Keep current item and selection when resorting, part 1

KFileItemModel now emits the itemsMoved signal when the model
is resorted, and KItemListSelectionManager has a new function
itemsMoved() which will be called indirectly when this signal
is emitted. Unit tests for the new functionality are included.
The following things are still needed to make the feature
work:
1. KFileItemMdel::resortAllItems() should not emit
   itemsAdded/itemsRemoved any more.
2. KItemListView::itemsMoved() must update the view according
   to the changes in the model, and it must call
   KItemListSelectionManager::itemsMoved().

1 files changed, 46 insertions, 0 deletions

diff --git a/src/kitemviews/kitemlistselectionmanager.cpp b/src/kitemviews/kitemlistselectionmanager.cpp
index 63306a3f2..131ee46e6 100644
--- a/src/kitemviews/kitemlistselectionmanager.cpp
+++ b/src/kitemviews/kitemlistselectionmanager.cpp
@@ -239,6 +239,7 @@ void KItemListSelectionManager::itemsInserted(const KItemRangeList& itemRanges)
     if (!m_selectedItems.isEmpty()) {
         const QSet<int> previous = m_selectedItems;
         m_selectedItems.clear();
+        m_selectedItems.reserve(previous.count());
         QSetIterator<int> it(previous);
         while (it.hasNext()) {
             const int index = it.next();
@@ -307,6 +308,7 @@ void KItemListSelectionManager::itemsRemoved(const KItemRangeList& itemRanges)
     if (!m_selectedItems.isEmpty()) {
         const QSet<int> previous = m_selectedItems;
         m_selectedItems.clear();
+        m_selectedItems.reserve(previous.count());
         QSetIterator<int> it(previous);
         while (it.hasNext()) {
             int index = it.next();
@@ -338,4 +340,48 @@ void KItemListSelectionManager::itemsRemoved(const KItemRangeList& itemRanges)
     }
 }
 
+void KItemListSelectionManager::itemsMoved(const KItemRange& itemRange, const QList<int>& movedToIndexes)
+{
+    // Store the current selection (needed in the selectionChanged() signal)
+    const QSet<int> previousSelection = selectedItems();
+
+    // Update the current item
+    if (m_currentItem >= itemRange.index && m_currentItem < itemRange.index + itemRange.count) {
+        const int previousCurrentItem = m_currentItem;
+        const int newCurrentItem = movedToIndexes.at(previousCurrentItem - itemRange.index);
+
+        // Calling setCurrentItem would trigger the selectionChanged signal, but we want to
+        // emit it only once in this function -> change the current item manually and emit currentChanged
+        m_currentItem = newCurrentItem;
+        emit currentChanged(newCurrentItem, previousCurrentItem);
+    }
+
+    // Update the anchor item
+    if (m_anchorItem >= itemRange.index && m_anchorItem < itemRange.index + itemRange.count) {
+        m_anchorItem = movedToIndexes.at(m_anchorItem - itemRange.index);
+    }
+
+    // Update the selections
+    if (!m_selectedItems.isEmpty()) {
+        const QSet<int> previous = m_selectedItems;
+        m_selectedItems.clear();
+        m_selectedItems.reserve(previous.count());
+        QSetIterator<int> it(previous);
+        while (it.hasNext()) {
+            const int index = it.next();
+            if (index >= itemRange.index && index < itemRange.index + itemRange.count) {
+                m_selectedItems.insert(movedToIndexes.at(index - itemRange.index));
+            }
+            else {
+                m_selectedItems.insert(index);
+            }
+        }
+    }
+
+    const QSet<int> selection = selectedItems();
+    if (selection != previousSelection) {
+        emit selectionChanged(selection, previousSelection);
+    }
+}
+
 #include "kitemlistselectionmanager.moc"