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Diffstat (limited to 'Windows/dateutil/tz/win.py')
| -rw-r--r-- | Windows/dateutil/tz/win.py | 370 |
1 files changed, 370 insertions, 0 deletions
diff --git a/Windows/dateutil/tz/win.py b/Windows/dateutil/tz/win.py new file mode 100644 index 00000000..cde07ba7 --- /dev/null +++ b/Windows/dateutil/tz/win.py @@ -0,0 +1,370 @@ +# -*- coding: utf-8 -*- +""" +This module provides an interface to the native time zone data on Windows, +including :py:class:`datetime.tzinfo` implementations. + +Attempting to import this module on a non-Windows platform will raise an +:py:obj:`ImportError`. +""" +# This code was originally contributed by Jeffrey Harris. +import datetime +import struct + +from six.moves import winreg +from six import text_type + +try: + import ctypes + from ctypes import wintypes +except ValueError: + # ValueError is raised on non-Windows systems for some horrible reason. + raise ImportError("Running tzwin on non-Windows system") + +from ._common import tzrangebase + +__all__ = ["tzwin", "tzwinlocal", "tzres"] + +ONEWEEK = datetime.timedelta(7) + +TZKEYNAMENT = r"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones" +TZKEYNAME9X = r"SOFTWARE\Microsoft\Windows\CurrentVersion\Time Zones" +TZLOCALKEYNAME = r"SYSTEM\CurrentControlSet\Control\TimeZoneInformation" + + +def _settzkeyname(): + handle = winreg.ConnectRegistry(None, winreg.HKEY_LOCAL_MACHINE) + try: + winreg.OpenKey(handle, TZKEYNAMENT).Close() + TZKEYNAME = TZKEYNAMENT + except WindowsError: + TZKEYNAME = TZKEYNAME9X + handle.Close() + return TZKEYNAME + + +TZKEYNAME = _settzkeyname() + + +class tzres(object): + """ + Class for accessing ``tzres.dll``, which contains timezone name related + resources. + + .. versionadded:: 2.5.0 + """ + p_wchar = ctypes.POINTER(wintypes.WCHAR) # Pointer to a wide char + + def __init__(self, tzres_loc='tzres.dll'): + # Load the user32 DLL so we can load strings from tzres + user32 = ctypes.WinDLL('user32') + + # Specify the LoadStringW function + user32.LoadStringW.argtypes = (wintypes.HINSTANCE, + wintypes.UINT, + wintypes.LPWSTR, + ctypes.c_int) + + self.LoadStringW = user32.LoadStringW + self._tzres = ctypes.WinDLL(tzres_loc) + self.tzres_loc = tzres_loc + + def load_name(self, offset): + """ + Load a timezone name from a DLL offset (integer). + + >>> from dateutil.tzwin import tzres + >>> tzr = tzres() + >>> print(tzr.load_name(112)) + 'Eastern Standard Time' + + :param offset: + A positive integer value referring to a string from the tzres dll. + + .. note:: + + Offsets found in the registry are generally of the form + ``@tzres.dll,-114``. The offset in this case is 114, not -114. + + """ + resource = self.p_wchar() + lpBuffer = ctypes.cast(ctypes.byref(resource), wintypes.LPWSTR) + nchar = self.LoadStringW(self._tzres._handle, offset, lpBuffer, 0) + return resource[:nchar] + + def name_from_string(self, tzname_str): + """ + Parse strings as returned from the Windows registry into the time zone + name as defined in the registry. + + >>> from dateutil.tzwin import tzres + >>> tzr = tzres() + >>> print(tzr.name_from_string('@tzres.dll,-251')) + 'Dateline Daylight Time' + >>> print(tzr.name_from_string('Eastern Standard Time')) + 'Eastern Standard Time' + + :param tzname_str: + A timezone name string as returned from a Windows registry key. + + :return: + Returns the localized timezone string from tzres.dll if the string + is of the form `@tzres.dll,-offset`, else returns the input string. + """ + if not tzname_str.startswith('@'): + return tzname_str + + name_splt = tzname_str.split(',-') + try: + offset = int(name_splt[1]) + except: + raise ValueError("Malformed timezone string.") + + return self.load_name(offset) + + +class tzwinbase(tzrangebase): + """tzinfo class based on win32's timezones available in the registry.""" + def __init__(self): + raise NotImplementedError('tzwinbase is an abstract base class') + + def __eq__(self, other): + # Compare on all relevant dimensions, including name. + if not isinstance(other, tzwinbase): + return NotImplemented + + return (self._std_offset == other._std_offset and + self._dst_offset == other._dst_offset and + self._stddayofweek == other._stddayofweek and + self._dstdayofweek == other._dstdayofweek and + self._stdweeknumber == other._stdweeknumber and + self._dstweeknumber == other._dstweeknumber and + self._stdhour == other._stdhour and + self._dsthour == other._dsthour and + self._stdminute == other._stdminute and + self._dstminute == other._dstminute and + self._std_abbr == other._std_abbr and + self._dst_abbr == other._dst_abbr) + + @staticmethod + def list(): + """Return a list of all time zones known to the system.""" + with winreg.ConnectRegistry(None, winreg.HKEY_LOCAL_MACHINE) as handle: + with winreg.OpenKey(handle, TZKEYNAME) as tzkey: + result = [winreg.EnumKey(tzkey, i) + for i in range(winreg.QueryInfoKey(tzkey)[0])] + return result + + def display(self): + """ + Return the display name of the time zone. + """ + return self._display + + def transitions(self, year): + """ + For a given year, get the DST on and off transition times, expressed + always on the standard time side. For zones with no transitions, this + function returns ``None``. + + :param year: + The year whose transitions you would like to query. + + :return: + Returns a :class:`tuple` of :class:`datetime.datetime` objects, + ``(dston, dstoff)`` for zones with an annual DST transition, or + ``None`` for fixed offset zones. + """ + + if not self.hasdst: + return None + + dston = picknthweekday(year, self._dstmonth, self._dstdayofweek, + self._dsthour, self._dstminute, + self._dstweeknumber) + + dstoff = picknthweekday(year, self._stdmonth, self._stddayofweek, + self._stdhour, self._stdminute, + self._stdweeknumber) + + # Ambiguous dates default to the STD side + dstoff -= self._dst_base_offset + + return dston, dstoff + + def _get_hasdst(self): + return self._dstmonth != 0 + + @property + def _dst_base_offset(self): + return self._dst_base_offset_ + + +class tzwin(tzwinbase): + """ + Time zone object created from the zone info in the Windows registry + + These are similar to :py:class:`dateutil.tz.tzrange` objects in that + the time zone data is provided in the format of a single offset rule + for either 0 or 2 time zone transitions per year. + + :param: name + The name of a Windows time zone key, e.g. "Eastern Standard Time". + The full list of keys can be retrieved with :func:`tzwin.list`. + """ + + def __init__(self, name): + self._name = name + + with winreg.ConnectRegistry(None, winreg.HKEY_LOCAL_MACHINE) as handle: + tzkeyname = text_type("{kn}\\{name}").format(kn=TZKEYNAME, name=name) + with winreg.OpenKey(handle, tzkeyname) as tzkey: + keydict = valuestodict(tzkey) + + self._std_abbr = keydict["Std"] + self._dst_abbr = keydict["Dlt"] + + self._display = keydict["Display"] + + # See http://ww_winreg.jsiinc.com/SUBA/tip0300/rh0398.htm + tup = struct.unpack("=3l16h", keydict["TZI"]) + stdoffset = -tup[0]-tup[1] # Bias + StandardBias * -1 + dstoffset = stdoffset-tup[2] # + DaylightBias * -1 + self._std_offset = datetime.timedelta(minutes=stdoffset) + self._dst_offset = datetime.timedelta(minutes=dstoffset) + + # for the meaning see the win32 TIME_ZONE_INFORMATION structure docs + # http://msdn.microsoft.com/en-us/library/windows/desktop/ms725481(v=vs.85).aspx + (self._stdmonth, + self._stddayofweek, # Sunday = 0 + self._stdweeknumber, # Last = 5 + self._stdhour, + self._stdminute) = tup[4:9] + + (self._dstmonth, + self._dstdayofweek, # Sunday = 0 + self._dstweeknumber, # Last = 5 + self._dsthour, + self._dstminute) = tup[12:17] + + self._dst_base_offset_ = self._dst_offset - self._std_offset + self.hasdst = self._get_hasdst() + + def __repr__(self): + return "tzwin(%s)" % repr(self._name) + + def __reduce__(self): + return (self.__class__, (self._name,)) + + +class tzwinlocal(tzwinbase): + """ + Class representing the local time zone information in the Windows registry + + While :class:`dateutil.tz.tzlocal` makes system calls (via the :mod:`time` + module) to retrieve time zone information, ``tzwinlocal`` retrieves the + rules directly from the Windows registry and creates an object like + :class:`dateutil.tz.tzwin`. + + Because Windows does not have an equivalent of :func:`time.tzset`, on + Windows, :class:`dateutil.tz.tzlocal` instances will always reflect the + time zone settings *at the time that the process was started*, meaning + changes to the machine's time zone settings during the run of a program + on Windows will **not** be reflected by :class:`dateutil.tz.tzlocal`. + Because ``tzwinlocal`` reads the registry directly, it is unaffected by + this issue. + """ + def __init__(self): + with winreg.ConnectRegistry(None, winreg.HKEY_LOCAL_MACHINE) as handle: + with winreg.OpenKey(handle, TZLOCALKEYNAME) as tzlocalkey: + keydict = valuestodict(tzlocalkey) + + self._std_abbr = keydict["StandardName"] + self._dst_abbr = keydict["DaylightName"] + + try: + tzkeyname = text_type('{kn}\\{sn}').format(kn=TZKEYNAME, + sn=self._std_abbr) + with winreg.OpenKey(handle, tzkeyname) as tzkey: + _keydict = valuestodict(tzkey) + self._display = _keydict["Display"] + except OSError: + self._display = None + + stdoffset = -keydict["Bias"]-keydict["StandardBias"] + dstoffset = stdoffset-keydict["DaylightBias"] + + self._std_offset = datetime.timedelta(minutes=stdoffset) + self._dst_offset = datetime.timedelta(minutes=dstoffset) + + # For reasons unclear, in this particular key, the day of week has been + # moved to the END of the SYSTEMTIME structure. + tup = struct.unpack("=8h", keydict["StandardStart"]) + + (self._stdmonth, + self._stdweeknumber, # Last = 5 + self._stdhour, + self._stdminute) = tup[1:5] + + self._stddayofweek = tup[7] + + tup = struct.unpack("=8h", keydict["DaylightStart"]) + + (self._dstmonth, + self._dstweeknumber, # Last = 5 + self._dsthour, + self._dstminute) = tup[1:5] + + self._dstdayofweek = tup[7] + + self._dst_base_offset_ = self._dst_offset - self._std_offset + self.hasdst = self._get_hasdst() + + def __repr__(self): + return "tzwinlocal()" + + def __str__(self): + # str will return the standard name, not the daylight name. + return "tzwinlocal(%s)" % repr(self._std_abbr) + + def __reduce__(self): + return (self.__class__, ()) + + +def picknthweekday(year, month, dayofweek, hour, minute, whichweek): + """ dayofweek == 0 means Sunday, whichweek 5 means last instance """ + first = datetime.datetime(year, month, 1, hour, minute) + + # This will work if dayofweek is ISO weekday (1-7) or Microsoft-style (0-6), + # Because 7 % 7 = 0 + weekdayone = first.replace(day=((dayofweek - first.isoweekday()) % 7) + 1) + wd = weekdayone + ((whichweek - 1) * ONEWEEK) + if (wd.month != month): + wd -= ONEWEEK + + return wd + + +def valuestodict(key): + """Convert a registry key's values to a dictionary.""" + dout = {} + size = winreg.QueryInfoKey(key)[1] + tz_res = None + + for i in range(size): + key_name, value, dtype = winreg.EnumValue(key, i) + if dtype == winreg.REG_DWORD or dtype == winreg.REG_DWORD_LITTLE_ENDIAN: + # If it's a DWORD (32-bit integer), it's stored as unsigned - convert + # that to a proper signed integer + if value & (1 << 31): + value = value - (1 << 32) + elif dtype == winreg.REG_SZ: + # If it's a reference to the tzres DLL, load the actual string + if value.startswith('@tzres'): + tz_res = tz_res or tzres() + value = tz_res.name_from_string(value) + + value = value.rstrip('\x00') # Remove trailing nulls + + dout[key_name] = value + + return dout |