evs/sampleDriver/EvsEnumerator.h

/*
 * Copyright (C) 2016-2019 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef ANDROID_HARDWARE_AUTOMOTIVE_EVS_V1_0_EVSCAMERAENUMERATOR_H
#define ANDROID_HARDWARE_AUTOMOTIVE_EVS_V1_0_EVSCAMERAENUMERATOR_H

#include <android/hardware/automotive/evs/1.0/IEvsEnumerator.h>
#include <android/hardware/automotive/evs/1.0/IEvsCamera.h>

#include <unordered_map>
#include <thread>
#include <atomic>

namespace android {
namespace hardware {
namespace automotive {
namespace evs {
namespace V1_0 {
namespace implementation {


class EvsV4lCamera;    // from EvsCamera.h
class EvsGlDisplay;    // from EvsGlDisplay.h

class EvsEnumerator : public IEvsEnumerator {
public:
    // Methods from ::android::hardware::automotive::evs::V1_0::IEvsEnumerator follow.
    Return<void> getCameraList(getCameraList_cb _hidl_cb)  override;
    Return<sp<IEvsCamera>> openCamera(const hidl_string& cameraId) override;
    Return<void> closeCamera(const ::android::sp<IEvsCamera>& carCamera)  override;
    Return<sp<IEvsDisplay>> openDisplay()  override;
    Return<void> closeDisplay(const ::android::sp<IEvsDisplay>& display)  override;
    Return<DisplayState> getDisplayState()  override;

    // Implementation details
    EvsEnumerator();

    // Listen to video device uevents
    static void EvsUeventThread(std::atomic<bool>& running);

private:
    struct CameraRecord {
        CameraDesc          desc;
        wp<EvsV4lCamera>    activeInstance;

        CameraRecord(const char *cameraId) : desc() { desc.cameraId = cameraId; }
    };

    static bool qualifyCaptureDevice(const char* deviceName);
    static CameraRecord* findCameraById(const std::string& cameraId);
    static void enumerateDevices();

    // NOTE:  All members values are static so that all clients operate on the same state
    //        That is to say, this is effectively a singleton despite the fact that HIDL
    //        constructs a new instance for each client.
    //        Because our server has a single thread in the thread pool, these values are
    //        never accessed concurrently despite potentially having multiple instance objects
    //        using them.
    static std::unordered_map<std::string,
                              CameraRecord> sCameraList;

    static wp<EvsGlDisplay>                 sActiveDisplay; // Weak pointer.
                                                            // Object destructs if client dies.

    static std::mutex                       sLock;          // Mutex on shared camera device list.
    static std::condition_variable          sCameraSignal;  // Signal on camera device addition.
};

} // namespace implementation
} // namespace V1_0
} // namespace evs
} // namespace automotive
} // namespace hardware
} // namespace android

#endif  // ANDROID_HARDWARE_AUTOMOTIVE_EVS_V1_0_EVSCAMERAENUMERATOR_H