Access font tables in memory

third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzFace.cpp

 /*
  * Copyright (c) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 32 matching lines @@
 #include <hb-ot.h>
 #include <hb.h>
 #if OS(MACOSX)
 #include <hb-coretext.h>
 #endif
 
 #include <SkPaint.h>
 #include <SkPath.h>
 #include <SkPoint.h>
 #include <SkRect.h>
+#include <SkStream.h>
 #include <SkTypeface.h>
 
 
 namespace blink {
 
 struct HbFontDeleter {
     void operator()(hb_font_t* font)
     {
         if (font)
             hb_font_destroy(font);
@@ skipping 241 matching lines @@
         return nullptr;
     size_t actualSize = typeface->getTableData(tag, 0, tableSize, buffer);
     if (tableSize != actualSize) {
         WTF::Partitions::fastFree(buffer);
         return nullptr;
     }
     return hb_blob_create(const_cast<char*>(buffer), tableSize, HB_MEMORY_MODE_WRITABLE, buffer, WTF::Partitions::fastFree);
 }
 #endif
 
+#if !OS(MACOSX)
+static void deleteTypefaceStream(void* streamAssetPtr)
+{
+    SkStreamAsset* streamAsset = reinterpret_cast<SkStreamAsset*>(streamAssetPtr);
+    delete streamAsset;
+}
+#endif
+
 hb_face_t* HarfBuzzFace::createFace()
 {
 #if OS(MACOSX)
     hb_face_t* face = hb_coretext_face_create(m_platformData->cgFont());
 #else
-    hb_face_t* face = hb_face_create_for_tables(harfBuzzSkiaGetTable, m_platformData->typeface(), 0);
+    hb_face_t* face = nullptr;
+
+    SkTypeface* typeface = m_platformData->typeface();
+    SkStreamAsset* typefaceStream = typeface->openStream(0);
+    if (typefaceStream->getMemoryBase()) {
+        std::unique_ptr<hb_blob_t, void(*)(hb_blob_t*)> faceBlob(hb_blob_create(
+            reinterpret_cast<const char*>(typefaceStream->getMemoryBase()),
+            typefaceStream->getLength(),
+            HB_MEMORY_MODE_READONLY,
+            typefaceStream,
+            deleteTypefaceStream),
+            hb_blob_destroy);
+        face = hb_face_create(faceBlob.get(), 0);

[behdad, 2016/06/23 13:27:36]

Instead of 0, you need the TTC index of the face.  Does Skia have that readily?

+    }
+
+    // Fallback to table copies if there is no in-memory access.
+    if (!face)
+        face = hb_face_create_for_tables(harfBuzzSkiaGetTable, m_platformData->typeface(), 0);
 #endif
     ASSERT(face);
     return face;
 }
 
 PassRefPtr<HbFontCacheEntry> createHbFontCacheEntry(hb_face_t* face)
 {
     HbFontUniquePtr otFont(hb_font_create(face));
     hb_ot_font_set_funcs(otFont.get());
     // Creating a sub font means that non-available functions
     // are found from the parent.
     hb_font_t* unscaledFont = hb_font_create_sub_font(otFont.get());
     RefPtr<HbFontCacheEntry> cacheEntry = HbFontCacheEntry::create(unscaledFont);
     hb_font_set_funcs(unscaledFont, harfBuzzSkiaGetFontFuncs(), cacheEntry->hbFontData(), nullptr);
     return cacheEntry;
 }
 
 hb_font_t* HarfBuzzFace::getScaledFont(PassRefPtr<UnicodeRangeSet> rangeSet) const
 {
     m_platformData->setupPaint(&m_harfBuzzFontData->m_paint);
     m_harfBuzzFontData->m_rangeSet = rangeSet;
     m_harfBuzzFontData->m_simpleFontData = FontCache::fontCache()->fontDataFromFontPlatformData(m_platformData).get();
     ASSERT(m_harfBuzzFontData->m_simpleFontData);
     int scale = SkiaScalarToHarfBuzzPosition(m_platformData->size());
     hb_font_set_scale(m_unscaledFont, scale, scale);
     return m_unscaledFont;
 }
 
 } // namespace blink