Move MessagePort implementation from android_webview to content

android_webview/java/src/org/chromium/android_webview/AwMessagePortService.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 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;
-
-/**
- * Provides the Message Channel functionality for Android Webview. 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 webview 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 AwMessagePortService. AwMessagePortService
- * keeps a strong ref to MessagePort objects until they are closed.
- *
- * Ownership: The Java AwMessagePortService is owned by Java AwBrowserContext.
- * The native AwMessagePortService is owned by native AwBrowserContext. 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("android_webview")
-public class AwMessagePortService {
-
-    private static final String TAG = "AwMessagePortService";
-
-    /**
-     * Observer for MessageChannel events.
-     */
-    public static interface MessageChannelObserver {
-        void onMessageChannelCreated();
-    }
-
-    // A thread safe storage for Message Ports.
-    private static class MessagePortStorage {
-        private SparseArray<AwMessagePort> mMessagePorts = new SparseArray<AwMessagePort>();
-        private final Object mLock = new Object();
-
-        public void remove(int portId) {
-            synchronized (mLock) {
-                mMessagePorts.remove(portId);
-            }
-        }
-
-        public void put(int portId, AwMessagePort m) {
-            synchronized (mLock) {
-                mMessagePorts.put(portId, m);
-            }
-        }
-        public AwMessagePort get(int portId) {
-            synchronized (mLock) {
-                return mMessagePorts.get(portId);
-            }
-        }
-    }
-
-    private long mNativeMessagePortService;
-    private MessagePortStorage mPortStorage = new MessagePortStorage();
-    private ObserverList<MessageChannelObserver> mObserverList =
-            new ObserverList<MessageChannelObserver>();
-
-    AwMessagePortService() {
-        mNativeMessagePortService = nativeInitAwMessagePortService();
-    }
-
-    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 webview still owns the port (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 webview owns all the ports that are transferred
-        if (sentPorts != null) {
-            for (int port : sentPorts) {
-                AwMessagePort p = mPortStorage.get(port);
-                if (p == null) {
-                    throw new IllegalStateException("Cannot transfer unknown port " + port);
-                }
-                mPortStorage.remove(port);
-            }
-        }
-    }
-
-    public AwMessagePort[] createMessageChannel() {
-        return new AwMessagePort[]{new AwMessagePort(this), new AwMessagePort(this)};
-    }
-
-    // Called on UI thread.
-    public void releaseMessages(int portId) {
-        if (mNativeMessagePortService == 0) return;
-        nativeReleaseMessages(mNativeMessagePortService, portId);
-    }
-
-    private AwMessagePort addPort(AwMessagePort m, int portId) {
-        if (mPortStorage.get(portId) != null) {
-            throw new IllegalStateException("Port already exists");
-        }
-        m.setPortId(portId);
-        mPortStorage.put(portId, m);
-        return m;
-    }
-
-    @CalledByNative
-    private void onMessageChannelCreated(int portId1, int portId2,
-            AwMessagePort[] 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) {
-        AwMessagePort[] messagePorts = null;
-        for (int i = 0; i < ports.length; i++) {
-            if (messagePorts == null) {
-                messagePorts = new AwMessagePort[ports.length];
-            }
-            messagePorts[i] = addPort(new AwMessagePort(this), ports[i]);
-        }
-        mPortStorage.get(portId).onReceivedMessage(message, messagePorts);
-    }
-
-    @CalledByNative
-    private void unregisterNativeAwMessagePortService() {
-        mNativeMessagePortService = 0;
-    }
-
-    private native long nativeInitAwMessagePortService();
-    private native void nativePostAppToWebMessage(long nativeAwMessagePortServiceImpl,
-            int senderId, String message, int[] portIds);
-    private native void nativeClosePort(long nativeAwMessagePortServiceImpl,
-            int messagePortId);
-    private native void nativeReleaseMessages(long nativeAwMessagePortServiceImpl,
-            int messagePortId);
-}