Factor addReferenceTo()-calls out of SVGUseElement::buildShadowTree

third_party/WebKit/Source/core/svg/SVGUseElement.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007 Rob Buis <buis@kde.org>
  * Copyright (C) Research In Motion Limited 2009-2010. All rights reserved.
  * Copyright (C) 2011 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  * Copyright (C) 2012 University of Szeged
  * Copyright (C) 2012 Renata Hodovan <reni@webkit.org>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 371 matching lines @@
     // Set up root SVG element in shadow tree.
     RefPtrWillBeRawPtr<Element> newChild = target.cloneElementWithoutChildren();
     m_targetElementInstance = toSVGElement(newChild.get());
     ShadowRoot* shadowTreeRootElement = userAgentShadowRoot();
     shadowTreeRootElement->appendChild(newChild.release());
 
     // Clone the target subtree into the shadow tree, not handling <use> and <symbol> yet.
 
     // SVG specification does not say a word about <use> & cycles. My view on this is: just ignore it!
     // Non-appearing <use> content is easier to debug, then half-appearing content.
-    buildShadowTree(target, *m_targetElementInstance, false);
+    buildShadowTree(target, *m_targetElementInstance);
 
-    if (instanceTreeIsLoading(m_targetElementInstance.get())) {
+    addReferencesToFirstDegreeNestedUseElements(target);
+
+    if (instanceTreeIsLoading()) {
         cloneNonMarkupEventListeners();
         return;
     }
 
     // Assure shadow tree building was successful.
     ASSERT(m_targetElementInstance);
     ASSERT(m_targetElementInstance->correspondingUseElement() == this);
     ASSERT(m_targetElementInstance->correspondingElement() == &target);
 
     // Expand all <use> elements in the shadow tree.
@@ skipping 68 matching lines @@
     // http://dev.w3.org/fxtf/css-masking-1/#the-clip-path
     if (!isDirectReference(element)) {
         // Spec: Indirect references are an error (14.3.5)
         document().accessSVGExtensions().reportError("Not allowed to use indirect reference in <clip-path>");
         return nullptr;
     }
 
     return &toSVGGraphicsElement(element);
 }
 
-void SVGUseElement::buildShadowTree(SVGElement& target, SVGElement& targetInstance, bool foundUse)
+void SVGUseElement::addReferencesToFirstDegreeNestedUseElements(SVGElement& target)
+{
+    // Don't track references to external documents.
+    if (isStructurallyExternal())
+        return;
+    // We only need to track first degree <use> dependencies. Indirect
+    // references are handled as the invalidation bubbles up the dependency
+    // chain.
+    SVGUseElement* useElement =
+        isSVGUseElement(target) ? toSVGUseElement(&target) : Traversal<SVGUseElement>::firstWithin(target);
+    for (; useElement; useElement = Traversal<SVGUseElement>::nextSkippingChildren(*useElement, &target))
+        addReferenceTo(useElement);
+}
+
+void SVGUseElement::buildShadowTree(SVGElement& target, SVGElement& targetInstance)
 {
     ASSERT(!isDisallowedElement(target));
 
-    // Spec: If the referenced object is itself a 'use', or if there are 'use' subelements within the referenced
-    // object, the instance tree will contain recursive expansion of the indirect references to form a complete tree.
-    if (isSVGUseElement(target)) {
-        // We only need to track first degree <use> dependencies. Indirect references are handled
-        // as the invalidation bubbles up the dependency chain.
-        if (!foundUse && !isStructurallyExternal()) {
-            addReferenceTo(&target);
-            foundUse = true;
-        }
-    }
-
     targetInstance.setCorrespondingElement(&target);
 
     for (RefPtrWillBeRawPtr<Node> child = target.firstChild(); child; child = child->nextSibling()) {
         // Skip any disallowed element.
         if (isDisallowedElement(*child))
             continue;
 
         RefPtrWillBeRawPtr<Node> newChild = child->cloneNode(false);
         targetInstance.appendChild(newChild.get());
         if (newChild->isSVGElement()) {
             // Enter recursion, appending new instance tree nodes to the "instance" object.
-            buildShadowTree(toSVGElement(*child), toSVGElement(*newChild), foundUse);
+            buildShadowTree(toSVGElement(*child), toSVGElement(*newChild));
         }
     }
 }
 
 void SVGUseElement::cloneNonMarkupEventListeners()
 {
     for (SVGElement& element : Traversal<SVGElement>::descendantsOf(*userAgentShadowRoot())) {
         if (EventTargetData* data = element.correspondingElement()->eventTargetData())
             data->eventListenerMap.copyEventListenersNotCreatedFromMarkupToTarget(&element);
     }
@@ skipping 243 matching lines @@
 }
 
 bool SVGUseElement::resourceIsValid() const
 {
     return m_resource
         && m_resource->isLoaded()
         && !m_resource->errorOccurred()
         && m_resource->document();
 }
 
-bool SVGUseElement::instanceTreeIsLoading(const SVGElement* targetInstance)
+bool SVGUseElement::instanceTreeIsLoading() const
 {
-    for (const SVGElement* element = targetInstance; element; element = Traversal<SVGElement>::next(*element, targetInstance)) {
-        if (isSVGUseElement(*element) && toSVGUseElement(*element).resourceIsStillLoading())
+    for (const SVGUseElement& useElement : Traversal<SVGUseElement>::descendantsOf(*userAgentShadowRoot())) {
+        if (useElement.resourceIsStillLoading())
             return true;
     }
     return false;
 }
 
 void SVGUseElement::setDocumentResource(PassRefPtrWillBeRawPtr<DocumentResource> resource)
 {
     if (m_resource == resource)
         return;
 
     if (m_resource)
         m_resource->removeClient(this);
 
     m_resource = resource;
     if (m_resource)
         m_resource->addClient(this);
 }
 
 } // namespace blink