third_party/WebKit/Source/core/layout/CounterNode.h

/*
 * Copyright (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
 * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
*/

#ifndef CounterNode_h
#define CounterNode_h

#include "wtf/Forward.h"
#include "wtf/Noncopyable.h"
#include "wtf/RefCounted.h"

// This implements a counter tree that is used for finding parents in counters()
// lookup, and for propagating count changes when nodes are added or removed.

// Parents represent unique counters and their scope, which are created either
// explicitly by "counter-reset" style rules or implicitly by referring to a
// counter that is not in scope.
// Such nodes are tagged as "reset" nodes, although they are not all due to
// "counter-reset".

// Not that layout tree children are often counter tree siblings due to counter
// scoping rules.

namespace blink {

class LayoutObject;
class LayoutCounter;

class CounterNode : public RefCounted<CounterNode> {
 public:
  static PassRefPtr<CounterNode> create(LayoutObject&, bool isReset, int value);
  ~CounterNode();
  bool actsAsReset() const { return m_hasResetType || !m_parent; }
  bool hasResetType() const { return m_hasResetType; }
  int value() const { return m_value; }
  int countInParent() const { return m_countInParent; }
  LayoutObject& owner() const { return m_owner; }
  void addLayoutObject(LayoutCounter*);
  void removeLayoutObject(LayoutCounter*);

  // Invalidates the text in the layoutObjects of this counter, if any.
  void resetLayoutObjects();

  CounterNode* parent() const { return m_parent; }
  CounterNode* previousSibling() const { return m_previousSibling; }
  CounterNode* nextSibling() const { return m_nextSibling; }
  CounterNode* firstChild() const { return m_firstChild; }
  CounterNode* lastChild() const { return m_lastChild; }
  CounterNode* lastDescendant() const;
  CounterNode* previousInPreOrder() const;
  CounterNode* nextInPreOrder(const CounterNode* stayWithin = nullptr) const;
  CounterNode* nextInPreOrderAfterChildren(
      const CounterNode* stayWithin = nullptr) const;

  void insertAfter(CounterNode* newChild,
                   CounterNode* beforeChild,
                   const AtomicString& identifier);

  // identifier must match the identifier of this counter.
  void removeChild(CounterNode*);

 private:
  CounterNode(LayoutObject&, bool isReset, int value);
  int computeCountInParent() const;
  // Invalidates the text in the layoutObject of this counter, if any,
  // and in the layoutObjects of all descendants of this counter, if any.
  void resetThisAndDescendantsLayoutObjects();
  void recount();

  bool m_hasResetType;
  int m_value;
  int m_countInParent;
  LayoutObject& m_owner;
  LayoutCounter* m_rootLayoutObject;

  CounterNode* m_parent;
  CounterNode* m_previousSibling;
  CounterNode* m_nextSibling;
  CounterNode* m_firstChild;
  CounterNode* m_lastChild;
};

}  // namespace blink

#ifndef NDEBUG
// Outside the WebCore namespace for ease of invocation from gdb.
void showCounterTree(const blink::CounterNode*);
#endif

#endif  // CounterNode_h