DirectShow: fix metadata signals when changing media.

The metaDataChanged() and metaDataAvailableChanged() signals should
be emitted immediately when changing or clearing the current media.

Change-Id: I3152e2c32420ba6f11cf6780013e02208a9d6599
Reviewed-by: Christian Stromme <christian.stromme@theqtcompany.com>

src/plugins/directshow/player/directshowmetadatacontrol.cpp

@@ -362,7 +362,18 @@ static QString convertBSTR(BSTR *string)
     return value;
 }
 
-void DirectShowMetaDataControl::updateGraph(IFilterGraph2 *graph, IBaseFilter *source, const QString &fileSrc)
+void DirectShowMetaDataControl::reset()
+{
+    bool hadMetadata = !m_metadata.isEmpty();
+    m_metadata.clear();
+
+    setMetadataAvailable(false);
+
+    if (hadMetadata)
+        emit metaDataChanged();
+}
+
+void DirectShowMetaDataControl::updateMetadata(IFilterGraph2 *graph, IBaseFilter *source, const QString &fileSrc)
 {
     m_metadata.clear();
 
@@ -568,13 +579,19 @@ void DirectShowMetaDataControl::customEvent(QEvent *event)
     if (event->type() == QEvent::Type(MetaDataChanged)) {
         event->accept();
 
-        bool oldAvailable = m_available;
-        m_available = !m_metadata.isEmpty();
-        if (m_available != oldAvailable)
-            emit metaDataAvailableChanged(m_available);
+        setMetadataAvailable(!m_metadata.isEmpty());
 
         emit metaDataChanged();
     } else {
         QMetaDataReaderControl::customEvent(event);
     }
 }
+
+void DirectShowMetaDataControl::setMetadataAvailable(bool available)
+{
+    if (m_available == available)
+        return;
+
+    m_available = available;
+    emit metaDataAvailableChanged(m_available);
+}

src/plugins/directshow/player/directshowmetadatacontrol.h

@@ -56,13 +56,16 @@ public:
     QVariant metaData(const QString &key) const;
     QStringList availableMetaData() const;
 
-    void updateGraph(IFilterGraph2 *graph, IBaseFilter *source,
-                     const QString &fileSrc = QString());
+    void reset();
+    void updateMetadata(IFilterGraph2 *graph, IBaseFilter *source,
+                        const QString &fileSrc = QString());
 
 protected:
     void customEvent(QEvent *event);
 
 private:
+    void setMetadataAvailable(bool available);
+
     enum Event
     {
         MetaDataChanged = QEvent::User

src/plugins/directshow/player/directshowplayerservice.cpp

@@ -231,7 +231,7 @@ void DirectShowPlayerService::load(const QMediaContent &media, QIODevice *stream
     m_seekable = false;
     m_atEnd = false;
     m_dontCacheNextSeekResult = false;
-    m_metaDataControl->updateGraph(0, 0);
+    m_metaDataControl->reset();
 
     if (m_resources.isEmpty() && !stream) {
         m_pendingTasks = 0;
@@ -570,9 +570,6 @@ void DirectShowPlayerService::doReleaseGraph(QMutexLocker *locker)
         control->Release();
     }
 
-    //release m_headerInfo -> decrease ref counter of m_source
-    m_metaDataControl->updateGraph(0, 0);
-
     if (m_source) {
         m_source->Release();
         m_source = 0;
@@ -1138,7 +1135,7 @@ void DirectShowPlayerService::customEvent(QEvent *event)
         QMutexLocker locker(&m_mutex);
 
         m_playerControl->updateMediaInfo(m_duration, m_streamTypes, m_seekable);
-        m_metaDataControl->updateGraph(m_graph, m_source, m_url.toString());
+        m_metaDataControl->updateMetadata(m_graph, m_source, m_url.toString());
 
         updateStatus();
     } else if (event->type() == QEvent::Type(Error)) {