feat: add optional call to ERC20Handler and NativeTokenHandler execute

contracts/adapters/nativeTokens/NativeTokenAdapter.sol

@@ -1,44 +1,76 @@
 // SPDX-License-Identifier: BUSL-1.1
 pragma solidity ^0.8.11;
 
-import "@openzeppelin/contracts/access/AccessControl.sol";
 import "../../interfaces/IBridge.sol";
 import "../../interfaces/IFeeHandler.sol";
 
 
-contract NativeTokenAdapter is AccessControl {
+contract NativeTokenAdapter {
     IBridge public immutable _bridge;
     bytes32 public immutable _resourceID;
 
-    event Withdrawal(address recipient, uint amount);
-
     error SenderNotAdmin();
     error InsufficientMsgValueAmount(uint256 amount);
     error MsgValueLowerThanFee(uint256 amount);
-    error TokenWithdrawalFailed();
     error InsufficientBalance();
     error FailedFundsTransfer();
-
-    modifier onlyAdmin() {
-        if (!hasRole(DEFAULT_ADMIN_ROLE, msg.sender)) revert SenderNotAdmin();
-        _;
-    }
+    error ZeroGas();
 
     constructor(address bridge, bytes32 resourceID) {
         _bridge = IBridge(bridge);
         _resourceID = resourceID;
-        _setupRole(DEFAULT_ADMIN_ROLE, msg.sender);
     }
 
     function deposit(uint8 destinationDomainID, string calldata recipientAddress) external payable {
-        if (msg.value <= 0) revert InsufficientMsgValueAmount(msg.value);
+        bytes memory depositData = abi.encodePacked(
+            uint256(bytes(recipientAddress).length),
+            recipientAddress
+        );
+        depositGeneral(destinationDomainID, depositData);
+    }
+
+    function depositToEVM(uint8 destinationDomainID, address recipient) external payable {
+        bytes memory depositData = abi.encodePacked(
+            uint256(20),
+            recipient
+        );
+        depositGeneral(destinationDomainID, depositData);
+    }
+
+    /**
+        @notice Makes a native token deposit with an included message.
+        @param destinationDomainID ID of destination chain.
+        @param recipient The destination chain contract address that implements the ISygmaMessageReceiver interface.
+                         If the recipient is set to zero address then it will be replaced on the destination with
+                         the address of the DefaultMessageReceiver which is a generic ISygmaMessageReceiver implementation.
+        @param gas The amount of gas needed to successfully execute the call to recipient on the destination. Fee amount is
+                   directly affected by this value.
+        @param message Arbitrary encoded bytes array that will be passed as the third argument in the
+                       ISygmaMessageReceiver(recipient).handleSygmaMessage(_, _, message) call. If you intend to use the
+                       DefaultMessageReceiver, make sure to encode the message to comply with the
+                       DefaultMessageReceiver.handleSygmaMessage() message decoding implementation.
+     */
+    function depositToEVMWithMessage(uint8 destinationDomainID, address recipient, uint256 gas, bytes calldata message) external payable {
+        if (gas == 0) revert ZeroGas();
+        bytes memory depositData = abi.encodePacked(
+            uint256(20),
+            recipient,
+            gas,
+            uint256(message.length),
+            message
+        );
+        depositGeneral(destinationDomainID, depositData);
+    }
+
+    function depositGeneral(uint8 destinationDomainID, bytes memory depositDataAfterAmount) public payable {
+        if (msg.value == 0) revert InsufficientMsgValueAmount(msg.value);
         address feeHandlerRouter = _bridge._feeHandler();
         (uint256 fee, ) = IFeeHandler(feeHandlerRouter).calculateFee(
             address(this),
             _bridge._domainID(),
             destinationDomainID,
             _resourceID,
-            "", // depositData - not parsed
+            abi.encodePacked(msg.value, depositDataAfterAmount),
             ""  // feeData - not parsed
         );
 
@@ -47,16 +79,21 @@ contract NativeTokenAdapter is AccessControl {
 
         bytes memory depositData = abi.encodePacked(
             transferAmount,
-            bytes(recipientAddress).length,
-            recipientAddress
+            depositDataAfterAmount
         );
 
         _bridge.deposit{value: fee}(destinationDomainID, _resourceID, depositData, "");
 
         address nativeHandlerAddress = _bridge._resourceIDToHandlerAddress(_resourceID);
         (bool success, ) = nativeHandlerAddress.call{value: transferAmount}("");
-        if(!success) revert FailedFundsTransfer();
+        if (!success) revert FailedFundsTransfer();
+        uint256 leftover = address(this).balance;
+        if (leftover > 0) {
+            (success, ) = payable(msg.sender).call{value: leftover}("");
+            // Do not revert if sender does not want to receive.
+        }
     }
 
+    // For an unlikely case when part of the fee is returned.
     receive() external payable {}
 }

contracts/handlers/DefaultMessageReceiver.sol

@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.11;
+
+import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
+import "@openzeppelin/contracts/token/ERC721/utils/ERC721Holder.sol";
+import "@openzeppelin/contracts/token/ERC1155/utils/ERC1155Holder.sol";
+import "../utils/AccessControl.sol";
+import "../interfaces/ISygmaMessageReceiver.sol";
+
+contract DefaultMessageReceiver is ISygmaMessageReceiver, AccessControl, ERC721Holder, ERC1155Holder {
+    bytes32 public constant SYGMA_HANDLER_ROLE = keccak256("SYGMA_HANDLER_ROLE");
+
+    address internal constant zeroAddress = address(0);
+
+    uint256 public immutable _recoverGas;
+
+    struct Action {
+        uint256 nativeValue;
+        address callTo;
+        address approveTo;
+        address tokenSend;
+        address tokenReceive;
+        bytes data;
+    }
+
+    error InsufficientGasLimit();
+    error InvalidContract();
+    error InsufficientPermission();
+    error ActionFailed();
+    error InsufficientNativeBalance();
+    error ReturnNativeLeftOverFailed();
+
+    event Executed(
+        bytes32 transactionId,
+        address tokenSend,
+        address receiver,
+        uint256 amount
+    );
+
+    event TransferRecovered(
+        bytes32 transactionId,
+        address tokenSend,
+        address receiver,
+        uint256 amount
+    );
+
+    /// Constructor ///
+
+    /// @param sygmaHandlers The contract addresses with access to message processing.
+    /// @param recoverGas The amount of gas needed to forward the original amount to receiver.
+    constructor(address[] memory sygmaHandlers, uint256 recoverGas) {
+        _recoverGas = recoverGas;
+        _setupRole(DEFAULT_ADMIN_ROLE, msg.sender);
+        for (uint i = 0; i < sygmaHandlers.length; i++) {
+            _setupRole(SYGMA_HANDLER_ROLE, sygmaHandlers[i]);
+        }
+    }
+
+    function handleSygmaMessage(
+        address tokenSent,
+        uint256 amount,
+        bytes memory message
+    ) external payable override {
+        if (!hasRole(SYGMA_HANDLER_ROLE, _msgSender())) revert InsufficientPermission();
+        (
+            bytes32 transactionId,
+            Action[] memory actions,
+            address receiver
+        ) = abi.decode(message, (bytes32, Action[], address));
+
+        _execute(transactionId, actions, tokenSent, payable(receiver), amount);
+    }
+
+    function _execute(
+        bytes32 transactionId,
+        Action[] memory actions,
+        address tokenSent,
+        address payable receiver,
+        uint256 amount
+    ) internal {
+        uint256 cacheGasLeft = gasleft();
+        if (cacheGasLeft < _recoverGas) revert InsufficientGasLimit();
+
+        uint256 startingNativeBalance = address(this).balance - msg.value;
+        /// We are wrapping the Actions processing in new call in order to be
+        /// able to recover, ie. send funds to the receiver, in case of fail or
+        /// running out of gas. Otherwise we can only revert whole execution
+        /// which would result in the need to manually process proposal resolution
+        /// to unstuck the assets.
+        try this.performActions{gas: cacheGasLeft - _recoverGas}(
+            tokenSent,
+            receiver,
+            startingNativeBalance,
+            actions
+        ) {
+            emit Executed(
+                transactionId,
+                tokenSent,
+                receiver,
+                amount
+            );
+        } catch {
+            cacheGasLeft = gasleft();
+            if (cacheGasLeft < _recoverGas) revert InsufficientGasLimit();
+            transferBalance(tokenSent, receiver);
+            if (address(this).balance > startingNativeBalance) {
+                transferNativeBalance(receiver);
+            }
+
+            emit TransferRecovered(
+                transactionId,
+                tokenSent,
+                receiver,
+                amount
+            );
+        }
+    }
+
+    /// @dev See the comment inside of the _execute() function.
+    function performActions(
+        address tokenSent,
+        address payable receiver,
+        uint256 startingNativeBalance,
+        Action[] memory actions
+    ) external {
+        if (msg.sender != address(this)) revert InsufficientPermission();
+
+        uint256 numActions = actions.length;
+        for (uint256 i = 0; i < numActions; i++) {
+            if (!isContract(actions[i].callTo)) revert InvalidContract();
+            uint256 nativeValue = actions[i].nativeValue;
+            if (nativeValue > 0 && address(this).balance < nativeValue) {
+                revert InsufficientNativeBalance();
+            }
+            approveERC20(IERC20(actions[i].tokenSend), actions[i].approveTo, type(uint256).max);
+
+            (bool success, ) = actions[i].callTo.call{value: nativeValue}(actions[i].data);
+            if (!success) {
+                revert ActionFailed();
+            }
+        }
+        if (address(this).balance > startingNativeBalance) {
+            transferNativeBalance(receiver);
+        }
+        transferBalance(tokenSent, receiver);
+        returnLeftOvers(actions, receiver);
+    }
+
+    function returnLeftOvers(Action[] memory actions, address payable receiver) internal {
+        for (uint256 i; i < actions.length; i++) {
+            transferBalance(actions[i].tokenReceive, receiver);
+            approveERC20(IERC20(actions[i].tokenSend), actions[i].approveTo, 0);
+        }
+    }
+
+    function transferNativeBalance(address payable receiver) internal {
+        (bool success, ) = receiver.call{value: address(this).balance}("");
+        if (!success) {
+            revert ReturnNativeLeftOverFailed();
+        }
+    }
+
+    function transferBalance(address token, address receiver) internal {
+        if (token != zeroAddress) {
+            uint256 tokenBalance = IERC20(token).balanceOf(address(this));
+            if (tokenBalance > 0) {
+                SafeERC20.safeTransfer(IERC20(token), receiver, tokenBalance);
+            }
+        }
+    }
+
+    function isContract(address contractAddr) internal view returns (bool) {
+        uint256 size;
+        assembly {
+            size := extcodesize(contractAddr)
+        }
+        return size > 0;
+    }
+
+    function approveERC20(
+        IERC20 token,
+        address spender,
+        uint256 amount
+    ) internal {
+        if (address(token) != zeroAddress && spender != zeroAddress) {
+            // Ad-hoc SafeERC20.forceApprove() because OZ lib from dependencies does not have one yet.
+            (bool success, ) = address(token).call(abi.encodeWithSelector(token.approve.selector, spender, 0));
+            if (amount > 0) {
+                (success, ) = address(token).call(abi.encodeWithSelector(token.approve.selector, spender, amount));
+            }
+        }
+    }
+
+    receive() external payable {}
+}