Windows font database: Resolve aliases for extra fonts.

Ensure QFontDataBase::hasFamily() deals with aliases.

Task-number: QTBUG-31689

Change-Id: Ia59bfcb93362ac9343c6d30dab1091a4db482dfa
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>

src/gui/text/qfontdatabase_qpa.cpp

@@ -101,6 +101,17 @@ Q_GUI_EXPORT void qt_registerAliasToFontFamily(const QString &familyName, const
     f->aliases.push_back(alias);
 }
 
+QString qt_resolveFontFamilyAlias(const QString &alias)
+{
+    if (!alias.isEmpty()) {
+        const QFontDatabasePrivate *d = privateDb();
+        for (int i = 0; i < d->count; ++i)
+            if (d->families[i]->matchesFamilyName(alias))
+                return d->families[i]->name;
+    }
+    return alias;
+}
+
 static QStringList fallbackFamilies(const QString &family, QFont::Style style, QFont::StyleHint styleHint, QChar::Script script)
 {
     QStringList retList = QGuiApplicationPrivate::platformIntegration()->fontDatabase()->fallbacksForFamily(family,style,styleHint,script);

src/gui/text/qplatformfontdatabase.cpp

@@ -379,9 +379,11 @@ QFont QPlatformFontDatabase::defaultFont() const
     \since 5.0
  */
 
+QString qt_resolveFontFamilyAlias(const QString &alias);
+
 QString QPlatformFontDatabase::resolveFontFamilyAlias(const QString &family) const
 {
-    return family;
+    return qt_resolveFontFamilyAlias(family);
 }
 
 /*!

src/platformsupport/fontdatabases/fontconfig/qfontconfigdatabase.cpp

@@ -768,6 +768,9 @@ QStringList QFontconfigDatabase::addApplicationFont(const QByteArray &fontData,
 
 QString QFontconfigDatabase::resolveFontFamilyAlias(const QString &family) const
 {
+    QString resolved = QBasicFontDatabase::resolveFontFamilyAlias(family);
+    if (!resolved.isEmpty() && resolved != family)
+        return resolved;
     FcPattern *pattern = FcPatternCreate();
     if (!pattern)
         return family;
@@ -781,7 +784,7 @@ QString QFontconfigDatabase::resolveFontFamilyAlias(const QString &family) const
 
     FcChar8 *familyAfterSubstitution = 0;
     FcPatternGetString(pattern, FC_FAMILY, 0, &familyAfterSubstitution);
-    QString resolved = QString::fromUtf8((const char *) familyAfterSubstitution);
+    resolved = QString::fromUtf8((const char *) familyAfterSubstitution);
     FcPatternDestroy(pattern);
 
     return resolved;

src/plugins/platforms/windows/qwindowsfontdatabase.cpp

@@ -1586,11 +1586,14 @@ static QStringList extraTryFontsForFamily(const QString& family)
                 break;
             }
         }
-        QStringList fm = QFontDatabase().families();
+        QFontDatabase db;
+        const QStringList families = db.families();
         const char **tf = tryFonts;
         while (tf && *tf) {
-            if (fm.contains(QLatin1String(*tf)))
-                result << QLatin1String(*tf);
+            // QTBUG-31689, family might be an English alias for a localized font name.
+            const QString family = QString::fromLatin1(*tf);
+            if (families.contains(family) || db.hasFamily(family))
+                result << family;
             ++tf;
         }
     }

tests/auto/gui/text/qfontdatabase/tst_qfontdatabase.cpp

@@ -73,6 +73,8 @@ private slots:
 
     void addAppFont_data();
     void addAppFont();
+
+    void aliases();
 };
 
 tst_QFontDatabase::tst_QFontDatabase()
@@ -268,5 +270,22 @@ void tst_QFontDatabase::addAppFont()
     QCOMPARE(db.families(), oldFamilies);
 }
 
+QT_BEGIN_NAMESPACE
+Q_GUI_EXPORT void qt_registerAliasToFontFamily(const QString &familyName, const QString &alias);
+QT_END_NAMESPACE
+
+void tst_QFontDatabase::aliases()
+{
+    QFontDatabase db;
+    const QStringList families = db.families();
+    QVERIFY(!families.isEmpty());
+    const QString firstFont = families.front();
+    QVERIFY(db.hasFamily(firstFont));
+    const QString alias = QStringLiteral("AliasToFirstFont") + firstFont;
+    QVERIFY(!db.hasFamily(alias));
+    qt_registerAliasToFontFamily(firstFont, alias);
+    QVERIFY(db.hasFamily(alias));
+}
+
 QTEST_MAIN(tst_QFontDatabase)
 #include "tst_qfontdatabase.moc"