Sergey Sharybin
7f42fdf5e8
Just some glue logic to query progress and results from benchmark. Needed to move files around, so oth standalone and addon are happy.
395 lines
12 KiB
Python
395 lines
12 KiB
Python
from six import PY3
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from functools import wraps
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from datetime import datetime, timedelta, tzinfo
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ZERO = timedelta(0)
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__all__ = ['tzname_in_python2', 'enfold']
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def tzname_in_python2(namefunc):
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"""Change unicode output into bytestrings in Python 2
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tzname() API changed in Python 3. It used to return bytes, but was changed
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to unicode strings
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"""
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def adjust_encoding(*args, **kwargs):
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name = namefunc(*args, **kwargs)
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if name is not None and not PY3:
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name = name.encode()
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return name
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return adjust_encoding
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# The following is adapted from Alexander Belopolsky's tz library
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# https://github.com/abalkin/tz
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if hasattr(datetime, 'fold'):
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# This is the pre-python 3.6 fold situation
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def enfold(dt, fold=1):
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"""
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Provides a unified interface for assigning the ``fold`` attribute to
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datetimes both before and after the implementation of PEP-495.
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:param fold:
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The value for the ``fold`` attribute in the returned datetime. This
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should be either 0 or 1.
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:return:
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Returns an object for which ``getattr(dt, 'fold', 0)`` returns
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``fold`` for all versions of Python. In versions prior to
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Python 3.6, this is a ``_DatetimeWithFold`` object, which is a
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subclass of :py:class:`datetime.datetime` with the ``fold``
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attribute added, if ``fold`` is 1.
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.. versionadded:: 2.6.0
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"""
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return dt.replace(fold=fold)
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else:
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class _DatetimeWithFold(datetime):
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"""
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This is a class designed to provide a PEP 495-compliant interface for
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Python versions before 3.6. It is used only for dates in a fold, so
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the ``fold`` attribute is fixed at ``1``.
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.. versionadded:: 2.6.0
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"""
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__slots__ = ()
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@property
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def fold(self):
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return 1
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def enfold(dt, fold=1):
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"""
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Provides a unified interface for assigning the ``fold`` attribute to
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datetimes both before and after the implementation of PEP-495.
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:param fold:
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The value for the ``fold`` attribute in the returned datetime. This
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should be either 0 or 1.
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:return:
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Returns an object for which ``getattr(dt, 'fold', 0)`` returns
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``fold`` for all versions of Python. In versions prior to
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Python 3.6, this is a ``_DatetimeWithFold`` object, which is a
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subclass of :py:class:`datetime.datetime` with the ``fold``
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attribute added, if ``fold`` is 1.
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.. versionadded:: 2.6.0
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"""
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if getattr(dt, 'fold', 0) == fold:
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return dt
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args = dt.timetuple()[:6]
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args += (dt.microsecond, dt.tzinfo)
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if fold:
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return _DatetimeWithFold(*args)
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else:
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return datetime(*args)
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def _validate_fromutc_inputs(f):
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"""
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The CPython version of ``fromutc`` checks that the input is a ``datetime``
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object and that ``self`` is attached as its ``tzinfo``.
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"""
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@wraps(f)
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def fromutc(self, dt):
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if not isinstance(dt, datetime):
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raise TypeError("fromutc() requires a datetime argument")
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if dt.tzinfo is not self:
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raise ValueError("dt.tzinfo is not self")
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return f(self, dt)
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return fromutc
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class _tzinfo(tzinfo):
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"""
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Base class for all ``dateutil`` ``tzinfo`` objects.
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"""
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def is_ambiguous(self, dt):
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"""
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Whether or not the "wall time" of a given datetime is ambiguous in this
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zone.
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:param dt:
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A :py:class:`datetime.datetime`, naive or time zone aware.
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:return:
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Returns ``True`` if ambiguous, ``False`` otherwise.
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.. versionadded:: 2.6.0
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"""
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dt = dt.replace(tzinfo=self)
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wall_0 = enfold(dt, fold=0)
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wall_1 = enfold(dt, fold=1)
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same_offset = wall_0.utcoffset() == wall_1.utcoffset()
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same_dt = wall_0.replace(tzinfo=None) == wall_1.replace(tzinfo=None)
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return same_dt and not same_offset
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def _fold_status(self, dt_utc, dt_wall):
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"""
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Determine the fold status of a "wall" datetime, given a representation
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of the same datetime as a (naive) UTC datetime. This is calculated based
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on the assumption that ``dt.utcoffset() - dt.dst()`` is constant for all
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datetimes, and that this offset is the actual number of hours separating
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``dt_utc`` and ``dt_wall``.
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:param dt_utc:
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Representation of the datetime as UTC
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:param dt_wall:
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Representation of the datetime as "wall time". This parameter must
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either have a `fold` attribute or have a fold-naive
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:class:`datetime.tzinfo` attached, otherwise the calculation may
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fail.
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"""
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if self.is_ambiguous(dt_wall):
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delta_wall = dt_wall - dt_utc
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_fold = int(delta_wall == (dt_utc.utcoffset() - dt_utc.dst()))
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else:
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_fold = 0
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return _fold
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def _fold(self, dt):
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return getattr(dt, 'fold', 0)
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def _fromutc(self, dt):
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"""
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Given a timezone-aware datetime in a given timezone, calculates a
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timezone-aware datetime in a new timezone.
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Since this is the one time that we *know* we have an unambiguous
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datetime object, we take this opportunity to determine whether the
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datetime is ambiguous and in a "fold" state (e.g. if it's the first
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occurence, chronologically, of the ambiguous datetime).
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:param dt:
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A timezone-aware :class:`datetime.datetime` object.
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"""
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# Re-implement the algorithm from Python's datetime.py
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dtoff = dt.utcoffset()
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if dtoff is None:
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raise ValueError("fromutc() requires a non-None utcoffset() "
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"result")
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# The original datetime.py code assumes that `dst()` defaults to
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# zero during ambiguous times. PEP 495 inverts this presumption, so
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# for pre-PEP 495 versions of python, we need to tweak the algorithm.
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dtdst = dt.dst()
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if dtdst is None:
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raise ValueError("fromutc() requires a non-None dst() result")
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delta = dtoff - dtdst
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dt += delta
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# Set fold=1 so we can default to being in the fold for
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# ambiguous dates.
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dtdst = enfold(dt, fold=1).dst()
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if dtdst is None:
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raise ValueError("fromutc(): dt.dst gave inconsistent "
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"results; cannot convert")
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return dt + dtdst
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@_validate_fromutc_inputs
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def fromutc(self, dt):
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"""
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Given a timezone-aware datetime in a given timezone, calculates a
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timezone-aware datetime in a new timezone.
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Since this is the one time that we *know* we have an unambiguous
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datetime object, we take this opportunity to determine whether the
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datetime is ambiguous and in a "fold" state (e.g. if it's the first
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occurance, chronologically, of the ambiguous datetime).
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:param dt:
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A timezone-aware :class:`datetime.datetime` object.
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"""
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dt_wall = self._fromutc(dt)
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# Calculate the fold status given the two datetimes.
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_fold = self._fold_status(dt, dt_wall)
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# Set the default fold value for ambiguous dates
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return enfold(dt_wall, fold=_fold)
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class tzrangebase(_tzinfo):
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"""
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This is an abstract base class for time zones represented by an annual
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transition into and out of DST. Child classes should implement the following
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methods:
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* ``__init__(self, *args, **kwargs)``
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* ``transitions(self, year)`` - this is expected to return a tuple of
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datetimes representing the DST on and off transitions in standard
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time.
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A fully initialized ``tzrangebase`` subclass should also provide the
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following attributes:
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* ``hasdst``: Boolean whether or not the zone uses DST.
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* ``_dst_offset`` / ``_std_offset``: :class:`datetime.timedelta` objects
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representing the respective UTC offsets.
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* ``_dst_abbr`` / ``_std_abbr``: Strings representing the timezone short
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abbreviations in DST and STD, respectively.
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* ``_hasdst``: Whether or not the zone has DST.
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.. versionadded:: 2.6.0
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"""
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def __init__(self):
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raise NotImplementedError('tzrangebase is an abstract base class')
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def utcoffset(self, dt):
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isdst = self._isdst(dt)
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if isdst is None:
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return None
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elif isdst:
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return self._dst_offset
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else:
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return self._std_offset
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def dst(self, dt):
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isdst = self._isdst(dt)
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if isdst is None:
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return None
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elif isdst:
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return self._dst_base_offset
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else:
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return ZERO
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@tzname_in_python2
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def tzname(self, dt):
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if self._isdst(dt):
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return self._dst_abbr
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else:
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return self._std_abbr
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def fromutc(self, dt):
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""" Given a datetime in UTC, return local time """
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if not isinstance(dt, datetime):
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raise TypeError("fromutc() requires a datetime argument")
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if dt.tzinfo is not self:
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raise ValueError("dt.tzinfo is not self")
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# Get transitions - if there are none, fixed offset
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transitions = self.transitions(dt.year)
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if transitions is None:
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return dt + self.utcoffset(dt)
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# Get the transition times in UTC
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dston, dstoff = transitions
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dston -= self._std_offset
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dstoff -= self._std_offset
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utc_transitions = (dston, dstoff)
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dt_utc = dt.replace(tzinfo=None)
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isdst = self._naive_isdst(dt_utc, utc_transitions)
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if isdst:
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dt_wall = dt + self._dst_offset
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else:
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dt_wall = dt + self._std_offset
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_fold = int(not isdst and self.is_ambiguous(dt_wall))
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return enfold(dt_wall, fold=_fold)
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def is_ambiguous(self, dt):
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"""
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Whether or not the "wall time" of a given datetime is ambiguous in this
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zone.
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:param dt:
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A :py:class:`datetime.datetime`, naive or time zone aware.
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:return:
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Returns ``True`` if ambiguous, ``False`` otherwise.
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.. versionadded:: 2.6.0
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"""
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if not self.hasdst:
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return False
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start, end = self.transitions(dt.year)
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dt = dt.replace(tzinfo=None)
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return (end <= dt < end + self._dst_base_offset)
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def _isdst(self, dt):
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if not self.hasdst:
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return False
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elif dt is None:
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return None
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transitions = self.transitions(dt.year)
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if transitions is None:
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return False
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dt = dt.replace(tzinfo=None)
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isdst = self._naive_isdst(dt, transitions)
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# Handle ambiguous dates
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if not isdst and self.is_ambiguous(dt):
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return not self._fold(dt)
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else:
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return isdst
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def _naive_isdst(self, dt, transitions):
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dston, dstoff = transitions
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dt = dt.replace(tzinfo=None)
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if dston < dstoff:
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isdst = dston <= dt < dstoff
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else:
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isdst = not dstoff <= dt < dston
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return isdst
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@property
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def _dst_base_offset(self):
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return self._dst_offset - self._std_offset
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__hash__ = None
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def __ne__(self, other):
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return not (self == other)
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def __repr__(self):
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return "%s(...)" % self.__class__.__name__
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__reduce__ = object.__reduce__
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def _total_seconds(td):
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# Python 2.6 doesn't have a total_seconds() method on timedelta objects
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return ((td.seconds + td.days * 86400) * 1000000 +
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td.microseconds) // 1000000
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_total_seconds = getattr(timedelta, 'total_seconds', _total_seconds)
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