Use RAII object to skip pending sorts in QTreeWidget

Cleanup: This patch does not change functionality.
In several places, sorting inside of the QTreeModel is disabled
and afterwards restored. There is a RAII class for this, which is
used in some places, but not in others. This patch introduces
more consistent usage of this RAII object.

Change-Id: I9802998ad31d0f9d4417824f72ff0abbb0c38a17
Reviewed-by: Ievgenii Meshcheriakov <ievgenii.meshcheriakov@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

2 files changed, 9 insertions, 19 deletions

diff --git a/src/widgets/itemviews/qtreewidget.cpp b/src/widgets/itemviews/qtreewidget.cpp
index 08b1137c5c..b684282e9d 100644
--- a/src/widgets/itemviews/qtreewidget.cpp
+++ b/src/widgets/itemviews/qtreewidget.cpp
@@ -112,8 +112,7 @@ public:
 */
 
 QTreeModel::QTreeModel(int columns, QTreeWidget *parent)
-    : QAbstractItemModel(parent), rootItem(new QTreeWidgetItem),
-      headerItem(new QTreeWidgetItem), skipPendingSort(false)
+    : QAbstractItemModel(parent), rootItem(new QTreeWidgetItem), headerItem(new QTreeWidgetItem)
 {
     rootItem->view = parent;
     rootItem->itemFlags = Qt::ItemIsDropEnabled;
@@ -127,8 +126,7 @@ QTreeModel::QTreeModel(int columns, QTreeWidget *parent)
 */
 
 QTreeModel::QTreeModel(QTreeModelPrivate &dd, QTreeWidget *parent)
-    : QAbstractItemModel(dd, parent), rootItem(new QTreeWidgetItem),
-      headerItem(new QTreeWidgetItem), skipPendingSort(false)
+    : QAbstractItemModel(dd, parent), rootItem(new QTreeWidgetItem), headerItem(new QTreeWidgetItem)
 {
     rootItem->view = parent;
     rootItem->itemFlags = Qt::ItemIsDropEnabled;
@@ -1563,11 +1561,8 @@ QTreeWidgetItem::QTreeWidgetItem(QTreeWidgetItem *parent, QTreeWidgetItem *after
 QTreeWidgetItem::~QTreeWidgetItem()
 {
     QTreeModel *model = treeModel();
-    bool wasSkipSort = false;
-    if (model) {
-        wasSkipSort = model->skipPendingSort;
-        model->skipPendingSort = true;
-    }
+    QTreeModel::SkipSorting skipSorting(model);
+
     if (par) {
         int i = par->children.indexOf(this);
         if (i >= 0) {
@@ -1606,9 +1601,6 @@ QTreeWidgetItem::~QTreeWidgetItem()
 
     children.clear();
     delete d;
-    if (model) {
-        model->skipPendingSort = wasSkipSort;
-    }
 }
 
 /*!
@@ -2008,8 +2000,7 @@ void QTreeWidgetItem::insertChild(int index, QTreeWidgetItem *child)
         return;
 
     if (QTreeModel *model = treeModel()) {
-        const bool wasSkipSort = model->skipPendingSort;
-        model->skipPendingSort = true;
+        QTreeModel::SkipSorting skipSorting(model);
         if (model->rootItem == this)
             child->par = nullptr;
         else
@@ -2033,7 +2024,6 @@ void QTreeWidgetItem::insertChild(int index, QTreeWidgetItem *child)
         children.insert(index, child);
         d->updateHiddenStatus(child, true);
         model->endInsertItems();
-        model->skipPendingSort = wasSkipSort;
     } else {
         child->par = this;
         children.insert(index, child);
diff --git a/src/widgets/itemviews/qtreewidget_p.h b/src/widgets/itemviews/qtreewidget_p.h
index be9ee1cfbd..1f10b06358 100644
--- a/src/widgets/itemviews/qtreewidget_p.h
+++ b/src/widgets/itemviews/qtreewidget_p.h
@@ -155,7 +155,7 @@ private:
     QList<QTreeWidgetItemIterator*> iterators;
 
     mutable QBasicTimer sortPendingTimer;
-    mutable bool skipPendingSort; //while doing internal operation we don't care about sorting
+    mutable bool skipPendingSort = false; // no sorting during internal operations
     bool inline executePendingSort() const;
 
     bool isChanging() const;
@@ -167,9 +167,9 @@ public:
     {
         const QTreeModel * const model;
         const bool previous;
-        SkipSorting(const QTreeModel *m) : model(m), previous(model->skipPendingSort)
-        { model->skipPendingSort = true; }
-        ~SkipSorting() { model->skipPendingSort = previous; }
+        SkipSorting(const QTreeModel *m) : model(m), previous(model ? model->skipPendingSort : false)
+        { if (model) model->skipPendingSort = true; }
+        ~SkipSorting() { if (model) model->skipPendingSort = previous; }
     };
     friend struct SkipSorting;
 };