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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.view;
     18 
     19 import android.annotation.NonNull;
     20 import android.os.Looper;
     21 import android.os.MessageQueue;
     22 
     23 import com.android.internal.util.VirtualRefBasePtr;
     24 
     25 import java.lang.ref.WeakReference;
     26 
     27 /**
     28  * Provides streaming access to frame stats information from the rendering
     29  * subsystem to apps.
     30  *
     31  * @hide
     32  */
     33 public class FrameMetricsObserver {
     34     private MessageQueue mMessageQueue;
     35 
     36     private WeakReference<Window> mWindow;
     37 
     38     private FrameMetrics mFrameMetrics;
     39 
     40     /* package */ Window.OnFrameMetricsAvailableListener mListener;
     41     /* package */ VirtualRefBasePtr mNative;
     42 
     43     /**
     44      * Creates a FrameMetricsObserver
     45      *
     46      * @param looper the looper to use when invoking callbacks
     47      */
     48     FrameMetricsObserver(@NonNull Window window, @NonNull Looper looper,
     49             @NonNull Window.OnFrameMetricsAvailableListener listener) {
     50         if (looper == null) {
     51             throw new NullPointerException("looper cannot be null");
     52         }
     53 
     54         mMessageQueue = looper.getQueue();
     55         if (mMessageQueue == null) {
     56             throw new IllegalStateException("invalid looper, null message queue\n");
     57         }
     58 
     59         mFrameMetrics = new FrameMetrics();
     60         mWindow = new WeakReference<>(window);
     61         mListener = listener;
     62     }
     63 
     64     // Called by native on the provided Handler
     65     @SuppressWarnings("unused")
     66     private void notifyDataAvailable(int dropCount) {
     67         final Window window = mWindow.get();
     68         if (window != null) {
     69             mListener.onFrameMetricsAvailable(window, mFrameMetrics, dropCount);
     70         }
     71     }
     72 }
     73