Shape across HarfBuzz runs

Source/platform/fonts/harfbuzz/HarfBuzzShaper.cpp

 /*
  * Copyright (c) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 BlackBerry Limited. 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.
@@ skipping 618 matching lines @@
     UErrorCode errorCode = U_ZERO_ERROR;
     UScriptCode nextScript = uscript_getScript(character, &errorCode);
     if (U_FAILURE(errorCode))
         return false;
 
     do {
         const UChar* currentCharacterPosition = iterator.characters();
         const SimpleFontData* currentFontData = nextFontData;
         UScriptCode currentScript = nextScript;
 
-        UChar32 lastCharacter = character;
         for (iterator.advance(clusterLength); iterator.consume(character, clusterLength); iterator.advance(clusterLength)) {
             if (Character::treatAsZeroWidthSpace(character))
                 continue;
 
             int length = handleMultipleUChar(character, clusterLength, currentFontData, currentCharacterPosition, iterator.characters() + clusterLength, normalizedBufferEnd);
             if (length) {
                 clusterLength = length;
                 continue;
             }
 
             nextFontData = font->glyphDataForCharacter(character, false).fontData;
             nextScript = uscript_getScript(character, &errorCode);
             if (U_FAILURE(errorCode))
                 return false;
-            if (lastCharacter == zeroWidthJoiner)
-                currentFontData = nextFontData;
             if ((nextFontData != currentFontData) || ((currentScript != nextScript) && (nextScript != USCRIPT_INHERITED) && (!uscript_hasScript(character, currentScript))))
                 break;
             currentCharacterPosition = iterator.characters();
-            lastCharacter = character;
         }
 
         CandidateRun run = { character, startIndexOfCurrentRun, iterator.currentCharacter(), currentFontData, currentScript };
         runs->append(run);
 
         startIndexOfCurrentRun = iterator.currentCharacter();
     } while (iterator.consume(character, clusterLength));
 
     return true;
 }
@@ skipping 184 matching lines @@
 
             runCache.remove(cachedResults);
         }
 
         // Add a space as pre-context to the buffer. This prevents showing dotted-circle
         // for combining marks at the beginning of runs.
         static const uint16_t preContext = ' ';
         hb_buffer_add_utf16(harfBuzzBuffer.get(), &preContext, 1, 1, 0);
 
         if (fontDescription.variant() == FontVariantSmallCaps && u_islower(m_normalizedBuffer[currentRun->startIndex()])) {
-            String upperText = String(m_normalizedBuffer.get() + currentRun->startIndex(), currentRun->numCharacters()).upper();
+            String upperText = String(m_normalizedBuffer.get(), m_normalizedBufferLength).upper();
             ASSERT(!upperText.is8Bit()); // m_normalizedBuffer is 16 bit, therefore upperText is 16 bit, even after we call makeUpper().
-            hb_buffer_add_utf16(harfBuzzBuffer.get(), toUint16(upperText.characters16()), currentRun->numCharacters(), 0, currentRun->numCharacters());
+            hb_buffer_add_utf16(harfBuzzBuffer.get(), toUint16(upperText.characters16()), currentRun->startIndex(), currentRun->startIndex(), 0);
+            hb_buffer_add_utf16(harfBuzzBuffer.get(), toUint16(upperText.characters16() + currentRun->startIndex()), m_normalizedBufferLength - currentRun->startIndex(), 0, currentRun->numCharacters());
         } else {
-            hb_buffer_add_utf16(harfBuzzBuffer.get(), toUint16(m_normalizedBuffer.get() + currentRun->startIndex()), currentRun->numCharacters(), 0, currentRun->numCharacters());
+            hb_buffer_add_utf16(harfBuzzBuffer.get(), toUint16(m_normalizedBuffer.get()), currentRun->startIndex(), currentRun->startIndex(), 0);
+            hb_buffer_add_utf16(harfBuzzBuffer.get(), toUint16(m_normalizedBuffer.get() + currentRun->startIndex()), m_normalizedBufferLength - currentRun->startIndex(), 0, currentRun->numCharacters());
         }
 
         if (fontDescription.orientation() == Vertical)
             face->setScriptForVerticalGlyphSubstitution(harfBuzzBuffer.get());
 
         HarfBuzzScopedPtr<hb_font_t> harfBuzzFont(face->createFont(), hb_font_destroy);
 
         hb_shape(harfBuzzFont.get(), harfBuzzBuffer.get(), m_features.isEmpty() ? 0 : m_features.data(), m_features.size());
         currentRun->applyShapeResult(harfBuzzBuffer.get());
         setGlyphPositionsForHarfBuzzRun(currentRun, harfBuzzBuffer.get());
@@ skipping 262 matching lines @@
             point.x() + fromX, point.x() + toX,
             point.y(), height);
     }
 
     return Font::pixelSnappedSelectionRect(
         point.x() + toX, point.x() + fromX,
         point.y(), height);
 }
 
 } // namespace blink