evm: Base Bridge request

Author: evan-gray

README.md

@@ -313,6 +313,15 @@ bytes4  prefix = "ERC2" // 4-byte prefix for this struct
 uint8   autoDiscover    // Currently, must be one.
 ```
 
+##### Base Bridge Request
+
+[Base Bridge](https://github.com/base/bridge)
+
+```solidity
+bytes4  prefix = "ERB1" // 4-byte prefix for this struct
+uint8   autoDiscover    // Currently, must be one.
+```
+
 #### Relay Instructions
 
 ##### Gas Instruction

evm/src/libraries/ExecutorMessages.sol

@@ -6,6 +6,7 @@ library ExecutorMessages {
     bytes4 private constant REQ_NTT_V1 = "ERN1";
     bytes4 private constant REQ_CCTP_V1 = "ERC1";
     bytes4 private constant REQ_CCTP_V2 = "ERC2";
+    bytes4 private constant REQ_BASE_V1 = "ERB1";
 
     /// @notice Payload length will not fit in a uint32.
     /// @dev Selector: 492f620d.
@@ -52,4 +53,12 @@ library ExecutorMessages {
     function makeCCTPv2Request() internal pure returns (bytes memory) {
         return abi.encodePacked(REQ_CCTP_V2, uint8(1));
     }
+
+    /// @notice Encodes a version 1 Base Bridge request payload.
+    ///         This request currently assumes the Executor will auto detect the event off chain.
+    ///         That may change in the future, in which case this interface would change.
+    /// @return bytes The encoded request.
+    function makeBaseBridgeV1Request() internal pure returns (bytes memory) {
+        return abi.encodePacked(REQ_BASE_V1, uint8(1));
+    }
 }

evm/test/ExecutorMessages.t.sol

@@ -35,4 +35,10 @@ contract ExecutorMessagesTest is Test {
         bytes memory buf = ExecutorMessages.makeCCTPv2Request();
         assertEq(keccak256(expected), keccak256(buf));
     }
+
+    function test_makeBaseBridgeV1Request() public pure {
+        bytes memory expected = abi.encodePacked("ERB1", uint8(1));
+        bytes memory buf = ExecutorMessages.makeBaseBridgeV1Request();
+        assertEq(keccak256(expected), keccak256(buf));
+    }
 }