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      */
FrameMetricsObserver(@onNull Window window, @NonNull Looper looper, @NonNull Window.OnFrameMetricsAvailableListener listener)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")
notifyDataAvailable(int dropCount)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