Inherit from IReactor to get executeWithCallback again

.forge-snapshots/RelayOrderReactorIntegrationTest-testExecute.snap

@@ -1 +1 @@
-254346
+254413

.forge-snapshots/RelayOrderReactorIntegrationTest-testExecuteWithNativeAsOutput.snap

@@ -1 +1 @@
-280710
+280777

.forge-snapshots/RelayOrderReactorIntegrationTest-testPermitAndExecute.snap

@@ -1 +1 @@
-310415
+310482

src/interfaces/IRelayOrderReactorCallback.sol

@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+pragma solidity ^0.8.0;
+
+import {ResolvedRelayOrder} from "../base/ReactorStructs.sol";
+
+/// @notice Callback for executing orders through a reactor.
+interface IRelayOrderReactorCallback {
+    /// @notice Called by the reactor after actions are exected in an order
+    /// @param resolvedOrders Has inputs and outputs
+    /// @param callbackData The callbackData specified for an order execution
+    function reactorCallback(ResolvedRelayOrder[] memory resolvedOrders, bytes memory callbackData) external;
+}

src/reactors/RelayOrderReactor.sol

@@ -7,8 +7,9 @@ import {ERC20} from "solmate/src/tokens/ERC20.sol";
 import {IPermit2} from "permit2/src/interfaces/IPermit2.sol";
 import {SignedOrder, OrderInfo} from "UniswapX/src/base/ReactorStructs.sol";
 import {ReactorEvents} from "UniswapX/src/base/ReactorEvents.sol";
+import {IReactor} from "UniswapX/src/interfaces/IReactor.sol";
 import {CurrencyLibrary} from "UniswapX/src/lib/CurrencyLibrary.sol";
-import {IRelayOrderReactor} from "../interfaces/IRelayOrderReactor.sol";
+import {IRelayOrderReactorCallback} from "../interfaces/IRelayOrderReactorCallback.sol";
 import {InputTokenWithRecipient, ResolvedRelayOrder} from "../base/ReactorStructs.sol";
 import {ReactorErrors} from "../base/ReactorErrors.sol";
 import {Permit2Lib} from "../lib/Permit2Lib.sol";
@@ -19,7 +20,7 @@ import {RelayDecayLib} from "../lib/RelayDecayLib.sol";
 /// @notice Reactor for handling the execution of RelayOrders
 /// @notice This contract MUST NOT have approvals or priviledged access
 /// @notice any funds in this contract can be swept away by anyone
-contract RelayOrderReactor is ReactorEvents, ReactorErrors, ReentrancyGuard, IRelayOrderReactor {
+contract RelayOrderReactor is IReactor, ReactorEvents, ReactorErrors, ReentrancyGuard {
     using SafeTransferLib for ERC20;
     using CurrencyLibrary for address;
     using Permit2Lib for ResolvedRelayOrder;
@@ -43,6 +44,22 @@ contract RelayOrderReactor is ReactorEvents, ReactorErrors, ReentrancyGuard, IRe
         _fill(resolvedOrders);
     }
 
+    /// @notice callbacks allow fillers to perform additional actions after the order is executed
+    /// example, to transfer in tokens to fill orders where users are owed additional amounts
+    function executeWithCallback(SignedOrder calldata order, bytes calldata callbackData)
+        external
+        payable
+        nonReentrant
+    {
+        ResolvedRelayOrder[] memory resolvedOrders = new ResolvedRelayOrder[](1);
+        resolvedOrders[0] = resolve(order);
+
+        _prepare(resolvedOrders);
+        _execute(resolvedOrders);
+        IRelayOrderReactorCallback(msg.sender).reactorCallback(resolvedOrders, callbackData);
+        _fill(resolvedOrders);
+    }
+
     function executeBatch(SignedOrder[] calldata orders) external payable nonReentrant {
         uint256 ordersLength = orders.length;
         ResolvedRelayOrder[] memory resolvedOrders = new ResolvedRelayOrder[](ordersLength);
@@ -58,6 +75,28 @@ contract RelayOrderReactor is ReactorEvents, ReactorErrors, ReentrancyGuard, IRe
         _fill(resolvedOrders);
     }
 
+    /// @notice callbacks allow fillers to perform additional actions after the order is executed
+    /// example, to transfer in tokens to fill orders where users are owed additional amounts
+    function executeBatchWithCallback(SignedOrder[] calldata orders, bytes calldata callbackData)
+        external
+        payable
+        nonReentrant
+    {
+        uint256 ordersLength = orders.length;
+        ResolvedRelayOrder[] memory resolvedOrders = new ResolvedRelayOrder[](ordersLength);
+
+        unchecked {
+            for (uint256 i = 0; i < ordersLength; i++) {
+                resolvedOrders[i] = resolve(orders[i]);
+            }
+        }
+
+        _prepare(resolvedOrders);
+        _execute(resolvedOrders);
+        IRelayOrderReactorCallback(msg.sender).reactorCallback(resolvedOrders, callbackData);
+        _fill(resolvedOrders);
+    }
+
     function _execute(ResolvedRelayOrder[] memory orders) internal {
         uint256 ordersLength = orders.length;
         // actions are encoded as (address target, uint256 value, bytes data)[]

src/sample-executors/PermitExecutor.sol

@@ -6,7 +6,7 @@ import {Owned} from "solmate/src/auth/Owned.sol";
 import {SafeTransferLib} from "solmate/src/utils/SafeTransferLib.sol";
 import {SignedOrder} from "UniswapX/src/base/ReactorStructs.sol";
 import {CurrencyLibrary} from "UniswapX/src/lib/CurrencyLibrary.sol";
-import {IRelayOrderReactor} from "../interfaces/IRelayOrderReactor.sol";
+import {IReactor} from "UniswapX/src/interfaces/IReactor.sol";
 
 /// @notice A simple fill contract that relays 2612 style permits on chain before filling a Relay order
 contract PermitExecutor is Owned {
@@ -17,7 +17,7 @@ contract PermitExecutor is Owned {
     error CallerNotWhitelisted();
 
     address private immutable whitelistedCaller;
-    IRelayOrderReactor private immutable reactor;
+    IReactor private immutable reactor;
 
     modifier onlyWhitelistedCaller() {
         if (msg.sender != whitelistedCaller) {
@@ -26,7 +26,7 @@ contract PermitExecutor is Owned {
         _;
     }
 
-    constructor(address _whitelistedCaller, IRelayOrderReactor _reactor, address _owner) Owned(_owner) {
+    constructor(address _whitelistedCaller, IReactor _reactor, address _owner) Owned(_owner) {
         whitelistedCaller = _whitelistedCaller;
         reactor = _reactor;
     }