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      1 /*
      2  * Copyright (C) 2017 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 #ifndef EVS_VTS_STREAMHANDLER_H
     18 #define EVS_VTS_STREAMHANDLER_H
     19 
     20 #include <queue>
     21 
     22 #include "ui/GraphicBuffer.h"
     23 
     24 #include <android/hardware/automotive/evs/1.0/IEvsCameraStream.h>
     25 #include <android/hardware/automotive/evs/1.0/IEvsCamera.h>
     26 #include <android/hardware/automotive/evs/1.0/IEvsDisplay.h>
     27 
     28 using namespace ::android::hardware::automotive::evs::V1_0;
     29 using ::android::hardware::Return;
     30 using ::android::hardware::Void;
     31 using ::android::hardware::hidl_vec;
     32 using ::android::hardware::hidl_handle;
     33 using ::android::sp;
     34 
     35 
     36 /*
     37  * StreamHandler:
     38  * This class can be used to receive camera imagery from an IEvsCamera implementation.  It will
     39  * hold onto the most recent image buffer, returning older ones.
     40  * Note that the video frames are delivered on a background thread, while the control interface
     41  * is actuated from the applications foreground thread.
     42  */
     43 class StreamHandler : public IEvsCameraStream {
     44 public:
     45     virtual ~StreamHandler() { shutdown(); };
     46 
     47     StreamHandler(android::sp <IEvsCamera> pCamera);
     48     void shutdown();
     49 
     50     bool startStream();
     51     void asyncStopStream();
     52     void blockingStopStream();
     53 
     54     bool isRunning();
     55 
     56     bool newFrameAvailable();
     57     const BufferDesc& getNewFrame();
     58     void doneWithFrame(const BufferDesc& buffer);
     59 
     60 private:
     61     // Implementation for ::android::hardware::automotive::evs::V1_0::ICarCameraStream
     62     Return<void> deliverFrame(const BufferDesc& buffer)  override;
     63 
     64     // Values initialized as startup
     65     android::sp <IEvsCamera>    mCamera;
     66 
     67     // Since we get frames delivered to us asnchronously via the ICarCameraStream interface,
     68     // we need to protect all member variables that may be modified while we're streaming
     69     // (ie: those below)
     70     std::mutex                  mLock;
     71     std::condition_variable     mSignal;
     72 
     73     bool                        mRunning = false;
     74 
     75     BufferDesc                  mBuffers[2];
     76     int                         mHeldBuffer = -1;   // Index of the one currently held by the client
     77     int                         mReadyBuffer = -1;  // Index of the newest available buffer
     78 };
     79 
     80 
     81 #endif //EVS_VTS_STREAMHANDLER_H
     82