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Merge "Provide SharedPreferences coherence guarantees for BackupAgent" into jb-mr2-dev

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This commit is contained in:
Christopher Tate
2013-04-19 22:34:01 +00:00
committed by Android (Google) Code Review
parent bcf3ec96a4 f85f5b2125
commit 18414c4db7
1 changed files with 48 additions and 0 deletions
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48
core/java/android/app/backup/BackupAgent.java
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@@ -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);