Merge "TTS: Fix a race condition between enqueueSpeechItem and stopForApp." (096c021d) · Commits · e / os / android_frameworks_base

core/java/android/speech/tts/TextToSpeechService.java

+30 −11

Original line number	Diff line number	Diff line
		@@ -502,10 +502,28 @@ public abstract class TextToSpeechService extends Service {
		return mCurrentSpeechItem;
		}

		private synchronized SpeechItem setCurrentSpeechItem(SpeechItem speechItem) {
		SpeechItem old = mCurrentSpeechItem;
		private synchronized boolean setCurrentSpeechItem(SpeechItem speechItem) {
		// Do not set as current if the item has already been flushed. The check is
		// intentionally put inside this synchronized method. Specifically, the following
		// racy sequence between this method and stopForApp() needs to be avoided.
		// (this method) (stopForApp)
		// 1. isFlushed
		// 2. startFlushingSpeechItems
		// 3. maybeRemoveCurrentSpeechItem
		// 4. set mCurrentSpeechItem
		// If it happens, stop() is never called on the item. The guard by synchornized(this)
		// ensures that the step 3 cannot interrupt between 1 and 4.
		if (speechItem != null && isFlushed(speechItem)) {
		return false;
		}
		mCurrentSpeechItem = speechItem;
		return old;
		return true;
		}

		private synchronized SpeechItem removeCurrentSpeechItem() {
		SpeechItem current = mCurrentSpeechItem;
		mCurrentSpeechItem = null;
		return current;
		}

		private synchronized SpeechItem maybeRemoveCurrentSpeechItem(Object callerIdentity) {
		@@ -527,7 +545,7 @@ public abstract class TextToSpeechService extends Service {
		// Don't process any more speech items
		getLooper().quit();
		// Stop the current speech item
		SpeechItem current = setCurrentSpeechItem(null);
		SpeechItem current = removeCurrentSpeechItem();
		if (current != null) {
		current.stop();
		}
		@@ -561,12 +579,12 @@ public abstract class TextToSpeechService extends Service {
		Runnable runnable = new Runnable() {
		@Override
		public void run() {
		if (isFlushed(speechItem)) {
		speechItem.stop();
		} else {
		setCurrentSpeechItem(speechItem);
		if (setCurrentSpeechItem(speechItem)) {
		speechItem.play();
		setCurrentSpeechItem(null);
		removeCurrentSpeechItem();
		} else {
		// The item is alreadly flushed. Stopping.
		speechItem.stop();
		}
		}
		};
		@@ -600,7 +618,8 @@ public abstract class TextToSpeechService extends Service {
		return TextToSpeech.ERROR;
		}

		// Flush pending messages from callerIdentity
		// Flush pending messages from callerIdentity.
		// See setCurrentSpeechItem on a subtlety around a race condition.
		startFlushingSpeechItems(callerIdentity);

		// This stops writing data to the file / or publishing
		@@ -634,7 +653,7 @@ public abstract class TextToSpeechService extends Service {
		startFlushingSpeechItems(null);

		// Stop the current speech item unconditionally .
		SpeechItem current = setCurrentSpeechItem(null);
		SpeechItem current = removeCurrentSpeechItem();
		if (current != null) {
		current.stop();
		}