/*
|
* Copyright (C) 2008 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.mozillaonline.providers.downloads;
|
|
import java.io.File;
|
import java.util.HashMap;
|
import java.util.HashSet;
|
import java.util.Iterator;
|
import java.util.Map;
|
import java.util.Set;
|
|
import android.app.AlarmManager;
|
import android.app.PendingIntent;
|
import android.app.Service;
|
import android.content.ContentUris;
|
import android.content.Context;
|
import android.content.Intent;
|
import android.content.SharedPreferences;
|
import android.content.SharedPreferences.Editor;
|
import android.database.ContentObserver;
|
import android.database.Cursor;
|
import android.net.Uri;
|
import android.os.Environment;
|
import android.os.Handler;
|
import android.os.IBinder;
|
import android.os.Process;
|
import android.util.Log;
|
|
/**
|
* Performs the background downloads requested by applications that use the
|
* Downloads provider.
|
*/
|
public class DownloadService extends Service {
|
/** Observer to get notified when the content observer's data changes */
|
private DownloadManagerContentObserver mObserver;
|
|
/** Class to handle Notification Manager updates */
|
private DownloadNotification mNotifier;
|
|
/**
|
* The Service's view of the list of downloads, mapping download IDs to the
|
* corresponding info object. This is kept independently from the content
|
* provider, and the Service only initiates downloads based on this data, so
|
* that it can deal with situation where the data in the content provider
|
* changes or disappears.
|
*/
|
private Map<Long, DownloadInfo> mDownloads = new HashMap<Long, DownloadInfo>();
|
|
/**
|
* The thread that updates the internal download list from the content
|
* provider.
|
*/
|
UpdateThread mUpdateThread;
|
|
/**
|
* Whether the internal download list should be updated from the content
|
* provider.
|
*/
|
private boolean mPendingUpdate;
|
|
SystemFacade mSystemFacade;
|
|
/**
|
* Receives notifications when the data in the content provider changes
|
* 接收一条通知当content provider 中的数据改变的时候
|
*/
|
private class DownloadManagerContentObserver extends ContentObserver {
|
|
public DownloadManagerContentObserver() {
|
super(new Handler());
|
}
|
|
/**
|
* Receives notification when the data in the observed content provider
|
* changes.接收通知当数据发现content provider改变的时候
|
*/
|
public void onChange(final boolean selfChange) {
|
if (Constants.LOGVV) {
|
Log.v(Constants.TAG,
|
"Service ContentObserver received notification");
|
}
|
updateFromProvider();
|
}
|
|
}
|
|
/**
|
* Returns an IBinder instance when someone wants to connect to this
|
* service. Binding to this service is not allowed.
|
*
|
* @throws UnsupportedOperationException
|
*/
|
public IBinder onBind(Intent i) {
|
throw new UnsupportedOperationException(
|
"Cannot bind to Download Manager Service");
|
}
|
|
/**
|
* Initializes the service when it is first created 第一次启动的时候初始化service
|
*
|
*/
|
public void onCreate() {
|
super.onCreate();
|
if (Constants.LOGVV) {
|
Log.v(Constants.TAG, "Service onCreate");
|
}
|
|
if (mSystemFacade == null) {
|
mSystemFacade = new RealSystemFacade(this);
|
}
|
|
mObserver = new DownloadManagerContentObserver();
|
getContentResolver().registerContentObserver(
|
Downloads.ALL_DOWNLOADS_CONTENT_URI, true, mObserver);
|
|
mNotifier = new DownloadNotification(this, mSystemFacade);
|
mSystemFacade.cancelAllNotifications();
|
|
updateFromProvider();
|
}
|
|
public interface IGetMHasActiveThread {
|
public void onGetActive(boolean mHasActiveThread);
|
}
|
|
private IGetMHasActiveThread getActiveThread = null;
|
|
public void SetMHasActiveThread(IGetMHasActiveThread getActiveThread) {
|
this.getActiveThread = getActiveThread;
|
}
|
|
/**
|
* service初始化后直接执行此类
|
*/
|
@Override
|
public int onStartCommand(Intent intent, int flags, int startId) {
|
int returnValue = super.onStartCommand(intent, flags, startId);
|
if (Constants.LOGVV) {
|
Log.v(Constants.TAG, "Service onStart");
|
}
|
SharedPreferences preferences = getSharedPreferences("restart",
|
Context.MODE_PRIVATE);
|
Editor editor = preferences.edit();
|
editor.putBoolean("mDownload", true);
|
editor.commit();
|
updateFromProvider();
|
return returnValue;
|
}
|
|
/**
|
* Cleans up when the service is destroyed 清除数据当service是被摧毁的时候
|
*/
|
public void onDestroy() {
|
getContentResolver().unregisterContentObserver(mObserver);
|
if (Constants.LOGVV) {
|
Log.v(Constants.TAG, "Service onDestroy");
|
}
|
super.onDestroy();
|
}
|
|
/**
|
* Parses data from the content provider into private array 从content
|
* provider中的私有序列中解析数据
|
*/
|
private void updateFromProvider() {
|
synchronized (this) {
|
mPendingUpdate = true;
|
if (mUpdateThread == null) {
|
mUpdateThread = new UpdateThread();
|
mSystemFacade.startThread(mUpdateThread);
|
}
|
}
|
}
|
|
int i = 0;
|
boolean isFirst = true;
|
|
private class UpdateThread extends Thread {
|
public UpdateThread() {
|
super("Download Service");
|
}
|
|
public void run() {
|
Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
|
|
// 如果数据里的存储的达到了1000以上时候，将会删除status>200即失败的记录
|
trimDatabase();
|
removeSpuriousFiles();
|
|
boolean keepService = false;
|
// for each update from the database, remember which download is
|
// supposed to get restarted soonest in the future
|
long wakeUp = Long.MAX_VALUE;
|
// 会一直在此循环，直到启动完所有下载任务
|
for (;;) {
|
synchronized (DownloadService.this) {
|
if (mUpdateThread != this) {
|
throw new IllegalStateException(
|
"multiple UpdateThreads in DownloadService");
|
}
|
if (!mPendingUpdate) {
|
mUpdateThread = null;
|
if (!keepService) {
|
stopSelf();// service停止
|
}
|
if (wakeUp != Long.MAX_VALUE) {
|
scheduleAlarm(wakeUp);// 闹钟唤醒
|
}
|
return;
|
}
|
mPendingUpdate = false;
|
}
|
|
if (i > 0) {
|
isFirst = false;
|
i = 1;
|
} else {
|
isFirst = true;
|
}
|
long now = mSystemFacade.currentTimeMillis();
|
keepService = false;
|
wakeUp = Long.MAX_VALUE;
|
Set<Long> idsNoLongerInDatabase = new HashSet<Long>(
|
mDownloads.keySet());
|
|
Cursor cursor = getContentResolver().query(
|
Downloads.ALL_DOWNLOADS_CONTENT_URI, null, null, null,
|
null);
|
if (cursor == null) {
|
continue;
|
}
|
try {
|
// Cursor c = getContentResolver().query(
|
// Downloads.ALL_DOWNLOADS_CONTENT_URI,
|
// new String[] { Downloads._ID },
|
// Downloads.COLUMN_STATUS + "=?",
|
// new String[] { Downloads.STATUS_RUNNING + "" },
|
// Downloads._ID + " ASC");
|
// String id1 = "";
|
// if (c.moveToNext() && c != null) {
|
// id1 = c.getString(0);
|
// }
|
// if (c.getCount() == 0 && cursor.getCount() >= 1) {
|
// ContentValues values = new ContentValues();
|
// values.put(Downloads.COLUMN_STATUS,
|
// Downloads.STATUS_RUNNING);
|
// getContentResolver().update(
|
// Downloads.ALL_DOWNLOADS_CONTENT_URI, values,
|
// Downloads._ID + "=?", new String[] { id1 });
|
// }
|
DownloadInfo.Reader reader = new DownloadInfo.Reader(
|
getContentResolver(), cursor);
|
if (getActiveThread != null) {
|
getActiveThread.onGetActive(false);
|
}
|
int idColumn = cursor.getColumnIndexOrThrow(Downloads._ID);
|
|
for (cursor.moveToFirst(); !cursor.isAfterLast(); cursor
|
.moveToNext()) {
|
long id = cursor.getLong(idColumn);
|
idsNoLongerInDatabase.remove(id);
|
|
DownloadInfo info = mDownloads.get(id);// 获取下载信息
|
if (info != null) {
|
updateDownload(reader, info, now);// 更新下载
|
} else {
|
info = insertDownload(reader, now);// 插入一个下载
|
}
|
if (info.hasCompletionNotification()) {
|
keepService = true;
|
}
|
long next = info.nextAction(now);
|
if (next == 0) {
|
keepService = true;
|
} else if (next > 0 && next < wakeUp) {
|
wakeUp = next;
|
}
|
}
|
} finally {
|
cursor.close();
|
}
|
|
for (Long id : idsNoLongerInDatabase) {
|
deleteDownload(id);
|
}
|
|
// is there a need to start the DownloadService? yes, if there
|
// are rows to be deleted.
|
|
for (DownloadInfo info : mDownloads.values()) {
|
if (info.mDeleted) {
|
keepService = true;
|
break;
|
}
|
}
|
|
mNotifier.updateNotification(mDownloads.values());
|
|
// look for all rows with deleted flag set and delete the rows
|
// from the database
|
// permanently
|
for (DownloadInfo info : mDownloads.values()) {
|
if (info.mDeleted) {
|
Helpers.deleteFile(getContentResolver(), info.mId,
|
info.mFileName, info.mMimeType);
|
}
|
}
|
i++;
|
}
|
}
|
|
private void scheduleAlarm(long wakeUp) {
|
AlarmManager alarms = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
|
if (alarms == null) {
|
Log.e(Constants.TAG, "couldn't get alarm manager");
|
return;
|
}
|
|
if (Constants.LOGV) {
|
Log.v(Constants.TAG, "scheduling retry in " + wakeUp + "ms");
|
}
|
|
Intent intent = new Intent(Constants.ACTION_RETRY);
|
intent.setClassName(getPackageName(),
|
DownloadReceiver.class.getName());
|
alarms.set(AlarmManager.RTC_WAKEUP,
|
mSystemFacade.currentTimeMillis() + wakeUp, PendingIntent
|
.getBroadcast(DownloadService.this, 0, intent,
|
PendingIntent.FLAG_ONE_SHOT));
|
}
|
}
|
|
/**
|
* Removes files that may have been left behind in the cache directory
|
*/
|
private void removeSpuriousFiles() {
|
File[] files = Environment.getDownloadCacheDirectory().listFiles();
|
if (files == null) {
|
// The cache folder doesn't appear to exist (this is likely the case
|
// when running the simulator).
|
return;
|
}
|
HashSet<String> fileSet = new HashSet<String>();
|
for (int i = 0; i < files.length; i++) {
|
if (files[i].getName().equals(Constants.KNOWN_SPURIOUS_FILENAME)) {
|
continue;
|
}
|
if (files[i].getName().equalsIgnoreCase(
|
Constants.RECOVERY_DIRECTORY)) {
|
continue;
|
}
|
fileSet.add(files[i].getPath());
|
}
|
|
Cursor cursor = getContentResolver().query(
|
Downloads.ALL_DOWNLOADS_CONTENT_URI,
|
new String[] { Downloads._DATA }, null, null, null);
|
if (cursor != null) {
|
if (cursor.moveToFirst()) {
|
do {
|
fileSet.remove(cursor.getString(0));
|
} while (cursor.moveToNext());
|
}
|
cursor.close();
|
}
|
Iterator<String> iterator = fileSet.iterator();
|
while (iterator.hasNext()) {
|
String filename = iterator.next();
|
if (Constants.LOGV) {
|
Log.v(Constants.TAG, "deleting spurious file " + filename);
|
}
|
new File(filename).delete();
|
}
|
}
|
|
/**
|
* Drops old rows from the database to prevent it from growing too large
|
*/
|
private void trimDatabase() {
|
Cursor cursor = getContentResolver().query(
|
Downloads.ALL_DOWNLOADS_CONTENT_URI,
|
new String[] { Downloads._ID },
|
Downloads.COLUMN_STATUS + " >= '200'", null,
|
Downloads.COLUMN_LAST_MODIFICATION);
|
if (cursor == null) {
|
// This isn't good - if we can't do basic queries in our database,
|
// nothing's gonna work
|
Log.e(Constants.TAG, "null cursor in trimDatabase");
|
return;
|
}
|
if (cursor.moveToFirst()) {
|
int numDelete = cursor.getCount() - Constants.MAX_DOWNLOADS;
|
int columnId = cursor.getColumnIndexOrThrow(Downloads._ID);
|
while (numDelete > 0) {
|
Uri downloadUri = ContentUris.withAppendedId(
|
Downloads.ALL_DOWNLOADS_CONTENT_URI,
|
cursor.getLong(columnId));
|
getContentResolver().delete(downloadUri, null, null);
|
if (!cursor.moveToNext()) {
|
break;
|
}
|
numDelete--;
|
}
|
}
|
cursor.close();
|
}
|
|
/**
|
* Keeps a local copy of the info about a download, and initiates the
|
* download if appropriate.保持一个下载在条件允许的情况下再启动一个下载
|
*/
|
private DownloadInfo insertDownload(DownloadInfo.Reader reader, long now) {
|
DownloadInfo info = reader.newDownloadInfo(this, mSystemFacade);
|
// 测试
|
// info.mStatus=Downloads.STATUS_RUNNING;
|
mDownloads.put(info.mId, info);
|
if (Constants.LOGVV) {
|
info.logVerboseInfo();
|
}
|
|
Cursor cursor = getContentResolver().query(
|
Downloads.ALL_DOWNLOADS_CONTENT_URI,
|
new String[] { Downloads.COLUMN_STATUS },
|
Downloads.COLUMN_STATUS + "=?",
|
new String[] { Downloads.STATUS_RUNNING + "" }, null);
|
if (isFirst && cursor.getCount() == 1 && info.mStatus == 192) {
|
info.startIfReady(now, 1);// 假如准备好就开始下载
|
} else if (cursor.getCount() == 0 && info.mStatus == 190) {
|
info.startIfReady(now, 0);// 假如准备好就开始下载
|
}
|
cursor.close();
|
return info;
|
}
|
|
/**
|
* Updates the local copy of the info about a download.更新有关下载信息的一个本地副本
|
*/
|
private void updateDownload(DownloadInfo.Reader reader, DownloadInfo info,
|
long now) {
|
int oldVisibility = info.mVisibility;
|
int oldStatus = info.mStatus;
|
reader.updateFromDatabase(info);
|
|
boolean lostVisibility = oldVisibility == Downloads.VISIBILITY_VISIBLE_NOTIFY_COMPLETED
|
&& info.mVisibility != Downloads.VISIBILITY_VISIBLE_NOTIFY_COMPLETED
|
&& Downloads.isStatusCompleted(info.mStatus);
|
boolean justCompleted = !Downloads.isStatusCompleted(oldStatus)
|
&& Downloads.isStatusCompleted(info.mStatus);
|
if (lostVisibility || justCompleted) {
|
mSystemFacade.cancelNotification(info.mId);
|
}
|
|
Cursor cursor = getContentResolver().query(
|
Downloads.ALL_DOWNLOADS_CONTENT_URI,
|
new String[] { Downloads.COLUMN_STATUS },
|
Downloads.COLUMN_STATUS + "=?",
|
new String[] { Downloads.STATUS_RUNNING + "" }, null);
|
System.out.println("下载中的文件有：" + cursor.getCount() + "个");
|
|
if (cursor.getCount() == 1 && info.mStatus == 192) {
|
if (isFirst) {
|
info.startIfReady(now);
|
} else {
|
info.startIfReady(now, 1);// 假如准备好久开始下载
|
}
|
}
|
if (cursor.getCount() == 0 && info.mStatus != 200) {
|
info.startIfReady(now, 0);
|
}
|
// if (cursor.getCount() == 1) {
|
// ContentValues values = new ContentValues();
|
// values.put(Downloads.COLUMN_STATUS, Downloads.STATUS_PENDING);
|
// getContentResolver().update(Downloads.ALL_DOWNLOADS_CONTENT_URI,
|
// values, Downloads.COLUMN_STATUS + "=?",
|
// new String[] { Downloads.STATUS_RUNNING + "" });
|
// } else
|
// if (cursor.getCount() == 0) {
|
// Cursor c = getContentResolver().query(
|
// Downloads.ALL_DOWNLOADS_CONTENT_URI,
|
// new String[] { Downloads._ID },
|
// Downloads.COLUMN_STATUS + "=? or "
|
// + Downloads.COLUMN_STATUS + "=?",
|
// new String[] { Downloads.STATUS_PENDING + "" },
|
// Downloads._ID + " ASC");
|
// String id = "";
|
// if (c.moveToNext()) {
|
// id = c.getString(0);
|
// }
|
// ContentValues values = new ContentValues();
|
// values.put(Downloads.COLUMN_STATUS, Downloads.STATUS_PENDING);
|
// getContentResolver().update(Downloads.ALL_DOWNLOADS_CONTENT_URI,
|
// values, Downloads._ID + "=?", new String[] { id });
|
// info.startIfReady(now, 0);
|
// }
|
cursor.close();
|
}
|
|
/**
|
* Removes the local copy of the info about a download. 删除下载
|
*/
|
private void deleteDownload(long id) {
|
DownloadInfo info = mDownloads.get(id);
|
if (info.mStatus == Downloads.STATUS_RUNNING) {
|
info.mStatus = Downloads.STATUS_CANCELED;
|
}
|
if (info.mDestination != Downloads.DESTINATION_EXTERNAL
|
&& info.mFileName != null) {
|
new File(info.mFileName).delete();
|
}
|
mSystemFacade.cancelNotification(info.mId);
|
mDownloads.remove(info.mId);
|
}
|
}
|
