SVG objects with same idrefs conflict when under different shadow root

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

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/svg/SVGTreeScopeResources.h"
+
+#include "core/dom/Element.h"
+#include "core/dom/TreeScope.h"
+#include "core/layout/svg/LayoutSVGResourceContainer.h"
+#include "wtf/text/AtomicString.h"
+
+namespace blink {
+
+SVGTreeScopeResources::SVGTreeScopeResources(TreeScope* treeScope) {
+  // Whenever an object of SVGTreeScopeResources is created, to keep the code
+  // behave as before,
+  // the document should also have an instance of SVGDocumentExtensions created.
+  // Thus below line is added.
+  treeScope->document().accessSVGExtensions();
+}
+
+SVGTreeScopeResources::~SVGTreeScopeResources() = default;
+
+void SVGTreeScopeResources::addResource(const AtomicString& id,
+                                        LayoutSVGResourceContainer* resource) {
+  DCHECK(resource);
+  if (id.isEmpty())
+    return;
+  // Replaces resource if already present, to handle potential id changes
+  m_resources.set(id, resource);
+}
+
+void SVGTreeScopeResources::removeResource(const AtomicString& id) {
+  if (id.isEmpty())
+    return;
+  m_resources.remove(id);
+}
+
+LayoutSVGResourceContainer* SVGTreeScopeResources::resourceById(
+    const AtomicString& id) const {
+  if (id.isEmpty())
+    return nullptr;
+  return m_resources.get(id);
+}
+
+void SVGTreeScopeResources::addPendingResource(const AtomicString& id,
+                                               Element* element) {
+  DCHECK(element);
+  DCHECK(element->isConnected());
+
+  if (id.isEmpty())
+    return;
+
+  HeapHashMap<AtomicString, Member<SVGPendingElements>>::AddResult result =
+      m_pendingResources.add(id, nullptr);
+  if (result.isNewEntry)
+    result.storedValue->value = new SVGPendingElements;
+  result.storedValue->value->add(element);
+
+  element->setHasPendingResources();
+}
+
+bool SVGTreeScopeResources::hasPendingResource(const AtomicString& id) const {
+  if (id.isEmpty())
+    return false;
+  return m_pendingResources.contains(id);
+}
+
+bool SVGTreeScopeResources::isElementPendingResources(Element* element) const {
+  // This algorithm takes time proportional to the number of pending resources
+  // and need not.
+  // If performance becomes an issue we can keep a counted set of elements and
+  // answer the question efficiently.
+  DCHECK(element);
+
+  for (const auto& entry : m_pendingResources) {
+    SVGPendingElements* elements = entry.value.get();
+    DCHECK(elements);
+    if (elements->contains(element))
+      return true;
+  }
+  return false;
+}
+
+bool SVGTreeScopeResources::isElementPendingResource(
+    Element* element,
+    const AtomicString& id) const {
+  DCHECK(element);
+  if (!hasPendingResource(id))
+    return false;
+  return m_pendingResources.get(id)->contains(element);
+}
+
+void SVGTreeScopeResources::clearHasPendingResourcesIfPossible(
+    Element* element) {
+  if (!isElementPendingResources(element))
+    element->clearHasPendingResources();
+}
+
+void SVGTreeScopeResources::removeElementFromPendingResources(
+    Element* element) {
+  DCHECK(element);
+
+  // Remove the element from pending resources.
+  if (!m_pendingResources.isEmpty() && element->hasPendingResources()) {
+    Vector<AtomicString> toBeRemoved;
+    for (const auto& entry : m_pendingResources) {
+      SVGPendingElements* elements = entry.value.get();
+      DCHECK(elements);
+      DCHECK(!elements->isEmpty());
+
+      elements->remove(element);
+      if (elements->isEmpty())
+        toBeRemoved.append(entry.key);
+    }
+
+    clearHasPendingResourcesIfPossible(element);
+
+    // We use the removePendingResource function here because it deals with set
+    // lifetime correctly.
+    for (const AtomicString& id : toBeRemoved)
+      removePendingResource(id);
+  }
+}
+
+SVGTreeScopeResources::SVGPendingElements*
+SVGTreeScopeResources::removePendingResource(const AtomicString& id) {
+  DCHECK(m_pendingResources.contains(id));
+  return m_pendingResources.take(id);
+}
+
+DEFINE_TRACE(SVGTreeScopeResources) {
+  visitor->trace(m_pendingResources);
+}
+}