mirror of
https://github.com/python/cpython.git
synced 2026-01-06 15:32:22 +00:00
5c55f50a71
zipinfo now supports the full range of values in the TZ string determined by RFC 8536 and detects all invalid formats. Both Python and C implementations now raise exceptions of the same type on invalid data. (cherry picked from commitab08ff7882) (cherry picked from commit72b0f0eaf5)
772 lines
24 KiB
Python
772 lines
24 KiB
Python
import bisect
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import calendar
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import collections
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import functools
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import re
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import weakref
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from datetime import datetime, timedelta, tzinfo
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from . import _common, _tzpath
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EPOCH = datetime(1970, 1, 1)
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EPOCHORDINAL = datetime(1970, 1, 1).toordinal()
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# It is relatively expensive to construct new timedelta objects, and in most
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# cases we're looking at the same deltas, like integer numbers of hours, etc.
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# To improve speed and memory use, we'll keep a dictionary with references
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# to the ones we've already used so far.
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#
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# Loading every time zone in the 2020a version of the time zone database
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# requires 447 timedeltas, which requires approximately the amount of space
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# that ZoneInfo("America/New_York") with 236 transitions takes up, so we will
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# set the cache size to 512 so that in the common case we always get cache
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# hits, but specifically crafted ZoneInfo objects don't leak arbitrary amounts
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# of memory.
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@functools.lru_cache(maxsize=512)
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def _load_timedelta(seconds):
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return timedelta(seconds=seconds)
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class ZoneInfo(tzinfo):
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_strong_cache_size = 8
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_strong_cache = collections.OrderedDict()
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_weak_cache = weakref.WeakValueDictionary()
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__module__ = "zoneinfo"
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def __init_subclass__(cls):
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cls._strong_cache = collections.OrderedDict()
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cls._weak_cache = weakref.WeakValueDictionary()
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def __new__(cls, key):
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instance = cls._weak_cache.get(key, None)
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if instance is None:
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instance = cls._weak_cache.setdefault(key, cls._new_instance(key))
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instance._from_cache = True
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# Update the "strong" cache
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cls._strong_cache[key] = cls._strong_cache.pop(key, instance)
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if len(cls._strong_cache) > cls._strong_cache_size:
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cls._strong_cache.popitem(last=False)
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return instance
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@classmethod
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def no_cache(cls, key):
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obj = cls._new_instance(key)
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obj._from_cache = False
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return obj
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@classmethod
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def _new_instance(cls, key):
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obj = super().__new__(cls)
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obj._key = key
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obj._file_path = obj._find_tzfile(key)
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if obj._file_path is not None:
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file_obj = open(obj._file_path, "rb")
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else:
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file_obj = _common.load_tzdata(key)
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with file_obj as f:
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obj._load_file(f)
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return obj
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@classmethod
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def from_file(cls, fobj, /, key=None):
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obj = super().__new__(cls)
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obj._key = key
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obj._file_path = None
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obj._load_file(fobj)
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obj._file_repr = repr(fobj)
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# Disable pickling for objects created from files
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obj.__reduce__ = obj._file_reduce
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return obj
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@classmethod
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def clear_cache(cls, *, only_keys=None):
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if only_keys is not None:
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for key in only_keys:
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cls._weak_cache.pop(key, None)
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cls._strong_cache.pop(key, None)
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else:
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cls._weak_cache.clear()
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cls._strong_cache.clear()
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@property
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def key(self):
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return self._key
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def utcoffset(self, dt):
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return self._find_trans(dt).utcoff
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def dst(self, dt):
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return self._find_trans(dt).dstoff
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def tzname(self, dt):
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return self._find_trans(dt).tzname
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def fromutc(self, dt):
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"""Convert from datetime in UTC to datetime in 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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timestamp = self._get_local_timestamp(dt)
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num_trans = len(self._trans_utc)
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if num_trans >= 1 and timestamp < self._trans_utc[0]:
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tti = self._tti_before
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fold = 0
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elif (
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num_trans == 0 or timestamp > self._trans_utc[-1]
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) and not isinstance(self._tz_after, _ttinfo):
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tti, fold = self._tz_after.get_trans_info_fromutc(
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timestamp, dt.year
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)
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elif num_trans == 0:
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tti = self._tz_after
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fold = 0
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else:
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idx = bisect.bisect_right(self._trans_utc, timestamp)
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if num_trans > 1 and timestamp >= self._trans_utc[1]:
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tti_prev, tti = self._ttinfos[idx - 2 : idx]
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elif timestamp > self._trans_utc[-1]:
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tti_prev = self._ttinfos[-1]
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tti = self._tz_after
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else:
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tti_prev = self._tti_before
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tti = self._ttinfos[0]
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# Detect fold
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shift = tti_prev.utcoff - tti.utcoff
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fold = shift.total_seconds() > timestamp - self._trans_utc[idx - 1]
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dt += tti.utcoff
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if fold:
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return dt.replace(fold=1)
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else:
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return dt
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def _find_trans(self, dt):
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if dt is None:
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if self._fixed_offset:
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return self._tz_after
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else:
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return _NO_TTINFO
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ts = self._get_local_timestamp(dt)
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lt = self._trans_local[dt.fold]
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num_trans = len(lt)
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if num_trans and ts < lt[0]:
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return self._tti_before
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elif not num_trans or ts > lt[-1]:
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if isinstance(self._tz_after, _TZStr):
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return self._tz_after.get_trans_info(ts, dt.year, dt.fold)
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else:
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return self._tz_after
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else:
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# idx is the transition that occurs after this timestamp, so we
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# subtract off 1 to get the current ttinfo
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idx = bisect.bisect_right(lt, ts) - 1
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assert idx >= 0
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return self._ttinfos[idx]
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def _get_local_timestamp(self, dt):
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return (
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(dt.toordinal() - EPOCHORDINAL) * 86400
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+ dt.hour * 3600
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+ dt.minute * 60
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+ dt.second
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)
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def __str__(self):
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if self._key is not None:
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return f"{self._key}"
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else:
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return repr(self)
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def __repr__(self):
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if self._key is not None:
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return f"{self.__class__.__name__}(key={self._key!r})"
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else:
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return f"{self.__class__.__name__}.from_file({self._file_repr})"
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def __reduce__(self):
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return (self.__class__._unpickle, (self._key, self._from_cache))
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def _file_reduce(self):
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import pickle
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raise pickle.PicklingError(
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"Cannot pickle a ZoneInfo file created from a file stream."
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)
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@classmethod
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def _unpickle(cls, key, from_cache, /):
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if from_cache:
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return cls(key)
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else:
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return cls.no_cache(key)
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def _find_tzfile(self, key):
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return _tzpath.find_tzfile(key)
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def _load_file(self, fobj):
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# Retrieve all the data as it exists in the zoneinfo file
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trans_idx, trans_utc, utcoff, isdst, abbr, tz_str = _common.load_data(
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fobj
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)
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# Infer the DST offsets (needed for .dst()) from the data
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dstoff = self._utcoff_to_dstoff(trans_idx, utcoff, isdst)
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# Convert all the transition times (UTC) into "seconds since 1970-01-01 local time"
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trans_local = self._ts_to_local(trans_idx, trans_utc, utcoff)
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# Construct `_ttinfo` objects for each transition in the file
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_ttinfo_list = [
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_ttinfo(
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_load_timedelta(utcoffset), _load_timedelta(dstoffset), tzname
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)
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for utcoffset, dstoffset, tzname in zip(utcoff, dstoff, abbr)
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]
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self._trans_utc = trans_utc
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self._trans_local = trans_local
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self._ttinfos = [_ttinfo_list[idx] for idx in trans_idx]
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# Find the first non-DST transition
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for i in range(len(isdst)):
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if not isdst[i]:
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self._tti_before = _ttinfo_list[i]
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break
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else:
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if self._ttinfos:
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self._tti_before = self._ttinfos[0]
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else:
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self._tti_before = None
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# Set the "fallback" time zone
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if tz_str is not None and tz_str != b"":
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self._tz_after = _parse_tz_str(tz_str.decode())
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else:
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if not self._ttinfos and not _ttinfo_list:
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raise ValueError("No time zone information found.")
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if self._ttinfos:
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self._tz_after = self._ttinfos[-1]
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else:
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self._tz_after = _ttinfo_list[-1]
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# Determine if this is a "fixed offset" zone, meaning that the output
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# of the utcoffset, dst and tzname functions does not depend on the
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# specific datetime passed.
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#
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# We make three simplifying assumptions here:
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#
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# 1. If _tz_after is not a _ttinfo, it has transitions that might
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# actually occur (it is possible to construct TZ strings that
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# specify STD and DST but no transitions ever occur, such as
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# AAA0BBB,0/0,J365/25).
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# 2. If _ttinfo_list contains more than one _ttinfo object, the objects
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# represent different offsets.
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# 3. _ttinfo_list contains no unused _ttinfos (in which case an
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# otherwise fixed-offset zone with extra _ttinfos defined may
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# appear to *not* be a fixed offset zone).
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#
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# Violations to these assumptions would be fairly exotic, and exotic
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# zones should almost certainly not be used with datetime.time (the
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# only thing that would be affected by this).
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if len(_ttinfo_list) > 1 or not isinstance(self._tz_after, _ttinfo):
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self._fixed_offset = False
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elif not _ttinfo_list:
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self._fixed_offset = True
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else:
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self._fixed_offset = _ttinfo_list[0] == self._tz_after
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@staticmethod
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def _utcoff_to_dstoff(trans_idx, utcoffsets, isdsts):
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# Now we must transform our ttis and abbrs into `_ttinfo` objects,
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# but there is an issue: .dst() must return a timedelta with the
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# difference between utcoffset() and the "standard" offset, but
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# the "base offset" and "DST offset" are not encoded in the file;
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# we can infer what they are from the isdst flag, but it is not
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# sufficient to just look at the last standard offset, because
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# occasionally countries will shift both DST offset and base offset.
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typecnt = len(isdsts)
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dstoffs = [0] * typecnt # Provisionally assign all to 0.
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dst_cnt = sum(isdsts)
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dst_found = 0
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for i in range(1, len(trans_idx)):
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if dst_cnt == dst_found:
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break
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idx = trans_idx[i]
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dst = isdsts[idx]
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# We're only going to look at daylight saving time
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if not dst:
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continue
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# Skip any offsets that have already been assigned
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if dstoffs[idx] != 0:
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continue
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dstoff = 0
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utcoff = utcoffsets[idx]
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comp_idx = trans_idx[i - 1]
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if not isdsts[comp_idx]:
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dstoff = utcoff - utcoffsets[comp_idx]
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if not dstoff and idx < (typecnt - 1):
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comp_idx = trans_idx[i + 1]
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# If the following transition is also DST and we couldn't
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# find the DST offset by this point, we're going to have to
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# skip it and hope this transition gets assigned later
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if isdsts[comp_idx]:
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continue
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dstoff = utcoff - utcoffsets[comp_idx]
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if dstoff:
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dst_found += 1
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dstoffs[idx] = dstoff
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else:
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# If we didn't find a valid value for a given index, we'll end up
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# with dstoff = 0 for something where `isdst=1`. This is obviously
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# wrong - one hour will be a much better guess than 0
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for idx in range(typecnt):
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if not dstoffs[idx] and isdsts[idx]:
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dstoffs[idx] = 3600
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return dstoffs
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@staticmethod
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def _ts_to_local(trans_idx, trans_list_utc, utcoffsets):
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"""Generate number of seconds since 1970 *in the local time*.
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This is necessary to easily find the transition times in local time"""
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if not trans_list_utc:
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return [[], []]
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# Start with the timestamps and modify in-place
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trans_list_wall = [list(trans_list_utc), list(trans_list_utc)]
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if len(utcoffsets) > 1:
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offset_0 = utcoffsets[0]
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offset_1 = utcoffsets[trans_idx[0]]
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if offset_1 > offset_0:
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offset_1, offset_0 = offset_0, offset_1
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else:
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offset_0 = offset_1 = utcoffsets[0]
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trans_list_wall[0][0] += offset_0
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trans_list_wall[1][0] += offset_1
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for i in range(1, len(trans_idx)):
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offset_0 = utcoffsets[trans_idx[i - 1]]
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offset_1 = utcoffsets[trans_idx[i]]
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if offset_1 > offset_0:
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offset_1, offset_0 = offset_0, offset_1
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trans_list_wall[0][i] += offset_0
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trans_list_wall[1][i] += offset_1
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return trans_list_wall
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class _ttinfo:
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__slots__ = ["utcoff", "dstoff", "tzname"]
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def __init__(self, utcoff, dstoff, tzname):
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self.utcoff = utcoff
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self.dstoff = dstoff
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self.tzname = tzname
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def __eq__(self, other):
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return (
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self.utcoff == other.utcoff
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and self.dstoff == other.dstoff
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and self.tzname == other.tzname
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)
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def __repr__(self): # pragma: nocover
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return (
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f"{self.__class__.__name__}"
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+ f"({self.utcoff}, {self.dstoff}, {self.tzname})"
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)
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_NO_TTINFO = _ttinfo(None, None, None)
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class _TZStr:
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__slots__ = (
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"std",
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"dst",
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"start",
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"end",
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"get_trans_info",
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"get_trans_info_fromutc",
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"dst_diff",
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)
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def __init__(
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self, std_abbr, std_offset, dst_abbr, dst_offset, start=None, end=None
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):
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self.dst_diff = dst_offset - std_offset
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std_offset = _load_timedelta(std_offset)
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self.std = _ttinfo(
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utcoff=std_offset, dstoff=_load_timedelta(0), tzname=std_abbr
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)
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self.start = start
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self.end = end
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dst_offset = _load_timedelta(dst_offset)
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delta = _load_timedelta(self.dst_diff)
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self.dst = _ttinfo(utcoff=dst_offset, dstoff=delta, tzname=dst_abbr)
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# These are assertions because the constructor should only be called
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# by functions that would fail before passing start or end
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assert start is not None, "No transition start specified"
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assert end is not None, "No transition end specified"
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self.get_trans_info = self._get_trans_info
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self.get_trans_info_fromutc = self._get_trans_info_fromutc
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def transitions(self, year):
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start = self.start.year_to_epoch(year)
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end = self.end.year_to_epoch(year)
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return start, end
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def _get_trans_info(self, ts, year, fold):
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"""Get the information about the current transition - tti"""
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start, end = self.transitions(year)
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# With fold = 0, the period (denominated in local time) with the
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# smaller offset starts at the end of the gap and ends at the end of
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# the fold; with fold = 1, it runs from the start of the gap to the
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# beginning of the fold.
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#
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# So in order to determine the DST boundaries we need to know both
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# the fold and whether DST is positive or negative (rare), and it
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# turns out that this boils down to fold XOR is_positive.
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if fold == (self.dst_diff >= 0):
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end -= self.dst_diff
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else:
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start += self.dst_diff
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if start < end:
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isdst = start <= ts < end
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else:
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isdst = not (end <= ts < start)
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return self.dst if isdst else self.std
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def _get_trans_info_fromutc(self, ts, year):
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start, end = self.transitions(year)
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start -= self.std.utcoff.total_seconds()
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end -= self.dst.utcoff.total_seconds()
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if start < end:
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isdst = start <= ts < end
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else:
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isdst = not (end <= ts < start)
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# For positive DST, the ambiguous period is one dst_diff after the end
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# of DST; for negative DST, the ambiguous period is one dst_diff before
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# the start of DST.
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if self.dst_diff > 0:
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ambig_start = end
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ambig_end = end + self.dst_diff
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else:
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ambig_start = start
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ambig_end = start - self.dst_diff
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fold = ambig_start <= ts < ambig_end
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return (self.dst if isdst else self.std, fold)
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def _post_epoch_days_before_year(year):
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"""Get the number of days between 1970-01-01 and YEAR-01-01"""
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y = year - 1
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return y * 365 + y // 4 - y // 100 + y // 400 - EPOCHORDINAL
|
|
|
|
|
|
class _DayOffset:
|
|
__slots__ = ["d", "julian", "hour", "minute", "second"]
|
|
|
|
def __init__(self, d, julian, hour=2, minute=0, second=0):
|
|
min_day = 0 + julian # convert bool to int
|
|
if not min_day <= d <= 365:
|
|
raise ValueError(f"d must be in [{min_day}, 365], not: {d}")
|
|
|
|
self.d = d
|
|
self.julian = julian
|
|
self.hour = hour
|
|
self.minute = minute
|
|
self.second = second
|
|
|
|
def year_to_epoch(self, year):
|
|
days_before_year = _post_epoch_days_before_year(year)
|
|
|
|
d = self.d
|
|
if self.julian and d >= 59 and calendar.isleap(year):
|
|
d += 1
|
|
|
|
epoch = (days_before_year + d) * 86400
|
|
epoch += self.hour * 3600 + self.minute * 60 + self.second
|
|
|
|
return epoch
|
|
|
|
|
|
class _CalendarOffset:
|
|
__slots__ = ["m", "w", "d", "hour", "minute", "second"]
|
|
|
|
_DAYS_BEFORE_MONTH = (
|
|
-1,
|
|
0,
|
|
31,
|
|
59,
|
|
90,
|
|
120,
|
|
151,
|
|
181,
|
|
212,
|
|
243,
|
|
273,
|
|
304,
|
|
334,
|
|
)
|
|
|
|
def __init__(self, m, w, d, hour=2, minute=0, second=0):
|
|
if not 1 <= m <= 12:
|
|
raise ValueError("m must be in [1, 12]")
|
|
|
|
if not 1 <= w <= 5:
|
|
raise ValueError("w must be in [1, 5]")
|
|
|
|
if not 0 <= d <= 6:
|
|
raise ValueError("d must be in [0, 6]")
|
|
|
|
self.m = m
|
|
self.w = w
|
|
self.d = d
|
|
self.hour = hour
|
|
self.minute = minute
|
|
self.second = second
|
|
|
|
@classmethod
|
|
def _ymd2ord(cls, year, month, day):
|
|
return (
|
|
_post_epoch_days_before_year(year)
|
|
+ cls._DAYS_BEFORE_MONTH[month]
|
|
+ (month > 2 and calendar.isleap(year))
|
|
+ day
|
|
)
|
|
|
|
# TODO: These are not actually epoch dates as they are expressed in local time
|
|
def year_to_epoch(self, year):
|
|
"""Calculates the datetime of the occurrence from the year"""
|
|
# We know year and month, we need to convert w, d into day of month
|
|
#
|
|
# Week 1 is the first week in which day `d` (where 0 = Sunday) appears.
|
|
# Week 5 represents the last occurrence of day `d`, so we need to know
|
|
# the range of the month.
|
|
first_day, days_in_month = calendar.monthrange(year, self.m)
|
|
|
|
# This equation seems magical, so I'll break it down:
|
|
# 1. calendar says 0 = Monday, POSIX says 0 = Sunday
|
|
# so we need first_day + 1 to get 1 = Monday -> 7 = Sunday,
|
|
# which is still equivalent because this math is mod 7
|
|
# 2. Get first day - desired day mod 7: -1 % 7 = 6, so we don't need
|
|
# to do anything to adjust negative numbers.
|
|
# 3. Add 1 because month days are a 1-based index.
|
|
month_day = (self.d - (first_day + 1)) % 7 + 1
|
|
|
|
# Now use a 0-based index version of `w` to calculate the w-th
|
|
# occurrence of `d`
|
|
month_day += (self.w - 1) * 7
|
|
|
|
# month_day will only be > days_in_month if w was 5, and `w` means
|
|
# "last occurrence of `d`", so now we just check if we over-shot the
|
|
# end of the month and if so knock off 1 week.
|
|
if month_day > days_in_month:
|
|
month_day -= 7
|
|
|
|
ordinal = self._ymd2ord(year, self.m, month_day)
|
|
epoch = ordinal * 86400
|
|
epoch += self.hour * 3600 + self.minute * 60 + self.second
|
|
return epoch
|
|
|
|
|
|
def _parse_tz_str(tz_str):
|
|
# The tz string has the format:
|
|
#
|
|
# std[offset[dst[offset],start[/time],end[/time]]]
|
|
#
|
|
# std and dst must be 3 or more characters long and must not contain
|
|
# a leading colon, embedded digits, commas, nor a plus or minus signs;
|
|
# The spaces between "std" and "offset" are only for display and are
|
|
# not actually present in the string.
|
|
#
|
|
# The format of the offset is ``[+|-]hh[:mm[:ss]]``
|
|
|
|
offset_str, *start_end_str = tz_str.split(",", 1)
|
|
|
|
parser_re = re.compile(
|
|
r"""
|
|
(?P<std>[^<0-9:.+-]+|<[a-zA-Z0-9+-]+>)
|
|
(?:
|
|
(?P<stdoff>[+-]?\d{1,3}(?::\d{2}(?::\d{2})?)?)
|
|
(?:
|
|
(?P<dst>[^0-9:.+-]+|<[a-zA-Z0-9+-]+>)
|
|
(?P<dstoff>[+-]?\d{1,3}(?::\d{2}(?::\d{2})?)?)?
|
|
)? # dst
|
|
)? # stdoff
|
|
""",
|
|
re.ASCII|re.VERBOSE
|
|
)
|
|
|
|
m = parser_re.fullmatch(offset_str)
|
|
|
|
if m is None:
|
|
raise ValueError(f"{tz_str} is not a valid TZ string")
|
|
|
|
std_abbr = m.group("std")
|
|
dst_abbr = m.group("dst")
|
|
dst_offset = None
|
|
|
|
std_abbr = std_abbr.strip("<>")
|
|
|
|
if dst_abbr:
|
|
dst_abbr = dst_abbr.strip("<>")
|
|
|
|
if std_offset := m.group("stdoff"):
|
|
try:
|
|
std_offset = _parse_tz_delta(std_offset)
|
|
except ValueError as e:
|
|
raise ValueError(f"Invalid STD offset in {tz_str}") from e
|
|
else:
|
|
std_offset = 0
|
|
|
|
if dst_abbr is not None:
|
|
if dst_offset := m.group("dstoff"):
|
|
try:
|
|
dst_offset = _parse_tz_delta(dst_offset)
|
|
except ValueError as e:
|
|
raise ValueError(f"Invalid DST offset in {tz_str}") from e
|
|
else:
|
|
dst_offset = std_offset + 3600
|
|
|
|
if not start_end_str:
|
|
raise ValueError(f"Missing transition rules: {tz_str}")
|
|
|
|
start_end_strs = start_end_str[0].split(",", 1)
|
|
try:
|
|
start, end = (_parse_dst_start_end(x) for x in start_end_strs)
|
|
except ValueError as e:
|
|
raise ValueError(f"Invalid TZ string: {tz_str}") from e
|
|
|
|
return _TZStr(std_abbr, std_offset, dst_abbr, dst_offset, start, end)
|
|
elif start_end_str:
|
|
raise ValueError(f"Transition rule present without DST: {tz_str}")
|
|
else:
|
|
# This is a static ttinfo, don't return _TZStr
|
|
return _ttinfo(
|
|
_load_timedelta(std_offset), _load_timedelta(0), std_abbr
|
|
)
|
|
|
|
|
|
def _parse_dst_start_end(dststr):
|
|
date, *time = dststr.split("/", 1)
|
|
type = date[:1]
|
|
if type == "M":
|
|
n_is_julian = False
|
|
m = re.fullmatch(r"M(\d{1,2})\.(\d).(\d)", date, re.ASCII)
|
|
if m is None:
|
|
raise ValueError(f"Invalid dst start/end date: {dststr}")
|
|
date_offset = tuple(map(int, m.groups()))
|
|
offset = _CalendarOffset(*date_offset)
|
|
else:
|
|
if type == "J":
|
|
n_is_julian = True
|
|
date = date[1:]
|
|
else:
|
|
n_is_julian = False
|
|
|
|
doy = int(date)
|
|
offset = _DayOffset(doy, n_is_julian)
|
|
|
|
if time:
|
|
offset.hour, offset.minute, offset.second = _parse_transition_time(time[0])
|
|
|
|
return offset
|
|
|
|
|
|
def _parse_transition_time(time_str):
|
|
match = re.fullmatch(
|
|
r"(?P<sign>[+-])?(?P<h>\d{1,3})(:(?P<m>\d{2})(:(?P<s>\d{2}))?)?",
|
|
time_str,
|
|
re.ASCII
|
|
)
|
|
if match is None:
|
|
raise ValueError(f"Invalid time: {time_str}")
|
|
|
|
h, m, s = (int(v or 0) for v in match.group("h", "m", "s"))
|
|
|
|
if h > 167:
|
|
raise ValueError(
|
|
f"Hour must be in [0, 167]: {time_str}"
|
|
)
|
|
|
|
if match.group("sign") == "-":
|
|
h, m, s = -h, -m, -s
|
|
|
|
return h, m, s
|
|
|
|
|
|
def _parse_tz_delta(tz_delta):
|
|
match = re.fullmatch(
|
|
r"(?P<sign>[+-])?(?P<h>\d{1,3})(:(?P<m>\d{2})(:(?P<s>\d{2}))?)?",
|
|
tz_delta,
|
|
re.ASCII
|
|
)
|
|
# Anything passed to this function should already have hit an equivalent
|
|
# regular expression to find the section to parse.
|
|
assert match is not None, tz_delta
|
|
|
|
h, m, s = (int(v or 0) for v in match.group("h", "m", "s"))
|
|
|
|
total = h * 3600 + m * 60 + s
|
|
|
|
if h > 24:
|
|
raise ValueError(
|
|
f"Offset hours must be in [0, 24]: {tz_delta}"
|
|
)
|
|
|
|
# Yes, +5 maps to an offset of -5h
|
|
if match.group("sign") != "-":
|
|
total = -total
|
|
|
|
return total
|