WebCore/BidiContext.h

   1 /*
   2  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
   3  * Copyright (C) 2003, 2004, 2006, 2007 Apple Inc.  All right 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 BidiContext_h
  23 #define BidiContext_h
  24
  25 #include <wtf/Assertions.h>
  26 #include <wtf/RefPtr.h>
  27 #include <wtf/unicode/Unicode.h>
  28
  29 namespace WebCore {
  30
  31 // Used to keep track of explicit embeddings.
  32 class BidiContext {
  33 public:
  34     BidiContext(unsigned char level, WTF::Unicode::Direction direction, bool override = false, BidiContext* parent = 0)
  35         : m_level(level)
  36         , m_direction(direction)
  37         , m_override(override)
  38         , m_parent(parent)
  39         , m_refCount(0)
  40     {
  41         ASSERT(direction == WTF::Unicode::LeftToRight || direction == WTF::Unicode::RightToLeft);
  42     }
  43
  44     void ref() const { m_refCount++; }
  45     void deref() const
  46     {
  47         m_refCount--;
  48         if (m_refCount <= 0)
  49             delete this;
  50     }
  51
  52     BidiContext* parent() const { return m_parent.get(); }
  53     unsigned char level() const { return m_level; }
  54     WTF::Unicode::Direction dir() const { return static_cast<WTF::Unicode::Direction>(m_direction); }
  55     bool override() const { return m_override; }
  56
  57 private:
  58     unsigned char m_level;
  59     unsigned m_direction : 5; // Direction
  60     bool m_override : 1;
  61     RefPtr<BidiContext> m_parent;
  62     mutable int m_refCount;
  63 };
  64
  65 bool operator==(const BidiContext&, const BidiContext&);
  66
  67 } // namespace WebCore
  68
  69 #endif // BidiContext_h