1 /*
2  * Copyright (C) 2023 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 /*
18  *  Manage the remote camera service native functions.
19  */
20 #pragma once
21 #include <jni.h>
22 #include <mutex>
23 #include <thread>
24 
25 namespace android {
26 namespace webcam {
27 
28 class UVCProvider;
29 class DeviceAsWebcamServiceManager {
30   public:
31     // Singleton instance. All member functions/fields should be accessed through this instance.
32     // It lives indefinitely. Ctor and Dtor should not be relied on for cleanup of resources.
33     static DeviceAsWebcamServiceManager* kInstance;
34 
35     // Returns true if the java service needs to be started. This is called by the USB Broadcast
36     // receiver which might multiple receive spurious calls to start the service.
37     bool shouldStartService(jobjectArray jIgnoredNodes);
38     // Inits the native side of the service. This function should be called by the Java service
39     // before any of the functions below it
40     int setupServicesAndStartListening(JNIEnv* env, jobject javaService,
41                                        jobjectArray jIgnoredNodes);
42     // Called by Java to encode a frame
43     int encodeImage(JNIEnv* env, jobject hardwareBuffer, jlong timestamp, jint rotation);
44     // Called by native service to set the stream configuration in the Java Service.
45     void setStreamConfig(bool mjpeg, uint32_t width, uint32_t height, uint32_t fps);
46     // Called by native service to notify the Java service to start streaming the camera.
47     void startStreaming();
48     // Called by native service to notify the Java service to stop streaming the camera.
49     void stopStreaming();
50     // Called by native service to return an Image to the Java service.
51     void returnImage(long timestamp);
52     // Called by the Native Service when it wants to signal the Java service to stop.
53     // This is non-blocking and does not guarantee that the Java service has stopped on return.
54     void stopService();
55     // Called by Java when the foreground service is being destroyed.
56     void onDestroy();
57 
58     ~DeviceAsWebcamServiceManager() = default;
59 
60   private:
61     DeviceAsWebcamServiceManager() = default;
62 
63     std::mutex mSerializationLock;   // Serializes all methods in class
64     bool mServiceRunning = false;    // if this is true, then the variables underneath can be
65                                      // considered safe to use without further checking.
66     jobject mJavaService = nullptr;  // strong reference to the current foreground service.
67     std::shared_ptr<UVCProvider> mUVCProvider;
68     std::thread mJniThread;  // thread to make asynchronous calls to Java
69 };
70 
71 }  // namespace webcam
72 }  // namespace android
73