intl/unicharutil/util/ICUUtils.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 #ifndef mozilla_ICUUtils_h__
   7 #define mozilla_ICUUtils_h__
   8
   9 // We only build the ICU utils if we're building ICU:
  10 #ifdef ENABLE_INTL_API
  11
  12 // The ICU utils implementation needs internal things like XPCOM strings and
  13 // nsGkAtom, so we only build when included into internal libs:
  14 #ifdef MOZILLA_INTERNAL_API
  15
  16 #include "mozilla/Scoped.h"
  17 #include "nsStringGlue.h"
  18 #include "unicode/unum.h" // for UNumberFormat
  19
  20 class nsIContent;
  21
  22 namespace {
  23   struct ScopedUNumberFormatTraits {
  24     typedef UNumberFormat* type;
  25     static type empty() { return nullptr; }
  26     static void release(type handle) { if (handle) unum_close(handle); }
  27   };
  28 };
  29 typedef mozilla::Scoped<ScopedUNumberFormatTraits> AutoCloseUNumberFormat;
  30
  31 class ICUUtils
  32 {
  33 public:
  34
  35   /**
  36    * This class is used to encapsulate an nsIContent object to allow lazy
  37    * iteration over its primary and fallback BCP 47 language tags.
  38    */
  39   class LanguageTagIterForContent {
  40   public:
  41     explicit LanguageTagIterForContent(nsIContent* aContent)
  42       : mContent(aContent)
  43       , mCurrentFallbackIndex(-1)
  44     {}
  45
  46     /**
  47      * Used to iterate over the nsIContent object's primary language tag and
  48      * its fallbacks tags. The following sources of language tag information
  49      * are tried in turn:
  50      *
  51      * 1) the "lang" of the nsIContent object (which is based on the 'lang'/
  52      *    'xml:lang' attribute on itself or the nearest ancestor to have such
  53      *    an attribute, if any);
  54      * 2) the Content-Language HTTP pragma directive or HTTP header;
  55      * 3) the configured language tag of the user-agent.
  56      *
  57      * Once all fallbacks have been exhausted then this function will set
  58      * aBCP47LangTag to the empty string.
  59      */
  60     void GetNext(nsACString& aBCP47LangTag);
  61
  62     bool IsAtStart() const {
  63       return mCurrentFallbackIndex < 0;
  64     }
  65
  66   private:
  67     nsIContent* mContent;
  68     int8_t mCurrentFallbackIndex;
  69   };
  70
  71   /**
  72    * Attempts to localize aValue and return the result via the aLocalizedValue
  73    * outparam. Returns true on success. Returns false on failure, in which
  74    * case aLocalizedValue will be untouched.
  75    */
  76   static bool LocalizeNumber(double aValue,
  77                              LanguageTagIterForContent& aLangTags,
  78                              nsAString& aLocalizedValue);
  79
  80   /**
  81    * Parses the localized number that is serialized in aValue using aLangTags
  82    * and returns the result as a double. Returns NaN on failure.
  83    */
  84   static double ParseNumber(nsAString& aValue,
  85                             LanguageTagIterForContent& aLangTags);
  86
  87   static void AssignUCharArrayToString(UChar* aICUString,
  88                                        int32_t aLength,
  89                                        nsAString& aMozString);
  90
  91 #if 0
  92   // Currently disabled because using C++ API doesn't play nicely with enabling
  93   // system ICU.
  94
  95   /**
  96    * Converts an IETF BCP 47 language code to an ICU Locale.
  97    */
  98   static Locale BCP47CodeToLocale(const nsAString& aBCP47Code);
  99
 100   static void ToMozString(UnicodeString& aICUString, nsAString& aMozString);
 101   static void ToICUString(nsAString& aMozString, UnicodeString& aICUString);
 102 #endif
 103 };
 104
 105 #endif /* ENABLE_INTL_API */
 106 #endif /* MOZILLA_INTERNAL_API */
 107
 108 #endif /* mozilla_ICUUtils_h__ */
 109