text: /*
   * Copyright (C) 2012 Google Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are
   * met:
   *
   *     * Redistributions of source code must retain the above copyright
   * notice, this list of conditions and the following disclaimer.
   *     * Neither the name of Google Inc. nor the names of its
   * contributors may be used to endorse or promote products derived from
   * this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #ifndef ElementShadow_h
  #define ElementShadow_h
  
  #include "core/CoreExport.h"
  #include "core/dom/shadow/InsertionPoint.h"
  #include "core/dom/shadow/SelectRuleFeatureSet.h"
  #include "core/dom/shadow/ShadowRoot.h"
  #include "platform/heap/Handle.h"
  #include "wtf/DoublyLinkedList.h"
  #include "wtf/HashMap.h"
  #include "wtf/Noncopyable.h"
  #include "wtf/PassOwnPtr.h"
  
  namespace blink {
  
  class CORE_EXPORT ElementShadow final : public NoBaseWillBeGarbageCollectedFinalized<ElementShadow> {
      WTF_MAKE_NONCOPYABLE(ElementShadow);
      WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED(ElementShadow);
  public:
      static PassOwnPtrWillBeRawPtr<ElementShadow> create();
      ~ElementShadow();
  
      Element* host() const;
      ShadowRoot* youngestShadowRoot() const { return m_shadowRoots.head(); }
      ShadowRoot* oldestShadowRoot() const { return m_shadowRoots.tail(); }
      ElementShadow* containingShadow() const;
  
      ShadowRoot& addShadowRoot(Element& shadowHost, ShadowRoot::ShadowRootType);
  
      bool hasSameStyles(const ElementShadow*) const;
  
      void attach(const Node::AttachContext&);
      void detach(const Node::AttachContext&);
  
      void willAffectSelector();
      const SelectRuleFeatureSet& ensureSelectFeatureSet();
  
      void distributeIfNeeded();
      void setNeedsDistributionRecalc();
  
      const InsertionPoint* finalDestinationInsertionPointFor(const Node*) const;
      const DestinationInsertionPoints* destinationInsertionPointsFor(const Node*) const;
  
      void didDistributeNode(const Node*, InsertionPoint*);
  
      DECLARE_TRACE();
  
  private:
      ElementShadow();
  
  #if !ENABLE(OILPAN)
      void removeDetachedShadowRoots();
  #endif
  
      void distribute();
      void clearDistribution();
  
      void collectSelectFeatureSetFrom(ShadowRoot&);
      void distributeNodeChildrenTo(InsertionPoint*, ContainerNode*);
  
      bool needsSelectFeatureSet() const { return m_needsSelectFeatureSet; }
      void setNeedsSelectFeatureSet() { m_needsSelectFeatureSet = true; }
  
  #if ENABLE(OILPAN)
      // The cost of |new| in Oilpan is lower than non-Oilpan.  We should reduce
      // the size of HashMap entry.
      typedef HeapHashMap<Member<const Node>, Member<DestinationInsertionPoints>> NodeToDestinationInsertionPoints;
  #else
      typedef HashMap<const Node*, DestinationInsertionPoints> NodeToDestinationInsertionPoints;
  #endif
      NodeToDestinationInsertionPoints m_nodeToInsertionPoints;
  
      SelectRuleFeatureSet m_selectFeatures;
      // FIXME: Oilpan: add a heap-based version of DoublyLinkedList<>.
      DoublyLinkedList<ShadowRoot> m_shadowRoots;
      bool m_needsDistributionRecalc;
      bool m_needsSelectFeatureSet;
  };
  
  inline Element* ElementShadow::host() const
  {
      ASSERT(!m_shadowRoots.isEmpty());
      return youngestShadowRoot()->host();
  }
  
  inline ShadowRoot* Node::youngestShadowRoot() const
  {
      if (!isElementNode())
          return 0;
      return toElement(this)->youngestShadowRoot();
  }
  
  inline ShadowRoot* Element::youngestShadowRoot() const
  {
      if (ElementShadow* shadow = this->shadow())
          return shadow->youngestShadowRoot();
      return 0;
  }
  
  inline ElementShadow* ElementShadow::containingShadow() const
  {
      if (ShadowRoot* parentRoot = host()->containingShadowRoot())
          return parentRoot->owner();
      return 0;
  }
  
  inline void ElementShadow::distributeIfNeeded()
  {
      if (m_needsDistributionRecalc)
          distribute();
      m_needsDistributionRecalc = false;
  }
  
  } // namespace
  
  #endif
  