Events refactor in Android session based capturing.

webrtc/api/android/java/src/org/webrtc/Camera2Session.java

Index: webrtc/api/android/java/src/org/webrtc/Camera2Session.java
diff --git a/webrtc/api/android/java/src/org/webrtc/Camera2Session.java b/webrtc/api/android/java/src/org/webrtc/Camera2Session.java
index a10ce8f5389422d5d2434465db5529130e2defb8..e4b26f411c430456b4fba3fe492f37c4a5f75c8a 100644
--- a/webrtc/api/android/java/src/org/webrtc/Camera2Session.java
+++ b/webrtc/api/android/java/src/org/webrtc/Camera2Session.java
@@ -46,11 +46,10 @@ public class Camera2Session implements CameraSession {
   private static enum SessionState { RUNNING, STOPPED };
 
   private final Handler cameraThreadHandler;
-  private final CameraManager cameraManager;
   private final CreateSessionCallback callback;
-  private final CameraVideoCapturer.CameraEventsHandler eventsHandler;
+  private final Events events;
   private final Context applicationContext;
-  private final CameraVideoCapturer.CapturerObserver capturerObserver;
+  private final CameraManager cameraManager;
   private final SurfaceTextureHelper surfaceTextureHelper;
   private final String cameraId;
   private final int width;
@@ -70,7 +69,6 @@ public class Camera2Session implements CameraSession {
 
   // Initialized when capture session is created
   private CameraCaptureSession captureSession;
-  private CameraVideoCapturer.CameraStatistics cameraStatistics;
 
   // State
   private SessionState state = SessionState.RUNNING;
@@ -134,7 +132,7 @@ public class Camera2Session implements CameraSession {
       checkIsOnCameraThread();
 
       Logging.d(TAG, "Camera device closed.");
-      eventsHandler.onCameraClosed();
+      events.onCameraClosed(Camera2Session.this);
     }
   }
 
@@ -191,7 +189,6 @@ public class Camera2Session implements CameraSession {
               }
 
               if (!firstFrameReported) {
-                eventsHandler.onFirstFrameAvailable();
                 firstFrameReported = true;
                 final int startTimeMs =
                     (int) TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - constructionTimeNs);
@@ -210,14 +207,10 @@ public class Camera2Session implements CameraSession {
               transformMatrix = RendererCommon.rotateTextureMatrix(
                   transformMatrix, -cameraOrientation);
 
-              cameraStatistics.addFrame();
-              capturerObserver.onTextureFrameCaptured(captureFormat.width, captureFormat.height,
-                  oesTextureId, transformMatrix, rotation, timestampNs);
+              events.onTextureFrameCaptured(Camera2Session.this, captureFormat.width,
+                  captureFormat.height, oesTextureId, transformMatrix, rotation, timestampNs);
             }
           });
-      capturerObserver.onCapturerStarted(true /* success */);
-      cameraStatistics = new CameraVideoCapturer.CameraStatistics(
-          surfaceTextureHelper, eventsHandler);
       Logging.d(TAG, "Camera device successfully started.");
       callback.onDone(Camera2Session.this);
     }
@@ -232,23 +225,20 @@ public class Camera2Session implements CameraSession {
   }
 
   public static void create(
-      CameraManager cameraManager, CreateSessionCallback callback,
-      CameraVideoCapturer.CameraEventsHandler eventsHandler, Context applicationContext,
-      CameraVideoCapturer.CapturerObserver capturerObserver,
+      CreateSessionCallback callback, Events events,
+      Context applicationContext, CameraManager cameraManager,
       SurfaceTextureHelper surfaceTextureHelper,
       String cameraId, int width, int height, int framerate) {
     new Camera2Session(
-        cameraManager, callback,
-        eventsHandler, applicationContext,
-        capturerObserver,
+        callback, events,
+        applicationContext, cameraManager,
         surfaceTextureHelper,
         cameraId, width, height, framerate);
   }
 
   private Camera2Session(
-      CameraManager cameraManager, CreateSessionCallback callback,
-      CameraVideoCapturer.CameraEventsHandler eventsHandler, Context applicationContext,
-      CameraVideoCapturer.CapturerObserver capturerObserver,
+      CreateSessionCallback callback, Events events,
+      Context applicationContext, CameraManager cameraManager,
       SurfaceTextureHelper surfaceTextureHelper,
       String cameraId, int width, int height, int framerate) {
     Logging.d(TAG, "Create new camera2 session on camera " + cameraId);
@@ -256,11 +246,10 @@ public class Camera2Session implements CameraSession {
     constructionTimeNs = System.nanoTime();
 
     this.cameraThreadHandler = new Handler();
-    this.cameraManager = cameraManager;
     this.callback = callback;
-    this.eventsHandler = eventsHandler;
+    this.events = events;
     this.applicationContext = applicationContext;
-    this.capturerObserver = capturerObserver;
+    this.cameraManager = cameraManager;
     this.surfaceTextureHelper = surfaceTextureHelper;
     this.cameraId = cameraId;
     this.width = width;
@@ -316,7 +305,7 @@ public class Camera2Session implements CameraSession {
     checkIsOnCameraThread();
 
     Logging.d(TAG, "Opening camera " + cameraId);
-    eventsHandler.onCameraOpening(cameraId);
+    events.onCameraOpening(this);
 
     try {
       cameraManager.openCamera(cameraId, new CameraStateCallback(), cameraThreadHandler);
@@ -332,7 +321,6 @@ public class Camera2Session implements CameraSession {
     if (Thread.currentThread() == cameraThreadHandler.getLooper().getThread()) {
       if (state != SessionState.STOPPED) {
         state = SessionState.STOPPED;
-        capturerObserver.onCapturerStopped();
         // Post the stopInternal to return earlier.
         cameraThreadHandler.post(new Runnable() {
           @Override
@@ -352,7 +340,6 @@ public class Camera2Session implements CameraSession {
         public void run() {
           if (state != SessionState.STOPPED) {
             state = SessionState.STOPPED;
-            capturerObserver.onCapturerStopped();
             stopLatch.countDown();
             stopInternal();
             final int stopTimeMs =
@@ -371,7 +358,6 @@ public class Camera2Session implements CameraSession {
     checkIsOnCameraThread();
 
     surfaceTextureHelper.stopListening();
-    cameraStatistics.release();
 
     captureSession.close();
     captureSession = null;
@@ -395,9 +381,9 @@ public class Camera2Session implements CameraSession {
 
       state = SessionState.STOPPED;
       callback.onFailure(error);
-      capturerObserver.onCapturerStarted(false /* success */);
     } else {
-      eventsHandler.onCameraError(error);
+      stop();

[magjed_webrtc, 2016/09/16 12:59:19]

I would like to flatten the number of function indirections and different code
paths. If we add null checks in stopInternal(), would it be possible to write
this function like:

final boolean startFailure = (cameraDevice == null);
state = SessionState.STOPPED;
stopInternal();
if (startFailure) {
  callback.onFailure(error);
} else {
  events.onCameraError(this, error);
}
?

[sakal, 2016/09/16 13:25:16]

Done.

+      events.onCameraError(this, error);
     }
   }