intl/locale/nsLanguageAtomService.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 /*
   7  * The nsILanguageAtomService provides a mapping from languages or charsets
   8  * to language groups, and access to the system locale language.
   9  */
  10
  11 #ifndef nsLanguageAtomService_h_
  12 #define nsLanguageAtomService_h_
  13
  14 #include "mozilla/NotNull.h"
  15 #include "nsCOMPtr.h"
  16 #include "nsAtomHashKeys.h"
  17 #include "nsTHashMap.h"
  18
  19 namespace mozilla {
  20 class Encoding;
  21 }
  22
  23 class nsLanguageAtomService final {
  24   using Encoding = mozilla::Encoding;
  25   template <typename T>
  26   using NotNull = mozilla::NotNull<T>;
  27
  28  public:
  29   static nsLanguageAtomService* GetService();
  30
  31   static void Shutdown();
  32
  33   nsStaticAtom* LookupLanguage(const nsACString& aLanguage);
  34   already_AddRefed<nsAtom> LookupCharSet(NotNull<const Encoding*> aCharSet);
  35   nsAtom* GetLocaleLanguage();
  36
  37   // Returns the language group that the specified language is a part of.
  38   //
  39   // aNeedsToCache is used for two things.  If null, it indicates that
  40   // the nsLanguageAtomService is safe to cache the result of the
  41   // language group lookup, either because we're on the main thread,
  42   // or because we're on a style worker thread but the font lock has
  43   // been acquired.  If non-null, it indicates that it's not safe to
  44   // cache the result of the language group lookup (because we're on
  45   // a style worker thread without the lock acquired).  In this case,
  46   // GetLanguageGroup will store true in *aNeedsToCache true if we
  47   // would have cached the result of a new lookup, and false if we
  48   // were able to use an existing cached result.  Thus, callers that
  49   // get a true *aNeedsToCache outparam value should make an effort
  50   // to re-call GetLanguageGroup when it is safe to cache, to avoid
  51   // recomputing the language group again later.
  52   nsStaticAtom* GetLanguageGroup(nsAtom* aLanguage,
  53                                  bool* aNeedsToCache = nullptr);
  54   nsStaticAtom* GetUncachedLanguageGroup(nsAtom* aLanguage) const;
  55
  56  private:
  57   nsTHashMap<RefPtr<nsAtom>, nsStaticAtom*> mLangToGroup;
  58   RefPtr<nsAtom> mLocaleLanguage;
  59 };
  60
  61 #endif