From 2329582577aab8ee35f93c193f3584e49eaeba34 Mon Sep 17 00:00:00 2001
From: Kim Motoyoshi Kalland <kim.kalland@nokia.com>
Date: Mon, 20 Jun 2011 10:53:34 +0200
Subject: [PATCH] Removed unnecessary calls to QSGNode::destroy().

---
 src/declarative/scenegraph/coreapi/qsgnode.cpp     |   18 ++++++++++++------
 src/declarative/scenegraph/coreapi/qsgnode.h       |   11 +++--------
 src/declarative/scenegraph/coreapi/qsgrenderer.cpp |    8 ++++++++
 3 files changed, 23 insertions(+), 14 deletions(-)

diff --git a/src/declarative/scenegraph/coreapi/qsgnode.cpp b/src/declarative/scenegraph/coreapi/qsgnode.cpp
index fa720a3..bfe17ca 100644
--- a/src/declarative/scenegraph/coreapi/qsgnode.cpp
+++ b/src/declarative/scenegraph/coreapi/qsgnode.cpp
@@ -174,6 +174,17 @@ bool QSGNode::isSubtreeBlocked() const
     return m_subtreeGeometryCount == 0;
 }
 
+/*!
+    \internal
+    Detaches the node from the scene graph and deletes any children it owns.
+
+    This function is called from QSGNode's and QSGRootNode's destructor. It
+    should not be called explicitly in user code. QSGRootNode needs to call
+    destroy() because destroy() calls removeChildNode() which in turn calls
+    markDirty() which type-casts the node to QSGRootNode. This type-cast is not
+    valid at the time QSGNode's destructor is called because the node will
+    already be partially destroyed at that point.
+*/
 
 void QSGNode::destroy()
 {
@@ -493,7 +504,6 @@ QSGBasicGeometryNode::QSGBasicGeometryNode(NodeType type)
 
 QSGBasicGeometryNode::~QSGBasicGeometryNode()
 {
-    destroy();
     if (flags() & OwnsGeometry)
         delete m_geometry;
 }
@@ -569,7 +579,6 @@ QSGGeometryNode::QSGGeometryNode()
 
 QSGGeometryNode::~QSGGeometryNode()
 {
-    destroy();
     if (flags() & OwnsMaterial)
         delete m_material;
     if (flags() & OwnsOpaqueMaterial)
@@ -731,7 +740,6 @@ QSGClipNode::QSGClipNode()
 
 QSGClipNode::~QSGClipNode()
 {
-    destroy();
 }
 
 
@@ -807,7 +815,6 @@ QSGTransformNode::QSGTransformNode()
 
 QSGTransformNode::~QSGTransformNode()
 {
-    destroy();
 }
 
 
@@ -881,7 +888,7 @@ QSGRootNode::~QSGRootNode()
 {
     while (!m_renderers.isEmpty())
         m_renderers.last()->setRootNode(0);
-    destroy();
+    destroy(); // Must call destroy() here because markDirty() casts this to QSGRootNode.
 }
 
 
@@ -940,7 +947,6 @@ QSGOpacityNode::QSGOpacityNode()
 
 QSGOpacityNode::~QSGOpacityNode()
 {
-    destroy();
 }
 
 
diff --git a/src/declarative/scenegraph/coreapi/qsgnode.h b/src/declarative/scenegraph/coreapi/qsgnode.h
index 2705958..cee6b76 100644
--- a/src/declarative/scenegraph/coreapi/qsgnode.h
+++ b/src/declarative/scenegraph/coreapi/qsgnode.h
@@ -152,16 +152,11 @@ public:
 protected:
     QSGNode(NodeType type);
 
-    // When a node is destroyed, it will detach from the scene graph and the renderer will be
-    // notified about the change. If the node is detached in the base node's destructor, the
-    // renderer can't safely cast the node to its original type, since at this point it has been
-    // partly destroyed already. To solve this problem, all the node destructors must call a common
-    // destroy method.
-
-    void destroy();
-
 private:
+    friend class QSGRootNode;
+
     void init();
+    void destroy();
 
     QSGNode *m_parent;
     NodeType m_type;
diff --git a/src/declarative/scenegraph/coreapi/qsgrenderer.cpp b/src/declarative/scenegraph/coreapi/qsgrenderer.cpp
index f56bf9a..48c34d3 100644
--- a/src/declarative/scenegraph/coreapi/qsgrenderer.cpp
+++ b/src/declarative/scenegraph/coreapi/qsgrenderer.cpp
@@ -293,6 +293,14 @@ void QSGRenderer::setClearColor(const QColor &color)
     m_clear_color = color;
 }
 
+/*!
+    Updates internal data structures and emits the sceneGraphChanged() signal.
+
+    If \a flags contains the QSGNode::DirtyNodeRemoved flag, the node might be
+    in the process of being destroyed. It is then not safe to downcast the node
+    pointer.
+*/
+
 void QSGRenderer::nodeChanged(QSGNode *node, QSGNode::DirtyFlags flags)
 {
     Q_UNUSED(node);
-- 
1.7.2.5