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/directshow/camera/dsvideodevicecontrol.cpp

@@ -153,7 +153,7 @@ void DSVideoDeviceControl::enumerateDevices(QList<QByteArray> *devices, QStringL
 
 void DSVideoDeviceControl::setSelectedDevice(int index)
 {
-    if (index >= 0 && index <= m_devices.count()) {
+    if (index >= 0 && index < m_devices.count()) {
         if (m_session) {
             QString device = m_devices.at(index);
             if (device.startsWith("ds:"))

src/plugins/directshow/dsserviceplugin.cpp

@@ -107,6 +107,20 @@ QMediaServiceProviderHint::Features DSServicePlugin::supportedFeatures(
         return QMediaServiceProviderHint::Features();
 }
 
+QByteArray DSServicePlugin::defaultDevice(const QByteArray &service) const
+{
+#ifdef QMEDIA_DIRECTSHOW_CAMERA
+    if (service == Q_MEDIASERVICE_CAMERA) {
+        if (m_cameraDevices.isEmpty())
+            updateDevices();
+
+        return m_defaultCameraDevice;
+    }
+#endif
+
+    return QByteArray();
+}
+
 QList<QByteArray> DSServicePlugin::devices(const QByteArray &service) const
 {
 #ifdef QMEDIA_DIRECTSHOW_CAMERA
@@ -140,10 +154,13 @@ QString DSServicePlugin::deviceDescription(const QByteArray &service, const QByt
 
 void DSServicePlugin::updateDevices() const
 {
+    m_defaultCameraDevice.clear();
     DSVideoDeviceControl::enumerateDevices(&m_cameraDevices, &m_cameraDescriptions);
 
     if (m_cameraDevices.isEmpty()) {
         qWarning() << "No camera devices found";
+    } else {
+        m_defaultCameraDevice = m_cameraDevices.first();
     }
 }
 #endif

src/plugins/directshow/dsserviceplugin.h

@@ -49,10 +49,12 @@ QT_USE_NAMESPACE
 class DSServicePlugin
     : public QMediaServiceProviderPlugin
     , public QMediaServiceSupportedDevicesInterface
+    , public QMediaServiceDefaultDeviceInterface
     , public QMediaServiceFeaturesInterface
 {
     Q_OBJECT
     Q_INTERFACES(QMediaServiceSupportedDevicesInterface)
+    Q_INTERFACES(QMediaServiceDefaultDeviceInterface)
     Q_INTERFACES(QMediaServiceFeaturesInterface)
     // The player service provided by the WMF-plugin should preferably be used.
     // DirectShow should then only provide the camera (see QTBUG-29172, QTBUG-29175).
@@ -68,6 +70,7 @@ 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);
 
@@ -75,6 +78,7 @@ private:
 #ifdef QMEDIA_DIRECTSHOW_CAMERA
     void updateDevices() const;
 
+    mutable QByteArray m_defaultCameraDevice;
     mutable QList<QByteArray> m_cameraDevices;
     mutable QStringList m_cameraDescriptions;
 #endif