| """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 |
| import copy |
| 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 |
| self._fallback = None |
| if fp: |
| 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 ugettext(self, message): |
| if self._fallback: |
| return self._fallback.ugettext(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): |
| try: |
| return self._catalog[message] |
| except KeyError: |
| if self._fallback: |
| return self._fallback.gettext(message) |
| return message |
| |
| def ugettext(self, message): |
| try: |
| tmsg = self._catalog[message] |
| except KeyError: |
| if self._fallback: |
| return self._fallback.ugettext(message) |
| tmsg = message |
| return unicode(tmsg, self._charset) |
| |
| |
| |
| # 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=0): |
| if class_ is None: |
| class_ = GNUTranslations |
| mofiles = find(domain, localedir, languages, all=1) |
| if len(mofiles)==0: |
| 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=0): |
| translation(domain, localedir, fallback=1).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 |