WebCore/CounterNode.h

   1 /*
   2  * Copyright (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
   3  * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Library General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Library General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Library General Public License
  16  * along with this library; see the file COPYING.LIB.  If not, write to
  17  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  18  * Boston, MA 02110-1301, USA.
  19  *
  20 */
  21
  22 #ifndef CounterNode_h
  23 #define CounterNode_h
  24
  25 #include <wtf/Noncopyable.h>
  26
  27 // This implements a counter tree that is used for finding parents in counters() lookup,
  28 // and for propagating count changes when nodes are added or removed.
  29
  30 // Parents represent unique counters and their scope, which are created either explicitly
  31 // by "counter-reset" style rules or implicitly by referring to a counter that is not in scope.
  32 // Such nodes are tagged as "reset" nodes, although they are not all due to "counter-reset".
  33
  34 // Not that render tree children are often counter tree siblings due to counter scoping rules.
  35
  36 namespace WebCore {
  37
  38 class RenderObject;
  39
  40 class CounterNode : Noncopyable {
  41 public:
  42     CounterNode(RenderObject*, bool isReset, int value);
  43
  44     bool isReset() const { return m_isReset; }
  45     int value() const { return m_value; }
  46     int countInParent() const { return m_countInParent; }
  47     RenderObject* renderer() const { return m_renderer; }
  48
  49     CounterNode* parent() const { return m_parent; }
  50     CounterNode* previousSibling() const { return m_previousSibling; }
  51     CounterNode* nextSibling() const { return m_nextSibling; }
  52     CounterNode* firstChild() const { return m_firstChild; }
  53     CounterNode* lastChild() const { return m_lastChild; }
  54
  55     void insertAfter(CounterNode* newChild, CounterNode* beforeChild);
  56     void removeChild(CounterNode*);
  57
  58 private:
  59     int computeCountInParent() const;
  60     void recount();
  61
  62     bool m_isReset;
  63     int m_value;
  64     int m_countInParent;
  65     RenderObject* m_renderer;
  66
  67     CounterNode* m_parent;
  68     CounterNode* m_previousSibling;
  69     CounterNode* m_nextSibling;
  70     CounterNode* m_firstChild;
  71     CounterNode* m_lastChild;
  72 };
  73
  74 } // namespace WebCore
  75
  76 #ifndef NDEBUG
  77 // Outside the WebCore namespace for ease of invocation from gdb.
  78 void showTree(const WebCore::CounterNode*);
  79 #endif
  80
  81 #endif // CounterNode_h