Store the selected items in a more efficient way

Since Dolphin 2.0, we have stored the selected items in a QSet<int>,
which is neither space-efficient nor particularly fast when inserting
many items which are in a consecutive range.

This commit replaces the QSet<int> by a new class "KItemSet", which
stores the items in a sorted list of ranges. For each range, we only
store the first index and the length of the range, so we need a lot
less memory for most common selection patterns, and we also save quite
a few CPU cycles in many situations, because adding an item to the
KItemSet will in many cases not need a memory allocation at all, and
it's particularly easy when inserting sorted items into the KItemSet in
a row.

KItemSet contains a minimal subset of QSet's API which makes it
suitable as a drop-in replacement for our needs. It also has iterators,
such that the items can be iterated through easily, also with foreach.
One advantage of KItemSet compared to QSet<int> is that the items are
always iterated through in ascending order.

REVIEW: 113488

1 files changed, 1 insertions, 1 deletions

diff --git a/src/kitemviews/kfileitemlistview.h b/src/kitemviews/kfileitemlistview.h
index bdc63b01b..2fd21edbf 100644
--- a/src/kitemviews/kfileitemlistview.h
+++ b/src/kitemviews/kfileitemlistview.h
@@ -73,7 +73,7 @@ public:
     QStringList enabledPlugins() const;
 
     /** @reimp */
-    virtual QPixmap createDragPixmap(const QSet<int>& indexes) const;
+    virtual QPixmap createDragPixmap(const KItemSet& indexes) const;
 
 protected:
     virtual KItemListWidgetCreatorBase* defaultWidgetCreator() const;