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VideoCaptureAndroid: don't deliver frames after stopCapture().

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Because stopCapture() and onPreviewFrame() are called on different threads, and
are both synchronized, it's possible for onPreviewFrame() to commence execution
after stopCapture() has completed, causing a SEGV because the native code is no
longer prepared to accept frames.
Clarify the contract around synchronized methods in this class to hopefully
avoid similar bugs in future.

BUG=2947
R=henrike@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/9339004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5639 4adac7df-926f-26a2-2b94-8c16560cd09d
This commit is contained in:
fischman@webrtc.org 2014-03-04 18:17:55 +00:00
parent be50ab645a
commit 7bd4a27502
1 changed files with 18 additions and 8 deletions
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26
webrtc/modules/video_capture/android/java/src/org/webrtc/videoengine/VideoCaptureAndroid.java
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@ -31,7 +31,9 @@ import android.view.SurfaceHolder.Callback;
// the entry points to this class are all synchronized. This shouldn't present
// a performance bottleneck because only onPreviewFrame() is called more than
// once (and is called serially on a single thread), so the lock should be
// uncontended.
// uncontended. Note that each of these synchronized methods must check
// |camera| for null to account for having possibly waited for stopCapture() to
// complete.
public class VideoCaptureAndroid implements PreviewCallback, Callback {
private final static String TAG = "WEBRTC-JC";
@ -149,7 +151,13 @@ public class VideoCaptureAndroid implements PreviewCallback, Callback {
private native void ProvideCameraFrame(
byte[] data, int length, long captureObject);
public synchronized void onPreviewFrame(byte[] data, Camera camera) {
public synchronized void onPreviewFrame(byte[] data, Camera callbackCamera) {
if (camera == null) {
return;
}
if (camera != callbackCamera) {
throw new RuntimeException("Unexpected camera in callback!");
}
ProvideCameraFrame(data, data.length, native_capturer);
camera.addCallbackBuffer(data);
}
@ -184,10 +192,11 @@ public class VideoCaptureAndroid implements PreviewCallback, Callback {
public synchronized void surfaceCreated(SurfaceHolder holder) {
Log.d(TAG, "VideoCaptureAndroid::surfaceCreated");
if (camera == null) {
return;
}
try {
if (camera != null) {
camera.setPreviewDisplay(holder);
}
camera.setPreviewDisplay(holder);
} catch (IOException e) {
throw new RuntimeException(e);
}
@ -195,10 +204,11 @@ public class VideoCaptureAndroid implements PreviewCallback, Callback {
public synchronized void surfaceDestroyed(SurfaceHolder holder) {
Log.d(TAG, "VideoCaptureAndroid::surfaceDestroyed");
if (camera == null) {
return;
}
try {
if (camera != null) {
camera.setPreviewDisplay(null);
}
camera.setPreviewDisplay(null);
} catch (IOException e) {
throw new RuntimeException(e);
}