Merge "Delay SharedPreferences.apply() by 50 ms" (a9db0fae) · Commits · e / os / android_frameworks_base

core/java/android/app/QueuedWork.java

+160 −49

Original line number	Diff line number	Diff line
		@@ -16,86 +16,197 @@

		package android.app;

		import java.util.concurrent.ConcurrentLinkedQueue;
		import java.util.concurrent.ExecutorService;
		import java.util.concurrent.Executors;
		import android.os.Handler;
		import android.os.HandlerThread;
		import android.os.Looper;
		import android.os.Message;
		import android.os.Process;
		import android.util.Log;

		import com.android.internal.annotations.GuardedBy;

		import java.util.LinkedList;

		/**
		* Internal utility class to keep track of process-global work that's
		* outstanding and hasn't been finished yet.
		* Internal utility class to keep track of process-global work that's outstanding and hasn't been
		* finished yet.
		*
		* New work will be {@link #queue queued}.
		*
		* It is possible to add 'finisher'-runnables that are {@link #waitToFinish guaranteed to be run}.
		* This is used to make sure the work has been finished.
		*
		* This was created for writing SharedPreference edits out
		* asynchronously so we'd have a mechanism to wait for the writes in
		* Activity.onPause and similar places, but we may use this mechanism
		* for other things in the future.
		* This was created for writing SharedPreference edits out asynchronously so we'd have a mechanism
		* to wait for the writes in Activity.onPause and similar places, but we may use this mechanism for
		* other things in the future.
		*
		* The queued asynchronous work is performed on a separate, dedicated thread.
		*
		* @hide
		*/
		public class QueuedWork {
		private static final String LOG_TAG = QueuedWork.class.getSimpleName();

		/** Delay for delayed runnables */
		private static final long DELAY = 50;

		/** Lock for this class */
		private static final Object sLock = new Object();

		// The set of Runnables that will finish or wait on any async
		// activities started by the application.
		private static final ConcurrentLinkedQueue<Runnable> sPendingWorkFinishers =
		new ConcurrentLinkedQueue<Runnable>();
		/** Finishers {@link #addFinisher added} and not yet {@link #removeFinisher removed} */
		@GuardedBy("sLock")
		private static final LinkedList<Runnable> sFinishers = new LinkedList<>();

		private static ExecutorService sSingleThreadExecutor = null; // lazy, guarded by class
		/** {@link #getHandler() Lazily} created handler */
		@GuardedBy("sLock")
		private static Handler sHandler = null;

		/** Work queued via {@link #queue} */
		@GuardedBy("sLock")
		private static final LinkedList<Runnable> sWork = new LinkedList<>();

		/** If new work can be delayed or not */
		@GuardedBy("sLock")
		private static boolean sCanDelay = true;

		/**
		* Returns a single-thread Executor shared by the entire process,
		* creating it if necessary.
		* Lazily create a handler on a separate thread.
		*
		* @return the handler
		*/
		public static ExecutorService singleThreadExecutor() {
		synchronized (QueuedWork.class) {
		if (sSingleThreadExecutor == null) {
		// TODO: can we give this single thread a thread name?
		sSingleThreadExecutor = Executors.newSingleThreadExecutor();
		private static Handler getHandler() {
		synchronized (sLock) {
		if (sHandler == null) {
		HandlerThread handlerThread = new HandlerThread("queued-work-looper",
		Process.THREAD_PRIORITY_BACKGROUND);
		handlerThread.start();

		sHandler = new QueuedWorkHandler(handlerThread.getLooper());
		}
		return sSingleThreadExecutor;
		return sHandler;
		}
		}

		/**
		* Add a runnable to finish (or wait for) a deferred operation
		* started in this context earlier. Typically finished by e.g.
		* an Activity#onPause. Used by SharedPreferences$Editor#startCommit().
		* Add a finisher-runnable to wait for {@link #queue asynchronously processed work}.
		*
		* Used by SharedPreferences$Editor#startCommit().
		*
		* Note that this doesn't actually start it running. This is just a scratch set for callers
		* doing async work to keep updated with what's in-flight. In the common case, caller code
		* (e.g. SharedPreferences) will pretty quickly call remove() after an add(). The only time
		* these Runnables are run is from {@link #waitToFinish}.
		*
		* Note that this doesn't actually start it running. This is just
		* a scratch set for callers doing async work to keep updated with
		* what's in-flight. In the common case, caller code
		* (e.g. SharedPreferences) will pretty quickly call remove()
		* after an add(). The only time these Runnables are run is from
		* waitToFinish(), below.
		* @param finisher The runnable to add as finisher
		*/
		public static void add(Runnable finisher) {
		sPendingWorkFinishers.add(finisher);
		public static void addFinisher(Runnable finisher) {
		synchronized (sLock) {
		sFinishers.add(finisher);
		}
		}

		public static void remove(Runnable finisher) {
		sPendingWorkFinishers.remove(finisher);
		/**
		* Remove a previously {@link #addFinisher added} finisher-runnable.
		*
		* @param finisher The runnable to remove.
		*/
		public static void removeFinisher(Runnable finisher) {
		synchronized (sLock) {
		sFinishers.remove(finisher);
		}
		}

		/**
		* Finishes or waits for async operations to complete.
		* (e.g. SharedPreferences$Editor#startCommit writes)
		* Trigger queued work to be processed immediately. The queued work is processed on a separate
		* thread asynchronous. While doing that run and process all finishers on this thread. The
		* finishers can be implemented in a way to check weather the queued work is finished.
		*
		* Is called from the Activity base class's onPause(), after
		* BroadcastReceiver's onReceive, after Service command handling,
		* etc. (so async work is never lost)
		* Is called from the Activity base class's onPause(), after BroadcastReceiver's onReceive,
		* after Service command handling, etc. (so async work is never lost)
		*/
		public static void waitToFinish() {
		Runnable toFinish;
		while ((toFinish = sPendingWorkFinishers.poll()) != null) {
		toFinish.run();
		Handler handler = getHandler();

		synchronized (sLock) {
		if (handler.hasMessages(QueuedWorkHandler.MSG_RUN)) {
		// Force the delayed work to be processed now
		handler.removeMessages(QueuedWorkHandler.MSG_RUN);
		handler.sendEmptyMessage(QueuedWorkHandler.MSG_RUN);
		}

		// We should not delay any work as this might delay the finishers
		sCanDelay = false;
		}

		try {
		while (true) {
		Runnable finisher;

		synchronized (sLock) {
		finisher = sFinishers.poll();
		}

		if (finisher == null) {
		break;
		}

		finisher.run();
		}
		} finally {
		sCanDelay = true;
		}
		}

		/**
		* Queue a work-runnable for processing asynchronously.
		*
		* @param work The new runnable to process
		* @param shouldDelay If the message should be delayed
		*/
		public static void queue(Runnable work, boolean shouldDelay) {
		Handler handler = getHandler();

		synchronized (sLock) {
		sWork.add(work);

		if (shouldDelay && sCanDelay) {
		handler.sendEmptyMessageDelayed(QueuedWorkHandler.MSG_RUN, DELAY);
		} else {
		handler.sendEmptyMessage(QueuedWorkHandler.MSG_RUN);
		}
		}
		}

		/**
		* Returns true if there is pending work to be done. Note that the
		* result is out of data as soon as you receive it, so be careful how you
		* use it.
		* @return True iff there is any {@link #queue async work queued}.
		*/
		public static boolean hasPendingWork() {
		return !sPendingWorkFinishers.isEmpty();
		synchronized (sLock) {
		return !sWork.isEmpty();
		}
		}

		private static class QueuedWorkHandler extends Handler {
		static final int MSG_RUN = 1;

		QueuedWorkHandler(Looper looper) {
		super(looper);
		}

		public void handleMessage(Message msg) {
		if (msg.what == MSG_RUN) {
		LinkedList<Runnable> work;

		synchronized (sWork) {
		work = (LinkedList<Runnable>) sWork.clone();
		sWork.clear();

		// Remove all msg-s as all work will be processed now
		removeMessages(MSG_RUN);
		}

		work.forEach(Runnable::run);
		}
		}
		}
		}

core/java/android/app/SharedPreferencesImpl.java

+4 −4

Original line number	Diff line number	Diff line
		@@ -379,12 +379,12 @@ final class SharedPreferencesImpl implements SharedPreferences {
		}
		};

		QueuedWork.add(awaitCommit);
		QueuedWork.addFinisher(awaitCommit);

		Runnable postWriteRunnable = new Runnable() {
		public void run() {
		awaitCommit.run();
		QueuedWork.remove(awaitCommit);
		QueuedWork.removeFinisher(awaitCommit);
		}
		};

		@@ -557,10 +557,10 @@ final class SharedPreferencesImpl implements SharedPreferences {
		}

		if (DEBUG) {
		Log.d(TAG, "added " + mcr.memoryStateGeneration + " -> " + mFile.getName());
		Log.d(TAG, "queued " + mcr.memoryStateGeneration + " -> " + mFile.getName());
		}

		QueuedWork.singleThreadExecutor().execute(writeToDiskRunnable);
		QueuedWork.queue(writeToDiskRunnable, !isFromSyncCommit);
		}

		private static FileOutputStream createFileOutputStream(File file) {

core/java/android/content/BroadcastReceiver.java

+3 −3

Original line number	Diff line number	Diff line
		@@ -375,16 +375,16 @@ public abstract class BroadcastReceiver {
		// of the list to finish the broadcast, so we don't block this
		// thread (which may be the main thread) to have it finished.
		//
		// Note that we don't need to use QueuedWork.add() with the
		// Note that we don't need to use QueuedWork.addFinisher() with the
		// runnable, since we know the AM is waiting for us until the
		// executor gets to it.
		QueuedWork.singleThreadExecutor().execute( new Runnable() {
		QueuedWork.queue(new Runnable() {
		@Override public void run() {
		if (ActivityThread.DEBUG_BROADCAST) Slog.i(ActivityThread.TAG,
		"Finishing broadcast after work to component " + mToken);
		sendFinished(mgr);
		}
		});
		}, false);
		} else {
		if (ActivityThread.DEBUG_BROADCAST) Slog.i(ActivityThread.TAG,
		"Finishing broadcast to component " + mToken);