chore(remotes): extract reuseOrReturnChannel to shared utility

Deduplicate the reuseOrReturnChannel function that existed in both
transport.ts and reconnection-orchestrator.ts by extracting it to a
new channel-utils.ts module.

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: sirtimid

packages/ocap-kernel/src/remotes/platform/channel-utils.ts

@@ -0,0 +1,44 @@
+import type { ConnectionFactory } from './connection-factory.ts';
+import type { PeerRegistry } from './peer-registry.ts';
+import type { Channel } from '../types.ts';
+
+/**
+ * Check if an existing channel exists for a peer, and if so, reuse it.
+ * Otherwise, return the dialed channel for the caller to register.
+ *
+ * @param peerId - The peer ID for the channel.
+ * @param dialedChannel - The newly dialed channel.
+ * @param peerRegistry - The peer registry to check for existing channels.
+ * @param connectionFactory - The connection factory to close channels.
+ * @returns The channel to use, or null if existing channel died and dialed was closed.
+ */
+export async function reuseOrReturnChannel(
+  peerId: string,
+  dialedChannel: Channel,
+  peerRegistry: PeerRegistry,
+  connectionFactory: ConnectionFactory,
+): Promise<Channel | null> {
+  const existingChannel = peerRegistry.getChannel(peerId);
+  if (existingChannel) {
+    if (dialedChannel !== existingChannel) {
+      await connectionFactory.closeChannel(dialedChannel, peerId);
+      const currentChannel = peerRegistry.getChannel(peerId);
+      if (currentChannel === existingChannel) {
+        return existingChannel;
+      }
+      if (currentChannel) {
+        return currentChannel;
+      }
+      return null;
+    }
+    const currentChannel = peerRegistry.getChannel(peerId);
+    if (currentChannel === existingChannel) {
+      return existingChannel;
+    }
+    if (currentChannel) {
+      return currentChannel;
+    }
+    return null;
+  }
+  return dialedChannel;
+}

packages/ocap-kernel/src/remotes/platform/reconnection-orchestrator.ts

@@ -6,6 +6,7 @@ import {
 import type { Logger } from '@metamask/logger';
 import { fromString } from 'uint8arrays';
 
+import { reuseOrReturnChannel } from './channel-utils.ts';
 import type { ConnectionFactory } from './connection-factory.ts';
 import type { MessageQueue } from './message-queue.ts';
 import type { PeerRegistry } from './peer-registry.ts';
@@ -111,43 +112,6 @@ export function makeReconnectionOrchestrator(
     }
   }
 
-  /**
-   * Check if an existing channel exists for a peer, and if so, reuse it.
-   * Otherwise, return the dialed channel for the caller to register.
-   *
-   * @param peerId - The peer ID for the channel.
-   * @param dialedChannel - The newly dialed channel.
-   * @returns The channel to use, or null if existing channel died and dialed was closed.
-   */
-  async function reuseOrReturnChannel(
-    peerId: string,
-    dialedChannel: Channel,
-  ): Promise<Channel | null> {
-    const existingChannel = peerRegistry.getChannel(peerId);
-    if (existingChannel) {
-      if (dialedChannel !== existingChannel) {
-        await connectionFactory.closeChannel(dialedChannel, peerId);
-        const currentChannel = peerRegistry.getChannel(peerId);
-        if (currentChannel === existingChannel) {
-          return existingChannel;
-        }
-        if (currentChannel) {
-          return currentChannel;
-        }
-        return null;
-      }
-      const currentChannel = peerRegistry.getChannel(peerId);
-      if (currentChannel === existingChannel) {
-        return existingChannel;
-      }
-      if (currentChannel) {
-        return currentChannel;
-      }
-      return null;
-    }
-    return dialedChannel;
-  }
-
   /**
    * Handle connection loss for a given peer ID.
    * Skips reconnection if the peer was intentionally closed.
@@ -244,7 +208,12 @@ export function makeReconnectionOrchestrator(
 
         queue = peerRegistry.getMessageQueue(peerId);
 
-        channel = await reuseOrReturnChannel(peerId, channel);
+        channel = await reuseOrReturnChannel(
+          peerId,
+          channel,
+          peerRegistry,
+          connectionFactory,
+        );
         if (channel === null) {
           logger.log(
             `${peerId}:: existing channel died during reuse check, continuing reconnection loop`,

packages/ocap-kernel/src/remotes/platform/transport.ts

@@ -4,6 +4,7 @@ import { Logger } from '@metamask/logger';
 import { fromString } from 'uint8arrays';
 
 import { makeChannelReader } from './channel-reader.ts';
+import { reuseOrReturnChannel } from './channel-utils.ts';
 import { ConnectionFactory } from './connection-factory.ts';
 import { PeerRegistry } from './peer-registry.ts';
 import { makeReconnectionOrchestrator } from './reconnection-orchestrator.ts';
@@ -246,42 +247,6 @@ export async function initNetwork(
     outputError,
   });
 
-  /**
-   * Check if an existing channel exists for a peer, and if so, reuse it.
-   *
-   * @param peerId - The peer ID for the channel.
-   * @param dialedChannel - The newly dialed channel.
-   * @returns The channel to use, or null if existing channel died and dialed was closed.
-   */
-  async function reuseOrReturnChannel(
-    peerId: string,
-    dialedChannel: Channel,
-  ): Promise<Channel | null> {
-    const existingChannel = peerRegistry.getChannel(peerId);
-    if (existingChannel) {
-      if (dialedChannel !== existingChannel) {
-        await connectionFactory.closeChannel(dialedChannel, peerId);
-        const currentChannel = peerRegistry.getChannel(peerId);
-        if (currentChannel === existingChannel) {
-          return existingChannel;
-        }
-        if (currentChannel) {
-          return currentChannel;
-        }
-        return null;
-      }
-      const currentChannel = peerRegistry.getChannel(peerId);
-      if (currentChannel === existingChannel) {
-        return existingChannel;
-      }
-      if (currentChannel) {
-        return currentChannel;
-      }
-      return null;
-    }
-    return dialedChannel;
-  }
-
   /**
    * Clean up stale peer data for peers inactive for more than stalePeerTimeoutMs.
    */
@@ -361,7 +326,12 @@ export async function initNetwork(
           return;
         }
 
-        channel = await reuseOrReturnChannel(targetPeerId, channel);
+        channel = await reuseOrReturnChannel(
+          targetPeerId,
+          channel,
+          peerRegistry,
+          connectionFactory,
+        );
         if (channel === null) {
           logger.log(
             `${targetPeerId}:: existing channel died during reuse check, triggering reconnection`,