Improve cache handling in KItemListWidget

Provide a hook for derived KItemListWidget where the cache
can be updated.

2 files changed, 33 insertions, 13 deletions

diff --git a/src/kitemviews/kfileitemlistwidget.cpp b/src/kitemviews/kfileitemlistwidget.cpp
index d162ed8a2..d9a1cbfd1 100644
--- a/src/kitemviews/kfileitemlistwidget.cpp
+++ b/src/kitemviews/kfileitemlistwidget.cpp
@@ -88,7 +88,7 @@ void KFileItemListWidget::paint(QPainter* painter, const QStyleOptionGraphicsIte
 {
     KItemListWidget::paint(painter, option, widget);
 
-    const_cast<KFileItemListWidget*>(this)->updateCache();
+    const_cast<KFileItemListWidget*>(this)->triggerCacheRefreshing();
 
     // Draw expansion toggle '>' or 'V'
     if (m_isDir && !m_expansionArea.isEmpty()) {
@@ -135,7 +135,7 @@ void KFileItemListWidget::paint(QPainter* painter, const QStyleOptionGraphicsIte
 
 QRectF KFileItemListWidget::iconBoundingRect() const
 {
-    const_cast<KFileItemListWidget*>(this)->updateCache();
+    const_cast<KFileItemListWidget*>(this)->triggerCacheRefreshing();
 
     QRectF bounds = m_hoverPixmapRect;
     const qreal margin = styleOption().margin;
@@ -145,16 +145,26 @@ QRectF KFileItemListWidget::iconBoundingRect() const
 
 QRectF KFileItemListWidget::textBoundingRect() const
 {
-    const_cast<KFileItemListWidget*>(this)->updateCache();
+    const_cast<KFileItemListWidget*>(this)->triggerCacheRefreshing();
     return m_textBoundingRect;
 }
 
 QRectF KFileItemListWidget::expansionToggleRect() const
 {
-    const_cast<KFileItemListWidget*>(this)->updateCache();
+    const_cast<KFileItemListWidget*>(this)->triggerCacheRefreshing();
     return m_isDir ? m_expansionArea : QRectF();
 }
 
+void KFileItemListWidget::invalidateCache()
+{
+    m_dirtyLayout = true;
+    m_dirtyContent = true;
+}
+
+void KFileItemListWidget::refreshCache()
+{
+}
+
 void KFileItemListWidget::setTextColor(const QColor& color)
 {
     if (color != m_customTextColor) {
@@ -171,13 +181,9 @@ QColor KFileItemListWidget::textColor() const
 
 void KFileItemListWidget::setOverlay(const QPixmap& overlay)
 {
-    const bool updateContent = (overlay.isNull() && !m_overlay.isNull()) ||
-                               (!overlay.isNull() && m_overlay.isNull());
-    if (updateContent) {
-        m_overlay = overlay;
-        m_dirtyContent = true;
-        update();
-    }
+    m_overlay = overlay;
+    m_dirtyContent = true;
+    update();
 }
 
 QPixmap KFileItemListWidget::overlay() const
@@ -263,12 +269,14 @@ void KFileItemListWidget::resizeEvent(QGraphicsSceneResizeEvent* event)
     m_dirtyLayout = true;
 }
 
-void KFileItemListWidget::updateCache()
+void KFileItemListWidget::triggerCacheRefreshing()
 {
     if ((!m_dirtyContent && !m_dirtyLayout) || index() < 0) {
         return;
     }
 
+    refreshCache();
+
     m_isDir = data()["isDir"].toBool();
 
     updateExpansionArea();
diff --git a/src/kitemviews/kfileitemlistwidget.h b/src/kitemviews/kfileitemlistwidget.h
index a16e75a8e..50e746fad 100644
--- a/src/kitemviews/kfileitemlistwidget.h
+++ b/src/kitemviews/kfileitemlistwidget.h
@@ -53,6 +53,18 @@ public:
     virtual QRectF expansionToggleRect() const;
 
 protected:
+    /**
+     * Invalidates the cache which results in calling KFileItemListWidget::refreshCache() as
+     * soon as the item need to gets repainted.
+     */
+    void invalidateCache();
+
+    /**
+     * Is called if the cache got invalidated by KFileItemListWidget::invalidateCache().
+     * The default implementation is empty.
+     */
+    virtual void refreshCache();
+
     void setTextColor(const QColor& color);
     QColor textColor() const;
 
@@ -80,7 +92,7 @@ private:
         TextIdCount // Mandatory last entry
     };
 
-    void updateCache();
+    void triggerCacheRefreshing();
     void updateExpansionArea();
     void updatePixmapCache();