mirror of
https://github.com/gristlabs/grist-core.git
synced 2024-10-27 20:44:07 +00:00
305b133c59
Summary: Biggest change is turning everything to unicode Test Plan: The tests Reviewers: dsagal, paulfitz Reviewed By: dsagal Differential Revision: https://phab.getgrist.com/D2875
261 lines
10 KiB
Python
261 lines
10 KiB
Python
from datetime import datetime, timedelta, tzinfo as _tzinfo
|
|
from collections import namedtuple
|
|
import marshal
|
|
from time import time
|
|
import bisect
|
|
import os
|
|
import moment_parse
|
|
import iso8601
|
|
import six
|
|
from six.moves import zip
|
|
|
|
# This is prepared by sandbox/install_tz.py
|
|
ZoneRecord = namedtuple("ZoneRecord", ("name", "abbrs", "offsets", "untils"))
|
|
|
|
# moment.py mirrors core functionality of moment-timezone.js
|
|
# moment.py includes function parse, located and documented in moment_parse.py
|
|
# Documentation: http://momentjs.com/timezone/docs/
|
|
|
|
EPOCH = datetime(1970, 1, 1)
|
|
DATE_EPOCH = EPOCH.date()
|
|
|
|
CURRENT_DATE = DATE_EPOCH + timedelta(seconds=time())
|
|
|
|
_TZDATA = None
|
|
|
|
# Returns a dictionary mapping timezone name to ZoneRecord object. It reads the data on first
|
|
# call, caches it, and returns cached data on all future calls.
|
|
def get_tz_data():
|
|
global _TZDATA # pylint: disable=global-statement
|
|
if _TZDATA is None:
|
|
all_zones = read_tz_raw_data()
|
|
# The marshalled data is an array of tuples (name, abbrs, offsets, untils)
|
|
_TZDATA = {x[0]: ZoneRecord._make(x) for x in all_zones}
|
|
return _TZDATA
|
|
|
|
# Reads and returns the marshalled tzdata file (produced by sandbox/install_tz.py).
|
|
# The return value is a list of tuples (name, abbrs, offsets, untils).
|
|
def read_tz_raw_data():
|
|
tzfile = os.path.join(os.path.dirname(__file__), "tzdata.data")
|
|
with open(tzfile, "rb") as tzdata:
|
|
return marshal.load(tzdata)
|
|
|
|
|
|
# Converts a UTC datetime to timestamp in milliseconds.
|
|
def utc_to_ts_ms(dt):
|
|
return (dt.replace(tzinfo=None) - EPOCH).total_seconds() * 1000
|
|
|
|
# Converts timestamp in seconds to datetime in the given timezone. If tzinfo is given, then zone
|
|
# is ignored and may be None.
|
|
def ts_to_dt(timestamp, zone, tzinfo=None):
|
|
return (EPOCH_UTC + timedelta(seconds=timestamp)).astimezone(tzinfo or zone.get_tzinfo(None))
|
|
|
|
# Converts datetime to timestamp in seconds. Optional timezone may be given to serve as the
|
|
# default if dt is unaware (has no associated timezone).
|
|
def dt_to_ts(dt, timezone=None):
|
|
offset = dt.utcoffset()
|
|
if offset is None:
|
|
offset = timezone.dt_offset(dt) if timezone else timedelta(0)
|
|
return (dt.replace(tzinfo=None) - offset - EPOCH).total_seconds()
|
|
|
|
# Converts timestamp in seconds to date.
|
|
def ts_to_date(timestamp):
|
|
return DATE_EPOCH + timedelta(seconds=timestamp)
|
|
|
|
# Converts date to timestamp of the midnight in seconds, in the given timezone, or UTC by default.
|
|
def date_to_ts(date, timezone=None):
|
|
ts = (date - DATE_EPOCH).total_seconds()
|
|
return ts if not timezone else ts - timezone.offset(ts * 1000).total_seconds()
|
|
|
|
# Calls parse from moment_parse.py
|
|
def parse(date_string, parse_format, zonelabel='UTC'):
|
|
return moment_parse.parse(date_string, parse_format, zonelabel)
|
|
|
|
# Parses a datetime in the ISO format, YYYY-MM-DDTHH:MM:SS.mmmmmm+HH:MM. Most parts are optional;
|
|
# see https://pypi.org/project/iso8601/ for details. Returns a timestamp in seconds.
|
|
def parse_iso(date_string, timezone=None):
|
|
dt = iso8601.parse_date(date_string, default_timezone=None)
|
|
return dt_to_ts(dt, timezone)
|
|
|
|
# Parses a date in ISO format, ignoring all time components. Returns timestamp of UTC midnight.
|
|
def parse_iso_date(date_string):
|
|
dt = iso8601.parse_date(date_string, default_timezone=None)
|
|
return date_to_ts(dt.date())
|
|
|
|
|
|
class tz(object):
|
|
"""Implements basics of moment.js and moment-timezone.js"""
|
|
# dt (datetime / number) - Either a local datetime in the time of the
|
|
# provided timezone or a timestamp since epoch in milliseconds.
|
|
# zonelabel (string) - The name of the timezone; should correspond to
|
|
# one of the names in the moment-timezone json data.
|
|
def __init__(self, dt, zonelabel="UTC"):
|
|
self._tzinfo = tzinfo(zonelabel)
|
|
if isinstance(dt, datetime):
|
|
timestamp = dt_to_ts(dt.replace(tzinfo=self._tzinfo)) * 1000
|
|
elif isinstance(dt, (float, six.integer_types)):
|
|
timestamp = dt
|
|
else:
|
|
raise TypeError("'dt' should be a datetime object or a numeric type")
|
|
self.timestamp = timestamp
|
|
|
|
# Returns the timestamp in seconds
|
|
def timestamp_s(self):
|
|
return self.timestamp / 1000
|
|
|
|
# Changes the timezone to the one corresponding to 'zonelabel' without
|
|
# changing the underlying time since epoch.
|
|
def tz(self, zonelabel):
|
|
self._tzinfo = tzinfo(zonelabel)
|
|
return self
|
|
|
|
# Returns a datetime object with the moment-timezone object's local time and the timezone
|
|
# at the current timestamp.
|
|
def datetime(self):
|
|
return ts_to_dt(self.timestamp / 1000.0, None, self._tzinfo)
|
|
|
|
def zoneName(self):
|
|
return self._tzinfo.zone.name
|
|
|
|
def zoneAbbr(self):
|
|
return self._tzinfo.zone.abbr(self.timestamp)
|
|
|
|
def zoneOffset(self):
|
|
return self._tzinfo.zone.offset(self.timestamp)
|
|
|
|
|
|
class TzInfo(_tzinfo):
|
|
"""
|
|
Implements datetime.tzinfo interface using moment-timezone data. If favor_offset is used, it
|
|
tells which offset to favor when a datetime is ambiguous. If None, the offset that's in effect
|
|
earlier is favored.
|
|
"""
|
|
def __init__(self, zone, favor_offset):
|
|
super(TzInfo, self).__init__()
|
|
self.zone = zone
|
|
self._favor_offset = favor_offset
|
|
|
|
def utcoffset(self, dt):
|
|
"""Implementation of tzinfo.utcoffset interface."""
|
|
return self.zone.dt_offset(dt, self._favor_offset)
|
|
|
|
def tzname(self, dt):
|
|
"""Implementation of tzinfo.tzname interface."""
|
|
abbr = self.zone.dt_tzname(dt, self._favor_offset)
|
|
if six.PY2 and isinstance(abbr, six.text_type):
|
|
abbr = abbr.encode('utf8')
|
|
return abbr
|
|
|
|
def dst(self, dt):
|
|
"""Implementation of tzinfo.dst interface."""
|
|
return self.utcoffset(dt) - self.zone.standard_offset
|
|
|
|
def fromutc(self, dt):
|
|
# This produces a datetime with a specific offset, and sets tzinfo that favors that offset.
|
|
offset = self.zone.offset(utc_to_ts_ms(dt))
|
|
return (dt + offset).replace(tzinfo=self.zone.get_tzinfo(offset))
|
|
|
|
def __repr__(self):
|
|
"""
|
|
Produces a friendly representation
|
|
>>> moment.tzinfo('America/New_York')
|
|
moment.tzinfo('America/New_York')
|
|
"""
|
|
return 'moment.tzinfo({!r})'.format(self.zone.name)
|
|
|
|
|
|
class Zone(object):
|
|
"""
|
|
Implements the zone object of moment-timezone.js, and contains the logic needed by TzInfo.
|
|
This is the class that interfaces directly with moment-timezone data.
|
|
"""
|
|
def __init__(self, zonelabel):
|
|
"""
|
|
Creates a Zone object for the given zonelabel, which must be a string key into the
|
|
moment-timezone json data.
|
|
"""
|
|
zone_data = get_tz_data()[zonelabel]
|
|
self.name = zonelabel
|
|
self.untils = zone_data.untils[:-1] # In ms. We omit the trailing None value.
|
|
self.abbrs = zone_data.abbrs
|
|
self.offsets = zone_data.offsets # Offsets in minutes.
|
|
self.standard_offset = timedelta(minutes=-self.offsets[0])
|
|
# "Until" times adjusted by the corresponding offsets. These are used in translating from
|
|
# datetime to absolute timestamp.
|
|
self.offset_untils = [until - offset * 60000 for (until, offset) in
|
|
zip(self.untils, self.offsets)]
|
|
# Cache of TzInfo objects for this Zone, used by get_tzinfo(). There could be multiple TzInfo
|
|
# objects, one for each possible offset, but their behavior only differs for ambiguous time.
|
|
self._tzinfo = {}
|
|
|
|
def dt_offset(self, dt, favor_offset=None):
|
|
"""Returns the timedelta for timezone offset east of UTC at the given datetime."""
|
|
i = self._index_dt(dt, favor_offset)
|
|
return timedelta(minutes = -self.offsets[i])
|
|
|
|
def dt_tzname(self, dt, favor_offset=None):
|
|
"""Returns the timezone abbreviation (e.g. EST or EDT) at the given datetime."""
|
|
i = self._index_dt(dt, favor_offset)
|
|
return self.abbrs[i]
|
|
|
|
def offset(self, timestamp_ms):
|
|
"""Returns the timedelta for timezone offset east of UTC at the given ms timestamp."""
|
|
i = self._index(timestamp_ms)
|
|
return timedelta(minutes = -self.offsets[i])
|
|
|
|
def abbr(self, timestamp_ms):
|
|
"""Returns the timezone abbreviation (e.g. EST or EDT) at the given ms timestamp."""
|
|
i = self._index(timestamp_ms)
|
|
return self.abbrs[i]
|
|
|
|
def _index(self, timestamp):
|
|
"""Helper to return the index into the offsets data corresponding to the given timestamp."""
|
|
return bisect.bisect_right(self.untils, timestamp)
|
|
|
|
def _index_dt(self, dt, favor_offset):
|
|
"""
|
|
Helper to return the index into the offsets data corresponding to the given datetime.
|
|
In case of ambiguous dates, will favor the given favor_offset. If it is None or doesn't match
|
|
the later of the two offsets, will use the offset that's was in effect earlier.
|
|
"""
|
|
timestamp = utc_to_ts_ms(dt)
|
|
i = bisect.bisect_right(self.offset_untils, timestamp)
|
|
if i < len(self.offset_untils) and timestamp >= self.untils[i] - self.offsets[i + 1] * 60000:
|
|
# We have an ambiguous time and can use self.offsets[i] or self.offsets[i + 1]. If
|
|
# favor_offset matches the later offset, use that. Otherwise, prefer the earlier one.
|
|
if timedelta(minutes=-self.offsets[i + 1]) == favor_offset:
|
|
return i + 1
|
|
return i
|
|
|
|
def get_tzinfo(self, favor_offset):
|
|
"""
|
|
Returns a TzInfo object for this Zone that favors the given offset in case of ambiguity.
|
|
If favor_offset is none, ambiguous times are resolved to the offset that comes into effect
|
|
earlier. This is used with a particular offset by TzInfo.fromutc() method, which is part of
|
|
implementation of TzInfo.astimezone(). We distinguish ambiguous times by using TzInfo variants
|
|
that favor one offset or another for different meanings of the ambiguous times.
|
|
"""
|
|
return (self._tzinfo.get(favor_offset) or
|
|
self._tzinfo.setdefault(favor_offset, TzInfo(self, favor_offset)))
|
|
|
|
|
|
|
|
_zone_cache = {}
|
|
|
|
def get_zone(zonelabel):
|
|
"""Returns Zone(zonelabel), with caching."""
|
|
return (_zone_cache.get(zonelabel) or
|
|
_zone_cache.setdefault(zonelabel, Zone(zonelabel)))
|
|
|
|
def tzinfo(zonelabel, favor_offset=None):
|
|
"""
|
|
Returns TzInfo instance for zonelabel, with the optional favor_offset (mainly for internal use
|
|
by astimezone via fromutc).
|
|
"""
|
|
return get_zone(zonelabel).get_tzinfo(favor_offset)
|
|
|
|
|
|
# Some more globals that rely on the machinery above.
|
|
TZ_UTC = tzinfo('UTC')
|
|
EPOCH_UTC = EPOCH.replace(tzinfo=TZ_UTC) # Same as EPOCH, but an "aware" instance.
|