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      1 /*
      2  * Copyright (C) 2010, 2013 Apple Inc. All rights reserved.
      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:
      7  * 1. Redistributions of source code must retain the above copyright
      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
     19  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     20  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     21  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     22  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
     23  * THE POSSIBILITY OF SUCH DAMAGE.
     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 WebCore {
     33 
     34 static const AtomicString& platformLanguage()
     35 {
     36     DEFINE_STATIC_LOCAL(AtomicString, computedDefaultLanguage, ());
     37     if (computedDefaultLanguage.isEmpty()) {
     38         computedDefaultLanguage = blink::Platform::current()->defaultLocale();
     39         ASSERT(!computedDefaultLanguage.isEmpty());
     40     }
     41     return computedDefaultLanguage;
     42 }
     43 
     44 AtomicString defaultLanguage()
     45 {
     46     Vector<AtomicString> languages = userPreferredLanguages();
     47     if (!languages.isEmpty())
     48         return languages[0];
     49 
     50     return emptyAtom;
     51 }
     52 
     53 static Vector<AtomicString>& preferredLanguagesOverride()
     54 {
     55     DEFINE_STATIC_LOCAL(Vector<AtomicString>, override, ());
     56     return override;
     57 }
     58 
     59 Vector<AtomicString> userPreferredLanguagesOverride()
     60 {
     61     return preferredLanguagesOverride();
     62 }
     63 
     64 void overrideUserPreferredLanguages(const Vector<AtomicString>& override)
     65 {
     66     preferredLanguagesOverride() = override;
     67 }
     68 
     69 Vector<AtomicString> userPreferredLanguages()
     70 {
     71     Vector<AtomicString>& override = preferredLanguagesOverride();
     72     if (!override.isEmpty())
     73         return override;
     74 
     75     Vector<AtomicString> languages;
     76     languages.reserveInitialCapacity(1);
     77     languages.append(platformLanguage());
     78     return languages;
     79 }
     80 
     81 static String canonicalLanguageIdentifier(const String& languageCode)
     82 {
     83     String lowercaseLanguageCode = languageCode.lower();
     84 
     85     if (lowercaseLanguageCode.length() >= 3 && lowercaseLanguageCode[2] == '_')
     86         lowercaseLanguageCode.replace(2, 1, "-");
     87 
     88     return lowercaseLanguageCode;
     89 }
     90 
     91 size_t indexOfBestMatchingLanguageInList(const AtomicString& language, const Vector<AtomicString>& languageList)
     92 {
     93     AtomicString languageWithoutLocaleMatch;
     94     AtomicString languageMatchButNotLocale;
     95     size_t languageWithoutLocaleMatchIndex = 0;
     96     size_t languageMatchButNotLocaleMatchIndex = 0;
     97     bool canMatchLanguageOnly = (language.length() == 2 || (language.length() >= 3 && language[2] == '-'));
     98 
     99     for (size_t i = 0; i < languageList.size(); ++i) {
    100         String canonicalizedLanguageFromList = canonicalLanguageIdentifier(languageList[i]);
    101 
    102         if (language == canonicalizedLanguageFromList)
    103             return i;
    104 
    105         if (canMatchLanguageOnly && canonicalizedLanguageFromList.length() >= 2) {
    106             if (language[0] == canonicalizedLanguageFromList[0] && language[1] == canonicalizedLanguageFromList[1]) {
    107                 if (!languageWithoutLocaleMatch.length() && canonicalizedLanguageFromList.length() == 2) {
    108                     languageWithoutLocaleMatch = languageList[i];
    109                     languageWithoutLocaleMatchIndex = i;
    110                 }
    111                 if (!languageMatchButNotLocale.length() && canonicalizedLanguageFromList.length() >= 3) {
    112                     languageMatchButNotLocale = languageList[i];
    113                     languageMatchButNotLocaleMatchIndex = i;
    114                 }
    115             }
    116         }
    117     }
    118 
    119     // If we have both a language-only match and a languge-but-not-locale match, return the
    120     // languge-only match as is considered a "better" match. For example, if the list
    121     // provided has both "en-GB" and "en" and the user prefers "en-US" we will return "en".
    122     if (languageWithoutLocaleMatch.length())
    123         return languageWithoutLocaleMatchIndex;
    124 
    125     if (languageMatchButNotLocale.length())
    126         return languageMatchButNotLocaleMatchIndex;
    127 
    128     return languageList.size();
    129 }
    130 
    131 }
    132