Thread safety for QFontEngineS60

On symbian, creating fonts requires a connection to the window server.
Window server sessions are not sharable across threads.
To avoid QFont crashing when used outside the GUI thread, we construct a
private session to the window server when the shared CONE session is not
available.
(CCoeEnv::Static() uses TLS, so it returns null outside of GUI thread)

The private session and screen device are stored in QThreadStorage, so
they are automatically deleted when the QThread exits.

Task-number: QTBUG-8874
Reviewed-by: mread

1 files changed, 10 insertions, 8 deletions

diff --git a/src/gui/text/qfontdatabase_s60.cpp b/src/gui/text/qfontdatabase_s60.cpp
index 40fe3b7..61c5271 100644
--- a/src/gui/text/qfontdatabase_s60.cpp
+++ b/src/gui/text/qfontdatabase_s60.cpp
@@ -218,17 +218,19 @@ QFontEngineFTS60::QFontEngineFTS60(const QFontDef &fd)
 */
 qreal QFontEngineS60::pixelsToPoints(qreal pixels, Qt::Orientation orientation)
 {
+    CWsScreenDevice* device = S60->screenDevice();
     return (orientation == Qt::Horizontal?
-        S60->screenDevice()->HorizontalPixelsToTwips(pixels)
-        :S60->screenDevice()->VerticalPixelsToTwips(pixels)) / KTwipsPerPoint;
+        device->HorizontalPixelsToTwips(pixels)
+        :device->VerticalPixelsToTwips(pixels)) / KTwipsPerPoint;
 }
 
 qreal QFontEngineS60::pointsToPixels(qreal points, Qt::Orientation orientation)
 {
+    CWsScreenDevice* device = S60->screenDevice();
     const int twips = points * KTwipsPerPoint;
     return orientation == Qt::Horizontal?
-        S60->screenDevice()->HorizontalTwipsToPixels(twips)
-        :S60->screenDevice()->VerticalTwipsToPixels(twips);
+        device->HorizontalTwipsToPixels(twips)
+        :device->VerticalTwipsToPixels(twips);
 }
 
 QFontEngineMultiS60::QFontEngineMultiS60(QFontEngine *first, int script, const QStringList &fallbackFamilies)
@@ -267,16 +269,16 @@ static void initializeDb()
 
     QSymbianFbsHeapLock lock(QSymbianFbsHeapLock::Unlock);
     
-    const int numTypeFaces = QS60Data::screenDevice()->NumTypefaces();
+    const int numTypeFaces = S60->screenDevice()->NumTypefaces();
     const QSymbianFontDatabaseExtrasImplementation *dbExtras =
             static_cast<const QSymbianFontDatabaseExtrasImplementation*>(db->symbianExtras);
     bool fontAdded = false;
     for (int i = 0; i < numTypeFaces; i++) {
         TTypefaceSupport typefaceSupport;
-        QS60Data::screenDevice()->TypefaceSupport(typefaceSupport, i);
+        S60->screenDevice()->TypefaceSupport(typefaceSupport, i);
         CFont *font; // We have to get a font instance in order to know all the details
         TFontSpec fontSpec(typefaceSupport.iTypeface.iName, 11);
-        if (QS60Data::screenDevice()->GetNearestFontInPixels(font, fontSpec) != KErrNone)
+        if (S60->screenDevice()->GetNearestFontInPixels(font, fontSpec) != KErrNone)
             continue;
         if (font->TypeUid() == KCFbsFontUid) {
             TOpenFontFaceAttrib faceAttrib;
@@ -318,7 +320,7 @@ static void initializeDb()
 
             fontAdded = true;
         }
-        QS60Data::screenDevice()->ReleaseFont(font);
+        S60->screenDevice()->ReleaseFont(font);
     }
 
     Q_ASSERT(fontAdded);