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# -*- coding: utf-8 -*-
import logging
import os
import warnings
import tempfile
import shutil
import json
from tarfile import TarFile
from pkgutil import get_data
from io import BytesIO
from contextlib import closing
from dateutil.tz import tzfile
__all__ = ["gettz", "gettz_db_metadata", "rebuild"]
ZONEFILENAME = "dateutil-zoneinfo.tar.gz"
METADATA_FN = 'METADATA'
# python2.6 compatability. Note that TarFile.__exit__ != TarFile.close, but
# it's close enough for python2.6
tar_open = TarFile.open
if not hasattr(TarFile, '__exit__'):
def tar_open(*args, **kwargs):
return closing(TarFile.open(*args, **kwargs))
class tzfile(tzfile):
def __reduce__(self):
return (gettz, (self._filename,))
def getzoneinfofile_stream():
try:
return BytesIO(get_data(__name__, ZONEFILENAME))
except IOError as e: # TODO switch to FileNotFoundError?
warnings.warn("I/O error({0}): {1}".format(e.errno, e.strerror))
return None
class ZoneInfoFile(object):
def __init__(self, zonefile_stream=None):
if zonefile_stream is not None:
with tar_open(fileobj=zonefile_stream, mode='r') as tf:
# dict comprehension does not work on python2.6
# TODO: get back to the nicer syntax when we ditch python2.6
# self.zones = {zf.name: tzfile(tf.extractfile(zf),
# filename = zf.name)
# for zf in tf.getmembers() if zf.isfile()}
self.zones = dict((zf.name, tzfile(tf.extractfile(zf),
filename=zf.name))
for zf in tf.getmembers()
if zf.isfile() and zf.name != METADATA_FN)
# deal with links: They'll point to their parent object. Less
# waste of memory
# links = {zl.name: self.zones[zl.linkname]
# for zl in tf.getmembers() if zl.islnk() or zl.issym()}
links = dict((zl.name, self.zones[zl.linkname])
for zl in tf.getmembers() if
zl.islnk() or zl.issym())
self.zones.update(links)
try:
metadata_json = tf.extractfile(tf.getmember(METADATA_FN))
metadata_str = metadata_json.read().decode('UTF-8')
self.metadata = json.loads(metadata_str)
except KeyError:
# no metadata in tar file
self.metadata = None
else:
self.zones = dict()
self.metadata = None
# The current API has gettz as a module function, although in fact it taps into
# a stateful class. So as a workaround for now, without changing the API, we
# will create a new "global" class instance the first time a user requests a
# timezone. Ugly, but adheres to the api.
#
# TODO: deprecate this.
_CLASS_ZONE_INSTANCE = list()
def gettz(name):
if len(_CLASS_ZONE_INSTANCE) == 0:
_CLASS_ZONE_INSTANCE.append(ZoneInfoFile(getzoneinfofile_stream()))
return _CLASS_ZONE_INSTANCE[0].zones.get(name)
def gettz_db_metadata():
""" Get the zonefile metadata
See `zonefile_metadata`_
:returns: A dictionary with the database metadata
"""
if len(_CLASS_ZONE_INSTANCE) == 0:
_CLASS_ZONE_INSTANCE.append(ZoneInfoFile(getzoneinfofile_stream()))
return _CLASS_ZONE_INSTANCE[0].metadata
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