/* * Copyright (C) 2009 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 android.content; import android.accounts.Account; import android.os.Bundle; import android.os.IBinder; import android.os.Process; import android.os.RemoteException; import java.util.HashMap; import java.util.concurrent.atomic.AtomicInteger; /** * An abstract implementation of a SyncAdapter that spawns a thread to invoke a sync operation. * If a sync operation is already in progress when a startSync() request is received then an error * will be returned to the new request and the existing request will be allowed to continue. * When a startSync() is received and there is no sync operation in progress then a thread * will be started to run the operation and {@link #onPerformSync} will be invoked on that thread. * If a cancelSync() is received that matches an existing sync operation then the thread * that is running that sync operation will be interrupted, which will indicate to the thread * that the sync has been canceled. *

* In order to be a sync adapter one must extend this class, provide implementations for the * abstract methods and write a service that returns the result of {@link #getSyncAdapterBinder()} * in the service's {@link android.app.Service#onBind(android.content.Intent)} when invoked * with an intent with action android.content.SyncAdapter. This service * must specify the following intent filter and metadata tags in its AndroidManifest.xml file *

 *   <intent-filter>
 *     <action android:name="android.content.SyncAdapter" />
 *   </intent-filter>
 *   <meta-data android:name="android.content.SyncAdapter"
 *             android:resource="@xml/syncadapter" />
 * 
* The android:resource attribute must point to a resource that looks like: *
 * <sync-adapter xmlns:android="http://schemas.android.com/apk/res/android"
 *    android:contentAuthority="authority"
 *    android:accountType="accountType"
 *    android:userVisible="true|false"
 *    android:supportsUploading="true|false"
 *    android:allowParallelSyncs="true|false"
 *    android:isAlwaysSyncable="true|false"
 *    android:syncAdapterSettingsAction="ACTION_OF_SETTINGS_ACTIVITY"
 * />
 * 
* */ public abstract class AbstractThreadedSyncAdapter { /** * Kernel event log tag. Also listed in data/etc/event-log-tags. * @deprecated Private constant. May go away in the next release. */ @Deprecated public static final int LOG_SYNC_DETAILS = 2743; private final Context mContext; private final AtomicInteger mNumSyncStarts; private final ISyncAdapterImpl mISyncAdapterImpl; // all accesses to this member variable must be synchronized on mSyncThreadLock private final HashMap mSyncThreads = new HashMap(); private final Object mSyncThreadLock = new Object(); private final boolean mAutoInitialize; private boolean mAllowParallelSyncs; /** * Creates an {@link AbstractThreadedSyncAdapter}. * @param context the {@link android.content.Context} that this is running within. * @param autoInitialize if true then sync requests that have * {@link ContentResolver#SYNC_EXTRAS_INITIALIZE} set will be internally handled by * {@link AbstractThreadedSyncAdapter} by calling * {@link ContentResolver#setIsSyncable(android.accounts.Account, String, int)} with 1 if it * is currently set to <0. */ public AbstractThreadedSyncAdapter(Context context, boolean autoInitialize) { this(context, autoInitialize, false /* allowParallelSyncs */); } /** * Creates an {@link AbstractThreadedSyncAdapter}. * @param context the {@link android.content.Context} that this is running within. * @param autoInitialize if true then sync requests that have * {@link ContentResolver#SYNC_EXTRAS_INITIALIZE} set will be internally handled by * {@link AbstractThreadedSyncAdapter} by calling * {@link ContentResolver#setIsSyncable(android.accounts.Account, String, int)} with 1 if it * is currently set to <0. * @param allowParallelSyncs if true then allow syncs for different accounts to run * at the same time, each in their own thread. This must be consistent with the setting * in the SyncAdapter's configuration file. */ public AbstractThreadedSyncAdapter(Context context, boolean autoInitialize, boolean allowParallelSyncs) { mContext = context; mISyncAdapterImpl = new ISyncAdapterImpl(); mNumSyncStarts = new AtomicInteger(0); mAutoInitialize = autoInitialize; mAllowParallelSyncs = allowParallelSyncs; } public Context getContext() { return mContext; } private Account toSyncKey(Account account) { if (mAllowParallelSyncs) { return account; } else { return null; } } private class ISyncAdapterImpl extends ISyncAdapter.Stub { public void startSync(ISyncContext syncContext, String authority, Account account, Bundle extras) { final SyncContext syncContextClient = new SyncContext(syncContext); boolean alreadyInProgress; // synchronize to make sure that mSyncThreads doesn't change between when we // check it and when we use it final Account threadsKey = toSyncKey(account); synchronized (mSyncThreadLock) { if (!mSyncThreads.containsKey(threadsKey)) { if (mAutoInitialize && extras != null && extras.getBoolean(ContentResolver.SYNC_EXTRAS_INITIALIZE, false)) { if (ContentResolver.getIsSyncable(account, authority) < 0) { ContentResolver.setIsSyncable(account, authority, 1); } syncContextClient.onFinished(new SyncResult()); return; } SyncThread syncThread = new SyncThread( "SyncAdapterThread-" + mNumSyncStarts.incrementAndGet(), syncContextClient, authority, account, extras); mSyncThreads.put(threadsKey, syncThread); syncThread.start(); alreadyInProgress = false; } else { alreadyInProgress = true; } } // do this outside since we don't want to call back into the syncContext while // holding the synchronization lock if (alreadyInProgress) { syncContextClient.onFinished(SyncResult.ALREADY_IN_PROGRESS); } } public void cancelSync(ISyncContext syncContext) { // synchronize to make sure that mSyncThreads doesn't change between when we // check it and when we use it SyncThread info = null; synchronized (mSyncThreadLock) { for (SyncThread current : mSyncThreads.values()) { if (current.mSyncContext.getSyncContextBinder() == syncContext.asBinder()) { info = current; break; } } } if (info != null) { if (mAllowParallelSyncs) { onSyncCanceled(info); } else { onSyncCanceled(); } } } public void initialize(Account account, String authority) throws RemoteException { Bundle extras = new Bundle(); extras.putBoolean(ContentResolver.SYNC_EXTRAS_INITIALIZE, true); startSync(null, authority, account, extras); } } /** * The thread that invokes {@link AbstractThreadedSyncAdapter#onPerformSync}. It also acquires * the provider for this sync before calling onPerformSync and releases it afterwards. Cancel * this thread in order to cancel the sync. */ private class SyncThread extends Thread { private final SyncContext mSyncContext; private final String mAuthority; private final Account mAccount; private final Bundle mExtras; private final Account mThreadsKey; private SyncThread(String name, SyncContext syncContext, String authority, Account account, Bundle extras) { super(name); mSyncContext = syncContext; mAuthority = authority; mAccount = account; mExtras = extras; mThreadsKey = toSyncKey(account); } public void run() { Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND); SyncResult syncResult = new SyncResult(); ContentProviderClient provider = null; try { if (isCanceled()) { return; } provider = mContext.getContentResolver().acquireContentProviderClient(mAuthority); if (provider != null) { AbstractThreadedSyncAdapter.this.onPerformSync(mAccount, mExtras, mAuthority, provider, syncResult); } else { syncResult.databaseError = true; } } finally { if (provider != null) { provider.release(); } if (!isCanceled()) { mSyncContext.onFinished(syncResult); } // synchronize so that the assignment will be seen by other threads // that also synchronize accesses to mSyncThreads synchronized (mSyncThreadLock) { mSyncThreads.remove(mThreadsKey); } } } private boolean isCanceled() { return Thread.currentThread().isInterrupted(); } } /** * @return a reference to the IBinder of the SyncAdapter service. */ public final IBinder getSyncAdapterBinder() { return mISyncAdapterImpl.asBinder(); } /** * Perform a sync for this account. SyncAdapter-specific parameters may * be specified in extras, which is guaranteed to not be null. Invocations * of this method are guaranteed to be serialized. * * @param account the account that should be synced * @param extras SyncAdapter-specific parameters * @param authority the authority of this sync request * @param provider a ContentProviderClient that points to the ContentProvider for this * authority * @param syncResult SyncAdapter-specific parameters */ public abstract void onPerformSync(Account account, Bundle extras, String authority, ContentProviderClient provider, SyncResult syncResult); /** * Indicates that a sync operation has been canceled. This will be invoked on a separate * thread than the sync thread and so you must consider the multi-threaded implications * of the work that you do in this method. *

* This will only be invoked when the SyncAdapter indicates that it doesn't support * parallel syncs. */ public void onSyncCanceled() { final SyncThread syncThread; synchronized (mSyncThreadLock) { syncThread = mSyncThreads.get(null); } if (syncThread != null) { syncThread.interrupt(); } } /** * Indicates that a sync operation has been canceled. This will be invoked on a separate * thread than the sync thread and so you must consider the multi-threaded implications * of the work that you do in this method. *

* This will only be invoked when the SyncAdapter indicates that it does support * parallel syncs. * @param thread the Thread of the sync that is to be canceled. */ public void onSyncCanceled(Thread thread) { thread.interrupt(); } }