mirror of
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6008cbd4c2
to iso-8859-1. GNUTranslations._parse(): Back out the addition of a test for Project-ID-Version in the metadata. This was deliberately removed in response to SF patch #700839. Also, re-organize the code in _parse() so we parse the metadata header containing the charset parameter before we try to decode any strings using charset.
489 lines
16 KiB
Python
489 lines
16 KiB
Python
"""Internationalization and localization support.
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This module provides internationalization (I18N) and localization (L10N)
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support for your Python programs by providing an interface to the GNU gettext
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message catalog library.
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I18N refers to the operation by which a program is made aware of multiple
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languages. L10N refers to the adaptation of your program, once
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internationalized, to the local language and cultural habits.
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"""
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# This module represents the integration of work, contributions, feedback, and
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# suggestions from the following people:
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#
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# Martin von Loewis, who wrote the initial implementation of the underlying
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# C-based libintlmodule (later renamed _gettext), along with a skeletal
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# gettext.py implementation.
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#
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# Peter Funk, who wrote fintl.py, a fairly complete wrapper around intlmodule,
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# which also included a pure-Python implementation to read .mo files if
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# intlmodule wasn't available.
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#
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# James Henstridge, who also wrote a gettext.py module, which has some
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# interesting, but currently unsupported experimental features: the notion of
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# a Catalog class and instances, and the ability to add to a catalog file via
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# a Python API.
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#
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# Barry Warsaw integrated these modules, wrote the .install() API and code,
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# and conformed all C and Python code to Python's coding standards.
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#
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# Francois Pinard and Marc-Andre Lemburg also contributed valuably to this
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# module.
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#
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# J. David Ibanez implemented plural forms. Bruno Haible fixed some bugs.
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#
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# TODO:
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# - Lazy loading of .mo files. Currently the entire catalog is loaded into
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# memory, but that's probably bad for large translated programs. Instead,
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# the lexical sort of original strings in GNU .mo files should be exploited
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# to do binary searches and lazy initializations. Or you might want to use
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# the undocumented double-hash algorithm for .mo files with hash tables, but
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# you'll need to study the GNU gettext code to do this.
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#
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# - Support Solaris .mo file formats. Unfortunately, we've been unable to
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# find this format documented anywhere.
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import copy, os, re, struct, sys
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from errno import ENOENT
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__all__ = ['NullTranslations', 'GNUTranslations', 'Catalog',
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'find', 'translation', 'install', 'textdomain', 'bindtextdomain',
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'dgettext', 'dngettext', 'gettext', 'ngettext',
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]
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_default_localedir = os.path.join(sys.prefix, 'share', 'locale')
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def test(condition, true, false):
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"""
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Implements the C expression:
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condition ? true : false
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Required to correctly interpret plural forms.
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"""
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if condition:
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return true
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else:
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return false
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def c2py(plural):
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"""
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Gets a C expression as used in PO files for plural forms and
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returns a Python lambda function that implements an equivalent
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expression.
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"""
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# Security check, allow only the "n" identifier
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from StringIO import StringIO
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import token, tokenize
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tokens = tokenize.generate_tokens(StringIO(plural).readline)
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try:
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danger = [ x for x in tokens if x[0] == token.NAME and x[1] != 'n' ]
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except tokenize.TokenError:
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raise ValueError, \
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'plural forms expression error, maybe unbalanced parenthesis'
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else:
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if danger:
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raise ValueError, 'plural forms expression could be dangerous'
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# Replace some C operators by their Python equivalents
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plural = plural.replace('&&', ' and ')
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plural = plural.replace('||', ' or ')
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expr = re.compile(r'\!([^=])')
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plural = expr.sub(' not \\1', plural)
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# Regular expression and replacement function used to transform
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# "a?b:c" to "test(a,b,c)".
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expr = re.compile(r'(.*?)\?(.*?):(.*)')
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def repl(x):
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return "test(%s, %s, %s)" % (x.group(1), x.group(2),
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expr.sub(repl, x.group(3)))
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# Code to transform the plural expression, taking care of parentheses
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stack = ['']
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for c in plural:
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if c == '(':
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stack.append('')
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elif c == ')':
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if len(stack) == 1:
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# Actually, we never reach this code, because unbalanced
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# parentheses get caught in the security check at the
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# beginning.
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raise ValueError, 'unbalanced parenthesis in plural form'
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s = expr.sub(repl, stack.pop())
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stack[-1] += '(%s)' % s
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else:
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stack[-1] += c
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plural = expr.sub(repl, stack.pop())
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return eval('lambda n: int(%s)' % plural)
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def _expand_lang(locale):
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from locale import normalize
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locale = normalize(locale)
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COMPONENT_CODESET = 1 << 0
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COMPONENT_TERRITORY = 1 << 1
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COMPONENT_MODIFIER = 1 << 2
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# split up the locale into its base components
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mask = 0
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pos = locale.find('@')
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if pos >= 0:
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modifier = locale[pos:]
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locale = locale[:pos]
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mask |= COMPONENT_MODIFIER
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else:
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modifier = ''
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pos = locale.find('.')
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if pos >= 0:
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codeset = locale[pos:]
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locale = locale[:pos]
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mask |= COMPONENT_CODESET
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else:
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codeset = ''
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pos = locale.find('_')
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if pos >= 0:
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territory = locale[pos:]
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locale = locale[:pos]
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mask |= COMPONENT_TERRITORY
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else:
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territory = ''
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language = locale
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ret = []
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for i in range(mask+1):
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if not (i & ~mask): # if all components for this combo exist ...
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val = language
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if i & COMPONENT_TERRITORY: val += territory
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if i & COMPONENT_CODESET: val += codeset
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if i & COMPONENT_MODIFIER: val += modifier
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ret.append(val)
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ret.reverse()
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return ret
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class NullTranslations:
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def __init__(self, fp=None):
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self._info = {}
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self._charset = None
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self._fallback = None
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if fp is not None:
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self._parse(fp)
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def _parse(self, fp):
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pass
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def add_fallback(self, fallback):
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if self._fallback:
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self._fallback.add_fallback(fallback)
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else:
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self._fallback = fallback
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def gettext(self, message):
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if self._fallback:
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return self._fallback.gettext(message)
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return message
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def ngettext(self, msgid1, msgid2, n):
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if self._fallback:
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return self._fallback.ngettext(msgid1, msgid2, n)
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if n == 1:
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return msgid1
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else:
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return msgid2
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def ugettext(self, message):
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if self._fallback:
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return self._fallback.ugettext(message)
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return unicode(message)
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def ungettext(self, msgid1, msgid2, n):
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if self._fallback:
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return self._fallback.ungettext(msgid1, msgid2, n)
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if n == 1:
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return unicode(msgid1)
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else:
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return unicode(msgid2)
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def info(self):
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return self._info
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def charset(self):
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return self._charset
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def install(self, unicode=0):
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import __builtin__
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__builtin__.__dict__['_'] = unicode and self.ugettext or self.gettext
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class GNUTranslations(NullTranslations):
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# Magic number of .mo files
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LE_MAGIC = 0x950412deL
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BE_MAGIC = 0xde120495L
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def __init__(self, fp=None, coerce=False):
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# Set this attribute before calling the base class constructor, since
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# the latter calls _parse() which depends on self._coerce.
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self._coerce = coerce
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NullTranslations.__init__(self, fp)
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def _parse(self, fp):
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"""Override this method to support alternative .mo formats."""
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unpack = struct.unpack
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filename = getattr(fp, 'name', '')
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# Parse the .mo file header, which consists of 5 little endian 32
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# bit words.
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self._catalog = catalog = {}
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self.plural = lambda n: int(n != 1) # germanic plural by default
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buf = fp.read()
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buflen = len(buf)
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# Are we big endian or little endian?
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magic = unpack('<I', buf[:4])[0]
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if magic == self.LE_MAGIC:
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version, msgcount, masteridx, transidx = unpack('<4I', buf[4:20])
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ii = '<II'
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elif magic == self.BE_MAGIC:
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version, msgcount, masteridx, transidx = unpack('>4I', buf[4:20])
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ii = '>II'
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else:
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raise IOError(0, 'Bad magic number', filename)
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# Now put all messages from the .mo file buffer into the catalog
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# dictionary.
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for i in xrange(0, msgcount):
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mlen, moff = unpack(ii, buf[masteridx:masteridx+8])
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mend = moff + mlen
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tlen, toff = unpack(ii, buf[transidx:transidx+8])
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tend = toff + tlen
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if mend < buflen and tend < buflen:
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msg = buf[moff:mend]
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tmsg = buf[toff:tend]
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else:
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raise IOError(0, 'File is corrupt', filename)
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# See if we're looking at GNU .mo conventions for metadata
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if mlen == 0:
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# Catalog description
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for item in tmsg.splitlines():
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item = item.strip()
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if not item:
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continue
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k, v = item.split(':', 1)
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k = k.strip().lower()
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v = v.strip()
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self._info[k] = v
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if k == 'content-type':
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self._charset = v.split('charset=')[1]
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elif k == 'plural-forms':
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v = v.split(';')
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## nplurals = v[0].split('nplurals=')[1]
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## nplurals = int(nplurals.strip())
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plural = v[1].split('plural=')[1]
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self.plural = c2py(plural)
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if msg.find('\x00') >= 0:
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# Plural forms
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msgid1, msgid2 = msg.split('\x00')
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tmsg = tmsg.split('\x00')
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if self._coerce:
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msgid1 = unicode(msgid1, self._charset)
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tmsg = [unicode(x, self._charset) for x in tmsg]
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for i in range(len(tmsg)):
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catalog[(msgid1, i)] = tmsg[i]
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else:
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if self._coerce:
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msg = unicode(msg, self._charset)
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tmsg = unicode(tmsg, self._charset)
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catalog[msg] = tmsg
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# advance to next entry in the seek tables
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masteridx += 8
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transidx += 8
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def gettext(self, message):
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try:
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return self._catalog[message]
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except KeyError:
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if self._fallback:
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return self._fallback.gettext(message)
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return message
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def ngettext(self, msgid1, msgid2, n):
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try:
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return self._catalog[(msgid1, self.plural(n))]
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except KeyError:
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if self._fallback:
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return self._fallback.ngettext(msgid1, msgid2, n)
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if n == 1:
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return msgid1
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else:
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return msgid2
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def ugettext(self, message):
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missing = object()
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tmsg = self._catalog.get(message, missing)
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if tmsg is missing:
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if self._fallback:
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return self._fallback.ugettext(message)
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tmsg = message
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if not self._coerce:
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return unicode(tmsg, self._charset)
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# The msgstr is already coerced to Unicode
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return tmsg
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def ungettext(self, msgid1, msgid2, n):
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try:
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tmsg = self._catalog[(msgid1, self.plural(n))]
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except KeyError:
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if self._fallback:
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return self._fallback.ungettext(msgid1, msgid2, n)
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if n == 1:
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tmsg = msgid1
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else:
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tmsg = msgid2
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if not self._coerce:
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return unicode(tmsg, self._charset)
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# The msgstr is already coerced to Unicode
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return tmsg
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# Locate a .mo file using the gettext strategy
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def find(domain, localedir=None, languages=None, all=0):
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# Get some reasonable defaults for arguments that were not supplied
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if localedir is None:
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localedir = _default_localedir
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if languages is None:
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languages = []
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for envar in ('LANGUAGE', 'LC_ALL', 'LC_MESSAGES', 'LANG'):
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val = os.environ.get(envar)
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if val:
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languages = val.split(':')
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break
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if 'C' not in languages:
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languages.append('C')
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# now normalize and expand the languages
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nelangs = []
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for lang in languages:
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for nelang in _expand_lang(lang):
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if nelang not in nelangs:
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nelangs.append(nelang)
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# select a language
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if all:
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result = []
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else:
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result = None
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for lang in nelangs:
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if lang == 'C':
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break
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mofile = os.path.join(localedir, lang, 'LC_MESSAGES', '%s.mo' % domain)
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if os.path.exists(mofile):
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if all:
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result.append(mofile)
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else:
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return mofile
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return result
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# a mapping between absolute .mo file path and Translation object
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_translations = {}
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def translation(domain, localedir=None, languages=None,
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class_=None, fallback=0):
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if class_ is None:
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class_ = GNUTranslations
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mofiles = find(domain, localedir, languages, all=1)
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if len(mofiles)==0:
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if fallback:
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return NullTranslations()
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raise IOError(ENOENT, 'No translation file found for domain', domain)
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# TBD: do we need to worry about the file pointer getting collected?
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# Avoid opening, reading, and parsing the .mo file after it's been done
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# once.
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result = None
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for mofile in mofiles:
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key = os.path.abspath(mofile)
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t = _translations.get(key)
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if t is None:
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t = _translations.setdefault(key, class_(open(mofile, 'rb')))
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# Copy the translation object to allow setting fallbacks.
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# All other instance data is shared with the cached object.
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t = copy.copy(t)
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if result is None:
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result = t
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else:
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result.add_fallback(t)
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return result
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def install(domain, localedir=None, unicode=0):
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translation(domain, localedir, fallback=1).install(unicode)
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# a mapping b/w domains and locale directories
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_localedirs = {}
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# current global domain, `messages' used for compatibility w/ GNU gettext
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_current_domain = 'messages'
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def textdomain(domain=None):
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global _current_domain
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if domain is not None:
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_current_domain = domain
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return _current_domain
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def bindtextdomain(domain, localedir=None):
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global _localedirs
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if localedir is not None:
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_localedirs[domain] = localedir
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return _localedirs.get(domain, _default_localedir)
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def dgettext(domain, message):
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try:
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t = translation(domain, _localedirs.get(domain, None))
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except IOError:
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return message
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return t.gettext(message)
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def dngettext(domain, msgid1, msgid2, n):
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try:
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t = translation(domain, _localedirs.get(domain, None))
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except IOError:
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if n == 1:
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return msgid1
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else:
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return msgid2
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return t.ngettext(msgid1, msgid2, n)
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def gettext(message):
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return dgettext(_current_domain, message)
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def ngettext(msgid1, msgid2, n):
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return dngettext(_current_domain, msgid1, msgid2, n)
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# dcgettext() has been deemed unnecessary and is not implemented.
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# James Henstridge's Catalog constructor from GNOME gettext. Documented usage
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# was:
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#
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# import gettext
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# cat = gettext.Catalog(PACKAGE, localedir=LOCALEDIR)
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# _ = cat.gettext
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# print _('Hello World')
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# The resulting catalog object currently don't support access through a
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# dictionary API, which was supported (but apparently unused) in GNOME
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# gettext.
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Catalog = translation
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