Implement the close() API for Message ports

android_webview/java/src/org/chromium/android_webview/PostMessageSender.java

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.android_webview;
 
 import java.util.ArrayDeque;
 
 /**
  * Sanity checks and sends post messages to web. Queues messages if necessary.
  */
 public class PostMessageSender implements AwMessagePortService.MessageChannelObserver {
 
     /**
      * The interface for message handler.
      */
     public static interface PostMessageSenderDelegate {
 
         /*
          * Posts a message to the destination frame for real. The unique message port
          * id of any transferred port should be known at this time.
          */
         void postMessageToWeb(String frameName, String message, String targetOrigin,
                 int[] sentPortIds);
+
+        /*
+         * Whether the post message sender is ready to post messages.
+         */
+        boolean isPostMessageSenderReady();
+
+        /*
+         * Informs that all messages are posted and message queue is empty.
+         */
+        void onPostMessageQueueEmpty();
     };
 
     // A struct to store Message parameters that are sent from App to Web.
     private static class PostMessageParams {
         public String frameName;
         public String message;
         public String targetOrigin;
         public MessagePort[] sentPorts;
 
         public PostMessageParams(String frameName, String message, String targetOrigin,
@@ skipping 12 matching lines @@
     // is not internally created yet), this message, and any following messages will be
     // queued until the transferred port becomes ready. This is necessary to prevent any
     // reordering.
     private ArrayDeque<PostMessageParams> mMessageQueue = new ArrayDeque<PostMessageParams>();
 
     public PostMessageSender(PostMessageSenderDelegate delegate, AwMessagePortService service) {
         mDelegate = delegate;
         mService = service;
     }
 
+    public boolean isMessageQueueEmpty() {
+        return mMessageQueue.size() > 0;

[hush (inactive), 2015/02/25 19:44:27]

shouldn't this be == 0? I will be surprised if the tests pass with this...

[sgurun-gerrit only, 2015/02/25 21:38:53]

Done.

+    }
+
     // Return true if any sent port is pending.
     private boolean anySentPortIsPending(MessagePort[] sentPorts) {
         if (sentPorts != null) {
             for (MessagePort port : sentPorts) {
                 if (!port.isReady()) {
                     return true;
                 }
             }
         }
         return false;
     }
 
-    // By default the sender is always ready.
-    protected boolean senderIsReady() {
-        return true;
-    }
-
     // A message to a frame is queued if:
     // 1. Sender is not ready to post. When posting messages to frames, sender is always
     // ready. However, when posting messages using message channels, sender may be in
     // a pending state.
     // 2. There are already queued messages
     // 3. The message includes a port that is not ready yet.
     private boolean shouldQueueMessage(MessagePort[] sentPorts) {
         // if messages to frames are already in queue mode, simply queue it, no need to
         // check ports.
-        if (mMessageQueue.size() > 0 || !senderIsReady()) {
+        if (mMessageQueue.size() > 0 || !mDelegate.isPostMessageSenderReady()) {

[hush (inactive), 2015/02/25 19:44:27]

use isMessageQueueEmpty() here since you have created such a method

[sgurun-gerrit only, 2015/02/25 21:38:53]

I think I can read this a lot faster :) the method is for public access

             return true;
         }
         if (anySentPortIsPending(sentPorts)) {
             return true;
         }
         return false;
     }
 
     private void postMessageToWeb(String frameName, String message, String targetOrigin,
             MessagePort[] sentPorts) {
@@ skipping 30 matching lines @@
             postMessageToWeb(frameName, message, targetOrigin, sentPorts);
         }
     }
 
     /*
      * Starts posting any messages that are queued.
      */
     public void onMessageChannelCreated() {
         PostMessageParams msg;
 
-        if (!senderIsReady()) {
+        if (!mDelegate.isPostMessageSenderReady()) {
             return;
         }
 
         while ((msg = mMessageQueue.peek()) != null) {
             // If there are still pending ports, message cannot be posted.
             if (anySentPortIsPending(msg.sentPorts)) {
                 return;
             }
             mMessageQueue.remove();
             postMessageToWeb(msg.frameName, msg.message, msg.targetOrigin, msg.sentPorts);
         }
+        mDelegate.onPostMessageQueueEmpty();
     }
 }