calibre-web/vendor/babel/localtime/__init__.py

77 lines
1.7 KiB
Python
Raw Normal View History

# -*- coding: utf-8 -*-
"""
babel.localtime
~~~~~~~~~~~~~~~
Babel specific fork of tzlocal to determine the local timezone
of the system.
:copyright: (c) 2013 by the Babel Team.
:license: BSD, see LICENSE for more details.
"""
import sys
import pytz
import time
from datetime import timedelta, datetime
from datetime import tzinfo
from threading import RLock
if sys.platform == 'win32':
from babel.localtime._win32 import _get_localzone
else:
from babel.localtime._unix import _get_localzone
_cached_tz = None
_cache_lock = RLock()
STDOFFSET = timedelta(seconds = -time.timezone)
if time.daylight:
DSTOFFSET = timedelta(seconds = -time.altzone)
else:
DSTOFFSET = STDOFFSET
DSTDIFF = DSTOFFSET - STDOFFSET
ZERO = timedelta(0)
class _FallbackLocalTimezone(tzinfo):
def utcoffset(self, dt):
if self._isdst(dt):
return DSTOFFSET
else:
return STDOFFSET
def dst(self, dt):
if self._isdst(dt):
return DSTDIFF
else:
return ZERO
def tzname(self, dt):
return time.tzname[self._isdst(dt)]
def _isdst(self, dt):
tt = (dt.year, dt.month, dt.day,
dt.hour, dt.minute, dt.second,
dt.weekday(), 0, -1)
stamp = time.mktime(tt)
tt = time.localtime(stamp)
return tt.tm_isdst > 0
def get_localzone():
"""Returns the current underlying local timezone object.
Generally this function does not need to be used, it's a
better idea to use the :data:`LOCALTZ` singleton instead.
"""
return _get_localzone()
try:
LOCALTZ = get_localzone()
except pytz.UnknownTimeZoneError:
LOCALTZ = _FallbackLocalTimezone()