gfx/thebes/gfxMathTable.h@97036ab72558 (annotated)
gfx/thebes/gfxMathTable.h
Tue, 06 Jan 2015 21:39:09 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Tue, 06 Jan 2015 21:39:09 +0100
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
- permissions
- -rw-r--r--
Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
| michael@0 | 1 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 2 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 3 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 4 | |
| michael@0 | 5 | #ifndef GFX_MATH_TABLE_H |
| michael@0 | 6 | #define GFX_MATH_TABLE_H |
| michael@0 | 7 | |
| michael@0 | 8 | #include "gfxFont.h" |
| michael@0 | 9 | |
| michael@0 | 10 | struct Coverage; |
| michael@0 | 11 | struct GlyphAssembly; |
| michael@0 | 12 | struct MATHTableHeader; |
| michael@0 | 13 | struct MathConstants; |
| michael@0 | 14 | struct MathGlyphConstruction; |
| michael@0 | 15 | struct MathGlyphInfo; |
| michael@0 | 16 | struct MathVariants; |
| michael@0 | 17 | |
| michael@0 | 18 | /** |
| michael@0 | 19 | * Used by |gfxFontEntry| to represent the MATH table of an OpenType font. |
| michael@0 | 20 | * Each |gfxFontEntry| owns at most one |gfxMathTable| instance. |
| michael@0 | 21 | */ |
| michael@0 | 22 | class gfxMathTable |
| michael@0 | 23 | { |
| michael@0 | 24 | public: |
| michael@0 | 25 | /** |
| michael@0 | 26 | * @param aMathTable The MATH table from the OpenType font |
| michael@0 | 27 | * |
| michael@0 | 28 | * The gfxMathTable object takes over ownership of the blob references |
| michael@0 | 29 | * that are passed in, and will hb_blob_destroy() them when finished; |
| michael@0 | 30 | * the caller should -not- destroy this reference. |
| michael@0 | 31 | */ |
| michael@0 | 32 | gfxMathTable(hb_blob_t* aMathTable); |
| michael@0 | 33 | |
| michael@0 | 34 | /** |
| michael@0 | 35 | * Releases our reference to the MATH table and cleans up everything else. |
| michael@0 | 36 | */ |
| michael@0 | 37 | ~gfxMathTable(); |
| michael@0 | 38 | |
| michael@0 | 39 | /** |
| michael@0 | 40 | * Returns the value of the specified constant from the MATH table. |
| michael@0 | 41 | */ |
| michael@0 | 42 | int32_t GetMathConstant(gfxFontEntry::MathConstant aConstant); |
| michael@0 | 43 | |
| michael@0 | 44 | /** |
| michael@0 | 45 | * If the MATH table contains an italic correction for that glyph, this |
| michael@0 | 46 | * function gets the value and returns true. Otherwise it returns false. |
| michael@0 | 47 | */ |
| michael@0 | 48 | bool |
| michael@0 | 49 | GetMathItalicsCorrection(uint32_t aGlyphID, int16_t* aItalicCorrection); |
| michael@0 | 50 | |
| michael@0 | 51 | /** |
| michael@0 | 52 | * @param aGlyphID glyph index of the character we want to stretch |
| michael@0 | 53 | * @param aVertical direction of the stretching (vertical/horizontal) |
| michael@0 | 54 | * @param aSize the desired size variant |
| michael@0 | 55 | * |
| michael@0 | 56 | * Returns the glyph index of the desired size variant or 0 if there is not |
| michael@0 | 57 | * any such size variant. |
| michael@0 | 58 | */ |
| michael@0 | 59 | uint32_t GetMathVariantsSize(uint32_t aGlyphID, bool aVertical, |
| michael@0 | 60 | uint16_t aSize); |
| michael@0 | 61 | |
| michael@0 | 62 | /** |
| michael@0 | 63 | * @param aGlyphID glyph index of the character we want to stretch |
| michael@0 | 64 | * @param aVertical direction of the stretching (vertical/horizontal) |
| michael@0 | 65 | * @param aGlyphs pre-allocated buffer of 4 elements where the glyph |
| michael@0 | 66 | * indexes (or 0 for absent parts) will be stored. The parts are stored in |
| michael@0 | 67 | * the order expected by the nsMathMLChar: Top (or Left), Middle, Bottom |
| michael@0 | 68 | * (or Right), Glue. |
| michael@0 | 69 | * |
| michael@0 | 70 | * Tries to fill-in aGlyphs with the relevant glyph indexes and returns |
| michael@0 | 71 | * whether the operation was successful. The function returns false if |
| michael@0 | 72 | * there is not any assembly for the character we want to stretch or if |
| michael@0 | 73 | * the format is not supported by the nsMathMLChar code. |
| michael@0 | 74 | * |
| michael@0 | 75 | */ |
| michael@0 | 76 | bool GetMathVariantsParts(uint32_t aGlyphID, bool aVertical, |
| michael@0 | 77 | uint32_t aGlyphs[4]); |
| michael@0 | 78 | |
| michael@0 | 79 | protected: |
| michael@0 | 80 | friend class gfxFontEntry; |
| michael@0 | 81 | // This allows gfxFontEntry to verify the validity of the main headers |
| michael@0 | 82 | // before starting to use the MATH table. |
| michael@0 | 83 | bool HasValidHeaders(); |
| michael@0 | 84 | |
| michael@0 | 85 | private: |
| michael@0 | 86 | // HarfBuzz blob where the MATH table is stored. |
| michael@0 | 87 | hb_blob_t* mMathTable; |
| michael@0 | 88 | |
| michael@0 | 89 | // Cached values for the latest (mGlyphID, mVertical) pair that has been |
| michael@0 | 90 | // accessed and the corresponding glyph construction. These are verified |
| michael@0 | 91 | // by SelectGlyphConstruction and updated if necessary. |
| michael@0 | 92 | // mGlyphConstruction will be set to nullptr if no construction is defined |
| michael@0 | 93 | // for the glyph. If non-null, its mGlyphAssembly and mVariantCount fields |
| michael@0 | 94 | // may be safely read, but no further validation will have been done. |
| michael@0 | 95 | const MathGlyphConstruction* mGlyphConstruction; |
| michael@0 | 96 | uint32_t mGlyphID; |
| michael@0 | 97 | bool mVertical; |
| michael@0 | 98 | void SelectGlyphConstruction(uint32_t aGlyphID, bool aVertical); |
| michael@0 | 99 | |
| michael@0 | 100 | // Access to some structures of the MATH table. |
| michael@0 | 101 | // These accessors just return a pointer, but do NOT themselves check the |
| michael@0 | 102 | // validity of anything. Until we've checked that HasValidHeaders (which |
| michael@0 | 103 | // does validate them) returns true, they might return pointers that cannot |
| michael@0 | 104 | // even safely be dereferenced. GetGlyphAssembly may return nullptr if the |
| michael@0 | 105 | // given glyph has no assembly defined. |
| michael@0 | 106 | const MATHTableHeader* GetMATHTableHeader(); |
| michael@0 | 107 | const MathConstants* GetMathConstants(); |
| michael@0 | 108 | const MathGlyphInfo* GetMathGlyphInfo(); |
| michael@0 | 109 | const MathVariants* GetMathVariants(); |
| michael@0 | 110 | const GlyphAssembly* GetGlyphAssembly(uint32_t aGlyphID, bool aVertical); |
| michael@0 | 111 | |
| michael@0 | 112 | // Verify whether a structure or an offset belongs to the math data and can |
| michael@0 | 113 | // be read safely. |
| michael@0 | 114 | bool ValidStructure(const char* aStructStart, uint16_t aStructSize); |
| michael@0 | 115 | bool ValidOffset(const char* aOffsetStart, uint16_t aOffset); |
| michael@0 | 116 | |
| michael@0 | 117 | // Get the coverage index of a glyph index from an Open Type coverage table |
| michael@0 | 118 | // or -1 if the glyph index is not found. |
| michael@0 | 119 | int32_t GetCoverageIndex(const Coverage* aCoverage, uint32_t aGlyph); |
| michael@0 | 120 | }; |
| michael@0 | 121 | |
| michael@0 | 122 | #endif |
