New QCameraInfo class.

The class allows to get the list of available cameras on the system as
well as getting some static information about them such as their unique
ID, display name, physical position and sensor orientation.

This makes QCamera::availableDevices() and QCamera::deviceDescription()
obsolete.

This patch contains the API, documentation and auto-tests but not the
actual implementation by each backend (except for retrieving the default
camera device).

[ChangeLog][QtMultimedia] Added new QCameraInfo class
[ChangeLog][QtMultimedia] QCamera: availableDevices() and
deviceDescription() are deprecated, use QCameraInfo instead

Change-Id: I64fd65729ab26a789468979ed5444ee90bb82cd0
Reviewed-by: Christian Stromme <christian.stromme@digia.com>

src/plugins/gstreamer/camerabin/camerabinserviceplugin.cpp

@@ -90,6 +90,18 @@ QMediaServiceProviderHint::Features CameraBinServicePlugin::supportedFeatures(
     return QMediaServiceProviderHint::Features();
 }
 
+QByteArray CameraBinServicePlugin::defaultDevice(const QByteArray &service) const
+{
+    if (service == Q_MEDIASERVICE_CAMERA) {
+        if (m_cameraDevices.isEmpty())
+            updateDevices();
+
+        return m_defaultCameraDevice;
+    }
+
+    return QByteArray();
+}
+
 QList<QByteArray> CameraBinServicePlugin::devices(const QByteArray &service) const
 {
     if (service == Q_MEDIASERVICE_CAMERA) {
@@ -126,6 +138,7 @@ QVariant CameraBinServicePlugin::deviceProperty(const QByteArray &service, const
 
 void CameraBinServicePlugin::updateDevices() const
 {
+    m_defaultCameraDevice.clear();
     m_cameraDevices.clear();
     m_cameraDescriptions.clear();
 
@@ -167,6 +180,9 @@ void CameraBinServicePlugin::updateDevices() const
         }
         ::close(fd);
     }
+
+    if (!m_cameraDevices.isEmpty())
+        m_defaultCameraDevice = m_cameraDevices.first();
 }
 
 QT_END_NAMESPACE

src/plugins/gstreamer/camerabin/camerabinserviceplugin.h

@@ -51,10 +51,12 @@ QT_BEGIN_NAMESPACE
 class CameraBinServicePlugin
     : public QMediaServiceProviderPlugin
     , public QMediaServiceSupportedDevicesInterface
+    , public QMediaServiceDefaultDeviceInterface
     , public QMediaServiceFeaturesInterface
 {
     Q_OBJECT
     Q_INTERFACES(QMediaServiceSupportedDevicesInterface)
+    Q_INTERFACES(QMediaServiceDefaultDeviceInterface)
     Q_INTERFACES(QMediaServiceFeaturesInterface)
     Q_PLUGIN_METADATA(IID "org.qt-project.qt.mediaserviceproviderfactory/5.0" FILE "camerabin.json")
 public:
@@ -63,6 +65,7 @@ public:
 
     QMediaServiceProviderHint::Features supportedFeatures(const QByteArray &service) const;
 
+    QByteArray defaultDevice(const QByteArray &service) const;
     QList<QByteArray> devices(const QByteArray &service) const;
     QString deviceDescription(const QByteArray &service, const QByteArray &device);
     QVariant deviceProperty(const QByteArray &service, const QByteArray &device, const QByteArray &property);
@@ -70,6 +73,7 @@ public:
 private:
     void updateDevices() const;
 
+    mutable QByteArray m_defaultCameraDevice;
     mutable QList<QByteArray> m_cameraDevices;
     mutable QStringList m_cameraDescriptions;
 };

src/plugins/gstreamer/mediacapture/qgstreamercaptureserviceplugin.cpp

@@ -95,6 +95,18 @@ QMediaServiceProviderHint::Features QGstreamerCaptureServicePlugin::supportedFea
     return QMediaServiceProviderHint::Features();
 }
 
+QByteArray QGstreamerCaptureServicePlugin::defaultDevice(const QByteArray &service) const
+{
+    if (service == Q_MEDIASERVICE_CAMERA) {
+        if (m_cameraDevices.isEmpty())
+            updateDevices();
+
+        return m_defaultCameraDevice;
+    }
+
+    return QByteArray();
+}
+
 QList<QByteArray> QGstreamerCaptureServicePlugin::devices(const QByteArray &service) const
 {
     if (service == Q_MEDIASERVICE_CAMERA) {
@@ -131,6 +143,7 @@ QVariant QGstreamerCaptureServicePlugin::deviceProperty(const QByteArray &servic
 
 void QGstreamerCaptureServicePlugin::updateDevices() const
 {
+    m_defaultCameraDevice.clear();
     m_cameraDevices.clear();
     m_cameraDescriptions.clear();
 
@@ -174,6 +187,9 @@ void QGstreamerCaptureServicePlugin::updateDevices() const
         }
         ::close(fd);
     }
+
+    if (!m_cameraDevices.isEmpty())
+        m_defaultCameraDevice = m_cameraDevices.first();
 }
 #endif
 

src/plugins/gstreamer/mediacapture/qgstreamercaptureserviceplugin.h

@@ -53,6 +53,7 @@ class QGstreamerCaptureServicePlugin
     : public QMediaServiceProviderPlugin
 #if defined(USE_GSTREAMER_CAMERA)
     , public QMediaServiceSupportedDevicesInterface
+    , public QMediaServiceDefaultDeviceInterface
     , public QMediaServiceFeaturesInterface
 #endif
     , public QMediaServiceSupportedFormatsInterface
@@ -60,6 +61,7 @@ class QGstreamerCaptureServicePlugin
     Q_OBJECT
 #if defined(USE_GSTREAMER_CAMERA)
     Q_INTERFACES(QMediaServiceSupportedDevicesInterface)
+    Q_INTERFACES(QMediaServiceDefaultDeviceInterface)
     Q_INTERFACES(QMediaServiceFeaturesInterface)
 #endif
     Q_INTERFACES(QMediaServiceSupportedFormatsInterface)
@@ -75,6 +77,7 @@ public:
 #if defined(USE_GSTREAMER_CAMERA)
     QMediaServiceProviderHint::Features supportedFeatures(const QByteArray &service) const;
 
+    QByteArray defaultDevice(const QByteArray &service) const;
     QList<QByteArray> devices(const QByteArray &service) const;
     QString deviceDescription(const QByteArray &service, const QByteArray &device);
     QVariant deviceProperty(const QByteArray &service, const QByteArray &device, const QByteArray &property);
@@ -87,6 +90,7 @@ private:
 #if defined(USE_GSTREAMER_CAMERA)
     void updateDevices() const;
 
+    mutable QByteArray m_defaultCameraDevice;
     mutable QList<QByteArray> m_cameraDevices;
     mutable QStringList m_cameraDescriptions;
 #endif