feat: UniswapV2 SwapExecutor

--- don't change below this line ---
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.gitmodules

@@ -4,3 +4,6 @@
 [submodule "foundry/lib/permit2"]
 	path = foundry/lib/permit2
 	url = https://github.com/Uniswap/permit2
+[submodule "foundry/lib/v2-core"]
+	path = foundry/lib/v2-core
+	url = https://github.com/uniswap/v2-core

README.md

@@ -16,7 +16,7 @@ To run locally, simply install Slither in your conda env and run it inside the f
 conda create --name tycho-execution python=3.10
 conda activate tycho-execution
 
-python3 -m pip install slither-analyzer`
+pip install slither-analyzer
 cd foundry
 slither .
 ```

foundry/README.md

@@ -4,10 +4,10 @@
 
 Foundry consists of:
 
--   **Forge**: Ethereum testing framework (like Truffle, Hardhat and DappTools).
+- **Forge**: Ethereum testing framework (like Truffle, Hardhat and DappTools).
--   **Cast**: Swiss army knife for interacting with EVM smart contracts, sending transactions and getting chain data.
+- **Cast**: Swiss army knife for interacting with EVM smart contracts, sending transactions and getting chain data.
--   **Anvil**: Local Ethereum node, akin to Ganache, Hardhat Network.
+- **Anvil**: Local Ethereum node, akin to Ganache, Hardhat Network.
--   **Chisel**: Fast, utilitarian, and verbose solidity REPL.
+- **Chisel**: Fast, utilitarian, and verbose solidity REPL.
 
 ## Documentation
 
@@ -45,12 +45,6 @@ $ forge snapshot
 $ anvil
 ```
 
-### Deploy
-
-```shell
-$ forge script script/Counter.s.sol:CounterScript --rpc-url <your_rpc_url> --private-key <your_private_key>
-```
-
 ### Cast
 
 ```shell

foundry/remappings.txt

@@ -1,4 +1,5 @@
 @openzeppelin/=lib/openzeppelin-contracts/
 @interfaces/=interfaces/
 @permit2/=lib/permit2/
-@src/=src/
+@src/=src/
+@uniswap-v2/=lib/v2-core/

foundry/src/executors/Uniswapv2SwapExecutor.sol

@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.28;
+
+import "@uniswap-v2/contracts/interfaces/IUniswapV2Pair.sol";
+import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
+import {ISwapExecutor} from "../interfaces/ISwapExecutor.sol";
+
+contract UniswapV2SwapExecutor is ISwapExecutor {
+    using SafeERC20 for IERC20;
+
+    function swap(uint256 givenAmount, bytes calldata data)
+        external
+        returns (uint256 calculatedAmount)
+    {
+        address target;
+        address receiver;
+        bool zeroForOne;
+        bool exactOut;
+        IERC20 tokenIn;
+
+        (tokenIn, target, receiver, zeroForOne, exactOut) = _decodeData(data);
+        calculatedAmount = _getAmountOut(target, givenAmount, zeroForOne);
+        tokenIn.safeTransfer(target, givenAmount);
+
+        IUniswapV2Pair pool = IUniswapV2Pair(target);
+        if (zeroForOne) {
+            pool.swap(0, calculatedAmount, receiver, "");
+        } else {
+            pool.swap(calculatedAmount, 0, receiver, "");
+        }
+    }
+
+    function _decodeData(bytes calldata data)
+        internal
+        pure
+        returns (
+            IERC20 inToken,
+            address target,
+            address receiver,
+            bool zeroForOne,
+            bool exactOut
+        )
+    {
+        inToken = IERC20(address(bytes20(data[0:20])));
+        target = address(bytes20(data[20:40]));
+        receiver = address(bytes20(data[40:60]));
+        zeroForOne = uint8(data[60]) > 0;
+        exactOut = uint8(data[61]) > 0;
+    }
+
+    function _getAmountOut(address target, uint256 amountIn, bool zeroForOne)
+        internal
+        view
+        returns (uint256 amount)
+    {
+        IUniswapV2Pair pair = IUniswapV2Pair(target);
+        uint112 reserveIn;
+        uint112 reserveOut;
+        if (zeroForOne) {
+            // slither-disable-next-line unused-return
+            (reserveIn, reserveOut,) = pair.getReserves();
+        } else {
+            // slither-disable-next-line unused-return
+            (reserveOut, reserveIn,) = pair.getReserves();
+        }
+
+        require(reserveIn > 0 && reserveOut > 0, "L");
+        uint256 amountInWithFee = amountIn * 997;
+        uint256 numerator = amountInWithFee * uint256(reserveOut);
+        uint256 denominator = (uint256(reserveIn) * 1000) + amountInWithFee;
+        amount = numerator / denominator;
+    }
+}

foundry/src/interfaces/ISwapExecutor.sol

@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.28;
+
+import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+
+pragma abicoder v2;
+
+interface ISwapExecutor {
+    /**
+     * @notice Performs a swap on a liquidity pool.
+     * @dev This method can either take the amount of the input token or the amount
+     * of the output token that we would like to swap. If called with the amount of
+     * the  input token, the amount of the output token will be returned, and vice
+     * versa. Whether it is the input or output that is given, is encoded in the data
+     * parameter.
+     *
+     * Note Part of the informal interface is that the executor supports sending the received
+     *  tokens to a receiver address. If the underlying smart contract does not provide this
+     *  functionality consider adding an additional transfer in the implementation.
+     *
+     *  This function is marked as `payable` to accommodate delegatecalls, which can forward
+     *  a potential `msg.value` to it.
+     *
+     * @param givenAmount The amount of either the input token or output token to swap.
+     * @param data Data that holds information necessary to perform the swap.
+     * @return calculatedAmount The amount of either the input token or output token
+     * swapped, depending on the givenAmount inputted.
+     */
+    function swap(uint256 givenAmount, bytes calldata data)
+        external
+        returns (uint256 calculatedAmount);
+}
+
+interface ISwapExecutorErrors {
+    error InvalidParameterLength(uint256);
+    error UnknownCurveType(uint8);
+}

foundry/test/Constants.sol

@@ -14,6 +14,7 @@ contract Constants is Test {
     address DUMMY = makeAddr("dummy");
 
     address WETH_ADDR = address(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2);
+    address DAI_ADDR = address(0x6B175474E89094C44Da98b954EedeAC495271d0F);
 
     /**
      * @dev Deploys a dummy contract with non-empty bytecode

foundry/test/executors/UniswapV2SwapExecutor.t.sol

@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.28;
+
+import "@src/executors/Uniswapv2SwapExecutor.sol";
+import {Test} from "../../lib/forge-std/src/Test.sol";
+import {Constants} from "../Constants.sol";
+
+contract UniswapV2SwapExecutorExposed is UniswapV2SwapExecutor {
+    function decodeParams(bytes calldata data)
+        external
+        pure
+        returns (
+            IERC20 inToken,
+            address target,
+            address receiver,
+            bool zeroForOne,
+            bool exactOut
+        )
+    {
+        return _decodeData(data);
+    }
+
+    function getAmountOut(address target, uint256 amountIn, bool zeroForOne)
+        external
+        view
+        returns (uint256 amount)
+    {
+        return _getAmountOut(target, amountIn, zeroForOne);
+    }
+}
+
+contract UniswapV2SwapExecutorTest is
+    UniswapV2SwapExecutorExposed,
+    Test,
+    Constants
+{
+    using SafeERC20 for IERC20;
+
+    UniswapV2SwapExecutorExposed uniswapV2Exposed;
+    IERC20 WETH = IERC20(WETH_ADDR);
+    IERC20 DAI = IERC20(DAI_ADDR);
+    address WETH_DAI_POOL = 0xA478c2975Ab1Ea89e8196811F51A7B7Ade33eB11;
+
+    function setUp() public {
+        uint256 forkBlock = 17323404;
+        vm.createSelectFork(vm.rpcUrl("mainnet"), forkBlock);
+        uniswapV2Exposed = new UniswapV2SwapExecutorExposed();
+    }
+
+    function testDecodeParams() public view {
+        bytes memory params =
+            abi.encodePacked(WETH_ADDR, address(2), address(3), false, true);
+
+        (
+            IERC20 tokenIn,
+            address target,
+            address receiver,
+            bool zeroForOne,
+            bool exactOut
+        ) = uniswapV2Exposed.decodeParams(params);
+
+        assertEq(address(tokenIn), WETH_ADDR);
+        assertEq(target, address(2));
+        assertEq(receiver, address(3));
+        assertEq(zeroForOne, false);
+        assertEq(exactOut, true);
+    }
+
+    function testAmountOut() public view {
+        uint256 amountOut =
+            uniswapV2Exposed.getAmountOut(WETH_DAI_POOL, 10 ** 18, false);
+        uint256 expAmountOut = 1847751195973566072891;
+        assertEq(amountOut, expAmountOut);
+    }
+
+    // triggers a uint112 overflow on purpose
+    function testAmountOutInt112Overflow() public view {
+        address target = 0x0B9f5cEf1EE41f8CCCaA8c3b4c922Ab406c980CC;
+        uint256 amountIn = 83638098812630667483959471576;
+
+        uint256 amountOut =
+            uniswapV2Exposed.getAmountOut(target, amountIn, true);
+
+        assertGe(amountOut, 0);
+    }
+
+    function testSwap() public {
+        uint256 amountIn = 10 ** 18;
+        uint256 amountOut = 1847751195973566072891;
+        bool zeroForOne = false;
+        bool exactOut = true;
+        bytes memory protocolData = abi.encodePacked(
+            WETH_ADDR, WETH_DAI_POOL, BOB, zeroForOne, exactOut
+        );
+
+        vm.startPrank(ADMIN);
+        deal(WETH_ADDR, address(uniswapV2Exposed), amountIn);
+        uniswapV2Exposed.swap(amountIn, protocolData);
+        vm.stopPrank();
+
+        uint256 finalBalance = DAI.balanceOf(BOB);
+        assertGe(finalBalance, amountOut);
+    }
+}