third_party/WebKit/Source/platform/Language.cpp

   1 /*
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   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
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   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
  14  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  15  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
  17  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  18  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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  20  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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  22  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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  24  */
  25
  26 #include "config.h"
  27 #include "platform/Language.h"
  28
  29 #include "public/platform/Platform.h"
  30 #include "wtf/text/WTFString.h"
  31
  32 namespace blink {
  33
  34 static String canonicalizeLanguageIdentifier(const String& languageCode)
  35 {
  36     String copiedCode = languageCode;
  37     // Platform::defaultLocale() might provide a language code with '_'.
  38     copiedCode.replace('_', '-');
  39     return copiedCode;
  40 }
  41
  42 static const AtomicString& platformLanguage()
  43 {
  44     DEFINE_STATIC_LOCAL(AtomicString, computedDefaultLanguage, ());
  45     if (computedDefaultLanguage.isEmpty()) {
  46         computedDefaultLanguage = AtomicString(canonicalizeLanguageIdentifier(Platform::current()->defaultLocale()));
  47         ASSERT(!computedDefaultLanguage.isEmpty());
  48     }
  49     return computedDefaultLanguage;
  50 }
  51
  52 static Vector<AtomicString>& preferredLanguagesOverride()
  53 {
  54     DEFINE_STATIC_LOCAL(Vector<AtomicString>, override, ());
  55     return override;
  56 }
  57
  58 void overrideUserPreferredLanguages(const Vector<AtomicString>& override)
  59 {
  60     Vector<AtomicString>& canonicalized = preferredLanguagesOverride();
  61     canonicalized.resize(0);
  62     canonicalized.reserveCapacity(override.size());
  63     for (const auto& lang : override)
  64         canonicalized.append(canonicalizeLanguageIdentifier(lang));
  65 }
  66
  67 AtomicString defaultLanguage()
  68 {
  69     Vector<AtomicString>& override = preferredLanguagesOverride();
  70     if (!override.isEmpty())
  71         return override[0];
  72     return platformLanguage();
  73 }
  74
  75 Vector<AtomicString> userPreferredLanguages()
  76 {
  77     Vector<AtomicString>& override = preferredLanguagesOverride();
  78     if (!override.isEmpty())
  79         return override;
  80
  81     Vector<AtomicString> languages;
  82     languages.reserveInitialCapacity(1);
  83     languages.append(platformLanguage());
  84     return languages;
  85 }
  86
  87 size_t indexOfBestMatchingLanguageInList(const AtomicString& language, const Vector<AtomicString>& languageList)
  88 {
  89     AtomicString languageWithoutLocaleMatch;
  90     AtomicString languageMatchButNotLocale;
  91     size_t languageWithoutLocaleMatchIndex = 0;
  92     size_t languageMatchButNotLocaleMatchIndex = 0;
  93     bool canMatchLanguageOnly = (language.length() == 2 || (language.length() >= 3 && language[2] == '-'));
  94
  95     for (size_t i = 0; i < languageList.size(); ++i) {
  96         String canonicalizedLanguageFromList = canonicalizeLanguageIdentifier(languageList[i]);
  97
  98         if (language == canonicalizedLanguageFromList)
  99             return i;
 100
 101         if (canMatchLanguageOnly && canonicalizedLanguageFromList.length() >= 2) {
 102             if (language[0] == canonicalizedLanguageFromList[0] && language[1] == canonicalizedLanguageFromList[1]) {
 103                 if (!languageWithoutLocaleMatch.length() && canonicalizedLanguageFromList.length() == 2) {
 104                     languageWithoutLocaleMatch = languageList[i];
 105                     languageWithoutLocaleMatchIndex = i;
 106                 }
 107                 if (!languageMatchButNotLocale.length() && canonicalizedLanguageFromList.length() >= 3) {
 108                     languageMatchButNotLocale = languageList[i];
 109                     languageMatchButNotLocaleMatchIndex = i;
 110                 }
 111             }
 112         }
 113     }
 114
 115     // If we have both a language-only match and a languge-but-not-locale match, return the
 116     // languge-only match as is considered a "better" match. For example, if the list
 117     // provided has both "en-GB" and "en" and the user prefers "en-US" we will return "en".
 118     if (languageWithoutLocaleMatch.length())
 119         return languageWithoutLocaleMatchIndex;
 120
 121     if (languageMatchButNotLocale.length())
 122         return languageMatchButNotLocaleMatchIndex;
 123
 124     return languageList.size();
 125 }
 126
 127 }