diff -r 000000000000 -r 6474c204b198 gfx/thebes/gfxDWriteTextAnalysis.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/thebes/gfxDWriteTextAnalysis.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,146 @@
+/* -*- 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_DWRITETEXTANALYSIS_H
+#define GFX_DWRITETEXTANALYSIS_H
+
+#include "gfxDWriteCommon.h"
+
+// Helper source/sink class for text analysis.
+class TextAnalysis
+    :   public IDWriteTextAnalysisSource,
+        public IDWriteTextAnalysisSink        
+{
+public:
+
+    // IUnknown interface
+    IFACEMETHOD(QueryInterface)(IID const& iid, OUT void** ppObject)
+    {
+        if (iid == __uuidof(IDWriteTextAnalysisSource)) {
+            *ppObject = static_cast<IDWriteTextAnalysisSource*>(this);
+            return S_OK;
+        } else if (iid == __uuidof(IDWriteTextAnalysisSink)) {
+            *ppObject = static_cast<IDWriteTextAnalysisSink*>(this);
+            return S_OK;
+        } else if (iid == __uuidof(IUnknown)) {
+            *ppObject = 
+                static_cast<IUnknown*>(static_cast<IDWriteTextAnalysisSource*>(this));
+            return S_OK;
+        } else {
+            return E_NOINTERFACE;
+        }
+    }
+
+    IFACEMETHOD_(ULONG, AddRef)()
+    {
+        return 1;
+    }
+
+    IFACEMETHOD_(ULONG, Release)()
+    {
+        return 1;
+    }
+
+    // A single contiguous run of characters containing the same analysis 
+    // results.
+    struct Run
+    {
+        UINT32 mTextStart;   // starting text position of this run
+        UINT32 mTextLength;  // number of contiguous code units covered
+        UINT32 mGlyphStart;  // starting glyph in the glyphs array
+        UINT32 mGlyphCount;  // number of glyphs associated with this run of 
+                             // text
+        DWRITE_SCRIPT_ANALYSIS mScript;
+        UINT8 mBidiLevel;
+        bool mIsSideways;
+
+        inline bool ContainsTextPosition(UINT32 aTextPosition) const
+        {
+            return aTextPosition >= mTextStart
+                && aTextPosition <  mTextStart + mTextLength;
+        }
+
+        Run *nextRun;
+    };
+
+public:
+    TextAnalysis(const wchar_t* text,
+                 UINT32 textLength,
+                 const wchar_t* localeName,
+                 DWRITE_READING_DIRECTION readingDirection);
+
+    ~TextAnalysis();
+
+    STDMETHODIMP GenerateResults(IDWriteTextAnalyzer* textAnalyzer,
+                                 Run **runHead);
+
+    // IDWriteTextAnalysisSource implementation
+
+    IFACEMETHODIMP GetTextAtPosition(UINT32 textPosition,
+                                     OUT WCHAR const** textString,
+                                     OUT UINT32* textLength);
+
+    IFACEMETHODIMP GetTextBeforePosition(UINT32 textPosition,
+                                         OUT WCHAR const** textString,
+                                         OUT UINT32* textLength);
+
+    IFACEMETHODIMP_(DWRITE_READING_DIRECTION) 
+        GetParagraphReadingDirection() throw();
+
+    IFACEMETHODIMP GetLocaleName(UINT32 textPosition,
+                                 OUT UINT32* textLength,
+                                 OUT WCHAR const** localeName);
+
+    IFACEMETHODIMP 
+        GetNumberSubstitution(UINT32 textPosition,
+                              OUT UINT32* textLength,
+                              OUT IDWriteNumberSubstitution** numberSubstitution);
+
+    // IDWriteTextAnalysisSink implementation
+
+    IFACEMETHODIMP 
+        SetScriptAnalysis(UINT32 textPosition,
+                          UINT32 textLength,
+                          DWRITE_SCRIPT_ANALYSIS const* scriptAnalysis);
+
+    IFACEMETHODIMP 
+        SetLineBreakpoints(UINT32 textPosition,
+                           UINT32 textLength,
+                           const DWRITE_LINE_BREAKPOINT* lineBreakpoints);
+
+    IFACEMETHODIMP SetBidiLevel(UINT32 textPosition,
+                                UINT32 textLength,
+                                UINT8 explicitLevel,
+                                UINT8 resolvedLevel);
+
+    IFACEMETHODIMP 
+        SetNumberSubstitution(UINT32 textPosition,
+                              UINT32 textLength,
+                              IDWriteNumberSubstitution* numberSubstitution);
+
+protected:
+    Run *FetchNextRun(IN OUT UINT32* textLength);
+
+    void SetCurrentRun(UINT32 textPosition);
+
+    void SplitCurrentRun(UINT32 splitPosition);
+
+protected:
+    // Input
+    // (weak references are fine here, since this class is a transient
+    //  stack-based helper that doesn't need to copy data)
+    UINT32 mTextLength;
+    const wchar_t* mText;
+    const wchar_t* mLocaleName;
+    DWRITE_READING_DIRECTION mReadingDirection;
+
+    // Current processing state.
+    Run *mCurrentRun;
+
+    // Output is a list of runs starting here
+    Run  mRunHead;
+};
+
+#endif /* GFX_DWRITETEXTANALYSIS_H */