Keep text position locally in SVGTextMetricsBuilder::measureTextRenderer

Source/core/rendering/svg/SVGTextMetricsBuilder.cpp

 /*
  * Copyright (C) Research In Motion Limited 2010-2012. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 12 matching lines @@
 
 #include "core/rendering/svg/RenderSVGInlineText.h"
 #include "core/rendering/svg/RenderSVGText.h"
 #include "platform/text/TextPath.h"
 
 namespace WebCore {
 
 SVGTextMetricsBuilder::SVGTextMetricsBuilder()
     : m_text(0)
     , m_run(static_cast<const UChar*>(0), 0)
-    , m_textPosition(0)
     , m_isComplexText(false)
     , m_totalWidth(0)
 {
 }
 
-inline bool SVGTextMetricsBuilder::currentCharacterStartsSurrogatePair() const
+inline bool SVGTextMetricsBuilder::currentCharacterStartsSurrogatePair(unsigned textPosition) const
 {
-    return U16_IS_LEAD(m_run[m_textPosition]) && int(m_textPosition + 1) < m_run.charactersLength() && U16_IS_TRAIL(m_run[m_textPosition + 1]);
+    return U16_IS_LEAD(m_run[textPosition]) && int(textPosition + 1) < m_run.charactersLength() && U16_IS_TRAIL(m_run[textPosition + 1]);
 }
 
-SVGTextMetrics SVGTextMetricsBuilder::computeMetricsForCurrentCharacterSimple()
+SVGTextMetrics SVGTextMetricsBuilder::computeMetricsForCurrentCharacterSimple(unsigned textPosition)
 {
     GlyphBuffer glyphBuffer;
-    unsigned metricsLength = m_simpleWidthIterator->advance(m_textPosition + 1, &glyphBuffer);
+    unsigned metricsLength = m_simpleWidthIterator->advance(textPosition + 1, &glyphBuffer);
     if (!metricsLength)
         return SVGTextMetrics();
 
     float currentWidth = m_simpleWidthIterator->runWidthSoFar() - m_totalWidth;
     m_totalWidth = m_simpleWidthIterator->runWidthSoFar();
 
     Glyph glyphId = glyphBuffer.glyphAt(0);
-    return SVGTextMetrics(m_text, m_textPosition, metricsLength, currentWidth, glyphId);
+    return SVGTextMetrics(m_text, textPosition, metricsLength, currentWidth, glyphId);
 }
 
-SVGTextMetrics SVGTextMetricsBuilder::computeMetricsForCurrentCharacterComplex()
+SVGTextMetrics SVGTextMetricsBuilder::computeMetricsForCurrentCharacterComplex(unsigned textPosition)
 {
-    unsigned metricsLength = currentCharacterStartsSurrogatePair() ? 2 : 1;
-    SVGTextMetrics metrics = SVGTextMetrics::measureCharacterRange(m_text, m_textPosition, metricsLength);
+    unsigned metricsLength = currentCharacterStartsSurrogatePair(textPosition) ? 2 : 1;
+    SVGTextMetrics metrics = SVGTextMetrics::measureCharacterRange(m_text, textPosition, metricsLength);
     ASSERT(metrics.length() == metricsLength);
 
-    SVGTextMetrics complexStartToCurrentMetrics = SVGTextMetrics::measureCharacterRange(m_text, 0, m_textPosition + metricsLength);
+    SVGTextMetrics complexStartToCurrentMetrics = SVGTextMetrics::measureCharacterRange(m_text, 0, textPosition + metricsLength);
     // Frequent case for Arabic text: when measuring a single character the arabic isolated form is taken
     // when rendering the glyph "in context" (with it's surrounding characters) it changes due to shaping.
     // So whenever currentWidth != currentMetrics.width(), we are processing a text run whose length is
     // not equal to the sum of the individual lengths of the glyphs, when measuring them isolated.
     float currentWidth = complexStartToCurrentMetrics.width() - m_totalWidth;
     if (currentWidth != metrics.width())
         metrics.setWidth(currentWidth);
 
     m_totalWidth = complexStartToCurrentMetrics.width();
     return metrics;
 }
 
-SVGTextMetrics SVGTextMetricsBuilder::computeMetricsForCurrentCharacter()
+SVGTextMetrics SVGTextMetricsBuilder::computeMetricsForCurrentCharacter(unsigned textPosition)
 {
     if (m_isComplexText)
-        return computeMetricsForCurrentCharacterComplex();
+        return computeMetricsForCurrentCharacterComplex(textPosition);
 
-    return computeMetricsForCurrentCharacterSimple();
+    return computeMetricsForCurrentCharacterSimple(textPosition);
 }
 
 void SVGTextMetricsBuilder::initializeMeasurementWithTextRenderer(RenderSVGInlineText* text)
 {
     m_text = text;
-    m_textPosition = 0;
     m_totalWidth = 0;
 
     const Font& scaledFont = text->scaledFont();
     m_run = SVGTextMetrics::constructTextRun(text, 0, text->textLength());
     CodePath codePath = scaledFont.codePath(m_run);
     m_isComplexText = codePath == ComplexPath;
     m_run.setCharacterScanForCodePath(!m_isComplexText);
 
     if (m_isComplexText)
         m_simpleWidthIterator.clear();
@@ skipping 24 matching lines @@
         if (data->allCharactersMap)
             attributes->clear();
         else
             textMetricsValues->clear();
     }
 
     initializeMeasurementWithTextRenderer(text);
     bool preserveWhiteSpace = text->style()->whiteSpace() == PRE;
     unsigned surrogatePairCharacters = 0;
     unsigned skippedCharacters = 0;
+    unsigned textPosition = 0;
     unsigned textLength = static_cast<unsigned>(m_run.charactersLength());
 
     SVGTextMetrics currentMetrics;
-    for (; m_textPosition < textLength; m_textPosition += currentMetrics.length()) {
-        currentMetrics = computeMetricsForCurrentCharacter();
+    for (; textPosition < textLength; textPosition += currentMetrics.length()) {
+        currentMetrics = computeMetricsForCurrentCharacter(textPosition);
         if (!currentMetrics.length())
             break;
 
-        bool characterIsWhiteSpace = m_run[m_textPosition] == ' ';
+        bool characterIsWhiteSpace = m_run[textPosition] == ' ';
         if (characterIsWhiteSpace && !preserveWhiteSpace && data->lastCharacterWasWhiteSpace) {
             if (processRenderer)
                 textMetricsValues->append(SVGTextMetrics(SVGTextMetrics::SkippedSpaceMetrics));
             if (data->allCharactersMap)
                 skippedCharacters += currentMetrics.length();
             continue;
         }
 
         if (processRenderer) {
             if (data->allCharactersMap) {
-                const SVGCharacterDataMap::const_iterator it = data->allCharactersMap->find(data->valueListPosition + m_textPosition - skippedCharacters - surrogatePairCharacters + 1);
+                const SVGCharacterDataMap::const_iterator it = data->allCharactersMap->find(data->valueListPosition + textPosition - skippedCharacters - surrogatePairCharacters + 1);
                 if (it != data->allCharactersMap->end())
-                    attributes->characterDataMap().set(m_textPosition + 1, it->value);
+                    attributes->characterDataMap().set(textPosition + 1, it->value);
             }
             textMetricsValues->append(currentMetrics);
         }
 
-        if (data->allCharactersMap && currentCharacterStartsSurrogatePair())
+        if (data->allCharactersMap && currentCharacterStartsSurrogatePair(textPosition))
             surrogatePairCharacters++;
 
         data->lastCharacterWasWhiteSpace = characterIsWhiteSpace;
     }
 
     if (!data->allCharactersMap)
         return;
 
-    data->valueListPosition += m_textPosition - skippedCharacters;
+    data->valueListPosition += textPosition - skippedCharacters;
 }
 
 void SVGTextMetricsBuilder::walkTree(RenderObject* start, RenderSVGInlineText* stopAtLeaf, MeasureTextData* data)
 {
     RenderObject* child = start->firstChild();
     while (child) {
         if (child->isSVGInlineText()) {
             RenderSVGInlineText* text = toRenderSVGInlineText(child);
             measureTextRenderer(text, data, !stopAtLeaf || stopAtLeaf == text);
             if (stopAtLeaf && stopAtLeaf == text)
@@ skipping 22 matching lines @@
 }
 
 void SVGTextMetricsBuilder::buildMetricsAndLayoutAttributes(RenderSVGText* textRoot, RenderSVGInlineText* stopAtLeaf, SVGCharacterDataMap& allCharactersMap)
 {
     ASSERT(textRoot);
     MeasureTextData data(&allCharactersMap);
     walkTree(textRoot, stopAtLeaf, &data);
 }
 
 }