Refactor: use lambdas for visitor pattern in QGraphicsSceneBspTree

This way, the visitor implementations are directly where they are used,
without the need for a virtual function call. The allocation of the
visitors on the heap was anyway overkill (they could just have been
allocated on the stack where they were used).

Change-Id: Ic41fd285e3a45daaf2e17aa5aeee07e754127a00
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

1 files changed, 2 insertions, 16 deletions

diff --git a/src/widgets/graphicsview/qgraphicsscene_bsp_p.h b/src/widgets/graphicsview/qgraphicsscene_bsp_p.h
index d81c0776ed..9327c396cb 100644
--- a/src/widgets/graphicsview/qgraphicsscene_bsp_p.h
+++ b/src/widgets/graphicsview/qgraphicsscene_bsp_p.h
@@ -61,10 +61,6 @@ QT_REQUIRE_CONFIG(graphicsview);
 QT_BEGIN_NAMESPACE
 
 class QGraphicsItem;
-class QGraphicsSceneBspTreeVisitor;
-class QGraphicsSceneInsertItemBspTreeVisitor;
-class QGraphicsSceneRemoveItemBspTreeVisitor;
-class QGraphicsSceneFindItemBspTreeVisitor;
 
 class QGraphicsSceneBspTree
 {
@@ -102,24 +98,14 @@ public:
 
 private:
     void initialize(const QRectF &rect, int depth, int index);
-    void climbTree(QGraphicsSceneBspTreeVisitor *visitor, const QRectF &rect, int index = 0) const;
+    template<typename Visitor>
+    void climbTree(Visitor &&visitor, const QRectF &rect, int index = 0) const;
     QRectF rectForIndex(int index) const;
 
     QList<Node> nodes;
     QList<QList<QGraphicsItem *>> leaves;
     int leafCnt;
     QRectF rect;
-
-    QGraphicsSceneInsertItemBspTreeVisitor *insertVisitor;
-    QGraphicsSceneRemoveItemBspTreeVisitor *removeVisitor;
-    QGraphicsSceneFindItemBspTreeVisitor *findVisitor;
-};
-
-class QGraphicsSceneBspTreeVisitor
-{
-public:
-    virtual ~QGraphicsSceneBspTreeVisitor() { }
-    virtual void visit(QList<QGraphicsItem *> *items) = 0;
 };
 
 QT_END_NAMESPACE