qt-everywhere-src-5.15.1/qtmultimedia/src/plugins/gstreamer/camerabin/camerabinserviceplugin.cpp

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#include <QtCore/qstring.h>
#include <QtCore/qdebug.h>
#include <QtCore/QDir>
#include <QtCore/QDebug>

#include "camerabinserviceplugin.h"

#include "camerabinservice.h"
#include <private/qgstutils_p.h>

QT_BEGIN_NAMESPACE

template <typename T, int N> static int lengthOf(const T(&)[N]) { return N; }

CameraBinServicePlugin::CameraBinServicePlugin()
    : m_sourceFactory(0)
{
}

CameraBinServicePlugin::~CameraBinServicePlugin()
{
    if (m_sourceFactory)
        gst_object_unref(GST_OBJECT(m_sourceFactory));
}

QMediaService* CameraBinServicePlugin::create(const QString &key)
{
    QGstUtils::initializeGst();

    if (key == QLatin1String(Q_MEDIASERVICE_CAMERA)) {
        if (!CameraBinService::isCameraBinAvailable()) {
            guint major, minor, micro, nano;
            gst_version(&major, &minor, &micro, &nano);
            qWarning("Error: cannot create camera service, the 'camerabin' plugin is missing for "
                     "GStreamer %u.%u."
                     "\nPlease install the 'bad' GStreamer plugin package.",
                     major, minor);
            return nullptr;
        }

        return new CameraBinService(sourceFactory());
    }

    qWarning() << "Gstreamer camerabin service plugin: unsupported key:" << key;
    return 0;
}

void CameraBinServicePlugin::release(QMediaService *service)
{
    delete service;
}

QMediaServiceProviderHint::Features CameraBinServicePlugin::supportedFeatures(
        const QByteArray &service) const
{
    if (service == Q_MEDIASERVICE_CAMERA)
        return QMediaServiceProviderHint::VideoSurface;

    return QMediaServiceProviderHint::Features();
}

QByteArray CameraBinServicePlugin::defaultDevice(const QByteArray &service) const
{
    return service == Q_MEDIASERVICE_CAMERA
            ? QGstUtils::enumerateCameras(sourceFactory()).value(0).name.toUtf8()
            : QByteArray();
}

QList<QByteArray> CameraBinServicePlugin::devices(const QByteArray &service) const
{

    return service == Q_MEDIASERVICE_CAMERA
            ? QGstUtils::cameraDevices(m_sourceFactory)
            : QList<QByteArray>();
}

QString CameraBinServicePlugin::deviceDescription(const QByteArray &service, const QByteArray &deviceName)
{
    return service == Q_MEDIASERVICE_CAMERA
            ? QGstUtils::cameraDescription(deviceName, m_sourceFactory)
            : QString();
}

QVariant CameraBinServicePlugin::deviceProperty(const QByteArray &service, const QByteArray &device, const QByteArray &property)
{
    Q_UNUSED(service);
    Q_UNUSED(device);
    Q_UNUSED(property);
    return QVariant();
}

QCamera::Position CameraBinServicePlugin::cameraPosition(const QByteArray &deviceName) const
{
    return QGstUtils::cameraPosition(deviceName, m_sourceFactory);
}

int CameraBinServicePlugin::cameraOrientation(const QByteArray &deviceName) const
{
    return QGstUtils::cameraOrientation(deviceName, m_sourceFactory);
}

GstElementFactory *CameraBinServicePlugin::sourceFactory() const
{
    if (!m_sourceFactory) {
        GstElementFactory *factory = 0;
        const QByteArray envCandidate = qgetenv("QT_GSTREAMER_CAMERABIN_SRC");
        if (!envCandidate.isEmpty())
            factory = gst_element_factory_find(envCandidate.constData());

        static const char *candidates[] = { "subdevsrc", "wrappercamerabinsrc" };
        for (int i = 0; !factory && i < lengthOf(candidates); ++i)
            factory = gst_element_factory_find(candidates[i]);

        if (factory) {
            m_sourceFactory = GST_ELEMENT_FACTORY(gst_plugin_feature_load(
                    GST_PLUGIN_FEATURE(factory)));
            gst_object_unref((GST_OBJECT(factory)));
        }
    }

    return m_sourceFactory;
}

QT_END_NAMESPACE