feat(bridge): add getMessageStatusSlot function

packages/protocol/contracts/L1/libs/LibProposing.sol

@@ -140,15 +140,6 @@ library LibProposing {
         emit BlockProposed(state.nextBlockId++, meta);
     }
 
-    function getProposedBlock(
-        TaikoData.State storage state,
-        uint256 maxNumBlocks,
-        uint256 id
-    ) internal view returns (TaikoData.ProposedBlock storage) {
-        require(id > state.latestVerifiedId && id < state.nextBlockId, "L1:id");
-        return state.getProposedBlock(maxNumBlocks, id);
-    }
-
     function getBlockFee(
         TaikoData.State storage state,
         TaikoData.Config memory config
@@ -185,6 +176,15 @@ library LibProposing {
             block.number >= commitHeight + commitConfirmations;
     }
 
+    function getProposedBlock(
+        TaikoData.State storage state,
+        uint256 maxNumBlocks,
+        uint256 id
+    ) internal view returns (TaikoData.ProposedBlock storage) {
+        require(id > state.latestVerifiedId && id < state.nextBlockId, "L1:id");
+        return state.getProposedBlock(maxNumBlocks, id);
+    }
+
     function _saveProposedBlock(
         TaikoData.State storage state,
         uint256 maxNumBlocks,

packages/protocol/contracts/bridge/Bridge.sol

@@ -161,4 +161,10 @@ contract Bridge is EssentialContract, IBridge {
         return
             LibBridgeSend.isDestChainEnabled(AddressResolver(this), _chainId);
     }
+
+    function getMessageStatusSlot(
+        bytes32 signal
+    ) public pure returns (bytes32) {
+        return LibBridgeStatus.getMessageStatusSlot(signal);
+    }
 }

packages/protocol/contracts/bridge/libs/LibBridgeSend.sol

@@ -26,8 +26,8 @@ library LibBridgeSend {
      *
      * @param message Specifies the `depositValue`, `callValue`,
      * and `processingFee`. These must sum to `msg.value`. It also specifies the
-     * `destChainId` which must have a `bridge` address set on the AddressResolver
-     * and differ from the current chain ID.
+     * `destChainId` which must have a `bridge` address set on the
+     * AddressResolver and differ from the current chain ID.
      *
      * @return signal The message is hashed, stored, and emitted as a signal.
      * This is picked up by an off-chain relayer which indicates a

packages/protocol/contracts/bridge/libs/LibBridgeStatus.sol

@@ -40,23 +40,25 @@ library LibBridgeStatus {
     function getMessageStatus(
         bytes32 signal
     ) internal view returns (MessageStatus) {
-        bytes32 k = _statusSlot(signal);
-        uint256 v;
+        bytes32 slot = getMessageStatusSlot(signal);
+        uint256 value;
         assembly {
-            v := sload(k)
+            value := sload(slot)
         }
-        return MessageStatus(v);
+        return MessageStatus(value);
+    }
+
+    function getMessageStatusSlot(
+        bytes32 signal
+    ) internal pure returns (bytes32) {
+        return keccak256(abi.encodePacked("MESSAGE_STATUS", signal));
     }
 
     function _setMessageStatus(bytes32 signal, MessageStatus status) private {
-        bytes32 k = _statusSlot(signal);
-        uint256 v = uint256(status);
+        bytes32 slot = getMessageStatusSlot(signal);
+        uint256 value = uint256(status);
         assembly {
-            sstore(k, v)
+            sstore(slot, value)
         }
     }
-
-    function _statusSlot(bytes32 signal) private pure returns (bytes32) {
-        return keccak256(abi.encodePacked("MESSAGE_STATUS", signal));
-    }
 }