Make QFontEngine not derive from QObject

Whilst having the objectName set for each engine is
somewhat handy when debugging, deriving from QObject just for that
is a wasting of memory in all other cases.
This also broke the font engine abstraction by allowing qobject_cast()
to access some private data; the only sane way to distinguish
engines is querying their Type value.

Change-Id: Ib1d195692859eb39089f6d8d9016cb8f9dcc0400
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

3 files changed, 12 insertions, 6 deletions

diff --git a/src/gui/text/qfontengine.cpp b/src/gui/text/qfontengine.cpp
index d561fcf823..88a24b5e6a 100644
--- a/src/gui/text/qfontengine.cpp
+++ b/src/gui/text/qfontengine.cpp
@@ -206,7 +206,7 @@ Q_AUTOTEST_EXPORT QList<QFontEngine *> QFontEngine_stopCollectingEngines()
 // QFontEngine
 
 QFontEngine::QFontEngine()
-    : QObject(), ref(0),
+    : ref(0),
       font_(0), font_destroy_func(0),
       face_(0), face_destroy_func(0)
 {
diff --git a/src/gui/text/qfontengine_p.h b/src/gui/text/qfontengine_p.h
index 4427000d03..1a6862898d 100644
--- a/src/gui/text/qfontengine_p.h
+++ b/src/gui/text/qfontengine_p.h
@@ -86,9 +86,8 @@ enum HB_Compat_Error {
 
 typedef void (*qt_destroy_func_t) (void *user_data);
 
-class Q_GUI_EXPORT QFontEngine : public QObject
+class Q_GUI_EXPORT QFontEngine
 {
-    Q_OBJECT
 public:
     enum Type {
         Box,
@@ -300,9 +299,13 @@ public:
     QImage currentlyLockedAlphaMap;
     int m_subPixelPositionCount; // Number of positions within a single pixel for this cache
 
+    inline QVariant userData() const { return m_userData; }
+
 protected:
     QFixed lastRightBearing(const QGlyphLayout &glyphs, bool round = false);
 
+    inline void setUserData(const QVariant &userData) { m_userData = userData; }
+
 private:
     struct GlyphCacheEntry {
         const void *context;
@@ -311,6 +314,9 @@ private:
     };
 
     mutable QLinkedList<GlyphCacheEntry> m_glyphCaches;
+
+private:
+    QVariant m_userData;
 };
 
 Q_DECLARE_OPERATORS_FOR_FLAGS(QFontEngine::ShaperFlags)
@@ -368,7 +374,6 @@ private:
 
 class Q_GUI_EXPORT QFontEngineMulti : public QFontEngine
 {
-    Q_OBJECT
 public:
     explicit QFontEngineMulti(int engineCount);
     ~QFontEngineMulti();
diff --git a/src/gui/text/qfontengine_qpa.cpp b/src/gui/text/qfontengine_qpa.cpp
index 0a730abcac..9b21d61aad 100644
--- a/src/gui/text/qfontengine_qpa.cpp
+++ b/src/gui/text/qfontengine_qpa.cpp
@@ -687,7 +687,6 @@ void QFontEngineMultiQPA::init(QFontEngine *fe)
     engines[0] = fe;
     fe->ref.ref();
     fontDef = engines[0]->fontDef;
-    setObjectName(QStringLiteral("QFontEngineMultiQPA"));
     cache_cost = fe->cache_cost;
 }
 
@@ -754,7 +753,9 @@ QFontEngine* QFontEngineMultiQPA::createMultiFontEngine(QFontEngine *fe, int scr
     QFontCache::EngineCache::Iterator it = fc->engineCache.find(key),
             end = fc->engineCache.end();
     while (it != end && it.key() == key) {
-        QFontEngineMulti *cachedEngine = qobject_cast<QFontEngineMulti *>(it.value().data);
+        QFontEngineMulti *cachedEngine = 0;
+        if (it.value().data->type() == QFontEngine::Multi)
+            cachedEngine = static_cast<QFontEngineMulti *>(it.value().data);
         if (faceIsLocal || (cachedEngine && fe == cachedEngine->engine(0))) {
             engine = cachedEngine;
             fc->updateHitCountAndTimeStamp(it.value());