--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/gettext.py Wed Nov 05 15:52:50 2008 +0100
@@ -0,0 +1,492 @@
+"""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.
+#
+# J. David Ibanez implemented plural forms. Bruno Haible fixed some bugs.
+#
+# 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 copy, os, re, struct, sys
+from errno import ENOENT
+
+
+__all__ = ['NullTranslations', 'GNUTranslations', 'Catalog',
+ 'find', 'translation', 'install', 'textdomain', 'bindtextdomain',
+ 'dgettext', 'dngettext', 'gettext', 'ngettext',
+ ]
+
+_default_localedir = os.path.join(sys.prefix, 'share', 'locale')
+
+
+def test(condition, true, false):
+ """
+ Implements the C expression:
+
+ condition ? true : false
+
+ Required to correctly interpret plural forms.
+ """
+ if condition:
+ return true
+ else:
+ return false
+
+
+def c2py(plural):
+ """Gets a C expression as used in PO files for plural forms and returns a
+ Python lambda function that implements an equivalent expression.
+ """
+ # Security check, allow only the "n" identifier
+ from StringIO import StringIO
+ import token, tokenize
+ tokens = tokenize.generate_tokens(StringIO(plural).readline)
+ try:
+ danger = [x for x in tokens if x[0] == token.NAME and x[1] != 'n']
+ except tokenize.TokenError:
+ raise ValueError, \
+ 'plural forms expression error, maybe unbalanced parenthesis'
+ else:
+ if danger:
+ raise ValueError, 'plural forms expression could be dangerous'
+
+ # Replace some C operators by their Python equivalents
+ plural = plural.replace('&&', ' and ')
+ plural = plural.replace('||', ' or ')
+
+ expr = re.compile(r'\!([^=])')
+ plural = expr.sub(' not \\1', plural)
+
+ # Regular expression and replacement function used to transform
+ # "a?b:c" to "test(a,b,c)".
+ expr = re.compile(r'(.*?)\?(.*?):(.*)')
+ def repl(x):
+ return "test(%s, %s, %s)" % (x.group(1), x.group(2),
+ expr.sub(repl, x.group(3)))
+
+ # Code to transform the plural expression, taking care of parentheses
+ stack = ['']
+ for c in plural:
+ if c == '(':
+ stack.append('')
+ elif c == ')':
+ if len(stack) == 1:
+ # Actually, we never reach this code, because unbalanced
+ # parentheses get caught in the security check at the
+ # beginning.
+ raise ValueError, 'unbalanced parenthesis in plural form'
+ s = expr.sub(repl, stack.pop())
+ stack[-1] += '(%s)' % s
+ else:
+ stack[-1] += c
+ plural = expr.sub(repl, stack.pop())
+
+ return eval('lambda n: int(%s)' % plural)
+
+
+
+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
+ self._fallback = None
+ if fp is not None:
+ self._parse(fp)
+
+ def _parse(self, fp):
+ pass
+
+ def add_fallback(self, fallback):
+ if self._fallback:
+ self._fallback.add_fallback(fallback)
+ else:
+ self._fallback = fallback
+
+ def gettext(self, message):
+ if self._fallback:
+ return self._fallback.gettext(message)
+ return message
+
+ def ngettext(self, msgid1, msgid2, n):
+ if self._fallback:
+ return self._fallback.ngettext(msgid1, msgid2, n)
+ if n == 1:
+ return msgid1
+ else:
+ return msgid2
+
+ def ugettext(self, message):
+ if self._fallback:
+ return self._fallback.ugettext(message)
+ return unicode(message)
+
+ def ungettext(self, msgid1, msgid2, n):
+ if self._fallback:
+ return self._fallback.ungettext(msgid1, msgid2, n)
+ if n == 1:
+ return unicode(msgid1)
+ else:
+ return unicode(msgid2)
+
+ def info(self):
+ return self._info
+
+ def charset(self):
+ return self._charset
+
+ def install(self, unicode=False):
+ import __builtin__
+ __builtin__.__dict__['_'] = unicode and self.ugettext or self.gettext
+
+
+class GNUTranslations(NullTranslations):
+ # Magic number of .mo files
+ LE_MAGIC = 0x950412deL
+ BE_MAGIC = 0xde120495L
+
+ def _parse(self, fp):
+ """Override this method to support alternative .mo formats."""
+ unpack = struct.unpack
+ filename = getattr(fp, 'name', '')
+ # Parse the .mo file header, which consists of 5 little endian 32
+ # bit words.
+ self._catalog = catalog = {}
+ self.plural = lambda n: int(n != 1) # germanic plural by default
+ buf = fp.read()
+ buflen = len(buf)
+ # Are we big endian or little endian?
+ magic = unpack('<I', buf[:4])[0]
+ 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)
+ # 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])
+ mend = moff + mlen
+ tlen, toff = unpack(ii, buf[transidx:transidx+8])
+ tend = toff + tlen
+ if mend < buflen and tend < buflen:
+ msg = buf[moff:mend]
+ tmsg = buf[toff:tend]
+ else:
+ raise IOError(0, 'File is corrupt', filename)
+ # See if we're looking at GNU .mo conventions for metadata
+ if mlen == 0:
+ # Catalog description
+ # don't handle multi-lines fields here, and skip
+ # lines which don't look like a header description
+ # (e.g. "header: value")
+ lastk = k = None
+ for item in tmsg.splitlines():
+ item = item.strip()
+ if not item or not ':' in 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]
+ elif k == 'plural-forms':
+ v = v.split(';')
+ plural = v[1].split('plural=')[1]
+ self.plural = c2py(plural)
+ # Note: we unconditionally convert both msgids and msgstrs to
+ # Unicode using the character encoding specified in the charset
+ # parameter of the Content-Type header. The gettext documentation
+ # strongly encourages msgids to be us-ascii, but some appliations
+ # require alternative encodings (e.g. Zope's ZCML and ZPT). For
+ # traditional gettext applications, the msgid conversion will
+ # cause no problems since us-ascii should always be a subset of
+ # the charset encoding. We may want to fall back to 8-bit msgids
+ # if the Unicode conversion fails.
+ if msg.find('\x00') >= 0:
+ # Plural forms
+ msgid1, msgid2 = msg.split('\x00')
+ tmsg = tmsg.split('\x00')
+ if self._charset:
+ msgid1 = unicode(msgid1, self._charset)
+ tmsg = [unicode(x, self._charset) for x in tmsg]
+ for i in range(len(tmsg)):
+ catalog[(msgid1, i)] = tmsg[i]
+ else:
+ if self._charset:
+ msg = unicode(msg, self._charset)
+ tmsg = unicode(tmsg, self._charset)
+ catalog[msg] = tmsg
+ # advance to next entry in the seek tables
+ masteridx += 8
+ transidx += 8
+
+ def gettext(self, message):
+ missing = object()
+ tmsg = self._catalog.get(message, missing)
+ if tmsg is missing:
+ if self._fallback:
+ return self._fallback.gettext(message)
+ return message
+ # Encode the Unicode tmsg back to an 8-bit string, if possible
+ if self._charset:
+ return tmsg.encode(self._charset)
+ return tmsg
+
+ def ngettext(self, msgid1, msgid2, n):
+ try:
+ tmsg = self._catalog[(msgid1, self.plural(n))]
+ if self._charset:
+ return tmsg.encode(self._charset)
+ return tmsg
+ except KeyError:
+ if self._fallback:
+ return self._fallback.ngettext(msgid1, msgid2, n)
+ if n == 1:
+ return msgid1
+ else:
+ return msgid2
+
+ def ugettext(self, message):
+ missing = object()
+ tmsg = self._catalog.get(message, missing)
+ if tmsg is missing:
+ if self._fallback:
+ return self._fallback.ugettext(message)
+ return unicode(message)
+ return tmsg
+
+ def ungettext(self, msgid1, msgid2, n):
+ try:
+ tmsg = self._catalog[(msgid1, self.plural(n))]
+ except KeyError:
+ if self._fallback:
+ return self._fallback.ungettext(msgid1, msgid2, n)
+ if n == 1:
+ tmsg = unicode(msgid1)
+ else:
+ tmsg = unicode(msgid2)
+ return tmsg
+
+
+# Locate a .mo file using the gettext strategy
+def find(domain, localedir=None, languages=None, all=0):
+ # 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
+ if all:
+ result = []
+ else:
+ result = None
+ for lang in nelangs:
+ if lang == 'C':
+ break
+ mofile = os.path.join(localedir, lang, 'LC_MESSAGES', '%s.mo' % domain)
+ if os.path.exists(mofile):
+ if all:
+ result.append(mofile)
+ else:
+ return mofile
+ return result
+
+
+
+# a mapping between absolute .mo file path and Translation object
+_translations = {}
+
+def translation(domain, localedir=None, languages=None,
+ class_=None, fallback=False):
+ if class_ is None:
+ class_ = GNUTranslations
+ mofiles = find(domain, localedir, languages, all=1)
+ if not mofiles:
+ if fallback:
+ return NullTranslations()
+ raise IOError(ENOENT, 'No translation file found for domain', domain)
+ # 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.
+ result = None
+ for mofile in mofiles:
+ key = os.path.abspath(mofile)
+ t = _translations.get(key)
+ if t is None:
+ t = _translations.setdefault(key, class_(open(mofile, 'rb')))
+ # Copy the translation object to allow setting fallbacks.
+ # All other instance data is shared with the cached object.
+ t = copy.copy(t)
+ if result is None:
+ result = t
+ else:
+ result.add_fallback(t)
+ return result
+
+
+def install(domain, localedir=None, unicode=False):
+ translation(domain, localedir, fallback=True).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 dngettext(domain, msgid1, msgid2, n):
+ try:
+ t = translation(domain, _localedirs.get(domain, None))
+ except IOError:
+ if n == 1:
+ return msgid1
+ else:
+ return msgid2
+ return t.ngettext(msgid1, msgid2, n)
+
+
+def gettext(message):
+ return dgettext(_current_domain, message)
+
+
+def ngettext(msgid1, msgid2, n):
+ return dngettext(_current_domain, msgid1, msgid2, n)
+
+
+# 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