1 files changed, 80 insertions, 17 deletions

diff --git a/src/gui/text/qfontdatabase.cpp b/src/gui/text/qfontdatabase.cpp
index 85a804acfe..aae84dc988 100644
--- a/src/gui/text/qfontdatabase.cpp
+++ b/src/gui/text/qfontdatabase.cpp
@@ -47,6 +47,7 @@
 #include <qpa/qplatformfontdatabase.h>
 #include <qpa/qplatformtheme.h>
 
+#include <QtCore/qcache.h>
 #include <QtCore/qmath.h>
 
 #include <stdlib.h>
@@ -413,11 +414,45 @@ void QtFontFamily::ensurePopulated()
     Q_ASSERT_X(populated, Q_FUNC_INFO, qPrintable(name));
 }
 
+
+struct FallbacksCacheKey {
+    QString family;
+    QFont::Style style;
+    QFont::StyleHint styleHint;
+    QChar::Script script;
+};
+
+inline bool operator==(const FallbacksCacheKey &lhs, const FallbacksCacheKey &rhs) Q_DECL_NOTHROW
+{
+    return lhs.script == rhs.script &&
+            lhs.styleHint == rhs.styleHint &&
+            lhs.style == rhs.style &&
+            lhs.family == rhs.family;
+}
+
+inline bool operator!=(const FallbacksCacheKey &lhs, const FallbacksCacheKey &rhs) Q_DECL_NOTHROW
+{
+    return !operator==(lhs, rhs);
+}
+
+inline uint qHash(const FallbacksCacheKey &key, uint seed = 0) Q_DECL_NOTHROW
+{
+    QtPrivate::QHashCombine hash;
+    seed = hash(seed, key.family);
+    seed = hash(seed, int(key.style));
+    seed = hash(seed, int(key.styleHint));
+    seed = hash(seed, int(key.script));
+    return seed;
+}
+
+
 class QFontDatabasePrivate
 {
 public:
     QFontDatabasePrivate()
-        : count(0), families(0), reregisterAppFonts(false)
+        : count(0), families(0),
+          fallbacksCache(64),
+          reregisterAppFonts(false)
     { }
 
     ~QFontDatabasePrivate() {
@@ -443,6 +478,7 @@ public:
     int count;
     QtFontFamily **families;
 
+    QCache<FallbacksCacheKey, QStringList> fallbacksCache;
 
 
     struct ApplicationFont {
@@ -461,6 +497,8 @@ public:
 void QFontDatabasePrivate::invalidate()
 {
     QFontCache::instance()->clear();
+
+    fallbacksCache.clear();
     free();
     QGuiApplicationPrivate::platformIntegration()->fontDatabase()->invalidate();
     emit static_cast<QGuiApplication *>(QCoreApplication::instance())->fontDatabaseChanged();
@@ -680,8 +718,10 @@ Q_GLOBAL_STATIC_WITH_ARGS(QMutex, fontDatabaseMutex, (QMutex::Recursive))
 void qt_cleanupFontDatabase()
 {
     QFontDatabasePrivate *db = privateDb();
-    if (db)
+    if (db) {
+        db->fallbacksCache.clear();
         db->free();
+    }
 }
 
 // used in qfontengine_x11.cpp
@@ -798,11 +838,17 @@ QStringList QPlatformFontDatabase::fallbacksForFamily(const QString &family, QFo
     return retList;
 }
 
-QStringList qt_fallbacksForFamily(const QString &family, QFont::Style style, QFont::StyleHint styleHint, QChar::Script script)
+static QStringList fallbacksForFamily(const QString &family, QFont::Style style, QFont::StyleHint styleHint, QChar::Script script)
 {
+    QFontDatabasePrivate *db = privateDb();
+
+    const FallbacksCacheKey cacheKey = { family, style, styleHint, script };
+
+    if (const QStringList *fallbacks = db->fallbacksCache.object(cacheKey))
+        return *fallbacks;
+
     // make sure that the db has all fallback families
     QStringList retList = QGuiApplicationPrivate::platformIntegration()->fontDatabase()->fallbacksForFamily(family,style,styleHint,script);
-    QFontDatabasePrivate *db = privateDb();
 
     QStringList::iterator i;
     for (i = retList.begin(); i != retList.end(); ++i) {
@@ -818,9 +864,18 @@ QStringList qt_fallbacksForFamily(const QString &family, QFont::Style style, QFo
             --i;
         }
     }
+
+    db->fallbacksCache.insert(cacheKey, new QStringList(retList));
+
     return retList;
 }
 
+QStringList qt_fallbacksForFamily(const QString &family, QFont::Style style, QFont::StyleHint styleHint, QChar::Script script)
+{
+    QMutexLocker locker(fontDatabaseMutex());
+    return fallbacksForFamily(family, style, styleHint, script);
+}
+
 static void registerFont(QFontDatabasePrivate::ApplicationFont *fnt);
 
 static void initializeDb()
@@ -935,7 +990,7 @@ QFontEngine *loadEngine(int script, const QFontDef &request,
             if (styleHint == QFont::AnyStyle && request.fixedPitch)
                 styleHint = QFont::TypeWriter;
 
-            fallbacks += qt_fallbacksForFamily(family->name, QFont::Style(style->key.style), styleHint, QChar::Script(script));
+            fallbacks += fallbacksForFamily(family->name, QFont::Style(style->key.style), styleHint, QChar::Script(script));
 
             pfMultiEngine->setFallbackFamiliesList(fallbacks);
         }
@@ -1413,22 +1468,30 @@ QList<QFontDatabase::WritingSystem> QFontDatabase::writingSystems() const
 
     QT_PREPEND_NAMESPACE(load)();
 
-    QList<WritingSystem> list;
+    quint64 writingSystemsFound = 0;
+    Q_STATIC_ASSERT(WritingSystemsCount < 64);
+
     for (int i = 0; i < d->count; ++i) {
         QtFontFamily *family = d->families[i];
         family->ensurePopulated();
 
         if (family->count == 0)
             continue;
-        for (int x = Latin; x < WritingSystemsCount; ++x) {
-            const WritingSystem writingSystem = WritingSystem(x);
-            if (!(family->writingSystems[writingSystem] & QtFontFamily::Supported))
-                continue;
-            if (!list.contains(writingSystem))
-                list.append(writingSystem);
+        for (uint x = Latin; x < uint(WritingSystemsCount); ++x) {
+            if (family->writingSystems[x] & QtFontFamily::Supported)
+                writingSystemsFound |= quint64(1) << x;
         }
     }
-    std::sort(list.begin(), list.end());
+
+    // mutex protection no longer needed - just working on local data now:
+    locker.unlock();
+
+    QList<WritingSystem> list;
+    list.reserve(qPopulationCount(writingSystemsFound));
+    for (uint x = Latin ; x < uint(WritingSystemsCount); ++x) {
+        if (writingSystemsFound & (quint64(1) << x))
+            list.push_back(WritingSystem(x));
+    }
     return list;
 }
 
@@ -2607,10 +2670,10 @@ QFontEngine *QFontDatabase::findFont(const QFontDef &request, int script)
                 styleHint = QFont::TypeWriter;
 
             QStringList fallbacks = request.fallBackFamilies
-                                  + qt_fallbacksForFamily(request.family,
-                                                          QFont::Style(request.style),
-                                                          styleHint,
-                                                          QChar::Script(script));
+                                  + fallbacksForFamily(request.family,
+                                                       QFont::Style(request.style),
+                                                       styleHint,
+                                                       QChar::Script(script));
             if (script > QChar::Script_Common)
                 fallbacks += QString(); // Find the first font matching the specified script.