/*
 * Copyright (C) 2006, 2010 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 FontFallbackList_h
#define FontFallbackList_h

#include "platform/fonts/FallbackListCompositeKey.h"
#include "platform/fonts/FontCache.h"
#include "platform/fonts/FontSelector.h"
#include "platform/fonts/SimpleFontData.h"
#include "platform/fonts/shaping/ShapeCache.h"
#include "wtf/Allocator.h"
#include "wtf/Forward.h"
#include "wtf/RefCounted.h"
#include "wtf/WeakPtr.h"

namespace blink {

class GlyphPageTreeNodeBase;
class FontDescription;

const int cAllFamiliesScanned = -1;

class PLATFORM_EXPORT FontFallbackList : public RefCounted<FontFallbackList> {
  WTF_MAKE_NONCOPYABLE(FontFallbackList);

 public:
  typedef HashMap<int, GlyphPageTreeNodeBase*, DefaultHash<int>::Hash>
      GlyphPages;

  class GlyphPagesStateSaver {
    STACK_ALLOCATED();

   public:
    GlyphPagesStateSaver(FontFallbackList& fallbackList)
        : m_fallbackList(fallbackList),
          m_pages(fallbackList.m_pages),
          m_pageZero(fallbackList.m_pageZero) {}

    ~GlyphPagesStateSaver() {
      m_fallbackList.m_pages = m_pages;
      m_fallbackList.m_pageZero = m_pageZero;
    }

   private:
    FontFallbackList& m_fallbackList;
    GlyphPages& m_pages;
    GlyphPageTreeNodeBase* m_pageZero;
  };

  static PassRefPtr<FontFallbackList> create() {
    return adoptRef(new FontFallbackList());
  }

  ~FontFallbackList() { releaseFontData(); }
  bool isValid() const;
  void invalidate(FontSelector*);

  bool loadingCustomFonts() const;
  bool shouldSkipDrawing() const;

  FontSelector* getFontSelector() const { return m_fontSelector.get(); }
  // FIXME: It should be possible to combine fontSelectorVersion and generation.
  unsigned fontSelectorVersion() const { return m_fontSelectorVersion; }
  unsigned generation() const { return m_generation; }

  ShapeCache* shapeCache(const FontDescription& fontDescription) const {
    if (!m_shapeCache) {
      FallbackListCompositeKey key = compositeKey(fontDescription);
      m_shapeCache = FontCache::fontCache()->getShapeCache(key)->weakPtr();
    }
    ASSERT(m_shapeCache);
    if (getFontSelector())
      m_shapeCache->clearIfVersionChanged(getFontSelector()->version());
    return m_shapeCache.get();
  }

  const SimpleFontData* primarySimpleFontData(
      const FontDescription& fontDescription) {
    ASSERT(isMainThread());
    if (!m_cachedPrimarySimpleFontData) {
      m_cachedPrimarySimpleFontData =
          determinePrimarySimpleFontData(fontDescription);
      ASSERT(m_cachedPrimarySimpleFontData);
    }
    return m_cachedPrimarySimpleFontData;
  }
  const FontData* fontDataAt(const FontDescription&, unsigned index) const;

  GlyphPageTreeNodeBase* getPageNode(unsigned pageNumber) const {
    return pageNumber ? m_pages.get(pageNumber) : m_pageZero;
  }

  void setPageNode(unsigned pageNumber, GlyphPageTreeNodeBase* node) {
    if (pageNumber)
      m_pages.set(pageNumber, node);
    else
      m_pageZero = node;
  }

  FallbackListCompositeKey compositeKey(const FontDescription&) const;

 private:
  FontFallbackList();

  PassRefPtr<FontData> getFontData(const FontDescription&,
                                   int& familyIndex) const;

  const SimpleFontData* determinePrimarySimpleFontData(
      const FontDescription&) const;

  void releaseFontData();

  mutable Vector<RefPtr<FontData>, 1> m_fontList;
  GlyphPages m_pages;
  GlyphPageTreeNodeBase* m_pageZero;
  mutable const SimpleFontData* m_cachedPrimarySimpleFontData;
  Persistent<FontSelector> m_fontSelector;
  unsigned m_fontSelectorVersion;
  mutable int m_familyIndex;
  unsigned short m_generation;
  mutable bool m_hasLoadingFallback : 1;
  mutable WeakPtr<ShapeCache> m_shapeCache;
};

}  // namespace blink

#endif
