roundup/i18n.py

   1 #
   2 # Copyright (c) 2001 Bizar Software Pty Ltd (http://www.bizarsoftware.com.au/)
   3 # This module is free software, and you may redistribute it and/or modify
   4 # under the same terms as Python, so long as this copyright message and
   5 # disclaimer are retained in their original form.
   6 #
   7 # IN NO EVENT SHALL BIZAR SOFTWARE PTY LTD BE LIABLE TO ANY PARTY FOR
   8 # DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING
   9 # OUT OF THE USE OF THIS CODE, EVEN IF THE AUTHOR HAS BEEN ADVISED OF THE
  10 # POSSIBILITY OF SUCH DAMAGE.
  11 #
  12 # BIZAR SOFTWARE PTY LTD SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  13 # BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  14 # FOR A PARTICULAR PURPOSE.  THE CODE PROVIDED HEREUNDER IS ON AN "AS IS"
  15 # BASIS, AND THERE IS NO OBLIGATION WHATSOEVER TO PROVIDE MAINTENANCE,
  16 # SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  17 #
  18 # $Id: i18n.py,v 1.15 2005-06-14 05:33:32 a1s Exp $
  19
  20 """
  21 RoundUp Internationalization (I18N)
  22
  23 To use this module, the following code should be used::
  24
  25     from roundup.i18n import _
  26     ...
  27     print _("Some text that can be translated")
  28
  29 Note that to enable re-ordering of inserted texts in formatting strings
  30 (which can easily happen if a sentence has to be re-ordered due to
  31 grammatical changes), translatable formats should use named format specs::
  32
  33     ... _('Index of %(classname)s') % {'classname': cn} ...
  34
  35 Also, this eases the job of translators since they have some context what
  36 the dynamic portion of a message really means.
  37 """
  38 __docformat__ = 'restructuredtext'
  39
  40 import errno
  41 import gettext as gettext_module
  42 import os
  43
  44 from roundup import msgfmt
  45
  46 # List of directories for mo file search (see SF bug 1219689)
  47 LOCALE_DIRS = [
  48     gettext_module._default_localedir,
  49 ]
  50 # compute mo location relative to roundup installation directory
  51 # (prefix/lib/python/site-packages/roundup/msgfmt.py on posix systems,
  52 # prefix/lib/site-packages/roundup/msgfmt.py on windows).
  53 # locale root is prefix/share/locale.
  54 if os.name == "nt":
  55     _mo_path = [".."] * 4 + ["share", "locale"]
  56 else:
  57     _mo_path = [".."] * 5 + ["share", "locale"]
  58 _mo_path = os.path.normpath(os.path.join(msgfmt.__file__, *_mo_path))
  59 if _mo_path not in LOCALE_DIRS:
  60     LOCALE_DIRS.append(_mo_path)
  61 del _mo_path
  62
  63 # Roundup text domain
  64 DOMAIN = "roundup"
  65
  66 if hasattr(gettext_module.GNUTranslations, "ngettext"):
  67     # gettext_module has everything needed
  68     RoundupNullTranslations = gettext_module.NullTranslations
  69     RoundupTranslations = gettext_module.GNUTranslations
  70 else:
  71     # prior to 2.3, there was no plural forms.  mix simple emulation in
  72     class PluralFormsMixIn:
  73         def ngettext(self, singular, plural, count):
  74             if count == 1:
  75                 _msg = singular
  76             else:
  77                 _msg = plural
  78             return self.gettext(_msg)
  79         def ungettext(self, singular, plural, count):
  80             if count == 1:
  81                 _msg = singular
  82             else:
  83                 _msg = plural
  84             return self.ugettext(_msg)
  85     class RoundupNullTranslations(
  86         gettext_module.NullTranslations, PluralFormsMixIn
  87     ):
  88         pass
  89     class RoundupTranslations(
  90         gettext_module.GNUTranslations, PluralFormsMixIn
  91     ):
  92         pass
  93
  94 def find_locales(language=None):
  95     """Return normalized list of locale names to try for given language
  96
  97     Argument 'language' may be a single language code or a list of codes.
  98     If 'language' is omitted or None, use locale settings in OS environment.
  99
 100     """
 101     # body of this function is borrowed from gettext_module.find()
 102     if language is None:
 103         languages = []
 104         for envar in ('LANGUAGE', 'LC_ALL', 'LC_MESSAGES', 'LANG'):
 105             val = os.environ.get(envar)
 106             if val:
 107                 languages = val.split(':')
 108                 break
 109     elif isinstance(language, str) or  isinstance(language, unicode):
 110         languages = [language]
 111     else:
 112         # 'language' must be iterable
 113         languages = language
 114     # now normalize and expand the languages
 115     nelangs = []
 116     for lang in languages:
 117         for nelang in gettext_module._expand_lang(lang):
 118             if nelang not in nelangs:
 119                 nelangs.append(nelang)
 120     return nelangs
 121
 122 def get_mofile(languages, localedir, domain=None):
 123     """Return the first of .mo files found in localedir for languages
 124
 125     Parameters:
 126         languages:
 127             list of locale names to try
 128         localedir:
 129             path to directory containing locale files.
 130             Usually this is either gettext_module._default_localedir
 131             or 'locale' subdirectory in the tracker home.
 132         domain:
 133             optional name of messages domain.
 134             If omitted or None, work with simplified
 135             locale directory, as used in tracker homes:
 136             message catalogs are kept in files locale.po
 137             instead of locale/LC_MESSAGES/domain.po
 138
 139     Return the path of the first .mo file found.
 140     If nothing found, return None.
 141
 142     Automatically compile .po files if necessary.
 143
 144     """
 145     for locale in languages:
 146         if locale == "C":
 147             break
 148         if domain:
 149             basename = os.path.join(localedir, locale, "LC_MESSAGES", domain)
 150         else:
 151             basename = os.path.join(localedir, locale)
 152         # look for message catalog files, check timestamps
 153         mofile = basename + ".mo"
 154         if os.path.isfile(mofile):
 155             motime = os.path.getmtime(mofile)
 156         else:
 157             motime = 0
 158         pofile = basename + ".po"
 159         if os.path.isfile(pofile):
 160             potime = os.path.getmtime(pofile)
 161         else:
 162             potime = 0
 163         # see what we've found
 164         if motime < potime:
 165             # compile
 166             msgfmt.make(pofile, mofile)
 167         elif motime == 0:
 168             # no files found - proceed to the next locale name
 169             continue
 170         # .mo file found or made
 171         return mofile
 172     return None
 173
 174 def get_translation(language=None, tracker_home=None,
 175     translation_class=RoundupTranslations,
 176     null_translation_class=RoundupNullTranslations
 177 ):
 178     """Return Translation object for given language and domain
 179
 180     Argument 'language' may be a single language code or a list of codes.
 181     If 'language' is omitted or None, use locale settings in OS environment.
 182
 183     Arguments 'translation_class' and 'null_translation_class'
 184     specify the classes that are instantiated for existing
 185     and non-existing translations, respectively.
 186
 187     """
 188     mofiles = []
 189     # locale directory paths
 190     if tracker_home is None:
 191         tracker_locale = None
 192     else:
 193         tracker_locale = os.path.join(tracker_home, "locale")
 194     # get the list of locales
 195     locales = find_locales(language)
 196     # add mofiles found in the tracker, then in the system locale directory
 197     if tracker_locale:
 198         mofiles.append(get_mofile(locales, tracker_locale))
 199     for system_locale in LOCALE_DIRS:
 200         mofiles.append(get_mofile(locales, system_locale, DOMAIN))
 201     # we want to fall back to english unless english is selected language
 202     if "en" not in locales:
 203         locales = find_locales("en")
 204         # add mofiles found in the tracker, then in the system locale directory
 205         if tracker_locale:
 206             mofiles.append(get_mofile(locales, tracker_locale))
 207         for system_locale in LOCALE_DIRS:
 208             mofiles.append(get_mofile(locales, system_locale, DOMAIN))
 209     # filter out elements that are not found
 210     mofiles = filter(None, mofiles)
 211     if mofiles:
 212         translator = translation_class(open(mofiles[0], "rb"))
 213         for mofile in mofiles[1:]:
 214             # note: current implementation of gettext_module
 215             #   always adds fallback to the end of the fallback chain.
 216             translator.add_fallback(translation_class(open(mofile, "rb")))
 217     else:
 218         translator = null_translation_class()
 219     return translator
 220
 221 # static translations object
 222 translation = get_translation()
 223 # static translation functions
 224 _ = gettext = translation.gettext
 225 ugettext = translation.ugettext
 226 ngettext = translation.ngettext
 227 ungettext = translation.ungettext
 228
 229 # vim: set filetype=python sts=4 sw=4 et si :