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 Computer, 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/PassRefPtr.h> 36 #include <wtf/RefCounted.h> 37 #include <wtf/unicode/Unicode.h> 38 39 #ifndef NDEBUG 40 void showGlyphPageTrees(); 41 void showGlyphPageTree(unsigned pageNumber); 42 #endif 43 44 namespace WebCore { 45 46 class FontData; 47 class 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. 69 class GlyphPageTreeNode { 70 public: GlyphPageTreeNode()71 GlyphPageTreeNode() 72 : m_parent(0) 73 , m_level(0) 74 , m_isSystemFallback(false) 75 , m_customFontCount(0) 76 , m_systemFallbackChild(0) 77 #ifndef NDEBUG 78 , m_pageNumber(0) 79 #endif 80 { 81 } 82 83 ~GlyphPageTreeNode(); 84 85 static HashMap<int, GlyphPageTreeNode*>* roots; 86 static GlyphPageTreeNode* pageZeroRoot; 87 getRootChild(const FontData * fontData,unsigned pageNumber)88 static GlyphPageTreeNode* getRootChild(const FontData* fontData, unsigned pageNumber) 89 { 90 return getRoot(pageNumber)->getChild(fontData, pageNumber); 91 } 92 93 static void pruneTreeCustomFontData(const FontData*); 94 static void pruneTreeFontData(const SimpleFontData*); 95 96 void pruneCustomFontData(const FontData*); 97 void pruneFontData(const SimpleFontData*, unsigned level = 0); 98 parent()99 GlyphPageTreeNode* parent() const { return m_parent; } 100 GlyphPageTreeNode* getChild(const FontData*, unsigned pageNumber); 101 102 // Returns a page of glyphs (or NULL if there are no glyphs in this page's character range). page()103 GlyphPage* page() const { return m_page.get(); } 104 105 // Returns the level of this node. See class-level comment. level()106 unsigned level() const { return m_level; } 107 108 // The system fallback font has special rules (see above). isSystemFallback()109 bool isSystemFallback() const { return m_isSystemFallback; } 110 111 static size_t treeGlyphPageCount(); 112 size_t pageCount() const; 113 114 private: 115 static GlyphPageTreeNode* getRoot(unsigned pageNumber); 116 void initializePage(const FontData*, unsigned pageNumber); 117 118 #ifndef NDEBUG 119 void showSubtree(); 120 #endif 121 122 GlyphPageTreeNode* m_parent; 123 RefPtr<GlyphPage> m_page; 124 unsigned m_level : 31; 125 bool m_isSystemFallback : 1; 126 unsigned m_customFontCount; 127 HashMap<const FontData*, GlyphPageTreeNode*> m_children; 128 GlyphPageTreeNode* m_systemFallbackChild; 129 130 #ifndef NDEBUG 131 unsigned m_pageNumber; 132 133 friend void ::showGlyphPageTree(unsigned pageNumber); 134 #endif 135 }; 136 137 } // namespace WebCore 138 139 #endif // GlyphPageTreeNode_h 140