1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
|
from datetime import datetime
import pytz_deprecation_shim as pds
try:
import _winreg as winreg
except ImportError:
import winreg
from tzlocal.windows_tz import win_tz
from tzlocal import utils
_cache_tz = None
_cache_tz_name = None
def valuestodict(key):
"""Convert a registry key's values to a dictionary."""
result = {}
size = winreg.QueryInfoKey(key)[1]
for i in range(size):
data = winreg.EnumValue(key, i)
result[data[0]] = data[1]
return result
def _get_dst_info(tz):
# Find the offset for when it doesn't have DST:
dst_offset = std_offset = None
has_dst = False
year = datetime.now().year
for dt in (datetime(year, 1, 1), datetime(year, 6, 1)):
if tz.dst(dt).total_seconds() == 0.0:
# OK, no DST during winter, get this offset
std_offset = tz.utcoffset(dt).total_seconds()
else:
has_dst = True
return has_dst, std_offset, dst_offset
def _get_localzone_name():
# Windows is special. It has unique time zone names (in several
# meanings of the word) available, but unfortunately, they can be
# translated to the language of the operating system, so we need to
# do a backwards lookup, by going through all time zones and see which
# one matches.
tzenv = utils._tz_name_from_env()
if tzenv:
return tzenv
handle = winreg.ConnectRegistry(None, winreg.HKEY_LOCAL_MACHINE)
TZLOCALKEYNAME = r"SYSTEM\CurrentControlSet\Control\TimeZoneInformation"
localtz = winreg.OpenKey(handle, TZLOCALKEYNAME)
keyvalues = valuestodict(localtz)
localtz.Close()
if "TimeZoneKeyName" in keyvalues:
# Windows 7 and later
# For some reason this returns a string with loads of NUL bytes at
# least on some systems. I don't know if this is a bug somewhere, I
# just work around it.
tzkeyname = keyvalues["TimeZoneKeyName"].split("\x00", 1)[0]
else:
# Don't support XP any longer
raise LookupError("Can not find Windows timezone configuration")
timezone = win_tz.get(tzkeyname)
if timezone is None:
# Nope, that didn't work. Try adding "Standard Time",
# it seems to work a lot of times:
timezone = win_tz.get(tzkeyname + " Standard Time")
# Return what we have.
if timezone is None:
raise utils.ZoneInfoNotFoundError(tzkeyname)
if keyvalues.get("DynamicDaylightTimeDisabled", 0) == 1:
# DST is disabled, so don't return the timezone name,
# instead return Etc/GMT+offset
tz = pds.timezone(timezone)
has_dst, std_offset, dst_offset = _get_dst_info(tz)
if not has_dst:
# The DST is turned off in the windows configuration,
# but this timezone doesn't have DST so it doesn't matter
return timezone
if std_offset is None:
raise utils.ZoneInfoNotFoundError(
f"{tzkeyname} claims to not have a non-DST time!?"
)
if std_offset % 3600:
# I can't convert this to an hourly offset
raise utils.ZoneInfoNotFoundError(
f"tzlocal can't support disabling DST in the {timezone} zone."
)
# This has whole hours as offset, return it as Etc/GMT
return f"Etc/GMT{-std_offset//3600:+.0f}"
return timezone
def get_localzone_name():
"""Get the zoneinfo timezone name that matches the Windows-configured timezone."""
global _cache_tz_name
if _cache_tz_name is None:
_cache_tz_name = _get_localzone_name()
return _cache_tz_name
def get_localzone():
"""Returns the zoneinfo-based tzinfo object that matches the Windows-configured timezone."""
global _cache_tz
if _cache_tz is None:
_cache_tz = pds.timezone(get_localzone_name())
if not utils._tz_name_from_env():
# If the timezone does NOT come from a TZ environment variable,
# verify that it's correct. If it's from the environment,
# we accept it, this is so you can run tests with different timezones.
utils.assert_tz_offset(_cache_tz)
return _cache_tz
def reload_localzone():
"""Reload the cached localzone. You need to call this if the timezone has changed."""
global _cache_tz
global _cache_tz_name
_cache_tz_name = _get_localzone_name()
_cache_tz = pds.timezone(_cache_tz_name)
utils.assert_tz_offset(_cache_tz)
return _cache_tz
|
