Home | History | Annotate | Download | only in webkit 
      1 /*
      2  * Copyright (C) 2007 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.webkit;
     18 
     19 import android.content.Context;
     20 import android.os.Handler;
     21 import android.os.Looper;
     22 import android.os.Message;
     23 import android.os.Process;
     24 import android.util.Log;
     25 
     26 abstract class WebSyncManager implements Runnable {
     27     // message code for sync message
     28     private static final int SYNC_MESSAGE = 101;
     29     // time delay in millisec for a sync (now) message
     30     private static int SYNC_NOW_INTERVAL = 100; // 100 millisec
     31     // time delay in millisec for a sync (later) message
     32     private static int SYNC_LATER_INTERVAL = 5 * 60 * 1000; // 5 minutes
     33     // thread for syncing
     34     private Thread mSyncThread;
     35     // Name of thread
     36     private String mThreadName;
     37     // handler of the sync thread
     38     protected Handler mHandler;
     39     // database for the persistent storage. Always null.
     40     protected WebViewDatabase mDataBase;
     41     // Ref count for calls to start/stop sync
     42     private int mStartSyncRefCount;
     43     // log tag
     44     protected static final String LOGTAG = "websync";
     45 
     46     private class SyncHandler extends Handler {
     47         @Override
     48         public void handleMessage(Message msg) {
     49             if (msg.what == SYNC_MESSAGE) {
     50                 if (DebugFlags.WEB_SYNC_MANAGER) {
     51                     Log.v(LOGTAG, "*** WebSyncManager sync ***");
     52                 }
     53                 syncFromRamToFlash();
     54 
     55                 // send a delayed message to request sync later
     56                 Message newmsg = obtainMessage(SYNC_MESSAGE);
     57                 sendMessageDelayed(newmsg, SYNC_LATER_INTERVAL);
     58             }
     59         }
     60     }
     61 
     62     protected WebSyncManager(Context context, String name) {
     63         this(name);
     64     }
     65 
     66     /** @hide */
     67     WebSyncManager(String name) {
     68         mThreadName = name;
     69         mSyncThread = new Thread(this);
     70         mSyncThread.setName(mThreadName);
     71         mSyncThread.start();
     72     }
     73 
     74     protected Object clone() throws CloneNotSupportedException {
     75         throw new CloneNotSupportedException("doesn't implement Cloneable");
     76     }
     77 
     78     public void run() {
     79         // prepare Looper for sync handler
     80         Looper.prepare();
     81         mHandler = new SyncHandler();
     82         onSyncInit();
     83         // lower the priority after onSyncInit() is done
     84         Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
     85 
     86         Message msg = mHandler.obtainMessage(SYNC_MESSAGE);
     87         mHandler.sendMessageDelayed(msg, SYNC_LATER_INTERVAL);
     88 
     89         Looper.loop();
     90     }
     91 
     92     /**
     93      * sync() forces sync manager to sync now
     94      */
     95     public void sync() {
     96         if (DebugFlags.WEB_SYNC_MANAGER) {
     97             Log.v(LOGTAG, "*** WebSyncManager sync ***");
     98         }
     99         if (mHandler == null) {
    100             return;
    101         }
    102         mHandler.removeMessages(SYNC_MESSAGE);
    103         Message msg = mHandler.obtainMessage(SYNC_MESSAGE);
    104         mHandler.sendMessageDelayed(msg, SYNC_NOW_INTERVAL);
    105     }
    106 
    107     /**
    108      * resetSync() resets sync manager's timer
    109      */
    110     public void resetSync() {
    111         if (DebugFlags.WEB_SYNC_MANAGER) {
    112             Log.v(LOGTAG, "*** WebSyncManager resetSync ***");
    113         }
    114         if (mHandler == null) {
    115             return;
    116         }
    117         mHandler.removeMessages(SYNC_MESSAGE);
    118         Message msg = mHandler.obtainMessage(SYNC_MESSAGE);
    119         mHandler.sendMessageDelayed(msg, SYNC_LATER_INTERVAL);
    120     }
    121 
    122     /**
    123      * startSync() requests sync manager to start sync
    124      */
    125     public void startSync() {
    126         if (DebugFlags.WEB_SYNC_MANAGER) {
    127             Log.v(LOGTAG, "***  WebSyncManager startSync ***, Ref count:" +
    128                     mStartSyncRefCount);
    129         }
    130         if (mHandler == null) {
    131             return;
    132         }
    133         if (++mStartSyncRefCount == 1) {
    134             Message msg = mHandler.obtainMessage(SYNC_MESSAGE);
    135             mHandler.sendMessageDelayed(msg, SYNC_LATER_INTERVAL);
    136         }
    137     }
    138 
    139     /**
    140      * stopSync() requests sync manager to stop sync. remove any SYNC_MESSAGE in
    141      * the queue to break the sync loop
    142      */
    143     public void stopSync() {
    144         if (DebugFlags.WEB_SYNC_MANAGER) {
    145             Log.v(LOGTAG, "*** WebSyncManager stopSync ***, Ref count:" +
    146                     mStartSyncRefCount);
    147         }
    148         if (mHandler == null) {
    149             return;
    150         }
    151         if (--mStartSyncRefCount == 0) {
    152             mHandler.removeMessages(SYNC_MESSAGE);
    153         }
    154     }
    155 
    156     protected void onSyncInit() {
    157     }
    158 
    159     abstract void syncFromRamToFlash();
    160 }
    161