/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.server;
import android.util.Log;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.InetAddress;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.BufferedWriter;
import java.io.OutputStreamWriter;
/**
* The ViewServer is local socket server that can be used to communicate with the
* views of the opened windows. Communication with the views is ensured by the
* {@link com.android.server.WindowManagerService} and is a cross-process operation.
*
* {@hide}
*/
class ViewServer implements Runnable {
/**
* The default port used to start view servers.
*/
public static final int VIEW_SERVER_DEFAULT_PORT = 4939;
// Debug facility
private static final String LOG_TAG = "ViewServer";
private static final String VALUE_PROTOCOL_VERSION = "2";
private static final String VALUE_SERVER_VERSION = "2";
// Protocol commands
// Returns the protocol version
private static final String COMMAND_PROTOCOL_VERSION = "PROTOCOL";
// Returns the server version
private static final String COMMAND_SERVER_VERSION = "SERVER";
// Lists all of the available windows in the system
private static final String COMMAND_WINDOW_MANAGER_LIST = "LIST";
private ServerSocket mServer;
private Thread mThread;
private final WindowManagerService mWindowManager;
private final int mPort;
/**
* Creates a new ViewServer associated with the specified window manager.
* The server uses the default port {@link #VIEW_SERVER_DEFAULT_PORT}. The server
* is not started by default.
*
* @param windowManager The window manager used to communicate with the views.
*
* @see #start()
*/
ViewServer(WindowManagerService windowManager) {
this(windowManager, VIEW_SERVER_DEFAULT_PORT);
}
/**
* Creates a new ViewServer associated with the specified window manager on the
* specified local port. The server is not started by default.
*
* @param windowManager The window manager used to communicate with the views.
* @param port The port for the server to listen to.
*
* @see #start()
*/
ViewServer(WindowManagerService windowManager, int port) {
mWindowManager = windowManager;
mPort = port;
}
/**
* Starts the server.
*
* @return True if the server was successfully created, or false if it already exists.
* @throws IOException If the server cannot be created.
*
* @see #stop()
* @see #isRunning()
* @see WindowManagerService#startViewServer(int)
*/
boolean start() throws IOException {
if (mThread != null) {
return false;
}
mServer = new ServerSocket(mPort, 1, InetAddress.getLocalHost());
mThread = new Thread(this, "Remote View Server [port=" + mPort + "]");
mThread.start();
return true;
}
/**
* Stops the server.
*
* @return True if the server was stopped, false if an error occured or if the
* server wasn't started.
*
* @see #start()
* @see #isRunning()
* @see WindowManagerService#stopViewServer()
*/
boolean stop() {
if (mThread != null) {
mThread.interrupt();
mThread = null;
try {
mServer.close();
mServer = null;
return true;
} catch (IOException e) {
Log.w(LOG_TAG, "Could not close the view server");
}
}
return false;
}
/**
* Indicates whether the server is currently running.
*
* @return True if the server is running, false otherwise.
*
* @see #start()
* @see #stop()
* @see WindowManagerService#isViewServerRunning()
*/
boolean isRunning() {
return mThread != null && mThread.isAlive();
}
/**
* Main server loop.
*/
public void run() {
final ServerSocket server = mServer;
while (Thread.currentThread() == mThread) {
Socket client = null;
// Any uncaught exception will crash the system process
try {
client = server.accept();
BufferedReader in = null;
try {
in = new BufferedReader(new InputStreamReader(client.getInputStream()), 1024);
final String request = in.readLine();
String command;
String parameters;
int index = request.indexOf(' ');
if (index == -1) {
command = request;
parameters = "";
} else {
command = request.substring(0, index);
parameters = request.substring(index + 1);
}
boolean result;
if (COMMAND_PROTOCOL_VERSION.equalsIgnoreCase(command)) {
result = writeValue(client, VALUE_PROTOCOL_VERSION);
} else if (COMMAND_SERVER_VERSION.equalsIgnoreCase(command)) {
result = writeValue(client, VALUE_SERVER_VERSION);
} else if (COMMAND_WINDOW_MANAGER_LIST.equalsIgnoreCase(command)) {
result = mWindowManager.viewServerListWindows(client);
} else {
result = mWindowManager.viewServerWindowCommand(client,
command, parameters);
}
if (!result) {
Log.w(LOG_TAG, "An error occured with the command: " + command);
}
} finally {
if (in != null) {
in.close();
}
}
} catch (Exception e) {
Log.w(LOG_TAG, "Connection error: ", e);
} finally {
if (client != null) {
try {
client.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
private static boolean writeValue(Socket client, String value) {
boolean result;
BufferedWriter out = null;
try {
OutputStream clientStream = client.getOutputStream();
out = new BufferedWriter(new OutputStreamWriter(clientStream), 8 * 1024);
out.write(value);
out.write("\n");
out.flush();
result = true;
} catch (Exception e) {
result = false;
} finally {
if (out != null) {
try {
out.close();
} catch (IOException e) {
result = false;
}
}
}
return result;
}
}