make event filters static to decrease installed filters on qApp

since seems there are so many event filters installed
on the QApplication installed that may give performanc
 issues, try to use separate, singleton watchers for them
to decrease the amount of eventfilters called

REVIEW:126113

src/declarativeimports/core/units.cpp

@@ -37,6 +37,28 @@ const QString plasmarc = QStringLiteral("plasmarc");
 const QString groupName = QStringLiteral("Units");
 const int defaultLongDuration = 120;
 
+
+SharedAppFilter::SharedAppFilter(QObject *parent)
+    : QObject(parent)
+{
+    QCoreApplication::instance()->installEventFilter(this);
+}
+
+SharedAppFilter::~SharedAppFilter()
+{}
+
+bool SharedAppFilter::eventFilter(QObject *watched, QEvent *event)
+{
+    if (watched == QCoreApplication::instance()) {
+        if (event->type() == QEvent::ApplicationFontChange) {
+            emit fontChanged();
+        }
+    }
+    return QObject::eventFilter(watched, event);
+}
+
+SharedAppFilter *Units::s_sharedAppFilter = nullptr;
+
 Units::Units(QObject *parent)
     : QObject(parent),
       m_gridUnit(-1),
@@ -45,12 +67,16 @@ Units::Units(QObject *parent)
       m_largeSpacing(-1),
       m_longDuration(defaultLongDuration) // default base value for animations
 {
+    if (!s_sharedAppFilter) {
+        s_sharedAppFilter = new SharedAppFilter();
+    }
+
     m_iconSizes = new QQmlPropertyMap(this);
     updateDevicePixelRatio(); // also updates icon sizes
     updateSpacing(); // updates gridUnit and *Spacing properties
 
     connect(KIconLoader::global(), &KIconLoader::iconLoaderSettingsChanged, this, &Units::iconLoaderSettingsChanged);
-    QCoreApplication::instance()->installEventFilter(this);
+    QObject::connect(s_sharedAppFilter, SIGNAL(fontChanged()), this, SLOT(updateSpacing()));
 
     const QString configFile = QStandardPaths::writableLocation(QStandardPaths::GenericConfigLocation) + QLatin1Char('/') + plasmarc;
     KDirWatch::self()->addFile(configFile);
@@ -236,13 +262,5 @@ int Units::shortDuration() const
     return m_longDuration / 5;
 }
 
-bool Units::eventFilter(QObject *watched, QEvent *event)
+#include "moc_units.cpp"
-{
-    if (watched == QCoreApplication::instance()) {
-        if (event->type() == QEvent::ApplicationFontChange || event->type() == QEvent::FontChange) {
-            updateSpacing();
-        }
-    }
-    return QObject::eventFilter(watched, event);
-}
 

src/declarativeimports/core/units.h

@@ -28,6 +28,20 @@
 
 class QQuickItem;
 
+class SharedAppFilter : public QObject
+{
+   Q_OBJECT
+public:
+    SharedAppFilter(QObject *parent = 0);
+    ~SharedAppFilter();
+
+Q_SIGNALS:
+    void fontChanged();
+
+protected:
+    bool eventFilter(QObject *watched, QEvent *event);
+};
+
 /**
  * @class Units
  * @short Expose sizes to QML
@@ -106,8 +120,6 @@ public:
     Units(QObject *parent = 0);
     ~Units();
 
-    bool eventFilter(QObject *watched, QEvent *event) Q_DECL_OVERRIDE;
-
     /**
      * @return pixel value for a grid Unit. Depends on DPI and font size.
      */
@@ -166,10 +178,10 @@ Q_SIGNALS:
 private Q_SLOTS:
     void iconLoaderSettingsChanged();
     void settingsFileChanged(const QString &file);
+    void updateSpacing();
 
 private:
     void updateDevicePixelRatio();
-    void updateSpacing();
     void updatePlasmaRCSettings();
     /**
      * @return The dpi-adjusted size for a given icon size
@@ -181,6 +193,7 @@ private:
     qreal m_dpi;
 
     QQmlPropertyMap *m_iconSizes;
+    static SharedAppFilter *s_sharedAppFilter;
 
     int m_smallSpacing;
     int m_largeSpacing;

src/plasma/private/svg_p.h

@@ -24,6 +24,7 @@
 #include <QSharedData>
 #include <QSvgRenderer>
 #include <QExplicitlySharedDataPointer>
+#include <QObject>
 
 namespace Plasma
 {

src/plasma/private/theme_p.cpp

@@ -363,6 +363,7 @@ void ThemePrivate::colorsChanged()
     buttonColorScheme = KColorScheme(QPalette::Active, KColorScheme::Button, colors);
     viewColorScheme = KColorScheme(QPalette::Active, KColorScheme::View, colors);
     scheduleThemeChangeNotification(PixmapCache);
+    emit applicationPaletteChange();
 }
 
 void ThemePrivate::scheduleThemeChangeNotification(CacheTypes caches)

src/plasma/private/theme_p.h

@@ -95,6 +95,7 @@ Q_SIGNALS:
     void themeChanged();
     void defaultFontChanged();
     void smallestFontChanged();
+    void applicationPaletteChange();
 
 public:
     static const char defaultTheme[];

src/plasma/svg.cpp

@@ -44,6 +44,7 @@
 namespace Plasma
 {
 
+
 SharedSvgRenderer::SharedSvgRenderer(QObject *parent)
     : QSvgRenderer(parent)
 {
@@ -579,20 +580,15 @@ void SvgPrivate::checkColorHints()
     // a colorscheme
     if (qApp) {
         if (usesColors && (!themed || !actualTheme()->colorScheme())) {
-            qApp->installEventFilter(q);
+            QObject::connect(actualTheme()->d, SIGNAL(applicationPaletteChange()), q, SLOT(colorsChanged()));
         } else {
-            qApp->removeEventFilter(q);
+            QObject::disconnect(actualTheme()->d, SIGNAL(applicationPaletteChange()), q, SLOT(colorsChanged()));
         }
     }
 }
 
 bool Svg::eventFilter(QObject *watched, QEvent *event)
 {
-    if (watched == QCoreApplication::instance()) {
-        if (event->type() == QEvent::ApplicationPaletteChange) {
-            d->colorsChanged();
-        }
-    }
     return QObject::eventFilter(watched, event);
 }
 
@@ -978,4 +974,5 @@ Theme *Svg::theme() const
 
 } // Plasma namespace
 
+#include "private/moc_svg_p.cpp"
 #include "moc_svg.cpp"