diff -r 000000000000 -r 6474c204b198 gfx/thebes/gfxHarfBuzzShaper.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/thebes/gfxHarfBuzzShaper.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,112 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GFX_HARFBUZZSHAPER_H
+#define GFX_HARFBUZZSHAPER_H
+
+#include "gfxFont.h"
+
+#include "harfbuzz/hb.h"
+
+class gfxHarfBuzzShaper : public gfxFontShaper {
+public:
+    gfxHarfBuzzShaper(gfxFont *aFont);
+    virtual ~gfxHarfBuzzShaper();
+
+    /*
+     * For HarfBuzz font callback functions, font_data is a ptr to a
+     * FontCallbackData struct
+     */
+    struct FontCallbackData {
+        gfxHarfBuzzShaper *mShaper;
+        gfxContext        *mContext;
+    };
+
+    bool Initialize();
+    virtual bool ShapeText(gfxContext      *aContext,
+                           const char16_t *aText,
+                           uint32_t         aOffset,
+                           uint32_t         aLength,
+                           int32_t          aScript,
+                           gfxShapedText   *aShapedText);
+
+    // get a given font table in harfbuzz blob form
+    hb_blob_t * GetFontTable(hb_tag_t aTag) const;
+
+    // map unicode character to glyph ID
+    hb_codepoint_t GetGlyph(hb_codepoint_t unicode,
+                            hb_codepoint_t variation_selector) const;
+
+    // get harfbuzz glyph advance, in font design units
+    hb_position_t GetGlyphHAdvance(gfxContext *aContext,
+                                   hb_codepoint_t glyph) const;
+
+    // get harfbuzz horizontal advance in 16.16 fixed point format.
+    static hb_position_t
+    HBGetGlyphHAdvance(hb_font_t *font, void *font_data,
+                       hb_codepoint_t glyph, void *user_data);
+
+    hb_position_t GetHKerning(uint16_t aFirstGlyph,
+                              uint16_t aSecondGlyph) const;
+
+protected:
+    nsresult SetGlyphsFromRun(gfxContext      *aContext,
+                              gfxShapedText   *aShapedText,
+                              uint32_t         aOffset,
+                              uint32_t         aLength,
+                              const char16_t *aText,
+                              hb_buffer_t     *aBuffer);
+
+    // retrieve glyph positions, applying advance adjustments and attachments
+    // returns results in appUnits
+    nscoord GetGlyphPositions(gfxContext *aContext,
+                              hb_buffer_t *aBuffer,
+                              nsTArray<nsPoint>& aPositions,
+                              uint32_t aAppUnitsPerDevUnit);
+
+    // harfbuzz face object: we acquire a reference from the font entry
+    // on shaper creation, and release it in our destructor
+    hb_face_t         *mHBFace;
+
+    // size-specific font object, owned by the gfxHarfBuzzShaper
+    hb_font_t         *mHBFont;
+
+    FontCallbackData   mCallbackData;
+
+    // Following table references etc are declared "mutable" because the
+    // harfbuzz callback functions take a const ptr to the shaper, but
+    // wish to cache tables here to avoid repeatedly looking them up
+    // in the font.
+
+    // Old-style TrueType kern table, if we're not doing GPOS kerning
+    mutable hb_blob_t *mKernTable;
+
+    // Cached copy of the hmtx table and numLongMetrics field from hhea,
+    // for use when looking up glyph metrics; initialized to 0 by the
+    // constructor so we can tell it hasn't been set yet.
+    // This is a signed value so that we can use -1 to indicate
+    // an error (if the hhea table was not available).
+    mutable hb_blob_t *mHmtxTable;
+    mutable int32_t    mNumLongMetrics;
+
+    // Cached pointer to cmap subtable to be used for char-to-glyph mapping.
+    // This comes from GetFontTablePtr; if it is non-null, our destructor
+    // must call ReleaseFontTablePtr to avoid permanently caching the table.
+    mutable hb_blob_t *mCmapTable;
+    mutable int32_t    mCmapFormat;
+    mutable uint32_t   mSubtableOffset;
+    mutable uint32_t   mUVSTableOffset;
+
+    // Whether the font implements GetGlyph, or we should read tables
+    // directly
+    bool mUseFontGetGlyph;
+    // Whether the font implements GetGlyphWidth, or we should read tables
+    // directly to get ideal widths
+    bool mUseFontGlyphWidths;
+
+    bool mInitialized;
+};
+
+#endif /* GFX_HARFBUZZSHAPER_H */