| """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 |
| lastk = k = None |
| for item in tmsg.splitlines(): |
| item = item.strip() |
| if not item: |
| continue |
| if ':' in item: |
| k, v = item.split(':', 1) |
| k = k.strip().lower() |
| v = v.strip() |
| self._info[k] = v |
| lastk = k |
| elif lastk: |
| self._info[lastk] += '\n' + item |
| 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 |