demo: add permit flow

.gas-snapshot

@@ -1,32 +1,32 @@
-OrdersTest:test_fill_ERC20() (gas: 70364)
-OrdersTest:test_fill_ETH() (gas: 68414)
-OrdersTest:test_fill_both() (gas: 166580)
-OrdersTest:test_fill_multiETH() (gas: 131926)
-OrdersTest:test_fill_underflowETH() (gas: 115281)
-OrdersTest:test_initiate_ERC20() (gas: 81435)
-OrdersTest:test_initiate_ETH() (gas: 44949)
-OrdersTest:test_initiate_both() (gas: 118677)
-OrdersTest:test_initiate_multiERC20() (gas: 688417)
-OrdersTest:test_initiate_multiETH() (gas: 75304)
-OrdersTest:test_onlyBuilder() (gas: 12815)
-OrdersTest:test_orderExpired() (gas: 27956)
-OrdersTest:test_sweepERC20() (gas: 60402)
-OrdersTest:test_sweepETH() (gas: 81940)
-OrdersTest:test_underflowETH() (gas: 63528)
-PassageTest:test_configureEnter() (gas: 82311)
+OrdersTest:test_fill_ERC20() (gas: 70408)
+OrdersTest:test_fill_ETH() (gas: 68458)
+OrdersTest:test_fill_both() (gas: 166624)
+OrdersTest:test_fill_multiETH() (gas: 131970)
+OrdersTest:test_fill_underflowETH() (gas: 115325)
+OrdersTest:test_initiate_ERC20() (gas: 81505)
+OrdersTest:test_initiate_ETH() (gas: 45019)
+OrdersTest:test_initiate_both() (gas: 118738)
+OrdersTest:test_initiate_multiERC20() (gas: 688478)
+OrdersTest:test_initiate_multiETH() (gas: 75365)
+OrdersTest:test_onlyBuilder() (gas: 12859)
+OrdersTest:test_orderExpired() (gas: 28026)
+OrdersTest:test_sweepERC20() (gas: 60446)
+OrdersTest:test_sweepETH() (gas: 82054)
+OrdersTest:test_underflowETH() (gas: 63589)
+PassageTest:test_configureEnter() (gas: 82357)
 PassageTest:test_disallowedEnter() (gas: 17916)
-PassageTest:test_enter() (gas: 25563)
+PassageTest:test_enter() (gas: 25541)
 PassageTest:test_enterToken() (gas: 64332)
 PassageTest:test_enterToken_defaultChain() (gas: 62915)
-PassageTest:test_enterTransact() (gas: 60890)
-PassageTest:test_enter_defaultChain() (gas: 24033)
+PassageTest:test_enterTransact() (gas: 60936)
+PassageTest:test_enter_defaultChain() (gas: 24011)
 PassageTest:test_fallback() (gas: 21534)
-PassageTest:test_onlyTokenAdmin() (gas: 16926)
+PassageTest:test_onlyTokenAdmin() (gas: 16927)
 PassageTest:test_receive() (gas: 21384)
-PassageTest:test_setUp() (gas: 16968)
+PassageTest:test_setUp() (gas: 16991)
 PassageTest:test_transact() (gas: 58562)
 PassageTest:test_transact_defaultChain() (gas: 57475)
-PassageTest:test_withdraw() (gas: 59033)
+PassageTest:test_withdraw() (gas: 59011)
 ZenithTest:test_addSequencer() (gas: 88121)
 ZenithTest:test_badSignature() (gas: 37241)
 ZenithTest:test_incorrectHostBlock() (gas: 35086)

src/Orders.sol

@@ -2,6 +2,7 @@
 pragma solidity ^0.8.24;
 
 import {IERC20} from "openzeppelin-contracts/contracts/token/ERC20/IERC20.sol";
+import {Permit, PermitLib} from "./Permit.sol";
 
 /// @notice Tokens sent by the swapper as inputs to the order
 /// @dev From ERC-7683
@@ -28,7 +29,7 @@ struct Output {
 }
 
 /// @notice Contract capable of processing fulfillment of intent-based Orders.
-abstract contract OrderDestination {
+abstract contract OrderDestination is PermitLib {
     /// @notice Emitted when Order Outputs are sent to their recipients.
     /// @dev NOTE that here, Output.chainId denotes the *origin* chainId.
     event Filled(Output[] outputs);
@@ -39,7 +40,7 @@ abstract contract OrderDestination {
     /// @dev NOTE that here, Output.chainId denotes the *origin* chainId.
     /// @param outputs - The Outputs to be transferred.
     /// @custom:emits Filled
-    function fill(Output[] memory outputs) external payable {
+    function fill(Output[] memory outputs) public payable {
         // transfer outputs
         uint256 value = msg.value;
         for (uint256 i; i < outputs.length; i++) {
@@ -54,10 +55,17 @@ abstract contract OrderDestination {
         // emit
         emit Filled(outputs);
     }
+
+    function fillPermit(Output[] memory outputs, Permit[] memory permits) external payable {
+        // first, execute token permissions to set token allowance
+        _permit(permits);
+        // then, fill orders
+        fill(outputs);
+    }
 }
 
 /// @notice Contract capable of registering initiation of intent-based Orders.
-abstract contract OrderOrigin {
+abstract contract OrderOrigin is PermitLib {
     /// @notice Thrown when an Order is submitted with a deadline that has passed.
     error OrderExpired();
 
@@ -86,7 +94,7 @@ abstract contract OrderOrigin {
     /// @param outputs - The token amounts that must be received on their target chain(s) in order for the Order to be executed.
     /// @custom:reverts OrderExpired if the deadline has passed.
     /// @custom:emits Order if the transaction mines.
-    function initiate(uint256 deadline, Input[] memory inputs, Output[] memory outputs) external payable {
+    function initiate(uint256 deadline, Input[] memory inputs, Output[] memory outputs) public payable {
         // check that the deadline hasn't passed
         if (block.timestamp > deadline) revert OrderExpired();
 
@@ -97,6 +105,16 @@ abstract contract OrderOrigin {
         emit Order(deadline, inputs, outputs);
     }
 
+    function initiatePermit(Permit[] memory permits, uint256 deadline, Input[] memory inputs, Output[] memory outputs)
+        external
+        payable
+    {
+        // first, execute token permissions to set token allowance
+        _permit(permits);
+        // then, initiate the Order
+        initiate(deadline, inputs, outputs);
+    }
+
     /// @notice Transfer the Order inputs to this contract, where they can be collected by the Order filler.
     function _transferInputs(Input[] memory inputs) internal {
         uint256 value = msg.value;

src/Passage.sol

@@ -2,10 +2,11 @@
 pragma solidity ^0.8.24;
 
 import {IERC20} from "openzeppelin-contracts/contracts/token/ERC20/IERC20.sol";
+import {Permit, PermitLib} from "./Permit.sol";
 
 /// @notice A contract deployed to Host chain that allows tokens to enter the rollup,
 ///         and enables Builders to fulfill requests to exchange tokens on the Rollup for tokens on the Host.
-contract Passage {
+contract Passage is PermitLib {
     /// @notice The chainId of rollup that Ether will be sent to by default when entering the rollup via fallback() or receive().
     uint256 public immutable defaultRollupChainId;
 
@@ -106,6 +107,18 @@ contract Passage {
         enterToken(defaultRollupChainId, rollupRecipient, token, amount);
     }
 
+    /// @notice Allows ERC20 tokens to enter the rollup with a permit message.
+    function enterTokenPermit(
+        uint256 rollupChainId,
+        address rollupRecipient,
+        address token,
+        uint256 amount,
+        Permit memory permit
+    ) external {
+        _permit(permit);
+        enterToken(rollupChainId, rollupRecipient, token, amount);
+    }
+
     /// @notice Allows a special transaction to be sent to the rollup with sender == L1 msg.sender.
     /// @dev Transaction is processed after normal rollup block execution.
     /// @dev See `enterTransact` for docs.

src/Permit.sol

@@ -0,0 +1,29 @@
+    // SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.24;
+
+import {IERC20Permit} from "openzeppelin-contracts/contracts/token/ERC20/extensions/IERC20Permit.sol";
+
+struct Permit {
+    address token;
+    address owner;
+    address spender;
+    uint256 value;
+    uint256 deadline;
+    uint8 v;
+    bytes32 r;
+    bytes32 s;
+}
+
+abstract contract PermitLib {
+    function _permit(Permit memory permit) internal {
+        IERC20Permit(permit.token).permit(
+            permit.owner, permit.spender, permit.value, permit.deadline, permit.v, permit.r, permit.s
+        );
+    }
+
+    function _permit(Permit[] memory permits) internal {
+        for (uint256 i; i < permits.length; i++) {
+            _permit(permits[i]);
+        }
+    }
+}