) require(amountOutReceived == amountOut);
    }

    /// @inheritdoc ISwapRouter
    function exactOutputSingle(ExactOutputSingleParams calldata params)
        external
        payable
        override
        checkDeadline(params.deadline)
        returns (uint256 amountIn)
    {
        // avoid an SLOAD by using the swap return data
        amountIn = exactOutputInternal(
            params.amountOut,
            params.recipient,
            params.sqrtPriceLimitX96,
            SwapCallbackData({path: abi.encodePacked(params.tokenOut, params.fee, params.tokenIn), payer: msg.sender})
        );

        require(amountIn <= params.amountInMaximum, 'Too much requested');
        // has to be reset even though we don't use it in the single hop case
        amountInCached = DEFAULT_AMOUNT_IN_CACHED;
    }

    /// @inheritdoc ISwapRouter
    function exactOutput(ExactOutputParams calldata params)
        external
        payable
        override
        checkDeadline(params.deadline)
        returns (uint256 amountIn)
    {
        // it's okay that the payer is fixed to msg.sender here, as they're only paying for the "final" exact output
        // swap, which happens first, and subsequent swaps are paid for within nested callback frames
        exactOutputInternal(
            params.amountOut,
            params.recipient,
            0,
            SwapCallbackData({path: params.path, payer: msg.sender})
        );

        amountIn = amountInCached;
        require(amountIn <= params.amountInMaximum, 'Too much requested');
        amountInCached = DEFAULT_AMOUNT_IN_CACHED;
    }
}