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
32namespace blink {
33
34static 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
44AtomicString defaultLanguage()
45{
46    Vector<AtomicString> languages = userPreferredLanguages();
47    if (!languages.isEmpty())
48        return languages[0];
49
50    return emptyAtom;
51}
52
53static Vector<AtomicString>& preferredLanguagesOverride()
54{
55    DEFINE_STATIC_LOCAL(Vector<AtomicString>, override, ());
56    return override;
57}
58
59Vector<AtomicString> userPreferredLanguagesOverride()
60{
61    return preferredLanguagesOverride();
62}
63
64void overrideUserPreferredLanguages(const Vector<AtomicString>& override)
65{
66    preferredLanguagesOverride() = override;
67}
68
69Vector<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
81static 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
91size_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