Fix overcaching the fallback families list for a requested family

The cached list didn't take fontStyle, styleHint and script into account.
As long as QFontCache isn't explicitly disabled, loadEngine() rarely
called for the same family, foundry, style and size - so avoid caching
anything here at all.

Change-Id: I7779bf33fc074edc00799f9a39d67327f8c88ccc
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

1 files changed, 6 insertions, 15 deletions

diff --git a/src/gui/text/qfontdatabase.cpp b/src/gui/text/qfontdatabase.cpp
index d07b1c5628..e77856c8d1 100644
--- a/src/gui/text/qfontdatabase.cpp
+++ b/src/gui/text/qfontdatabase.cpp
@@ -346,7 +346,6 @@ struct  QtFontFamily
         populated(false),
         fixedPitch(false),
         name(n), count(0), foundries(0)
-        , askedForFallback(false)
     {
         memset(writingSystems, 0, sizeof(writingSystems));
     }
@@ -364,8 +363,6 @@ struct  QtFontFamily
     int count;
     QtFontFoundry **foundries;
 
-    QStringList fallbackFamilies;
-    bool askedForFallback;
     unsigned char writingSystems[QFontDatabase::WritingSystemsCount];
 
     bool matchesFamilyName(const QString &familyName) const;
@@ -759,6 +756,7 @@ QString qt_resolveFontFamilyAlias(const QString &alias)
 
 static QStringList fallbackFamilies(const QString &family, QFont::Style style, QFont::StyleHint styleHint, QChar::Script script)
 {
+    // make sure that the db has all fallback families
     QStringList retList = QGuiApplicationPrivate::platformIntegration()->fontDatabase()->fallbacksForFamily(family,style,styleHint,script);
     QFontDatabasePrivate *db = privateDb();
 
@@ -884,20 +882,13 @@ QFontEngine *loadEngine(int script, const QFontDef &request,
     QFontEngine *engine = loadSingleEngine(script, request, family, foundry, style, size);
     Q_ASSERT(!engine || engine->type() != QFontEngine::Multi);
     if (engine && !(request.styleStrategy & QFont::NoFontMerging) && !engine->symbol) {
-        // make sure that the db has all fallback families
-        if (family && !family->askedForFallback) {
-            QFont::Style fontStyle = QFont::Style(style->key.style);
-            QFont::StyleHint styleHint = QFont::StyleHint(request.styleHint);
-            if (styleHint == QFont::AnyStyle && request.fixedPitch)
-                styleHint = QFont::TypeWriter;
-            family->fallbackFamilies = fallbackFamilies(family->name, fontStyle, styleHint, QChar::Script(script));
+        QStringList fallbacks = request.fallBackFamilies;
 
-            family->askedForFallback = true;
-        }
+        QFont::StyleHint styleHint = QFont::StyleHint(request.styleHint);
+        if (styleHint == QFont::AnyStyle && request.fixedPitch)
+            styleHint = QFont::TypeWriter;
 
-        QStringList fallbacks = request.fallBackFamilies;
-        if (family)
-            fallbacks += family->fallbackFamilies;
+        fallbacks += fallbackFamilies(family->name, QFont::Style(style->key.style), styleHint, QChar::Script(script));
 
         QPlatformFontDatabase *pfdb = QGuiApplicationPrivate::platformIntegration()->fontDatabase();
         QFontEngineMulti *pfMultiEngine = pfdb->fontEngineMulti(engine, QChar::Script(script));