QTreeView: fix drawing branches of model that adds or remove rows dynamically

The lasts commits in the treeview did put the flags weither
item has child or is the last in cache in the viewItem vector.
But the cache was not updated while the model is modified.

Reviewed-by: Thierry

2 files changed, 37 insertions, 4 deletions

diff --git a/src/gui/itemviews/qtreeview.cpp b/src/gui/itemviews/qtreeview.cpp
index be64c46fed..3856293afd 100644
--- a/src/gui/itemviews/qtreeview.cpp
+++ b/src/gui/itemviews/qtreeview.cpp
@@ -2434,7 +2434,9 @@ void QTreeView::rowsInserted(const QModelIndex &parent, int start, int end)
         return;
     }
 
-    if (parent != d->root && !d->isIndexExpanded(parent) && d->model->rowCount(parent) > (end - start) + 1) {
+    const int parentRowCount = d->model->rowCount(parent);
+    const int delta = end - start + 1;
+    if (parent != d->root && !d->isIndexExpanded(parent) && parentRowCount > delta) {
         QAbstractItemView::rowsInserted(parent, start, end);
         return;
     }
@@ -2449,11 +2451,29 @@ void QTreeView::rowsInserted(const QModelIndex &parent, int start, int end)
                                                     ? d->viewItems.count()
                                                     : d->viewItems.at(parentItem).total) - 1;
 
-        const int delta = end - start + 1;
+        if (parentRowCount == end + 1 && start > 0) {
+            //need to Update hasMoreSiblings
+            int previousRow = start - 1;
+            QModelIndex previousSibilingModelIndex = d->model->index(previousRow, 0, parent);
+            bool isHidden = d->isRowHidden(previousSibilingModelIndex);
+            while (isHidden && previousRow > 0) {
+                previousRow--;
+                previousSibilingModelIndex = d->model->index(previousRow, 0, parent);
+                isHidden = d->isRowHidden(previousSibilingModelIndex);
+            }
+            if (!isHidden) {
+                const int previousSibilling = d->viewIndex(previousSibilingModelIndex);
+                if(previousSibilling != -1)
+                    d->viewItems[previousSibilling].hasMoreSiblings = true;
+            }
+        }
+
         QVector<QTreeViewItem> insertedItems(delta);
         for (int i = 0; i < delta; ++i) {
             insertedItems[i].index = d->model->index(i + start, 0, parent);
             insertedItems[i].level = childLevel;
+            insertedItems[i].hasChildren = d->hasVisibleChildren(insertedItems[i].index);
+            insertedItems[i].hasMoreSiblings = !((i == delta - 1) && (parentRowCount == end +1));
         }
         if (d->viewItems.isEmpty())
             d->defaultItemHeight = indexRowSizeHint(insertedItems[0].index);
@@ -2495,13 +2515,17 @@ void QTreeView::rowsInserted(const QModelIndex &parent, int start, int end)
                   d->viewItems.begin() + insertPos + 1);
         }
 
+        if (parentItem != -1)
+            d->viewItems[parentItem].hasChildren = true;
         d->updateChildCount(parentItem, delta);
+
         updateGeometries();
         viewport()->update();
     } else if ((parentItem != -1) && d->viewItems.at(parentItem).expanded) {
         d->doDelayedItemsLayout();
     } else if (parentItem != -1 && (d->model->rowCount(parent) == end - start + 1)) {
-        // the parent just went from 0 children to having some update to re-paint the decoration
+        // the parent just went from 0 children to more. update to re-paint the decoration
+        d->viewItems[parentItem].hasChildren = true;
         viewport()->update();
     }
     QAbstractItemView::rowsInserted(parent, start, end);
@@ -3706,6 +3730,7 @@ void QTreeViewPrivate::rowsRemoved(const QModelIndex &parent,
 
         const int delta = end - start + 1;
 
+        int previousSibiling = -1;
         int removedCount = 0;
         for (int item = firstChildItem; item <= lastChildItem; ) {
             Q_ASSERT(viewItems.at(item).level == childLevel);
@@ -3713,6 +3738,7 @@ void QTreeViewPrivate::rowsRemoved(const QModelIndex &parent,
             //Q_ASSERT(modelIndex.parent() == parent);
             const int count = viewItems.at(item).total + 1;
             if (modelIndex.row() < start) {
+                previousSibiling = item;
                 // not affected by the removal
                 item += count;
             } else if (modelIndex.row() <= end) {
@@ -3730,7 +3756,13 @@ void QTreeViewPrivate::rowsRemoved(const QModelIndex &parent,
             }
         }
 
+        if (previousSibiling != -1 && after && model->rowCount(parent) == start)
+            viewItems[previousSibiling].hasMoreSiblings = false;
+
+
         updateChildCount(parentItem, -removedCount);
+        if (parentItem != -1 && viewItems.at(parentItem).total == 0)
+            viewItems[parentItem].hasChildren = false; //every children have been removed;
         if (after) {
             q->updateGeometries();
             viewport->update();
diff --git a/src/gui/itemviews/qtreeview_p.h b/src/gui/itemviews/qtreeview_p.h
index 62676d8da1..aad5837599 100644
--- a/src/gui/itemviews/qtreeview_p.h
+++ b/src/gui/itemviews/qtreeview_p.h
@@ -62,7 +62,8 @@ QT_BEGIN_NAMESPACE
 
 struct QTreeViewItem
 {
-    QTreeViewItem() : expanded(false), spanning(false), total(0), level(0), height(0) {}
+    QTreeViewItem() : expanded(false), spanning(false), hasChildren(false),
+                      hasMoreSiblings(false), total(0), level(0), height(0) {}
     QModelIndex index; // we remove items whenever the indexes are invalidated
     uint expanded : 1;
     uint spanning : 1;