Get CV2X service status

This sample app demonstrates how to use the C-V2X Radio Manager API to get the C-V2X status.

1. Create a RequestCv2xStatusCallback method

static Cv2xStatus gCv2xStatus;
static promise<ErrorCode> gCallbackPromise;

static map<Cv2xStatusType, string> gCv2xStatusToString = {
    {Cv2xStatusType::INACTIVE, "Inactive"},
    {Cv2xStatusType::ACTIVE, "Active"},
    {Cv2xStatusType::SUSPENDED, "SUSPENDED"},
    {Cv2xStatusType::UNKNOWN, "UNKNOWN"},
};

// Callback method for Cv2xRadioManager->requestCv2xStatus
static void cv2xStatusCallback(Cv2xStatus status, ErrorCode error) {
    if (ErrorCode::SUCCESS == error) {
        gCv2xStatus = status;
    }
    gCallbackPromise.set_value(error);
}

Note: as an alternative, we can use a Lambda function which would eliminate the need for this global scope.

2. Implement initialization callback and get the Cv2xRadioManager instance

Optionally initialization callback can be provided with get manager instance. CV2X factory will call callback when manager initialization is complete.

2.1 Create a InitResponseCb lambda function

bool cv2xRadioManagerStatusUpdated = false;
telux::common::ServiceStatus cv2xRadioManagerStatus =
    telux::common::ServiceStatus::SERVICE_UNAVAILABLE;
std::condition_variable cv;
std::mutex mtx;
auto statusCb = [&](telux::common::ServiceStatus status) {
    std::lock_guard<std::mutex> lock(mtx);
    cv2xRadioManagerStatusUpdated = true;
    cv2xRadioManagerStatus = status;
    cv.notify_all();
};

2.2 Get a handle to the ICv2xRadioManager instance

auto & cv2xFactory = Cv2xFactory::getInstance();
auto cv2xRadioManager = cv2xFactory.getCv2xRadioManager(statusCb);

2.3 Wait for C-V2X Radio Manager readiness

std::unique_lock<std::mutex> lck(mtx);
cv.wait(lck, [&] { return cv2xRadioManagerStatusUpdated; });

2.4 Check C-V2X Radio Manager initialization state

If cv2xRadioManager initialization failed, new initialization attempt can be accomplished by calling step 2.2. If initialization succeed, proceed to step 3.

if (status == telux::common::ServiceStatus::SERVICE_AVAILABLE) {
   // Go to step 3
}
else {
   // Go to step 2.2 for another initialization attempt
}

3. Request the C-V2X status

if (Status::SUCCESS != cv2xRadioManager->requestCv2xStatus(cv2xStatusCallback)) {
    cout << "Error : request for C-V2X status failed." << endl;
    return EXIT_FAILURE;
}
if (ErrorCode::SUCCESS != gCallbackPromise.get_future().get()) {
    cout << "Error : failed to retrieve C-V2X status." << endl;
        return EXIT_FAILURE;
}

if (Cv2xStatusType::ACTIVE == gCv2xStatus.rxStatus) {
    cout << "C-V2X Status:" << endl
         << "  RX : " << gCv2xStatusToString[gCv2xStatus.rxStatus] << endl
         << "  TX : " << gCv2xStatusToString[gCv2xStatus.txStatus] << endl;
}