"""Internationalization and localization support.

This module provides internationalization (I18N) and localization (L10N)

support for your Python programs by providing an interface to the GNU gettext

message catalog library.

I18N refers to the operation by which a program is made aware of multiple

languages. L10N refers to the adaptation of your program, once

internationalized, to the local language and cultural habits.

"""

# This module represents the integration of work, contributions, feedback, and

# suggestions from the following people:

#

# Martin von Loewis, who wrote the initial implementation of the underlying

# C-based libintlmodule (later renamed _gettext), along with a skeletal

# gettext.py implementation.

#

# Peter Funk, who wrote fintl.py, a fairly complete wrapper around intlmodule,

# which also included a pure-Python implementation to read .mo files if

# intlmodule wasn't available.

#

# James Henstridge, who also wrote a gettext.py module, which has some

# interesting, but currently unsupported experimental features: the notion of

# a Catalog class and instances, and the ability to add to a catalog file via

# a Python API.

#

# Barry Warsaw integrated these modules, wrote the .install() API and code,

# and conformed all C and Python code to Python's coding standards.

#

# Francois Pinard and Marc-Andre Lemburg also contributed valuably to this

# module.

#

# TODO:

# - Lazy loading of .mo files. Currently the entire catalog is loaded into

# memory, but that's probably bad for large translated programs. Instead,

# the lexical sort of original strings in GNU .mo files should be exploited

# to do binary searches and lazy initializations. Or you might want to use

# the undocumented double-hash algorithm for .mo files with hash tables, but

# you'll need to study the GNU gettext code to do this.

#

# - Support Solaris .mo file formats. Unfortunately, we've been unable to

# find this format documented anywhere.

import os

import sys

import struct

from errno import ENOENT

__all__ = ["bindtextdomain","textdomain","gettext","dgettext",

"find","translation","install","Catalog"]

_default_localedir = os.path.join(sys.prefix, 'share', 'locale')

def _expand_lang(locale):

from locale import normalize

locale = normalize(locale)

COMPONENT_CODESET = 1 << 0

COMPONENT_TERRITORY = 1 << 1

COMPONENT_MODIFIER = 1 << 2

# split up the locale into its base components

mask = 0

pos = locale.find('@')

if pos >= 0:

modifier = locale[pos:]

locale = locale[:pos]

mask |= COMPONENT_MODIFIER

else:

modifier = ''

pos = locale.find('.')

if pos >= 0:

codeset = locale[pos:]

locale = locale[:pos]

mask |= COMPONENT_CODESET

else:

codeset = ''

pos = locale.find('_')

if pos >= 0:

territory = locale[pos:]

locale = locale[:pos]

mask |= COMPONENT_TERRITORY

else:

territory = ''

language = locale

ret = []

for i in range(mask+1):

if not (i & ~mask): # if all components for this combo exist ...

val = language

if i & COMPONENT_TERRITORY: val += territory

if i & COMPONENT_CODESET: val += codeset

if i & COMPONENT_MODIFIER: val += modifier

ret.append(val)

ret.reverse()

return ret

class NullTranslations:

def __init__(self, fp=None):

self._info = {}

self._charset = None

if fp:

self._parse(fp)

def _parse(self, fp):

pass

def gettext(self, message):

return message

def ugettext(self, message):

return unicode(message)

def info(self):

return self._info

def charset(self):

return self._charset

def install(self, unicode=0):

import __builtin__

__builtin__.__dict__['_'] = unicode and self.ugettext or self.gettext

class GNUTranslations(NullTranslations):

# Magic number of .mo files

LE_MAGIC = 0x950412de

BE_MAGIC = 0xde120495

def _parse(self, fp):

"""Override this method to support alternative .mo formats."""

# We need to & all 32 bit unsigned integers with 0xffffffff for

# portability to 64 bit machines.

MASK = 0xffffffff

unpack = struct.unpack

filename = getattr(fp, 'name', '')

# Parse the .mo file header, which consists of 5 little endian 32

# bit words.

self._catalog = catalog = {}

buf = fp.read()

buflen = len(buf)

# Are we big endian or little endian?

magic = unpack('<i', buf[:4])[0] & MASK

if magic == self.LE_MAGIC:

version, msgcount, masteridx, transidx = unpack('<4i', buf[4:20])

ii = '<ii'

elif magic == self.BE_MAGIC:

version, msgcount, masteridx, transidx = unpack('>4i', buf[4:20])

ii = '>ii'

else:

raise IOError(0, 'Bad magic number', filename)

# more unsigned ints

msgcount &= MASK

masteridx &= MASK

transidx &= MASK

# Now put all messages from the .mo file buffer into the catalog

# dictionary.

for i in xrange(0, msgcount):

mlen, moff = unpack(ii, buf[masteridx:masteridx+8])

moff &= MASK

mend = moff + (mlen & MASK)

tlen, toff = unpack(ii, buf[transidx:transidx+8])

toff &= MASK

tend = toff + (tlen & MASK)

if mend < buflen and tend < buflen:

tmsg = buf[toff:tend]

catalog[buf[moff:mend]] = tmsg

else:

raise IOError(0, 'File is corrupt', filename)

# See if we're looking at GNU .mo conventions for metadata

if mlen == 0 and tmsg.lower().startswith('project-id-version:'):

# Catalog description

for item in tmsg.split('\n'):

item = item.strip()

if not item:

continue

k, v = item.split(':', 1)

k = k.strip().lower()

v = v.strip()

self._info[k] = v

if k == 'content-type':

self._charset = v.split('charset=')[1]

# advance to next entry in the seek tables

masteridx += 8

transidx += 8

def gettext(self, message):

return self._catalog.get(message, message)

def ugettext(self, message):

tmsg = self._catalog.get(message, message)

return unicode(tmsg, self._charset)

# Locate a .mo file using the gettext strategy

def find(domain, localedir=None, languages=None):

# Get some reasonable defaults for arguments that were not supplied

if localedir is None:

localedir = _default_localedir

if languages is None:

languages = []

for envar in ('LANGUAGE', 'LC_ALL', 'LC_MESSAGES', 'LANG'):

val = os.environ.get(envar)

if val:

languages = val.split(':')

break

if 'C' not in languages:

languages.append('C')

# now normalize and expand the languages

nelangs = []

for lang in languages:

for nelang in _expand_lang(lang):

if nelang not in nelangs:

nelangs.append(nelang)

# select a language

for lang in nelangs:

if lang == 'C':

break

mofile = os.path.join(localedir, lang, 'LC_MESSAGES', '%s.mo' % domain)

if os.path.exists(mofile):

return mofile

return None

# a mapping between absolute .mo file path and Translation object

_translations = {}

def translation(domain, localedir=None, languages=None, class_=None):

if class_ is None:

class_ = GNUTranslations

mofile = find(domain, localedir, languages)

if mofile is None:

raise IOError(ENOENT, 'No translation file found for domain', domain)

key = os.path.abspath(mofile)

# TBD: do we need to worry about the file pointer getting collected?

# Avoid opening, reading, and parsing the .mo file after it's been done

# once.

t = _translations.get(key)

if t is None:

t = _translations.setdefault(key, class_(open(mofile, 'rb')))

return t

def install(domain, localedir=None, unicode=0):

translation(domain, localedir).install(unicode)

# a mapping b/w domains and locale directories

_localedirs = {}

# current global domain, `messages' used for compatibility w/ GNU gettext

_current_domain = 'messages'

def textdomain(domain=None):

global _current_domain

if domain is not None:

_current_domain = domain

return _current_domain

def bindtextdomain(domain, localedir=None):

global _localedirs

if localedir is not None:

_localedirs[domain] = localedir

return _localedirs.get(domain, _default_localedir)

def dgettext(domain, message):

try:

t = translation(domain, _localedirs.get(domain, None))

except IOError:

return message

return t.gettext(message)

def gettext(message):

return dgettext(_current_domain, message)

# dcgettext() has been deemed unnecessary and is not implemented.

# James Henstridge's Catalog constructor from GNOME gettext. Documented usage

# was:

#

# import gettext

# cat = gettext.Catalog(PACKAGE, localedir=LOCALEDIR)

# _ = cat.gettext

# print _('Hello World')

# The resulting catalog object currently don't support access through a

# dictionary API, which was supported (but apparently unused) in GNOME

# gettext.

Catalog = translation