HTML MessagePort as mojo::MessagePipeHandle

content/public/android/java/src/org/chromium/content/browser/AppWebMessagePortService.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.content.browser;
 
-import android.util.SparseArray;
-
-import org.chromium.base.ObserverList;
-import org.chromium.base.ThreadUtils;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
 import org.chromium.content_public.browser.MessagePortService;
 
 /**
  * Provides the Message Channel functionality for Android Apps
  * (including WebView embedders and Chrome Custom Tabs clients). Specifically
  * manages the message ports that are associated with a message channel and
  * handles posting/receiving messages to/from them.
  * See https://html.spec.whatwg.org/multipage/comms.html#messagechannel for
  * further information on message channels.
  *
  * The message ports have unique IDs. In Android implementation,
  * the message ports are only known by their IDs at the native side.
  * At the java side, the embedder deals with MessagePort objects. The mapping
  * from an ID to an object is in AppWebMessagePortService. AppWebMessagePortService
  * keeps a strong ref to MessagePort objects until they are closed.
  *
  * Ownership: The Java AppWebMessagePortService has to be owned by Java side global.
  * The native AppWebMessagePortService is a singleton. The
  * native peer maintains a weak ref to the java object and deregisters itself
  * before being deleted.
  *
  * All methods are called on UI thread except as noted.
  */
 @JNINamespace("content")
 public class AppWebMessagePortService implements MessagePortService {
     private static final String TAG = "AppWebMessagePortService";
 
-    /**
-     * Observer for MessageChannel events.
-     */
-    public static interface MessageChannelObserver { void onMessageChannelCreated(); }
-
-    // A thread safe storage for Message Ports.
-    private static class MessagePortStorage {
-        private SparseArray<AppWebMessagePort> mMessagePorts = new SparseArray<AppWebMessagePort>();
-        private final Object mLock = new Object();
-
-        public void remove(int portId) {
-            synchronized (mLock) {
-                mMessagePorts.remove(portId);
-            }
-        }
-
-        public void put(int portId, AppWebMessagePort m) {
-            synchronized (mLock) {
-                mMessagePorts.put(portId, m);
-            }
-        }
-        public AppWebMessagePort get(int portId) {
-            synchronized (mLock) {
-                return mMessagePorts.get(portId);
-            }
-        }
-    }
-
     private long mNativeMessagePortService;
-    private MessagePortStorage mPortStorage = new MessagePortStorage();
-    private ObserverList<MessageChannelObserver> mObserverList =
-            new ObserverList<MessageChannelObserver>();
 
     public AppWebMessagePortService() {
         mNativeMessagePortService = nativeInitAppWebMessagePortService();
     }
 
-    public void addObserver(MessageChannelObserver observer) {
-        mObserverList.addObserver(observer);
-    }
-
-    public void removeObserver(MessageChannelObserver observer) {
-        mObserverList.removeObserver(observer);
-    }
-
-    public void closePort(int messagePortId) {
-        mPortStorage.remove(messagePortId);
-        if (mNativeMessagePortService == 0) return;
-        nativeClosePort(mNativeMessagePortService, messagePortId);
-    }
-
-    public void postMessage(int senderId, String message, int[] sentPorts) {
-        // verify that the port is owned by service still (not transferred).
-        if (mPortStorage.get(senderId) == null) {
-            throw new IllegalStateException("Cannot post to unknown port " + senderId);
-        }
-        if (mNativeMessagePortService == 0) return;
-        nativePostAppToWebMessage(mNativeMessagePortService, senderId, message, sentPorts);
-    }
-
-    public void removeSentPorts(int[] sentPorts) {
-        // verify that this service still owns all the ports that are transferred
-        if (sentPorts != null) {
-            for (int port : sentPorts) {
-                AppWebMessagePort p = mPortStorage.get(port);
-                if (p == null) {
-                    throw new IllegalStateException("Cannot transfer unknown port " + port);
-                }
-                mPortStorage.remove(port);
-            }
-        }
-    }
-
     @Override
     public AppWebMessagePort[] createMessageChannel() {
-        return new AppWebMessagePort[] {new AppWebMessagePort(this), new AppWebMessagePort(this)};
-    }
-
-    // Called on UI thread.
-    public void releaseMessages(int portId) {
-        if (mNativeMessagePortService == 0) return;
-        nativeReleaseMessages(mNativeMessagePortService, portId);
-    }
-
-    private AppWebMessagePort addPort(AppWebMessagePort m, int portId) {
-        if (mPortStorage.get(portId) != null) {
-            throw new IllegalStateException("Port already exists");
-        }
-        m.setPortId(portId);
-        mPortStorage.put(portId, m);
-        return m;
+        return new AppWebMessagePort[] {new AppWebMessagePort(), new AppWebMessagePort()};

[Yusuf, 2017/01/26 22:53:54]

does this mean, we maybe don't need this class to exist on the java side
anymore?

The native part of this is a singleton in implementation and this seems to be
the only useful java call which can be a static inside AppWebMessagePort as
well. Then we might actually need a content/public interface for the message
port on the native side (and get rid of app_web_message_port_service.h as well.)

[sgurun-gerrit only, 2017/01/27 01:16:37]

yes, that is what I noticed too. 
please get rid of this file and move createMessageChannel functionality to
WebContentsImpl.java

     }
 
     @CalledByNative
-    private void onMessageChannelCreated(int portId1, int portId2, AppWebMessagePort[] ports) {
-        ThreadUtils.assertOnUiThread();
-        addPort(ports[0], portId1);
-        addPort(ports[1], portId2);
-        for (MessageChannelObserver observer : mObserverList) {
-            observer.onMessageChannelCreated();
-        }
-    }
-
-    // Called on IO thread.
-    @CalledByNative
-    private void onReceivedMessage(int portId, String message, int[] ports) {
-        AppWebMessagePort[] messagePorts = null;
-        for (int i = 0; i < ports.length; i++) {
-            if (messagePorts == null) {
-                messagePorts = new AppWebMessagePort[ports.length];
-            }
-            messagePorts[i] = addPort(new AppWebMessagePort(this), ports[i]);
-        }
-        mPortStorage.get(portId).onReceivedMessage(message, messagePorts);
-    }
-
-    @CalledByNative
     private void unregisterNativeAppWebMessagePortService() {
         mNativeMessagePortService = 0;
     }
 
     private native long nativeInitAppWebMessagePortService();
-    private native void nativePostAppToWebMessage(
-            long nativeAppWebMessagePortServiceImpl, int senderId, String message, int[] portIds);
-    private native void nativeClosePort(long nativeAppWebMessagePortServiceImpl, int messagePortId);
-    private native void nativeReleaseMessages(
-            long nativeAppWebMessagePortServiceImpl, int messagePortId);
 }