1/* 2 * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of Apple Inc. ("Apple") nor the names of 14 * its contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY 18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY 21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29#ifndef GlyphPageTreeNode_h 30#define GlyphPageTreeNode_h 31 32#include "GlyphPage.h" 33#include <string.h> 34#include <wtf/HashMap.h> 35#include <wtf/OwnPtr.h> 36#include <wtf/PassRefPtr.h> 37#include <wtf/RefCounted.h> 38 39#ifndef NDEBUG 40void showGlyphPageTrees(); 41void showGlyphPageTree(unsigned pageNumber); 42#endif 43 44namespace WebCore { 45 46class FontData; 47class SimpleFontData; 48 49// The glyph page tree is a data structure that maps (FontData, glyph page number) 50// to a GlyphPage. Level 0 (the "root") is special. There is one root 51// GlyphPageTreeNode for each glyph page number. The roots do not have a 52// GlyphPage associated with them, and their initializePage() function is never 53// called to fill the glyphs. 54// 55// Each root node maps a FontData pointer to another GlyphPageTreeNode at 56// level 1 (the "root child") that stores the actual glyphs for a specific font data. 57// These nodes will only have a GlyphPage if they have glyphs for that range. 58// 59// Levels greater than one correspond to subsequent levels of the fallback list 60// for that font. These levels override their parent's page of glyphs by 61// filling in holes with the new font (thus making a more complete page). 62// 63// A NULL FontData pointer corresponds to the system fallback 64// font. It is tracked separately from the regular pages and overrides so that 65// the glyph pages do not get polluted with these last-resort glyphs. The 66// system fallback page is not populated at construction like the other pages, 67// but on demand for each glyph, because the system may need to use different 68// fallback fonts for each. This lazy population is done by the Font. 69class GlyphPageTreeNode { 70 WTF_MAKE_FAST_ALLOCATED; 71public: 72 static GlyphPageTreeNode* getRootChild(const FontData* fontData, unsigned pageNumber) 73 { 74 return getRoot(pageNumber)->getChild(fontData, pageNumber); 75 } 76 77 static void pruneTreeCustomFontData(const FontData*); 78 static void pruneTreeFontData(const SimpleFontData*); 79 80 void pruneCustomFontData(const FontData*); 81 void pruneFontData(const SimpleFontData*, unsigned level = 0); 82 83 GlyphPageTreeNode* parent() const { return m_parent; } 84 GlyphPageTreeNode* getChild(const FontData*, unsigned pageNumber); 85 86 // Returns a page of glyphs (or NULL if there are no glyphs in this page's character range). 87 GlyphPage* page() const { return m_page.get(); } 88 89 // Returns the level of this node. See class-level comment. 90 unsigned level() const { return m_level; } 91 92 // The system fallback font has special rules (see above). 93 bool isSystemFallback() const { return m_isSystemFallback; } 94 95 static size_t treeGlyphPageCount(); 96 size_t pageCount() const; 97 98private: 99 GlyphPageTreeNode() 100 : m_parent(0) 101 , m_level(0) 102 , m_isSystemFallback(false) 103 , m_customFontCount(0) 104#ifndef NDEBUG 105 , m_pageNumber(0) 106#endif 107 { 108 } 109 110 static GlyphPageTreeNode* getRoot(unsigned pageNumber); 111 void initializePage(const FontData*, unsigned pageNumber); 112 113#ifndef NDEBUG 114 void showSubtree(); 115#endif 116 117 static HashMap<int, GlyphPageTreeNode*>* roots; 118 static GlyphPageTreeNode* pageZeroRoot; 119 120 typedef HashMap<const FontData*, OwnPtr<GlyphPageTreeNode>> GlyphPageTreeNodeMap; 121 122 GlyphPageTreeNodeMap m_children; 123 GlyphPageTreeNode* m_parent; 124 RefPtr<GlyphPage> m_page; 125 unsigned m_level : 31; 126 bool m_isSystemFallback : 1; 127 unsigned m_customFontCount; 128 OwnPtr<GlyphPageTreeNode> m_systemFallbackChild; 129 130#ifndef NDEBUG 131 unsigned m_pageNumber; 132 133 friend void ::showGlyphPageTrees(); 134 friend void ::showGlyphPageTree(unsigned pageNumber); 135#endif 136}; 137 138} // namespace WebCore 139 140#endif // GlyphPageTreeNode_h 141