Android: Make base interface for camera1 and camera2

This CL adds a new interface CameraVideoCapturer that extends VideoCapturer with a switchCamera() function. It also moves moves CameraEventsHandler, CameraStatistics, and CameraSwitchHandler from VideoCapturerAndroid to this new interface. The purpose is to prepare for a camera2 implementation that will use the same interfaces and helper class.

BUG=webrtc:5519

Review-Url: https://codereview.webrtc.org/1895483002
Cr-Commit-Position: refs/heads/master@{#12723}

webrtc/api/java/android/org/webrtc/CameraVideoCapturer.java

@@ -0,0 +1,128 @@
+/*
+ *  Copyright 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+package org.webrtc;
+
+/**
+ * Base interface for camera1 and camera2 implementations. Extends VideoCapturer with a
+ * switchCamera() function. Also provides subinterfaces for handling camera events, and a helper
+ * class for detecting camera freezes.
+ */
+public interface CameraVideoCapturer extends VideoCapturer {
+  /**
+   * Camera events handler - can be used to be notifed about camera events. The callbacks are
+   * executed from an arbitrary thread.
+   */
+  public interface CameraEventsHandler {
+    // Camera error handler - invoked when camera can not be opened
+    // or any camera exception happens on camera thread.
+    void onCameraError(String errorDescription);
+
+    // Invoked when camera stops receiving frames.
+    void onCameraFreezed(String errorDescription);
+
+    // Callback invoked when camera is opening.
+    void onCameraOpening(int cameraId);
+
+    // Callback invoked when first camera frame is available after camera is started.
+    void onFirstFrameAvailable();
+
+    // Callback invoked when camera is closed.
+    void onCameraClosed();
+  }
+
+  /**
+   * Camera switch handler - one of these functions are invoked with the result of switchCamera().
+   * The callback may be called on an arbitrary thread.
+   */
+  public interface CameraSwitchHandler {
+    // Invoked on success. |isFrontCamera| is true if the new camera is front facing.
+    void onCameraSwitchDone(boolean isFrontCamera);
+
+    // Invoked on failure, e.g. camera is stopped or only one camera available.
+    void onCameraSwitchError(String errorDescription);
+  }
+
+  /**
+   * Switch camera to the next valid camera id. This can only be called while the camera is running.
+   * This function can be called from any thread.
+   */
+  void switchCamera(CameraSwitchHandler switchEventsHandler);
+
+  /**
+   * Helper class to log framerate and detect if the camera freezes. It will run periodic callbacks
+   * on the SurfaceTextureHelper thread passed in the ctor, and should only be operated from that
+   * thread.
+   */
+  public static class CameraStatistics {
+    private final static String TAG = "CameraStatistics";
+    private final static int CAMERA_OBSERVER_PERIOD_MS = 2000;
+    private final static int CAMERA_FREEZE_REPORT_TIMOUT_MS = 4000;
+
+    private final SurfaceTextureHelper surfaceTextureHelper;
+    private final CameraEventsHandler eventsHandler;
+    private int frameCount;
+    private int freezePeriodCount;
+    // Camera observer - monitors camera framerate. Observer is executed on camera thread.
+    private final Runnable cameraObserver = new Runnable() {
+      @Override
+      public void run() {
+        final int cameraFps = Math.round(frameCount * 1000.0f / CAMERA_OBSERVER_PERIOD_MS);
+        Logging.d(TAG, "Camera fps: " + cameraFps +".");
+        if (frameCount == 0) {
+          ++freezePeriodCount;
+          if (CAMERA_OBSERVER_PERIOD_MS * freezePeriodCount >= CAMERA_FREEZE_REPORT_TIMOUT_MS
+              && eventsHandler != null) {
+            Logging.e(TAG, "Camera freezed.");
+            if (surfaceTextureHelper.isTextureInUse()) {
+              // This can only happen if we are capturing to textures.
+              eventsHandler.onCameraFreezed("Camera failure. Client must return video buffers.");
+            } else {
+              eventsHandler.onCameraFreezed("Camera failure.");
+            }
+            return;
+          }
+        } else {
+          freezePeriodCount = 0;
+        }
+        frameCount = 0;
+        surfaceTextureHelper.getHandler().postDelayed(this, CAMERA_OBSERVER_PERIOD_MS);
+      }
+    };
+
+    public CameraStatistics(
+        SurfaceTextureHelper surfaceTextureHelper, CameraEventsHandler eventsHandler) {
+      if (surfaceTextureHelper == null) {
+        throw new IllegalArgumentException("SurfaceTextureHelper is null");
+      }
+      this.surfaceTextureHelper = surfaceTextureHelper;
+      this.eventsHandler = eventsHandler;
+      this.frameCount = 0;
+      this.freezePeriodCount = 0;
+      surfaceTextureHelper.getHandler().postDelayed(cameraObserver, CAMERA_OBSERVER_PERIOD_MS);
+    }
+
+    private void checkThread() {
+      if (Thread.currentThread() != surfaceTextureHelper.getHandler().getLooper().getThread()) {
+        throw new IllegalStateException("Wrong thread");
+      }
+    }
+
+    public void addFrame() {
+      checkThread();
+      ++frameCount;
+    }
+
+    public void release() {
+      checkThread();
+      surfaceTextureHelper.getHandler().removeCallbacks(cameraObserver);
+    }
+  }
+}

webrtc/api/java/android/org/webrtc/VideoCapturerAndroid.java

@@ -38,14 +38,13 @@ import java.util.concurrent.TimeUnit;
 // arbitrary Java threads. All public entry points are thread safe, and delegate the work to the
 // camera thread. The internal *OnCameraThread() methods must check |camera| for null to check if
 // the camera has been stopped.
+// TODO(magjed): This class name is now confusing - rename to Camera1VideoCapturer.
 @SuppressWarnings("deprecation")
 public class VideoCapturerAndroid implements
-    VideoCapturer,
+    CameraVideoCapturer,
     android.hardware.Camera.PreviewCallback,
     SurfaceTextureHelper.OnTextureFrameAvailableListener {
   private final static String TAG = "VideoCapturerAndroid";
-  private final static int CAMERA_OBSERVER_PERIOD_MS = 2000;
-  private final static int CAMERA_FREEZE_REPORT_TIMOUT_MS = 4000;
   private static final int CAMERA_STOP_TIMEOUT_MS = 7000;
 
   private boolean isDisposed = false;
@@ -60,7 +59,7 @@ public class VideoCapturerAndroid implements
   private final Object cameraIdLock = new Object();
   private int id;
   private android.hardware.Camera.CameraInfo info;
-  private final CameraStatistics cameraStatistics;
+  private CameraStatistics cameraStatistics;
   // Remember the requested format in case we want to switch cameras.
   private int requestedWidth;
   private int requestedHeight;
@@ -104,84 +103,6 @@ public class VideoCapturerAndroid implements
     }
   };
 
-  // Camera observer - monitors camera framerate. Observer is executed on camera thread.
-  private final Runnable cameraObserver = new Runnable() {
-    private int freezePeriodCount;
-    @Override
-    public void run() {
-      int cameraFramesCount = cameraStatistics.getAndResetFrameCount();
-      int cameraFps = (cameraFramesCount * 1000 + CAMERA_OBSERVER_PERIOD_MS / 2)
-          / CAMERA_OBSERVER_PERIOD_MS;
-
-      Logging.d(TAG, "Camera fps: " + cameraFps +".");
-      if (cameraFramesCount == 0) {
-        ++freezePeriodCount;
-        if (CAMERA_OBSERVER_PERIOD_MS * freezePeriodCount >= CAMERA_FREEZE_REPORT_TIMOUT_MS
-            && eventsHandler != null) {
-          Logging.e(TAG, "Camera freezed.");
-          if (surfaceHelper.isTextureInUse()) {
-            // This can only happen if we are capturing to textures.
-            eventsHandler.onCameraFreezed("Camera failure. Client must return video buffers.");
-          } else {
-            eventsHandler.onCameraFreezed("Camera failure.");
-          }
-          return;
-        }
-      } else {
-        freezePeriodCount = 0;
-      }
-      maybePostDelayedOnCameraThread(CAMERA_OBSERVER_PERIOD_MS, this);
-    }
-  };
-
-  private static class CameraStatistics {
-    private int frameCount = 0;
-    private final ThreadUtils.ThreadChecker threadChecker = new ThreadUtils.ThreadChecker();
-
-    CameraStatistics() {
-      threadChecker.detachThread();
-    }
-
-    public void addFrame() {
-      threadChecker.checkIsOnValidThread();
-      ++frameCount;
-    }
-
-    public int getAndResetFrameCount() {
-      threadChecker.checkIsOnValidThread();
-      int count = frameCount;
-      frameCount = 0;
-      return count;
-    }
-  }
-
-  public static interface CameraEventsHandler {
-    // Camera error handler - invoked when camera can not be opened
-    // or any camera exception happens on camera thread.
-    void onCameraError(String errorDescription);
-
-    // Invoked when camera stops receiving frames
-    void onCameraFreezed(String errorDescription);
-
-    // Callback invoked when camera is opening.
-    void onCameraOpening(int cameraId);
-
-    // Callback invoked when first camera frame is available after camera is opened.
-    void onFirstFrameAvailable();
-
-    // Callback invoked when camera closed.
-    void onCameraClosed();
-  }
-
-  // Camera switch handler - one of these functions are invoked with the result of switchCamera().
-  // The callback may be called on an arbitrary thread.
-  public interface CameraSwitchHandler {
-    // Invoked on success. |isFrontCamera| is true if the new camera is front facing.
-    void onCameraSwitchDone(boolean isFrontCamera);
-    // Invoked on failure, e.g. camera is stopped or only one camera available.
-    void onCameraSwitchError(String errorDescription);
-  }
-
   public static VideoCapturerAndroid create(String name,
       CameraEventsHandler eventsHandler) {
     return VideoCapturerAndroid.create(name, eventsHandler, false /* captureToTexture */);
@@ -216,6 +137,7 @@ public class VideoCapturerAndroid implements
 
   // Switch camera to the next valid camera id. This can only be called while
   // the camera is running.
+  @Override
   public void switchCamera(final CameraSwitchHandler switchEventsHandler) {
     if (android.hardware.Camera.getNumberOfCameras() < 2) {
       if (switchEventsHandler != null) {
@@ -299,7 +221,6 @@ public class VideoCapturerAndroid implements
     this.id = cameraId;
     this.eventsHandler = eventsHandler;
     isCapturingToTexture = captureToTexture;
-    cameraStatistics = new CameraStatistics();
     Logging.d(TAG, "VideoCapturerAndroid isCapturingToTexture : " + isCapturingToTexture);
   }
 
@@ -460,7 +381,7 @@ public class VideoCapturerAndroid implements
       }
 
       // Start camera observer.
-      maybePostDelayedOnCameraThread(CAMERA_OBSERVER_PERIOD_MS, cameraObserver);
+      cameraStatistics = new CameraStatistics(surfaceHelper, eventsHandler);
       return;
     } catch (RuntimeException e) {
       error = e;
@@ -613,8 +534,10 @@ public class VideoCapturerAndroid implements
     if (surfaceHelper != null) {
       surfaceHelper.stopListening();
     }
-    cameraThreadHandler.removeCallbacks(cameraObserver);
+    if (cameraStatistics != null) {
-    cameraStatistics.getAndResetFrameCount();
+      cameraStatistics.release();
+      cameraStatistics = null;
+    }
     Logging.d(TAG, "Stop preview.");
     if (camera != null) {
       camera.stopPreview();