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 "platform/fonts/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 #include "wtf/unicode/Unicode.h" 39 40 namespace blink { 41 42 class FontData; 43 class SimpleFontData; 44 45 // The glyph page tree is a data structure that maps (FontData, glyph page number) 46 // to a GlyphPage. Level 0 (the "root") is special. There is one root 47 // GlyphPageTreeNode for each glyph page number. The roots do not have a 48 // GlyphPage associated with them, and their initializePage() function is never 49 // called to fill the glyphs. 50 // 51 // Each root node maps a FontData pointer to another GlyphPageTreeNode at 52 // level 1 (the "root child") that stores the actual glyphs for a specific font data. 53 // These nodes will only have a GlyphPage if they have glyphs for that range. 54 // 55 // Levels greater than one correspond to subsequent levels of the fallback list 56 // for that font. These levels override their parent's page of glyphs by 57 // filling in holes with the new font (thus making a more complete page). 58 // 59 // A NULL FontData pointer corresponds to the system fallback 60 // font. It is tracked separately from the regular pages and overrides so that 61 // the glyph pages do not get polluted with these last-resort glyphs. The 62 // system fallback page is not populated at construction like the other pages, 63 // but on demand for each glyph, because the system may need to use different 64 // fallback fonts for each. This lazy population is done by the Font. 65 class PLATFORM_EXPORT GlyphPageTreeNode { 66 WTF_MAKE_FAST_ALLOCATED; WTF_MAKE_NONCOPYABLE(GlyphPageTreeNode); 67 public: 68 static GlyphPageTreeNode* getRootChild(const FontData* fontData, unsigned pageNumber) 69 { 70 return getRoot(pageNumber)->getChild(fontData, pageNumber); 71 } 72 73 static void pruneTreeCustomFontData(const FontData*); 74 static void pruneTreeFontData(const SimpleFontData*); 75 76 void pruneCustomFontData(const FontData*); 77 void pruneFontData(const SimpleFontData*, unsigned level = 0); 78 79 GlyphPageTreeNode* parent() const { return m_parent; } 80 GlyphPageTreeNode* getChild(const FontData*, unsigned pageNumber); 81 82 // Returns a page of glyphs (or NULL if there are no glyphs in this page's character range). 83 GlyphPage* page() const { return m_page.get(); } 84 85 // Returns the level of this node. See class-level comment. 86 unsigned level() const { return m_level; } 87 88 // The system fallback font has special rules (see above). 89 bool isSystemFallback() const { return m_isSystemFallback; } 90 91 static size_t treeGlyphPageCount(); 92 size_t pageCount() const; 93 94 private: 95 GlyphPageTreeNode() 96 : m_parent(0) 97 , m_level(0) 98 , m_isSystemFallback(false) 99 , m_customFontCount(0) 100 #if ENABLE(ASSERT) 101 , m_pageNumber(0) 102 #endif 103 { 104 } 105 106 static GlyphPageTreeNode* getRoot(unsigned pageNumber); 107 void initializePage(const FontData*, unsigned pageNumber); 108 109 #ifndef NDEBUG 110 void showSubtree(); 111 #endif 112 113 static HashMap<int, GlyphPageTreeNode*>* roots; 114 static GlyphPageTreeNode* pageZeroRoot; 115 116 typedef HashMap<const FontData*, OwnPtr<GlyphPageTreeNode> > GlyphPageTreeNodeMap; 117 118 GlyphPageTreeNodeMap m_children; 119 GlyphPageTreeNode* m_parent; 120 RefPtr<GlyphPage> m_page; 121 unsigned m_level : 31; 122 bool m_isSystemFallback : 1; 123 unsigned m_customFontCount; 124 OwnPtr<GlyphPageTreeNode> m_systemFallbackChild; 125 126 #if ENABLE(ASSERT) 127 unsigned m_pageNumber; 128 #endif 129 }; 130 131 } // namespace blink 132 133 #endif // GlyphPageTreeNode_h 134
