Merge "Prevent onImageAvailable from being called on stale listeners" (fee4185e) · Commits · e / os / android_frameworks_base

media/java/android/media/ImageReader.java

+42 −20

Original line number	Diff line number	Diff line
		@@ -43,6 +43,7 @@ import java.util.Objects;
		import java.util.concurrent.CopyOnWriteArrayList;
		import java.util.concurrent.Executor;
		import java.util.concurrent.atomic.AtomicBoolean;
		import java.util.concurrent.locks.StampedLock;

		/**
		* <p>The ImageReader class allows direct application access to image data
		@@ -675,7 +676,8 @@ public class ImageReader implements AutoCloseable {
		* If no handler specified and the calling thread has no looper.
		*/
		public void setOnImageAvailableListener(OnImageAvailableListener listener, Handler handler) {
		synchronized (mListenerLock) {
		long writeStamp = mListenerLock.writeLock();
		try {
		if (listener != null) {
		Looper looper = handler != null ? handler.getLooper() : Looper.myLooper();
		if (looper == null) {
		@@ -691,6 +693,8 @@ public class ImageReader implements AutoCloseable {
		mListenerExecutor = null;
		}
		mListener = listener;
		} finally {
		mListenerLock.unlockWrite(writeStamp);
		}
		}

		@@ -713,9 +717,12 @@ public class ImageReader implements AutoCloseable {
		throw new IllegalArgumentException("executor must not be null");
		}

		synchronized (mListenerLock) {
		long writeStamp = mListenerLock.writeLock();
		try {
		mListenerExecutor = executor;
		mListener = listener;
		} finally {
		mListenerLock.unlockWrite(writeStamp);
		}
		}

		@@ -731,6 +738,8 @@ public class ImageReader implements AutoCloseable {
		/**
		* Callback that is called when a new image is available from ImageReader.
		*
		* This callback must not modify or close the passed {@code reader}.
		*
		* @param reader the ImageReader the callback is associated with.
		* @see ImageReader
		* @see Image
		@@ -889,28 +898,41 @@ public class ImageReader implements AutoCloseable {
		return;
		}

		synchronized (ir.mCloseLock) {
		if (!ir.mIsReaderValid) {
		// It's dangerous to fire onImageAvailable() callback when the ImageReader
		// is being closed, as application could acquire next image in the
		// onImageAvailable() callback.
		return;
		}
		}

		final Executor executor;
		final OnImageAvailableListener listener;
		synchronized (ir.mListenerLock) {
		final long readStamp = ir.mListenerLock.readLock();
		try {
		executor = ir.mListenerExecutor;
		listener = ir.mListener;
		if (executor == null) {
		return;
		}
		final boolean isReaderValid;
		synchronized (ir.mCloseLock) {
		isReaderValid = ir.mIsReaderValid;
		} finally {
		ir.mListenerLock.unlockRead(readStamp);
		}

		// It's dangerous to fire onImageAvailable() callback when the ImageReader
		// is being closed, as application could acquire next image in the
		// onImageAvailable() callback.
		if (executor != null && listener != null && isReaderValid) {
		executor.execute(new Runnable() {
		@Override
		public void run() {
		listener.onImageAvailable(ir);
		executor.execute(() -> {
		// Acquire readlock to ensure that the ImageReader does not change its
		// state while a listener is actively processing.
		final long rStamp = ir.mListenerLock.readLock();
		try {
		// Fire onImageAvailable of the latest non-null listener
		// This ensures that if the listener changes while messages are in queue, the
		// in-flight messages will call onImageAvailable of the new listener instead
		if (ir.mListener != null) {
		ir.mListener.onImageAvailable(ir);
		}
		});
		} finally {
		ir.mListenerLock.unlockRead(rStamp);
		}
		});
		}

		/**
		@@ -1070,7 +1092,7 @@ public class ImageReader implements AutoCloseable {
		private Surface mSurface;
		private int mEstimatedNativeAllocBytes;

		private final Object mListenerLock = new Object();
		private final StampedLock mListenerLock = new StampedLock();
		private final Object mCloseLock = new Object();
		private boolean mIsReaderValid = false;
		private OnImageAvailableListener mListener;