root/MGET/Trunk/PythonPackage/src/GeoEco/Internationalization.py

# Internationalization.py - Provides internationalization/localization
# infrastructure for the GeoEco Python package.
#
# Copyright (C) 2007 Jason J. Roberts
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License (available in the file LICENSE.TXT)
# for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

import codecs
import locale
import gettext
import inspect
import os
import os.path
import sys
import types

def _InitializeTranslationsClass():

    # Build a list of languages, prioritized according to what the user might
    # want to view.

    languages = []

    # First use the current process-wide locale. If we're being called from a
    # language-aware application, it may have set the locale. If not, this
    # function will return None.
    
    lc = locale.getlocale()[0]
    if lc is not None:
        languages.append(lc)

    # Next try the default locale.
    
    lc = locale.getdefaultlocale()[0]
    if lc is not None:
        languages.append(lc)

    # Next search the environment variables that might specify languages. These
    # are typically only present on UNIX. locale.getdefaultlocale also searches
    # these but returns only the first one it finds. We want the others to be in
    # our list, so if the first one is not available, we'll fall back to the
    # others.

    for variable in ['LANGUAGE', 'LC_ALL', 'LC_MESSAGES', 'LANG']:
        if os.environ.has_key(variable):
            value = os.environ[variable]
            languages.extend(value.split(':'))

    # Return the Translations instance.

    gettext.translation(domain='GeoEco',
                        localedir=os.path.join(os.path.dirname(inspect.getfile(sys.modules[__name__])), u'LanguageFiles'),
                        languages=languages,
                        fallback=True)

_Translations = None
try:
    _Translations = _InitializeTranslationsClass()
except:
    pass

def _gettext(s):
    return s

if _Translations is not None:
    _ = _Translations.ugettext
else:
    _ = _gettext

_UserPreferredEncoder = None

def UnicodeToUserPreferredEncoding(obj):
    if isinstance(obj, types.ListType):
        return _EncodeList(obj)
    if isinstance(obj, types.TupleType):
        l = list(obj)
        l = _EncodeList(l)
        return tuple(l)
    if not isinstance(obj, types.UnicodeType):
        return obj
    if globals()['_UserPreferredEncoder'] is None:
        try:
            globals()['_UserPreferredEncoder'] = codecs.getencoder(locale.getpreferredencoding(do_setlocale=False))
        except:
            globals()['_UserPreferredEncoder'] = codecs.getencoder('ascii')
    return globals()['_UserPreferredEncoder'](obj, 'strict')[0]

def _EncodeList(obj):
    for i in range(len(obj)):
        obj[i] = UnicodeToUserPreferredEncoding(obj[i])
    return obj

_UserPreferredDecoder = None

def UserPreferredEncodingToUnicode(obj):
    if isinstance(obj, types.ListType):
        return _DecodeList(obj)
    if isinstance(obj, types.TupleType):
        l = list(obj)
        l = _DecodeList(l)
        return tuple(l)
    if not isinstance(obj, types.StringType):
        return obj
    if globals()['_UserPreferredDecoder'] is None:
        try:
            globals()['_UserPreferredDecoder'] = codecs.getdecoder(locale.getpreferredencoding(do_setlocale=False))
        except:
            globals()['_UserPreferredDecoder'] = codecs.getdecoder('ascii')
    return globals()['_UserPreferredDecoder'](obj, 'strict')[0]

def _DecodeList(obj):
    for i in range(len(obj)):
        obj[i] = UserPreferredEncodingToUnicode(obj[i])
    return obj
        

###############################################################################
# Names exported by this module
###############################################################################

__all__ = ['_', 'UnicodeToUserPreferredEncoding', 'UserPreferredEncodingToUnicode']