Expand WidthCache for complex text width queries

Source/platform/fonts/Font.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2006, 2010, 2011 Apple Inc. 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.
@@ skipping 132 matching lines @@
     if (codePathToUse != ComplexPath) {
         // The complex path is more restrictive about returning fallback fonts than the simple path, so we need an explicit test to make their behaviors match.
         if (!FontPlatformFeatures::canReturnFallbackFontsForComplexText())
             fallbackFonts = 0;
         // The simple path can optimize the case where glyph overflow is not observable.
         if (codePathToUse != SimpleWithGlyphOverflowPath && (glyphOverflow && !glyphOverflow->computeBounds))
             glyphOverflow = 0;
     }
 
     bool hasKerningOrLigatures = fontDescription().typesettingFeatures() & (Kerning | Ligatures);
-    bool hasWordSpacingOrLetterSpacing = fontDescription().wordSpacing() || fontDescription().letterSpacing();
-    float* cacheEntry = m_fontFallbackList->widthCache().add(run, std::numeric_limits<float>::quiet_NaN(), hasKerningOrLigatures, hasWordSpacingOrLetterSpacing, glyphOverflow);
-    if (cacheEntry && !std::isnan(*cacheEntry))
-        return *cacheEntry;
+    float* cacheEntry;
+    if (codePathToUse == ComplexPath || hasKerningOrLigatures) {

[Dominik Röttsches, 2014/03/21 06:24:48]

Now the decision on whether the cache is used is in two places. Perhaps it's
better to only have one, by either adding a "isComplexPath" parameter to the add
function or remove all parameters and move all conditions into this line here.

+        bool hasWordSpacingOrLetterSpacing = fontDescription().wordSpacing() || fontDescription().letterSpacing();
+        cacheEntry = m_fontFallbackList->widthCache().add(run, std::numeric_limits<float>::quiet_NaN(), hasWordSpacingOrLetterSpacing, glyphOverflow);
+        if (cacheEntry && !std::isnan(*cacheEntry))
+            return *cacheEntry;
+    } else {
+        cacheEntry = 0;
+    }
 
     float result;
     if (codePathToUse == ComplexPath)
         result = floatWidthForComplexText(run, fallbackFonts, glyphOverflow);
     else
         result = floatWidthForSimpleText(run, fallbackFonts, glyphOverflow);
 
     if (cacheEntry && (!fallbackFonts || fallbackFonts->isEmpty()))
         *cacheEntry = result;
     return result;
@@ skipping 653 matching lines @@
                 if (delta <= 0)
                     break;
             }
         }
     }
 
     return offset;
 }
 
 }