Fixed performance issues related to selections and deleting of files:

- Don't connect to KDirLister::itemDeleted(const KFileItem&), but KDirLister::itemsDeleted(const KFileItemList&). Otherwise Dolphin is informed about each single file deletion instead of getting the deleted items as a list. Thanks to David Faure for the hint!

- DolphinViewContainer::updateStatusBar() can be expensive when a lot of files are selected, as the file size must get retrieved. Assure that fast calls for updateStatusBar() don't trigger a synchronous update, do the update after 300 ms where no further update has been triggered.

- Dolphin provides a list of file items when emitting the selectionChanged() signal. Collecting the file items is a quite expensive operation, so use the same approach as when updating the statusbar: only emit the selection changed signal when no change has been done within 300 ms. This improves the performance when doing huge selections a lot.

- Make updateStatusBar() a private method, the main window should not need to take care about updating the statusbar (this is done internally now by DolphinViewContainer).

BUG: 199090
BUG: 195787
CCBUG: 199352
CCBUG: 188218

svn path=/trunk/KDE/kdebase/apps/; revision=995015

1 files changed, 17 insertions, 2 deletions

diff --git a/src/dolphinview.cpp b/src/dolphinview.cpp
index d4dbbd2c2..4a81b12ea 100644
--- a/src/dolphinview.cpp
+++ b/src/dolphinview.cpp
@@ -98,6 +98,7 @@ DolphinView::DolphinView(QWidget* parent,
     m_columnView(0),
     m_fileItemDelegate(0),
     m_selectionModel(0),
+    m_selectionChangedTimer(0),
     m_dolphinModel(dolphinModel),
     m_dirLister(dirLister),
     m_proxyModel(proxyModel),
@@ -188,7 +189,7 @@ void DolphinView::setActive(bool active)
 
     QColor color = KColorScheme(QPalette::Active, KColorScheme::View).background().color();
     if (active) {
-        emit selectionChanged(selectedItems());
+        emitSelectionChangedSignal();
     } else {
         color.setAlpha(150);
     }
@@ -958,6 +959,14 @@ void DolphinView::triggerItem(const KFileItem& item)
     emit itemTriggered(item); // caught by DolphinViewContainer or DolphinPart
 }
 
+void DolphinView::emitDelayedSelectionChangedSignal()
+{
+    // Invoke emitSelectionChangedSignal() with a delay of 300 ms. This assures
+    // that fast selection changes don't result in expensive operations to
+    // collect all file items for the signal (see DolphinView::selectedItems()).
+    m_selectionChangedTimer->start();
+}
+
 void DolphinView::emitSelectionChangedSignal()
 {
     emit selectionChanged(DolphinView::selectedItems());
@@ -1436,6 +1445,12 @@ void DolphinView::createView()
         m_selectionModel = view->selectionModel();
     }
 
+    m_selectionChangedTimer = new QTimer(this);
+    m_selectionChangedTimer->setSingleShot(true);
+    m_selectionChangedTimer->setInterval(300);
+    connect(m_selectionChangedTimer, SIGNAL(timeout()),
+            this, SLOT(emitSelectionChangedSignal()));
+
     // reparent the selection model, as it should not be deleted
     // when deleting the model
     m_selectionModel->setParent(this);
@@ -1454,7 +1469,7 @@ void DolphinView::createView()
     m_topLayout->insertWidget(1, view);
 
     connect(view->selectionModel(), SIGNAL(selectionChanged(const QItemSelection&, const QItemSelection&)),
-            this, SLOT(emitSelectionChangedSignal()));
+            this, SLOT(emitDelayedSelectionChangedSignal()));
     connect(view->verticalScrollBar(), SIGNAL(valueChanged(int)),
             this, SLOT(emitContentsMoved()));
     connect(view->horizontalScrollBar(), SIGNAL(valueChanged(int)),