Fixed crash which occurs when switching between video clips

When Phonon::MediaObject::setCurrentSource() is called when the
MediaObject is connected to a Phonon::VideoWidget, the
MMF::AbstractVideoOutput pointer is propagated inside the backend
from the first MMF::AbstractVideoPlayer to the second.

If the VideoWidget is subsquently re-sized, the code path enters
the ScaleFactors branch of the
MMF::SurfaceVideoPlayer::handleParametersChanged function.  At this
point, m_displayWindow is still set to the inital null value, and the
assertion therefore fails.

This change ensures that m_displayWindow is updated before attempting
to apply the scale factor change.

Task-number: QTBUG-11377
Reviewed-by: Thierry Bastian

2 files changed, 32 insertions, 13 deletions

diff --git a/src/3rdparty/phonon/mmf/videoplayer_surface.cpp b/src/3rdparty/phonon/mmf/videoplayer_surface.cpp
index 5d8db268d0..343370c685 100644
--- a/src/3rdparty/phonon/mmf/videoplayer_surface.cpp
+++ b/src/3rdparty/phonon/mmf/videoplayer_surface.cpp
@@ -118,23 +118,14 @@ void MMF::SurfaceVideoPlayer::handleParametersChanged(VideoParameters parameters
     if (player) {
         int err = KErrNone;
         if (parameters & WindowHandle) {
-            if (m_displayWindow)
-                player->RemoveDisplayWindow(*m_displayWindow);
-
-            RWindow *window = static_cast<RWindow *>(m_window);
-            if (window) {
-                window->SetBackgroundColor(TRgb(0, 0, 0, 255));
-                TRAP(err, player->AddDisplayWindowL(m_wsSession, m_screenDevice, *window, rect, rect));
-                if (KErrNone != err) {
-                    setError(tr("Video display error"), err);
-                    window = 0;
-                }
-            }
-            m_displayWindow = window;
+            removeDisplayWindow();
+            addDisplayWindow(rect);
         }
 
         if (KErrNone == err) {
             if (parameters & ScaleFactors) {
+                if (!m_displayWindow)
+                    addDisplayWindow(rect);
                 Q_ASSERT(m_displayWindow);
                 TRAP(err, player->SetVideoExtentL(*m_displayWindow, rect));
                 if (KErrNone == err)
@@ -148,5 +139,30 @@ void MMF::SurfaceVideoPlayer::handleParametersChanged(VideoParameters parameters
     }
 }
 
+void MMF::SurfaceVideoPlayer::addDisplayWindow(const TRect &rect)
+{
+    Q_ASSERT(!m_displayWindow);
+    RWindow *window = static_cast<RWindow *>(m_window);
+    if (window) {
+        window->SetBackgroundColor(TRgb(0, 0, 0, 255));
+        CVideoPlayerUtility2 *player = static_cast<CVideoPlayerUtility2 *>(m_player.data());
+        Q_ASSERT(player);
+        TRAPD(err, player->AddDisplayWindowL(m_wsSession, m_screenDevice, *window, rect, rect));
+        if (KErrNone == err)
+            m_displayWindow = window;
+        else
+            setError(tr("Video display error"), err);
+    }
+}
+
+void MMF::SurfaceVideoPlayer::removeDisplayWindow()
+{
+    CVideoPlayerUtility2 *player = static_cast<CVideoPlayerUtility2 *>(m_player.data());
+    if (player && m_displayWindow) {
+        player->RemoveDisplayWindow(*m_displayWindow);
+        m_displayWindow = 0;
+    }
+}
+
 QT_END_NAMESPACE
 
diff --git a/src/3rdparty/phonon/mmf/videoplayer_surface.h b/src/3rdparty/phonon/mmf/videoplayer_surface.h
index c05da9ca70..8572fdc6ba 100644
--- a/src/3rdparty/phonon/mmf/videoplayer_surface.h
+++ b/src/3rdparty/phonon/mmf/videoplayer_surface.h
@@ -62,6 +62,9 @@ private:
     void handleVideoWindowChanged();
     void handleParametersChanged(VideoParameters parameters);
 
+    void addDisplayWindow(const TRect &rect);
+    void removeDisplayWindow();
+
 private:
     // Window handle which has been passed to the MMF via
     // CVideoPlayerUtility2::SetDisplayWindowL