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/*
* 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.backup;
import android.annotation.SdkConstant;
import android.annotation.SdkConstant.SdkConstantType;
import android.app.Service;
import android.backup.IBackupService;
import android.content.Intent;
import android.os.IBinder;
import android.os.ParcelFileDescriptor;
import android.os.RemoteException;
import android.util.Log;
/**
* This is the central interface between an application and Android's
* settings backup mechanism.
*
* In order to use the backup service, your application must implement a
* subclass of BackupService, and declare an intent filter
* in the application manifest specifying that your BackupService subclass
* handles the {@link BackupService#SERVICE_ACTION} intent action. For example:
*
* <pre class="prettyprint">
* <!-- Use the class "MyBackupService" to perform backups for my app -->
* <service android:name=".MyBackupService">
* <intent-filter>
* <action android:name="android.backup.BackupService.SERVICE" />
* </intent-filter>
* </service></pre>
*
* @hide pending API solidification
*/
public abstract class BackupService extends Service {
/**
* Service Action: Participate in the backup infrastructure. Applications
* that wish to use the Android backup mechanism must provide an exported
* subclass of BackupService and give it an {@link android.content.IntentFilter
* IntentFilter} that accepts this action.
*/
@SdkConstant(SdkConstantType.SERVICE_ACTION)
public static final String SERVICE_ACTION = "android.backup.BackupService.SERVICE";
/**
* The application is being asked to write any data changed since the
* last time it performed a backup operation. The state data recorded
* during the last backup pass is provided in the oldState file descriptor.
* If oldState is null, no old state is available and the application should perform
* a full backup. In both cases, a representation of the final backup state after
* this pass should be written to the file pointed to by the newStateFd file descriptor.
*
* @param oldState An open, read-only ParcelFileDescriptor pointing to the last backup
* state provided by the application. May be null, in which
* case no prior state is being provided and the application should
* perform a full backup.
* @param data An open, read/write ParcelFileDescriptor pointing to the backup data
* destination. Typically the application will use backup helper
* classes to write to this file.
* @param newState An open, read/write ParcelFileDescriptor pointing to an empty
* file. The application should record the final backup state
* here after writing the requested data to dataFd.
*/
public abstract void onBackup(ParcelFileDescriptor oldState, BackupDataOutput data,
ParcelFileDescriptor newState);
/**
* The application is being restored from backup, and should replace any
* existing data with the contents of the backup. The backup data is
* provided in the file pointed to by the dataFd file descriptor. Once
* the restore is finished, the application should write a representation
* of the final state to the newStateFd file descriptor,
*
* @param data An open, read-only ParcelFileDescriptor pointing to a full snapshot
* of the application's data.
* @param newState An open, read/write ParcelFileDescriptor pointing to an empty
* file. The application should record the final backup state
* here after restoring its data from dataFd.
*/
public abstract void onRestore(ParcelFileDescriptor /* TODO: BackupDataInput */ data, ParcelFileDescriptor newState);
// ----- Core implementation -----
/**
* Returns the private interface called by the backup system. Applications will
* not typically override this.
*/
public IBinder onBind(Intent intent) {
if (intent.getAction().equals(SERVICE_ACTION)) {
return mBinder;
}
return null;
}
private final IBinder mBinder = new BackupServiceBinder().asBinder();
// ----- IBackupService binder interface -----
private class BackupServiceBinder extends IBackupService.Stub {
public void doBackup(ParcelFileDescriptor oldState,
ParcelFileDescriptor data,
ParcelFileDescriptor newState) throws RemoteException {
// !!! TODO - real implementation; for now just invoke the callbacks directly
Log.v("BackupServiceBinder", "doBackup() invoked");
BackupDataOutput output = new BackupDataOutput(BackupService.this,
data.getFileDescriptor());
try {
BackupService.this.onBackup(oldState, output, newState);
} catch (RuntimeException ex) {
Log.d("BackupService", "onBackup ("
+ BackupService.this.getClass().getName() + ") threw", ex);
throw ex;
}
}
public void doRestore(ParcelFileDescriptor data,
ParcelFileDescriptor newState) throws RemoteException {
// !!! TODO - real implementation; for now just invoke the callbacks directly
Log.v("BackupServiceBinder", "doRestore() invoked");
BackupService.this.onRestore(data, newState);
}
}
}
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