Fix possible endless recursion when using the rubberband

If the autoscrolling has been activated when using the rubberband,
it was possible that an endless recursion occured as the
autoscrolling triggered a change of the rubberband which triggered
a change of the autoscrolling etc.

1 files changed, 26 insertions, 11 deletions

diff --git a/src/kitemviews/kitemlistview.cpp b/src/kitemviews/kitemlistview.cpp
index 3b6b4e2e9..f6cfed984 100644
--- a/src/kitemviews/kitemlistview.cpp
+++ b/src/kitemviews/kitemlistview.cpp
@@ -678,7 +678,9 @@ void KItemListView::slotCurrentChanged(int current, int previous)
             }
         }
 
-        emit scrollTo(newOffset);
+        if (newOffset != offset()) {
+            emit scrollTo(newOffset);
+        }
     }
 }
 
@@ -749,7 +751,11 @@ void KItemListView::slotRubberBandStartPosChanged()
 
 void KItemListView::slotRubberBandEndPosChanged()
 {
-    triggerAutoScrolling();
+    // The autoscrolling is triggered asynchronously otherwise it
+    // might be possible to have an endless recursion: The autoscrolling
+    // might adjust the position which might result in updating the
+    // rubberband end-position.
+    QTimer::singleShot(0, this, SLOT(triggerAutoScrolling()));
     update();
 }
 
@@ -766,6 +772,24 @@ void KItemListView::slotRubberBandActivationChanged(bool active)
     update();
 }
 
+void KItemListView::triggerAutoScrolling()
+{
+    int pos = 0;
+    int visibleSize = 0;
+    if (scrollOrientation() == Qt::Vertical) {
+        pos = m_mousePos.y();
+        visibleSize = size().height();
+    } else {
+        pos = m_mousePos.x();
+        visibleSize = size().width();
+    }
+
+    const int inc = calculateAutoScrollingIncrement(pos, visibleSize);
+    if (inc != 0) {
+        emit scrollTo(offset() + inc);
+    }
+}
+
 void KItemListView::setController(KItemListController* controller)
 {
     if (m_controller != controller) {
@@ -1172,15 +1196,6 @@ void KItemListView::updateWidgetProperties(KItemListWidget* widget, int index)
     widget->setData(m_model->data(index));
 }
 
-void KItemListView::triggerAutoScrolling()
-{
-    const int pos = (scrollOrientation() == Qt::Vertical) ? m_mousePos.y() : m_mousePos.x();
-    const int inc = calculateAutoScrollingIncrement(pos, size().height());
-    if (inc != 0) {
-        emit scrollTo(offset() + inc);
-    }
-}
-
 int KItemListView::calculateAutoScrollingIncrement(int pos, int size)
 {
     int inc = 0;