Populate application fonts via font descriptors on Apple platforms

Instead of registering the font via CTFontManagerRegister we just create
a font descriptor for the data/URL and populate that like normal system
fonts. This makes the code more similar to how we deal with other fonts,
shaves off a ms during font registration due to not registering the font,
and fixes an issue on iOS where CTFontManagerRegister would invalidate
earlier populated system font descriptors.

Task-number: QTBUG-56765
Change-Id: I002a65075b15837c9a2d22573020d4c834111837
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>

2 files changed, 22 insertions, 56 deletions

diff --git a/src/platformsupport/fontdatabases/mac/qcoretextfontdatabase.mm b/src/platformsupport/fontdatabases/mac/qcoretextfontdatabase.mm
index ce9b61ba4c..d0b28b856b 100644
--- a/src/platformsupport/fontdatabases/mac/qcoretextfontdatabase.mm
+++ b/src/platformsupport/fontdatabases/mac/qcoretextfontdatabase.mm
@@ -199,10 +199,6 @@ static CFArrayRef availableFamilyNames()
 
 void QCoreTextFontDatabase::populateFontDatabase()
 {
-    // The caller (QFontDB) expects the db to be populate only with system fonts, so we need
-    // to make sure that any previously registered app fonts become invisible.
-    removeApplicationFonts();
-
     QCFType<CFArrayRef> familyNames = availableFamilyNames();
     const int numberOfFamilies = CFArrayGetCount(familyNames);
     for (int i = 0; i < numberOfFamilies; ++i) {
@@ -585,21 +581,19 @@ QStringList QCoreTextFontDatabase::fallbacksForFamily(const QString &family, QFo
 }
 
 template <>
-CFArrayRef QCoreTextFontDatabaseEngineFactory<QCoreTextFontEngine>::createDescriptorArrayForFont(CTFontRef font, const QString &fileName)
+CFArrayRef QCoreTextFontDatabaseEngineFactory<QCoreTextFontEngine>::createDescriptorArrayForDescriptor(CTFontDescriptorRef descriptor, const QString &fileName)
 {
     Q_UNUSED(fileName)
     CFMutableArrayRef array = CFArrayCreateMutable(kCFAllocatorDefault, 0, &kCFTypeArrayCallBacks);
-    QCFType<CTFontDescriptorRef> descriptor = CTFontCopyFontDescriptor(font);
     CFArrayAppendValue(array, descriptor);
     return array;
 }
 
 #ifndef QT_NO_FREETYPE
 template <>
-CFArrayRef QCoreTextFontDatabaseEngineFactory<QFontEngineFT>::createDescriptorArrayForFont(CTFontRef font, const QString &fileName)
+CFArrayRef QCoreTextFontDatabaseEngineFactory<QFontEngineFT>::createDescriptorArrayForDescriptor(CTFontDescriptorRef descriptor, const QString &fileName)
 {
     CFMutableArrayRef array = CFArrayCreateMutable(kCFAllocatorDefault, 0, &kCFTypeArrayCallBacks);
-    QCFType<CTFontDescriptorRef> descriptor = CTFontCopyFontDescriptor(font);
 
     // The physical font source URL (usually a local file or Qt resource) is only required for
     // FreeType, when using non-system fonts, and needs some hackery to attach in a format
@@ -630,44 +624,36 @@ CFArrayRef QCoreTextFontDatabaseEngineFactory<QFontEngineFT>::createDescriptorAr
 QStringList QCoreTextFontDatabase::addApplicationFont(const QByteArray &fontData, const QString &fileName)
 {
     QCFType<CFArrayRef> fonts;
-    QStringList families;
 
-    CFErrorRef error = 0;
     if (!fontData.isEmpty()) {
         QByteArray* fontDataCopy = new QByteArray(fontData);
         QCFType<CGDataProviderRef> dataProvider = CGDataProviderCreateWithData(fontDataCopy,
                 fontDataCopy->constData(), fontDataCopy->size(), releaseFontData);
-        QCFType<CGFontRef> cgFont = CGFontCreateWithDataProvider(dataProvider);
-        if (cgFont) {
-            if (CTFontManagerRegisterGraphicsFont(cgFont, &error)) {
-                QCFType<CTFontRef> font = CTFontCreateWithGraphicsFont(cgFont, 0.0, NULL, NULL);
-                fonts = createDescriptorArrayForFont(font, fileName);
-                m_applicationFonts.append(QVariant::fromValue(QCFType<CGFontRef>::constructFromGet(cgFont)));
-            }
+        if (QCFType<CGFontRef> cgFont = CGFontCreateWithDataProvider(dataProvider)) {
+            QCFType<CTFontRef> ctFont = CTFontCreateWithGraphicsFont(cgFont, 0.0, NULL, NULL);
+            QCFType<CTFontDescriptorRef> descriptor = CTFontCopyFontDescriptor(ctFont);
+            fonts = createDescriptorArrayForDescriptor(descriptor, fileName);
         }
     } else {
-        QCFType<CFURLRef> fontURL = CFURLCreateWithFileSystemPath(NULL, QCFString(fileName), kCFURLPOSIXPathStyle, false);
-        if (CTFontManagerRegisterFontsForURL(fontURL, kCTFontManagerScopeProcess, &error)) {
-            fonts = CTFontManagerCreateFontDescriptorsFromURL(fontURL);
-            m_applicationFonts.append(QVariant::fromValue(QCFType<CFURLRef>::constructFromGet(fontURL)));
-        }
+        QCFType<CFURLRef> fontURL = QUrl::fromLocalFile(fileName).toCFURL();
+        fonts = CTFontManagerCreateFontDescriptorsFromURL(fontURL);
     }
 
-    if (error) {
-        NSLog(@"Unable to register font: %@", error);
-        CFRelease(error);
-    }
+    if (!fonts)
+        return QStringList();
 
-    if (fonts) {
-        const int numFonts = CFArrayGetCount(fonts);
-        for (int i = 0; i < numFonts; ++i) {
-            CTFontDescriptorRef fontDescriptor = CTFontDescriptorRef(CFArrayGetValueAtIndex(fonts, i));
-            populateFromDescriptor(fontDescriptor);
-            QCFType<CFStringRef> familyName = CFStringRef(CTFontDescriptorCopyAttribute(fontDescriptor, kCTFontFamilyNameAttribute));
-            families.append(QCFString(familyName));
-        }
+    QStringList families;
+    const int numFonts = CFArrayGetCount(fonts);
+    for (int i = 0; i < numFonts; ++i) {
+        CTFontDescriptorRef fontDescriptor = CTFontDescriptorRef(CFArrayGetValueAtIndex(fonts, i));
+        populateFromDescriptor(fontDescriptor);
+        QCFType<CFStringRef> familyName = CFStringRef(CTFontDescriptorCopyAttribute(fontDescriptor, kCTFontFamilyNameAttribute));
+        families.append(QString::fromCFString(familyName));
     }
 
+    // Note: We don't do font matching via CoreText for application fonts, so we don't
+    // need to enable font matching for them via CTFontManagerEnableFontDescriptors.
+
     return families;
 }
 
@@ -846,22 +832,5 @@ QList<int> QCoreTextFontDatabase::standardSizes() const
     return ret;
 }
 
-void QCoreTextFontDatabase::removeApplicationFonts()
-{
-    if (m_applicationFonts.isEmpty())
-        return;
-
-    for (const QVariant &font : qAsConst(m_applicationFonts)) {
-        CFErrorRef error;
-        if (font.canConvert(qMetaTypeId<QCFType<CGFontRef> >())) {
-            CTFontManagerUnregisterGraphicsFont(font.value<QCFType<CGFontRef> >(), &error);
-        } else if (font.canConvert(qMetaTypeId<QCFType<CFURLRef> >())) {
-            CTFontManagerUnregisterFontsForURL(font.value<QCFType<CFURLRef> >(), kCTFontManagerScopeProcess, &error);
-        }
-    }
-
-    m_applicationFonts.clear();
-}
-
 QT_END_NAMESPACE
 
diff --git a/src/platformsupport/fontdatabases/mac/qcoretextfontdatabase_p.h b/src/platformsupport/fontdatabases/mac/qcoretextfontdatabase_p.h
index 8edf60b5fa..11ea0bea02 100644
--- a/src/platformsupport/fontdatabases/mac/qcoretextfontdatabase_p.h
+++ b/src/platformsupport/fontdatabases/mac/qcoretextfontdatabase_p.h
@@ -91,13 +91,10 @@ public:
 
 private:
     void populateFromDescriptor(CTFontDescriptorRef font, const QString &familyName = QString());
-    virtual CFArrayRef createDescriptorArrayForFont(CTFontRef font, const QString &fileName) = 0;
+    virtual CFArrayRef createDescriptorArrayForDescriptor(CTFontDescriptorRef descriptor, const QString &fileName) = 0;
 
     mutable QString defaultFontName;
 
-    void removeApplicationFonts();
-
-    QVector<QVariant> m_applicationFonts;
     mutable QSet<CTFontDescriptorRef> m_systemFontDescriptors;
     mutable QHash<QPlatformTheme::Font, QFont *> m_themeFonts;
 };
@@ -112,7 +109,7 @@ public:
     QFontEngine *fontEngine(const QFontDef &fontDef, void *handle) override;
     QFontEngine *fontEngine(const QByteArray &fontData, qreal pixelSize, QFont::HintingPreference hintingPreference) override;
 protected:
-    CFArrayRef createDescriptorArrayForFont(CTFontRef font, const QString &fileName) override;
+    CFArrayRef createDescriptorArrayForDescriptor(CTFontDescriptorRef descriptor, const QString &fileName) override;
 };
 
 QT_END_NAMESPACE