Merge "Provide SharedPreferences coherence guarantees for BackupAgent" into jb-mr2-dev (18414c4d) · Commits · e / os / android_frameworks_base

core/java/android/app/backup/BackupAgent.java

+48 −0

Original line number	Diff line number	Diff line
		@@ -17,12 +17,15 @@
		package android.app.backup;

		import android.app.IBackupAgent;
		import android.app.QueuedWork;
		import android.app.backup.IBackupManager;
		import android.content.Context;
		import android.content.ContextWrapper;
		import android.content.pm.ApplicationInfo;
		import android.os.Binder;
		import android.os.Handler;
		import android.os.IBinder;
		import android.os.Looper;
		import android.os.ParcelFileDescriptor;
		import android.os.Process;
		import android.os.RemoteException;
		@@ -33,6 +36,7 @@ import java.io.FileOutputStream;
		import java.io.IOException;
		import java.util.HashSet;
		import java.util.LinkedList;
		import java.util.concurrent.CountDownLatch;

		import libcore.io.ErrnoException;
		import libcore.io.Libcore;
		@@ -122,6 +126,32 @@ public abstract class BackupAgent extends ContextWrapper {
		/** @hide */
		public static final int TYPE_SYMLINK = 3;

		Handler mHandler = null;

		class SharedPrefsSynchronizer implements Runnable {
		public final CountDownLatch mLatch = new CountDownLatch(1);

		@Override
		public void run() {
		QueuedWork.waitToFinish();
		mLatch.countDown();
		}
		};

		// Syncing shared preferences deferred writes needs to happen on the main looper thread
		private void waitForSharedPrefs() {
		if (mHandler == null) {
		mHandler = new Handler(Looper.getMainLooper());
		}

		final SharedPrefsSynchronizer s = new SharedPrefsSynchronizer();
		mHandler.postAtFrontOfQueue(s);
		try {
		s.mLatch.await();
		} catch (InterruptedException e) { /* ignored */ }
		}


		public BackupAgent() {
		super(null);
		}
		@@ -542,6 +572,11 @@ public abstract class BackupAgent extends ContextWrapper {
		Log.d(TAG, "onBackup (" + BackupAgent.this.getClass().getName() + ") threw", ex);
		throw ex;
		} finally {
		// Ensure that any SharedPreferences writes have landed after the backup,
		// in case the app code has side effects (since apps cannot provide this
		// guarantee themselves).
		waitForSharedPrefs();

		Binder.restoreCallingIdentity(ident);
		try {
		callbackBinder.opComplete(token);
		@@ -569,6 +604,9 @@ public abstract class BackupAgent extends ContextWrapper {
		Log.d(TAG, "onRestore (" + BackupAgent.this.getClass().getName() + ") threw", ex);
		throw ex;
		} finally {
		// Ensure that any side-effect SharedPreferences writes have landed
		waitForSharedPrefs();

		Binder.restoreCallingIdentity(ident);
		try {
		callbackBinder.opComplete(token);
		@@ -586,6 +624,10 @@ public abstract class BackupAgent extends ContextWrapper {

		if (DEBUG) Log.v(TAG, "doFullBackup() invoked");

		// Ensure that any SharedPreferences writes have landed before
		// we potentially try to back up the underlying files directly.
		waitForSharedPrefs();

		try {
		BackupAgent.this.onFullBackup(new FullBackupDataOutput(data));
		} catch (IOException ex) {
		@@ -595,6 +637,9 @@ public abstract class BackupAgent extends ContextWrapper {
		Log.d(TAG, "onBackup (" + BackupAgent.this.getClass().getName() + ") threw", ex);
		throw ex;
		} finally {
		// ... and then again after, as in the doBackup() case
		waitForSharedPrefs();

		// Send the EOD marker indicating that there is no more data
		// forthcoming from this agent.
		try {
		@@ -624,6 +669,9 @@ public abstract class BackupAgent extends ContextWrapper {
		} catch (IOException e) {
		throw new RuntimeException(e);
		} finally {
		// Ensure that any side-effect SharedPreferences writes have landed
		waitForSharedPrefs();

		Binder.restoreCallingIdentity(ident);
		try {
		callbackBinder.opComplete(token);