Improve the internal NodeVisitorEx API

Allow the implementation of visit to control whether the children should be
processed afterwards or not. This is modelled after the JS AST visitor in
Qml.

Change-Id: I5b1adf5e1aefd8899bf444e993ddfbf2c5c125c9
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

1 files changed, 15 insertions, 9 deletions

diff --git a/src/quick/scenegraph/qsgadaptationlayer.cpp b/src/quick/scenegraph/qsgadaptationlayer.cpp
index 68b1882c3f..1ed4122ce9 100644
--- a/src/quick/scenegraph/qsgadaptationlayer.cpp
+++ b/src/quick/scenegraph/qsgadaptationlayer.cpp
@@ -297,22 +297,22 @@ void QSGNodeVisitorEx::visitChildren(QSGNode *node)
         switch (child->type()) {
         case QSGNode::ClipNodeType: {
             QSGClipNode *c = static_cast<QSGClipNode*>(child);
-            visit(c);
-            visitChildren(c);
+            if (visit(c))
+                visitChildren(c);
             endVisit(c);
             break;
         }
         case QSGNode::TransformNodeType: {
             QSGTransformNode *c = static_cast<QSGTransformNode*>(child);
-            visit(c);
-            visitChildren(c);
+            if (visit(c))
+                visitChildren(c);
             endVisit(c);
             break;
         }
         case QSGNode::OpacityNodeType: {
             QSGOpacityNode *c = static_cast<QSGOpacityNode*>(child);
-            visit(c);
-            visitChildren(c);
+            if (visit(c))
+                visitChildren(c);
             endVisit(c);
             break;
         }
@@ -322,13 +322,19 @@ void QSGNodeVisitorEx::visitChildren(QSGNode *node)
                 v->accept(this);
             } else {
                 QSGGeometryNode *c = static_cast<QSGGeometryNode*>(child);
-                visit(c);
-                visitChildren(c);
+                if (visit(c))
+                    visitChildren(c);
                 endVisit(c);
             }
             break;
         }
-        case QSGNode::RootNodeType: // fall through
+        case QSGNode::RootNodeType: {
+            QSGRootNode *root = static_cast<QSGRootNode*>(child);
+            if (visit(root))
+                visitChildren(root);
+            endVisit(root);
+            break;
+        }
         case QSGNode::BasicNodeType: {
             visitChildren(child);
             break;