Avoiding multiple text/string parsing while creating TextRun

Source/core/rendering/RenderText.cpp

Index: Source/core/rendering/RenderText.cpp
diff --git a/Source/core/rendering/RenderText.cpp b/Source/core/rendering/RenderText.cpp
old mode 100644
new mode 100755
index b89ddc756ba895becf08f1e0450384710bd4f2af..7d84cbe34c102b97007e559896cb6d0b1656b1c7
--- a/Source/core/rendering/RenderText.cpp
+++ b/Source/core/rendering/RenderText.cpp
@@ -56,6 +56,7 @@ struct SameSizeAsRenderText : public RenderObject {
     float widths[4];
     String text;
     void* pointers[2];
+    CodePath someCodePath;

[eseidel, 2013/12/27 04:36:45]

nit: I would have called this "codePath".

 };
 
 COMPILE_ASSERT(sizeof(RenderText) == sizeof(SameSizeAsRenderText), RenderText_should_stay_small);
@@ -767,6 +768,7 @@ ALWAYS_INLINE float RenderText::widthFromCache(const Font& f, int start, int len
     run.setCharacterScanForCodePath(!canUseSimpleFontCodePath());
     run.setTabSize(!style()->collapseWhiteSpace(), style()->tabSize());
     run.setXPos(xPos);
+
     return f.width(run, fallbackFonts, glyphOverflow);
 }
 
@@ -1805,11 +1807,13 @@ int RenderText::nextOffset(int current) const
     return result;
 }
 
-bool RenderText::computeCanUseSimpleFontCodePath() const
+bool RenderText::computeCanUseSimpleFontCodePath()

[eseidel, 2013/12/27 04:36:45]

We could also just have made codepath mutable. Unclear which is better.

 {

[eae, 2013/12/30 19:29:14]

This method didn't use to have a side effect and now it does, have you ensured
that this is _always_ called now (to set m_textCodePath) and that additional
calls use the new codePath getter instead?

[h.joshi, 2013/12/31 06:07:43]

This method is always called when RenderText is created and this does not have
issue. It just with new changes we are storing the value returned by the
CodePath search which we were not.

+    m_textCodePath = AutoPath;
     if (isAllASCII() || m_text.is8Bit())
         return true;
-    return Font::characterRangeCodePath(characters16(), length()) == Font::Simple;
+    m_textCodePath = Font::characterRangeCodePath(characters16(), length());
+    return (m_textCodePath == SimplePath);
 }
 
 #ifndef NDEBUG