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- # -*- test-case-name: twisted.python.test.test_tzhelper -*-
- # Copyright (c) Twisted Matrix Laboratories.
- # See LICENSE for details.
-
- """
- Time zone utilities.
- """
-
- from datetime import datetime as DateTime, timedelta as TimeDelta, tzinfo as TZInfo
- from typing import Optional
-
- __all__ = [
- "FixedOffsetTimeZone",
- "UTC",
- ]
-
-
- class FixedOffsetTimeZone(TZInfo):
- """
- Represents a fixed timezone offset (without daylight saving time).
-
- @ivar name: A L{str} giving the name of this timezone; the name just
- includes how much time this offset represents.
-
- @ivar offset: A L{TimeDelta} giving the amount of time this timezone is
- offset.
- """
-
- def __init__(self, offset: TimeDelta, name: Optional[str] = None) -> None:
- """
- Construct a L{FixedOffsetTimeZone} with a fixed offset.
-
- @param offset: a delta representing the offset from UTC.
- @param name: A name to be given for this timezone.
- """
- self.offset = offset
- self.name = name
-
- @classmethod
- def fromSignHoursMinutes(
- cls, sign: str, hours: int, minutes: int
- ) -> "FixedOffsetTimeZone":
- """
- Construct a L{FixedOffsetTimeZone} from an offset described by sign
- ('+' or '-'), hours, and minutes.
-
- @note: For protocol compatibility with AMP, this method never uses 'Z'
-
- @param sign: A string describing the positive or negative-ness of the
- offset.
- @param hours: The number of hours in the offset.
- @param minutes: The number of minutes in the offset
-
- @return: A time zone with the given offset, and a name describing the
- offset.
- """
- name = "%s%02i:%02i" % (sign, hours, minutes)
- if sign == "-":
- hours = -hours
- minutes = -minutes
- elif sign != "+":
- raise ValueError(f"Invalid sign for timezone {sign!r}")
- return cls(TimeDelta(hours=hours, minutes=minutes), name)
-
- @classmethod
- def fromLocalTimeStamp(cls, timeStamp: float) -> "FixedOffsetTimeZone":
- """
- Create a time zone with a fixed offset corresponding to a time stamp in
- the system's locally configured time zone.
- """
- offset = DateTime.fromtimestamp(timeStamp) - DateTime.utcfromtimestamp(
- timeStamp
- )
- return cls(offset)
-
- def utcoffset(self, dt: Optional[DateTime]) -> TimeDelta:
- """
- Return the given timezone's offset from UTC.
- """
- return self.offset
-
- def dst(self, dt: Optional[DateTime]) -> TimeDelta:
- """
- Return a zero L{TimeDelta} for the daylight saving time
- offset, since there is never one.
- """
- return TimeDelta(0)
-
- def tzname(self, dt: Optional[DateTime]) -> str:
- """
- Return a string describing this timezone.
- """
- if self.name is not None:
- return self.name
- # XXX this is wrong; the tests are
- dt = DateTime.fromtimestamp(0, self)
- return dt.strftime("UTC%z")
-
-
- UTC = FixedOffsetTimeZone.fromSignHoursMinutes("+", 0, 0)
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