Pending surface might not get destroyed if no flush() happens

in between graphics system change. This patch ensures that all
old surfaces are destroyed before new graphics system is
activated.

Reviewed-by: Jason Barron
(cherry picked from commit d3ab1fccea2b1e011e7518269a29045a53f0a30b)

3 files changed, 9 insertions, 16 deletions

diff --git a/src/gui/kernel/qapplication_s60.cpp b/src/gui/kernel/qapplication_s60.cpp
index a14b1a7..c3824f9 100644
--- a/src/gui/kernel/qapplication_s60.cpp
+++ b/src/gui/kernel/qapplication_s60.cpp
@@ -1067,7 +1067,7 @@ void QSymbianControl::Draw(const TRect& controlRect) const
         if (QApplicationPrivate::runtime_graphics_system) {
             QRuntimeWindowSurface *rtSurface =
                     static_cast<QRuntimeWindowSurface*>(qwidget->windowSurface());
-            s60Surface = static_cast<QS60WindowSurface *>(rtSurface->m_windowSurface);
+            s60Surface = static_cast<QS60WindowSurface *>(rtSurface->m_windowSurface.data());
         } else
 #endif
             s60Surface = static_cast<QS60WindowSurface *>(qwidget->windowSurface());
diff --git a/src/gui/painting/qgraphicssystem_runtime.cpp b/src/gui/painting/qgraphicssystem_runtime.cpp
index f670702..6db8bc4 100644
--- a/src/gui/painting/qgraphicssystem_runtime.cpp
+++ b/src/gui/painting/qgraphicssystem_runtime.cpp
@@ -251,7 +251,7 @@ QPixmapData* QRuntimePixmapData::runtimeData() const
 }
 
 QRuntimeWindowSurface::QRuntimeWindowSurface(const QRuntimeGraphicsSystem *gs, QWidget *window)
-    : QWindowSurface(window), m_windowSurface(0), m_pendingWindowSurface(0), m_graphicsSystem(gs)
+    : QWindowSurface(window), m_graphicsSystem(gs)
 {
 
 }
@@ -259,7 +259,6 @@ QRuntimeWindowSurface::QRuntimeWindowSurface(const QRuntimeGraphicsSystem *gs, Q
 QRuntimeWindowSurface::~QRuntimeWindowSurface()
 {
     m_graphicsSystem->removeWindowSurface(this);
-    delete m_windowSurface;
 }
 
 QPaintDevice *QRuntimeWindowSurface::paintDevice()
@@ -278,8 +277,7 @@ void QRuntimeWindowSurface::flush(QWidget *widget, const QRegion &region,
 #ifdef QT_DEBUG
         qDebug() << "QRuntimeWindowSurface::flush() - destroy pending window surface";
 #endif
-        delete m_pendingWindowSurface;
-        m_pendingWindowSurface = 0;
+        m_pendingWindowSurface.reset();
     }
 }
 
@@ -352,7 +350,7 @@ QWindowSurface *QRuntimeGraphicsSystem::createWindowSurface(QWidget *widget) con
 {
     Q_ASSERT(m_graphicsSystem);
     QRuntimeWindowSurface *rtSurface = new QRuntimeWindowSurface(this, widget);
-    rtSurface->m_windowSurface = m_graphicsSystem->createWindowSurface(widget);
+    rtSurface->m_windowSurface.reset(m_graphicsSystem->createWindowSurface(widget));
     widget->setWindowSurface(rtSurface);
     m_windowSurfaces << rtSurface;
     return rtSurface;
@@ -376,7 +374,6 @@ void QRuntimeGraphicsSystem::setGraphicsSystem(const QString &name)
     for (int i = 0; i < m_pixmapDatas.size(); ++i) {
         QRuntimePixmapData *proxy = m_pixmapDatas.at(i);
         QPixmapData *newData = m_graphicsSystem->createPixmapData(proxy->m_data);
-        // ### TODO Optimize. Openvg and s60raster graphics systems could switch internal ARGB32_PRE QImage buffers.
         newData->fromImage(proxy->m_data->toImage(), Qt::NoOpaqueDetection);
         delete proxy->m_data;
         proxy->m_data = newData;
@@ -387,14 +384,10 @@ void QRuntimeGraphicsSystem::setGraphicsSystem(const QString &name)
         QRuntimeWindowSurface *proxy = m_windowSurfaces.at(i);
         QWidget *widget = proxy->m_windowSurface->window();
 
-        if(m_windowSurfaceDestroyPolicy == DestroyImmediately) {
-            delete proxy->m_windowSurface;
-            proxy->m_pendingWindowSurface = 0;
-        } else {
-            proxy->m_pendingWindowSurface = proxy->m_windowSurface;
-        }
+        if(m_windowSurfaceDestroyPolicy == DestroyAfterFirstFlush)
+            proxy->m_pendingWindowSurface.reset(proxy->m_windowSurface.take());
 
-        proxy->m_windowSurface = m_graphicsSystem->createWindowSurface(widget);
+        proxy->m_windowSurface.reset(m_graphicsSystem->createWindowSurface(widget));
         qt_widget_private(widget)->invalidateBuffer(widget->rect());
     }
 }
diff --git a/src/gui/painting/qgraphicssystem_runtime_p.h b/src/gui/painting/qgraphicssystem_runtime_p.h
index d4c9152..0232241 100644
--- a/src/gui/painting/qgraphicssystem_runtime_p.h
+++ b/src/gui/painting/qgraphicssystem_runtime_p.h
@@ -129,8 +129,8 @@ public:
 
     virtual QPoint offset(const QWidget *widget) const;
 
-    QWindowSurface *m_windowSurface;
-    QWindowSurface *m_pendingWindowSurface;
+    QScopedPointer<QWindowSurface> m_windowSurface;
+    QScopedPointer<QWindowSurface> m_pendingWindowSurface;
 
 private:
     const QRuntimeGraphicsSystem *m_graphicsSystem;