1 /*
2  * Copyright 2024 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 static android.Manifest.permission.DETECT_SCREEN_RECORDING;
20 import static android.view.WindowManager.SCREEN_RECORDING_STATE_NOT_VISIBLE;
21 import static android.view.WindowManager.SCREEN_RECORDING_STATE_VISIBLE;
22 
23 import android.annotation.CallbackExecutor;
24 import android.annotation.NonNull;
25 import android.annotation.RequiresPermission;
26 import android.os.Binder;
27 import android.os.RemoteException;
28 import android.util.ArrayMap;
29 import android.view.WindowManager.ScreenRecordingState;
30 import android.window.IScreenRecordingCallback;
31 
32 import java.util.ArrayList;
33 import java.util.List;
34 import java.util.Objects;
35 import java.util.concurrent.Executor;
36 import java.util.function.Consumer;
37 
38 /**
39  * This class is responsible for calling app-registered screen recording callbacks. This class
40  * registers a single screen recording callback with WindowManagerService and calls the
41  * app-registered callbacks whenever that WindowManagerService callback is called.
42  *
43  * @hide
44  */
45 public final class ScreenRecordingCallbacks {
46 
47     private static ScreenRecordingCallbacks sInstance;
48     private static final Object sLock = new Object();
49 
50     private final ArrayMap<Consumer<@ScreenRecordingState Integer>, Executor> mCallbacks =
51             new ArrayMap<>();
52 
53     private IScreenRecordingCallback mCallbackNotifier;
54     private @ScreenRecordingState int mState = SCREEN_RECORDING_STATE_NOT_VISIBLE;
55 
ScreenRecordingCallbacks()56     private ScreenRecordingCallbacks() {}
57 
getWindowManagerService()58     private static @NonNull IWindowManager getWindowManagerService() {
59         return Objects.requireNonNull(WindowManagerGlobal.getWindowManagerService());
60     }
61 
getInstance()62     static ScreenRecordingCallbacks getInstance() {
63         synchronized (sLock) {
64             if (sInstance == null) {
65                 sInstance = new ScreenRecordingCallbacks();
66             }
67             return sInstance;
68         }
69     }
70 
71     @RequiresPermission(DETECT_SCREEN_RECORDING)
72     @ScreenRecordingState
addCallback( @onNull @allbackExecutor Executor executor, @NonNull Consumer<@ScreenRecordingState Integer> callback)73     int addCallback(
74             @NonNull @CallbackExecutor Executor executor,
75             @NonNull Consumer<@ScreenRecordingState Integer> callback) {
76         synchronized (sLock) {
77             if (mCallbackNotifier == null) {
78                 mCallbackNotifier =
79                         new IScreenRecordingCallback.Stub() {
80                             @Override
81                             public void onScreenRecordingStateChanged(
82                                     boolean visibleInScreenRecording) {
83                                 int state =
84                                         visibleInScreenRecording
85                                                 ? SCREEN_RECORDING_STATE_VISIBLE
86                                                 : SCREEN_RECORDING_STATE_NOT_VISIBLE;
87                                 notifyCallbacks(state);
88                             }
89                         };
90                 try {
91                     boolean visibleInScreenRecording =
92                             getWindowManagerService()
93                                     .registerScreenRecordingCallback(mCallbackNotifier);
94                     mState =
95                             visibleInScreenRecording
96                                     ? SCREEN_RECORDING_STATE_VISIBLE
97                                     : SCREEN_RECORDING_STATE_NOT_VISIBLE;
98                 } catch (RemoteException e) {
99                     e.rethrowFromSystemServer();
100                 }
101             }
102             mCallbacks.put(callback, executor);
103             return mState;
104         }
105     }
106 
107     @RequiresPermission(DETECT_SCREEN_RECORDING)
removeCallback(@onNull Consumer<@ScreenRecordingState Integer> callback)108     void removeCallback(@NonNull Consumer<@ScreenRecordingState Integer> callback) {
109         synchronized (sLock) {
110             mCallbacks.remove(callback);
111             if (mCallbacks.isEmpty()) {
112                 try {
113                     getWindowManagerService().unregisterScreenRecordingCallback(mCallbackNotifier);
114                 } catch (RemoteException e) {
115                     e.rethrowFromSystemServer();
116                 }
117                 mCallbackNotifier = null;
118             }
119         }
120     }
121 
notifyCallbacks(@creenRecordingState int state)122     private void notifyCallbacks(@ScreenRecordingState int state) {
123         List<Runnable> callbacks;
124         synchronized (sLock) {
125             mState = state;
126             if (mCallbacks.isEmpty()) {
127                 return;
128             }
129 
130             callbacks = new ArrayList<>();
131             for (int i = 0; i < mCallbacks.size(); i++) {
132                 Consumer<Integer> callback = mCallbacks.keyAt(i);
133                 Executor executor = mCallbacks.valueAt(i);
134                 callbacks.add(() -> executor.execute(() -> callback.accept(state)));
135             }
136         }
137         final long token = Binder.clearCallingIdentity();
138         try {
139             for (int i = 0; i < callbacks.size(); i++) {
140                 callbacks.get(i).run();
141             }
142         } finally {
143             Binder.restoreCallingIdentity(token);
144         }
145     }
146 }
147