content: /*
   * Copyright (C) 2016 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package android.view;
  
  import android.annotation.NonNull;
  import android.annotation.UnsupportedAppUsage;
  import android.os.Looper;
  import android.os.MessageQueue;
  
  import com.android.internal.util.VirtualRefBasePtr;
  
  import java.lang.ref.WeakReference;
  
  /**
   * Provides streaming access to frame stats information from the rendering
   * subsystem to apps.
   *
   * @hide
   */
  public class FrameMetricsObserver {
      @UnsupportedAppUsage
      private MessageQueue mMessageQueue;
  
      private WeakReference<Window> mWindow;
  
      @UnsupportedAppUsage
      private FrameMetrics mFrameMetrics;
  
      /* pacage */ Window.OnFrameMetricsAvailableListener mListener;
      /** @hide */
      public VirtualRefBasePtr mNative;
  
      /**
       * Creates a FrameMetricsObserver
       *
       * @param looper the looper to use when invoking callbacks
       */
      FrameMetricsObserver(@NonNull Window window, @NonNull Looper looper,
              @NonNull Window.OnFrameMetricsAvailableListener listener) {
          if (looper == null) {
              throw new NullPointerException("looper cannot be null");
          }
  
          mMessageQueue = looper.getQueue();
          if (mMessageQueue == null) {
              throw new IllegalStateException("invalid looper, null message queue\n");
          }
  
          mFrameMetrics = new FrameMetrics();
          mWindow = new WeakReference<>(window);
          mListener = listener;
      }
  
      // Called by native on the provided Handler
      @SuppressWarnings("unused")
      @UnsupportedAppUsage
      private void notifyDataAvailable(int dropCount) {
          final Window window = mWindow.get();
          if (window != null) {
              mListener.onFrameMetricsAvailable(window, mFrameMetrics, dropCount);
          }
      }
  }
  