4 files changed, 58 insertions, 13 deletions

diff --git a/src/kitemviews/kfileitemmodel.cpp b/src/kitemviews/kfileitemmodel.cpp
index 1b4911dec..c7e1c8600 100644
--- a/src/kitemviews/kfileitemmodel.cpp
+++ b/src/kitemviews/kfileitemmodel.cpp
@@ -689,7 +689,6 @@ void KFileItemModel::resortAllItems()
         oldUrls.append(itemData->item.url());
     }
 
-    m_groups.clear();
     m_items.clear();
 
     // Resort the items
@@ -698,20 +697,45 @@ void KFileItemModel::resortAllItems()
         m_items.insert(m_itemData.at(i)->item.url(), i);
     }
 
-    // Determine the indexes that have been moved
-    QList<int> movedToIndexes;
-    movedToIndexes.reserve(itemCount);
-    for (int i = 0; i < itemCount; i++) {
-        const int newIndex = m_items.value(oldUrls.at(i));
-        movedToIndexes.append(newIndex);
+    // Determine the first index that has been moved.
+    int firstMovedIndex = 0;
+    while (firstMovedIndex < itemCount
+           && firstMovedIndex == m_items.value(oldUrls.at(firstMovedIndex))) {
+        ++firstMovedIndex;
     }
 
-    // Don't check whether items have really been moved and always emit a
-    // itemsMoved() signal after resorting: In case of grouped items
-    // the groups might change even if the items themselves don't change their
-    // position. Let the receiver of the signal decide whether a check for moved
-    // items makes sense.
-    emit itemsMoved(KItemRange(0, itemCount), movedToIndexes);
+    const bool itemsHaveMoved = firstMovedIndex < itemCount;
+    if (itemsHaveMoved) {
+        m_groups.clear();
+
+        int lastMovedIndex = itemCount - 1;
+        while (lastMovedIndex > firstMovedIndex
+               && lastMovedIndex == m_items.value(oldUrls.at(lastMovedIndex))) {
+            --lastMovedIndex;
+        }
+
+        Q_ASSERT(firstMovedIndex <= lastMovedIndex);
+
+        // Create a list movedToIndexes, which has the property that
+        // movedToIndexes[i] is the new index of the item with the old index
+        // firstMovedIndex + i.
+        const int movedItemsCount = lastMovedIndex - firstMovedIndex + 1;
+        QList<int> movedToIndexes;
+        movedToIndexes.reserve(movedItemsCount);
+        for (int i = firstMovedIndex; i <= lastMovedIndex; ++i) {
+            const int newIndex = m_items.value(oldUrls.at(i));
+            movedToIndexes.append(newIndex);
+        }
+
+        emit itemsMoved(KItemRange(firstMovedIndex, movedItemsCount), movedToIndexes);
+    } else if (groupedSorting()) {
+        // The groups might have changed even if the order of the items has not.
+        const QList<QPair<int, QVariant> > oldGroups = m_groups;
+        m_groups.clear();
+        if (groups() != oldGroups) {
+            emit groupsChanged();
+        }
+    }
 
 #ifdef KFILEITEMMODEL_DEBUG
     kDebug() << "[TIME] Resorting of" << itemCount << "items:" << timer.elapsed();
diff --git a/src/kitemviews/kitemlistview.cpp b/src/kitemviews/kitemlistview.cpp
index 0c3183cd5..80a4ba7e3 100644
--- a/src/kitemviews/kitemlistview.cpp
+++ b/src/kitemviews/kitemlistview.cpp
@@ -1229,6 +1229,13 @@ void KItemListView::slotItemsChanged(const KItemRangeList& itemRanges,
     QAccessible::updateAccessibility(this, 0, QAccessible::TableModelChanged);
 }
 
+void KItemListView::slotGroupsChanged()
+{
+    updateVisibleGroupHeaders();
+    doLayout(NoAnimation);
+    updateSiblingsInformation();
+}
+
 void KItemListView::slotGroupedSortingChanged(bool current)
 {
     m_grouped = current;
@@ -1521,6 +1528,8 @@ void KItemListView::setModel(KItemModelBase* model)
                    this,    SLOT(slotItemsRemoved(KItemRangeList)));
         disconnect(m_model, SIGNAL(itemsMoved(KItemRange,QList<int>)),
                    this,    SLOT(slotItemsMoved(KItemRange,QList<int>)));
+        disconnect(m_model, SIGNAL(groupsChanged()),
+                   this,    SLOT(slotGroupsChanged()));
         disconnect(m_model, SIGNAL(groupedSortingChanged(bool)),
                    this,    SLOT(slotGroupedSortingChanged(bool)));
         disconnect(m_model, SIGNAL(sortOrderChanged(Qt::SortOrder,Qt::SortOrder)),
@@ -1544,6 +1553,8 @@ void KItemListView::setModel(KItemModelBase* model)
                 this,    SLOT(slotItemsRemoved(KItemRangeList)));
         connect(m_model, SIGNAL(itemsMoved(KItemRange,QList<int>)),
                 this,    SLOT(slotItemsMoved(KItemRange,QList<int>)));
+        connect(m_model, SIGNAL(groupsChanged()),
+                this,    SLOT(slotGroupsChanged()));
         connect(m_model, SIGNAL(groupedSortingChanged(bool)),
                 this,    SLOT(slotGroupedSortingChanged(bool)));
         connect(m_model, SIGNAL(sortOrderChanged(Qt::SortOrder,Qt::SortOrder)),
diff --git a/src/kitemviews/kitemlistview.h b/src/kitemviews/kitemlistview.h
index 6467b8c91..14360b02b 100644
--- a/src/kitemviews/kitemlistview.h
+++ b/src/kitemviews/kitemlistview.h
@@ -394,6 +394,7 @@ protected slots:
     virtual void slotItemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
     virtual void slotItemsChanged(const KItemRangeList& itemRanges,
                                   const QSet<QByteArray>& roles);
+    virtual void slotGroupsChanged();
 
     virtual void slotGroupedSortingChanged(bool current);
     virtual void slotSortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);
diff --git a/src/kitemviews/kitemmodelbase.h b/src/kitemviews/kitemmodelbase.h
index 70f688390..7545192da 100644
--- a/src/kitemviews/kitemmodelbase.h
+++ b/src/kitemviews/kitemmodelbase.h
@@ -218,11 +218,20 @@ signals:
      * with the items 5 and 6 then the parameters look like this:
      * - itemRange: has the index 0 and a count of 7.
      * - movedToIndexes: Contains the seven values 5, 6, 2, 3, 4, 0, 1
+     *
+     * This signal implies that the groups might have changed. Therefore,
+     * gropusChanged() is not emitted if this signal is emitted.
      */
     void itemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes);
 
     void itemsChanged(const KItemRangeList& itemRanges, const QSet<QByteArray>& roles);
 
+    /**
+     * Is emitted if the groups have changed, even though the order of the
+     * items has not been modified.
+     */
+    void groupsChanged();
+
     void groupedSortingChanged(bool current);
     void sortRoleChanged(const QByteArray& current, const QByteArray& previous);
     void sortOrderChanged(Qt::SortOrder current, Qt::SortOrder previous);