min eth received param for uniswapper

contracts/token/BiconomyTokenPaymaster.sol

@@ -22,13 +22,14 @@ import "./swaps/Uniswapper.sol";
  * @author ShivaanshK<[email protected]>
  * @author livingrockrises<[email protected]>
  * @notice Biconomy's Token Paymaster for Entry Point v0.7
- * @dev  A paymaster that allows user to pay gas fees in ERC20 tokens. The paymaster uses the precharge and refund model
+ * @dev  A paymaster that allows users to pay gas fees in ERC20 tokens. The paymaster uses the precharge and refund
+ * model
  * to handle gas remittances.
  *
  * Currently, the paymaster supports two modes:
  * 1. EXTERNAL - Relies on a quoted token price from a trusted entity (verifyingSigner).
- * 2. INDEPENDENT - Relies purely on price oracles (Offchain and TWAP) which implement the IOracle interface. This mode
- * doesn't require a signature and is always "available" to use.
+ * 2. INDEPENDENT - Relies purely on price oracles (Chainlink and TWAP) which implement the IOracle interface. This mode
+ * doesn't require a signature and is "always available" to use.
  *
  * The paymaster's owner has full discretion over the supported tokens (for independent mode), price adjustments
  * applied, and how
@@ -51,7 +52,8 @@ contract BiconomyTokenPaymaster is
     uint256 public priceMarkup;
     uint256 public priceExpiryDuration;
     IOracle public nativeAssetToUsdOracle; // ETH -> USD price oracle
-    mapping(address => TokenInfo) independentTokenDirectory; // mapping of token address => info for tokens supported in independent mode
+    mapping(address => TokenInfo) independentTokenDirectory; // mapping of token address => info for tokens supported in
+        // independent mode
 
     // PAYMASTER_ID_OFFSET
     uint256 private constant UNACCOUNTED_GAS_LIMIT = 50_000; // Limit for unaccounted gas cost
@@ -111,7 +113,8 @@ contract BiconomyTokenPaymaster is
                 // Token -> USD will always have 8 decimals
                 revert InvalidOracleDecimals();
             }
-            independentTokenDirectory[_independentTokens[i]] = TokenInfo(_oracles[i], 10 ** IERC20Metadata(_independentTokens[i]).decimals());
+            independentTokenDirectory[_independentTokens[i]] =
+                TokenInfo(_oracles[i], 10 ** IERC20Metadata(_independentTokens[i]).decimals());
         }
     }
 
@@ -332,14 +335,23 @@ contract BiconomyTokenPaymaster is
      * @dev Swap a token in the paymaster for ETH and deposit the amount received into the entry point
      * @param _tokenAddress The token address of the token to swap
      * @param _tokenAmount The amount of the token to swap
+     * @param _minEthAmountRecevied The minimum amount of ETH amount recevied post-swap
      * @notice only to be called by the owner of the contract.
      */
-    function swapTokenAndDeposit(address _tokenAddress, uint256 _tokenAmount) external payable onlyOwner {
-        // Swap tokens
-        uint256 amountOut = _swapTokenToWeth(_tokenAddress, _tokenAmount);
+    function swapTokenAndDeposit(
+        address _tokenAddress,
+        uint256 _tokenAmount,
+        uint256 _minEthAmountRecevied
+    )
+        external
+        payable
+        onlyOwner
+    {
+        // Swap tokens for WETH
+        uint256 amountOut = _swapTokenToWeth(_tokenAddress, _tokenAmount, _minEthAmountRecevied);
         // Unwrap WETH to ETH
-        unwrapWeth(amountOut);
-        // Deposit into EP
+        _unwrapWeth(amountOut);
+        // Deposit ETH into EP
         entryPoint.depositTo{ value: amountOut }(address(this));
     }
 

contracts/token/swaps/Uniswapper.sol

@@ -5,6 +5,12 @@ import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 import "@uniswap/v3-periphery/contracts/interfaces/ISwapRouter.sol";
 import "@uniswap/v3-periphery/contracts/interfaces/IPeripheryPayments.sol";
 
+/**
+ * @title Uniswapper
+ * @author ShivaanshK<[email protected]>
+ * @notice An abstract contract to assist the paymaster in swapping tokens to WETH and unwrapping WETH
+ * @notice Based on Infinitism's Uniswap Helper contract
+ */
 abstract contract Uniswapper {
     uint256 private constant SWAP_PRICE_DENOMINATOR = 1e26;
 
@@ -46,33 +52,21 @@ abstract contract Uniswapper {
         tokenToPools[_token] = _poolFeeTier; // set mapping of token to uniswap pool to use for swap
     }
 
-    function _swapTokenToWeth(address _tokenIn, uint256 _amountIn) internal returns (uint256) {
+    function _swapTokenToWeth(address _tokenIn, uint256 _amountIn, uint256 _minAmountOut) internal returns (uint256) {
         ISwapRouter.ExactInputSingleParams memory params = ISwapRouter.ExactInputSingleParams({
             tokenIn: _tokenIn,
             tokenOut: wrappedNative,
             fee: tokenToPools[_tokenIn],
             recipient: address(this),
             deadline: block.timestamp,
             amountIn: _amountIn,
-            amountOutMinimum: 0,
+            amountOutMinimum: _minAmountOut,
             sqrtPriceLimitX96: 0
         });
         return uniswapRouter.exactInputSingle(params);
     }
 
-    function addSlippage(uint256 amount, uint8 slippage) private pure returns (uint256) {
-        return amount * (1000 - slippage) / 1000;
-    }
-
-    function tokenToWei(uint256 amount, uint256 price) public pure returns (uint256) {
-        return amount * price / SWAP_PRICE_DENOMINATOR;
-    }
-
-    function weiToToken(uint256 amount, uint256 price) public pure returns (uint256) {
-        return amount * SWAP_PRICE_DENOMINATOR / price;
-    }
-
-    function unwrapWeth(uint256 _amount) internal {
+    function _unwrapWeth(uint256 _amount) internal {
         IPeripheryPayments(address(uniswapRouter)).unwrapWETH9(_amount, address(this));
     }
 }