Language.{h,cpp} clean-up.

Source/platform/Language.cpp

 /*
  * Copyright (C) 2010, 2013 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 13 matching lines @@
  */
 
 #include "config.h"
 #include "platform/Language.h"
 
 #include "public/platform/Platform.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
+static String canonicalizeLanguageIdentifier(const String& languageCode)
+{
+    String lowercaseLanguageCode = languageCode.lower();
+    // Platform::defaultLocale() might provide a language code with '_'.
+    lowercaseLanguageCode.replace('_', '-');
+    return lowercaseLanguageCode;
+}
+
 static const AtomicString& platformLanguage()
 {
     DEFINE_STATIC_LOCAL(AtomicString, computedDefaultLanguage, ());
     if (computedDefaultLanguage.isEmpty()) {
-        computedDefaultLanguage = blink::Platform::current()->defaultLocale();
+        computedDefaultLanguage = AtomicString(canonicalizeLanguageIdentifier(Platform::current()->defaultLocale()));
         ASSERT(!computedDefaultLanguage.isEmpty());
     }
     return computedDefaultLanguage;
 }
 
-AtomicString defaultLanguage()
-{
-    Vector<AtomicString> languages = userPreferredLanguages();
-    if (!languages.isEmpty())
-        return languages[0];
-
-    return emptyAtom;
-}
-
 static Vector<AtomicString>& preferredLanguagesOverride()
 {
     DEFINE_STATIC_LOCAL(Vector<AtomicString>, override, ());
     return override;
 }
 
-Vector<AtomicString> userPreferredLanguagesOverride()
+void overrideUserPreferredLanguages(const Vector<AtomicString>& override)
 {

[Kunihiko Sakamoto, 2014/11/06 03:56:02]

I don't understand why this implementation is better than old one
(Vector::operator=). Can you explain?

[tkent, 2014/11/06 04:02:21]

This is not better than the original code.  We need to iterate over items
because we need to apply canonicalizedLanguageIdentifier() to each of items.

[Kunihiko Sakamoto, 2014/11/06 04:03:47]

Oh, I missed that part. Got it, thanks!

-    return preferredLanguagesOverride();
+    Vector<AtomicString>& canonicalized = preferredLanguagesOverride();
+    canonicalized.resize(0);
+    canonicalized.reserveCapacity(override.size());
+    for (const auto& lang : override)
+        canonicalized.append(canonicalizeLanguageIdentifier(lang));
 }
 
-void overrideUserPreferredLanguages(const Vector<AtomicString>& override)
+AtomicString defaultLanguage()
 {
-    preferredLanguagesOverride() = override;
+    Vector<AtomicString>& override = preferredLanguagesOverride();
+    if (!override.isEmpty())
+        return override[0];
+    return platformLanguage();
 }
 
 Vector<AtomicString> userPreferredLanguages()
 {
     Vector<AtomicString>& override = preferredLanguagesOverride();
     if (!override.isEmpty())
         return override;
 
     Vector<AtomicString> languages;
     languages.reserveInitialCapacity(1);
     languages.append(platformLanguage());
     return languages;
 }
 
-static String canonicalLanguageIdentifier(const String& languageCode)
-{
-    String lowercaseLanguageCode = languageCode.lower();
-
-    if (lowercaseLanguageCode.length() >= 3 && lowercaseLanguageCode[2] == '_')
-        lowercaseLanguageCode.replace(2, 1, "-");
-
-    return lowercaseLanguageCode;
-}
-
 size_t indexOfBestMatchingLanguageInList(const AtomicString& language, const Vector<AtomicString>& languageList)
 {
     AtomicString languageWithoutLocaleMatch;
     AtomicString languageMatchButNotLocale;
     size_t languageWithoutLocaleMatchIndex = 0;
     size_t languageMatchButNotLocaleMatchIndex = 0;
     bool canMatchLanguageOnly = (language.length() == 2 || (language.length() >= 3 && language[2] == '-'));
 
     for (size_t i = 0; i < languageList.size(); ++i) {
-        String canonicalizedLanguageFromList = canonicalLanguageIdentifier(languageList[i]);
+        String canonicalizedLanguageFromList = canonicalizeLanguageIdentifier(languageList[i]);
 
         if (language == canonicalizedLanguageFromList)
             return i;
 
         if (canMatchLanguageOnly && canonicalizedLanguageFromList.length() >= 2) {
             if (language[0] == canonicalizedLanguageFromList[0] && language[1] == canonicalizedLanguageFromList[1]) {
                 if (!languageWithoutLocaleMatch.length() && canonicalizedLanguageFromList.length() == 2) {
                     languageWithoutLocaleMatch = languageList[i];
                     languageWithoutLocaleMatchIndex = i;
                 }
@@ skipping 11 matching lines @@
     if (languageWithoutLocaleMatch.length())
         return languageWithoutLocaleMatchIndex;
 
     if (languageMatchButNotLocale.length())
         return languageMatchButNotLocaleMatchIndex;
 
     return languageList.size();
 }
 
 }