gecko-dev/intl/locale/MozLocale.h

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode:nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_intl_MozLocale_h__
#define mozilla_intl_MozLocale_h__

#include "nsString.h"
#include "nsTArray.h"

namespace mozilla {
namespace intl {

/**
 * Locale class is a core representation of a single locale.
 *
 * A locale is a data object representing a combination of language, script,
 * region, variant and a set of regional extension preferences that may further specify
 * particular user choices like calendar, numbering system, etc.
 *
 * A locale can be expressed as a language tag string, like a simple "fr" for French,
 * or a more specific "sr-Cyrl-RS-u-hc-h12" for Serbian in Russia with a Cyrylic script,
 * and hour cycle selected to be `h12`.
 *
 * The format of the language tag follows BCP47 standard and implements a subset of it.
 * In the future we expect to extend this class to cover more subtags and extensions.
 *
 * BCP47: https://tools.ietf.org/html/bcp47
 *
 * The aim of this class it aid in validation, parsing and canonicalization of the
 * string.
 *
 * It allows the user to input any well-formed BCP47 language tag and operate
 * on its subtags in a canonicalized form.
 *
 * It should be used for all operations on language tags, and together with
 * LocaleService::NegotiateLanguages for language negotiation.
 *
 * Example:
 *
 *     Locale loc = Locale("de-at");
 *
 *     ASSERT_TRUE(loc.GetLanguage().Equals("de"));
 *     ASSERT_TRUE(loc.GetScript().IsEmpty());
 *     ASSERT_TRUE(loc.GetRegion().Equals("AT")); // canonicalized to upper case
 *
 *
 * Note: The file name is `MozLocale` to avoid compilation problems on case-insensitive
 * Windows. The class name is `Locale`.
 */
class Locale {
  public:
    explicit Locale(const nsACString& aLocale);
    explicit Locale(const char* aLocale)
      : Locale(nsDependentCString(aLocale))
      { };

    const nsACString& GetLanguage() const;
    const nsACString& GetScript() const;
    const nsACString& GetRegion() const;
    const nsTArray<nsCString>& GetVariants() const;

    bool IsValid() const {
      return mIsValid;
    }

    const nsCString AsString() const;

    bool Matches(const Locale& aOther, bool aThisRange, bool aOtherRange) const;
    bool AddLikelySubtags();
    void ClearVariants();
    void ClearRegion();

    // Mark the object as invalid, meaning we shouldn't use it any more.
    void Invalidate() {
      mIsValid = false;
    }

    bool operator== (const Locale& aOther) {
      // Note: invalid Locale objects are never treated as equal to anything
      // (even other invalid ones).
      return IsValid() &&
             aOther.IsValid() &&
             mLanguage.Equals(aOther.mLanguage) &&
             mScript.Equals(aOther.mScript) &&
             mRegion.Equals(aOther.mRegion) &&
             mVariants == aOther.mVariants;
    }

  private:
    nsAutoCStringN<3> mLanguage;
    nsAutoCStringN<4> mScript;
    nsAutoCStringN<2> mRegion;
    nsTArray<nsCString> mVariants;
    bool mIsValid = true;
};

} // intl
} // namespace mozilla

DECLARE_USE_COPY_CONSTRUCTORS(mozilla::intl::Locale)

#endif /* mozilla_intl_MozLocale_h__ */