Minor improvements on resource-policy interfaces

Change-Id: I3e9c7c4d1fca90e0fb97b0058e9b5a5e34940025
Reviewed-by: Michael Goddard <michael.goddard@nokia.com>
Reviewed-by: Dmytro Poplavskiy <dmytro.poplavskiy@nokia.com>
Reviewed-by: Jonas Rabbe <jonas.rabbe@nokia.com>

src/multimedia/qmediaresourcepolicy_p.cpp

@@ -86,9 +86,10 @@ QObject* QMediaResourcePolicy::createResourceSet(const QString& interfaceId)
     QMediaResourceSetFactoryInterface *factory =
             qobject_cast<QMediaResourceSetFactoryInterface*>(resourcePolicyLoader()
                                                              ->instance(QLatin1String("default")));
-    if (!factory)
-        return 0;
-    QObject* obj = factory->create(interfaceId);
+    QObject* obj = 0;
+    if (factory)
+        obj = factory->create(interfaceId);
+
     if (!obj) {
         if (interfaceId == QLatin1String(QMediaPlayerResourceSetInterface_iid)) {
             obj = new QDummyMediaPlayerResourceSet(dummyRoot());
@@ -107,6 +108,7 @@ void QMediaResourcePolicy::destroyResourceSet(QObject* resourceSet)
     QMediaResourceSetFactoryInterface *factory =
             qobject_cast<QMediaResourceSetFactoryInterface*>(resourcePolicyLoader()
                                                              ->instance(QLatin1String("default")));
+    Q_ASSERT(factory);
     if (!factory)
         return;
     return factory->destroy(resourceSet);

src/multimedia/qmediaresourcepolicy_p.h

@@ -55,16 +55,16 @@ class Q_MULTIMEDIA_EXPORT QMediaResourcePolicy
 public:
     //a dummy object will always be provided if the interfaceId is not supported
     template<typename T>
-    static T* createResourceSet(const QString& interfaceId);
+    static T* createResourceSet();
     static void destroyResourceSet(QObject* resourceSet);
 private:
     static QObject* createResourceSet(const QString& interfaceId);
 };
 
 template<typename T>
-T* QMediaResourcePolicy::createResourceSet(const QString& interfaceId)
+T* QMediaResourcePolicy::createResourceSet()
 {
-    return qobject_cast<T*>(QMediaResourcePolicy::createResourceSet(interfaceId));
+    return qobject_cast<T*>(QMediaResourcePolicy::createResourceSet(T::iid()));
 }
 
 QT_END_NAMESPACE

src/multimedia/qmediaresourceset_p.cpp

@@ -48,4 +48,9 @@ QMediaPlayerResourceSetInterface::QMediaPlayerResourceSetInterface(QObject *pare
 {
 }
 
+QString QMediaPlayerResourceSetInterface::iid()
+{
+    return QString(QMediaPlayerResourceSetInterface_iid);
+}
+
 QT_END_NAMESPACE

src/multimedia/qmediaresourceset_p.h

@@ -65,6 +65,8 @@ public:
     virtual void release() = 0;
     virtual void setVideoEnabled(bool enabled) = 0;
 
+    static QString iid();
+
 Q_SIGNALS:
     void resourcesGranted();
     void resourcesLost();