blob: 7be9de072ea112432631fda9b0acec9cadb12e1a [file] [log] [blame]
# Copyright 2018 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Time-related utilities."""
import datetime
import time
import uuid
import graphyte_common # pylint: disable=unused-import
from graphyte.utils import platform_utils
MonotonicTime = platform_utils.GetProvider('MonotonicTime')
# pylint: disable=unused-argument
class TZUTC(datetime.tzinfo):
"""A tzinfo about UTC."""
def utcoffset(self, dt):
return datetime.timedelta(0)
def dst(self, dt):
return datetime.timedelta(0)
def tzname(self, dt):
return 'UTC'
def FormatElapsedTime(elapsed_secs):
"""Formats an elapsed time.
elapsed_secs: An integer number of seconds.
The time in HH:MM:SS format.
negative = elapsed_secs < 0
if negative:
elapsed_secs = -elapsed_secs
secs = elapsed_secs % 60
elapsed_secs /= 60
mins = elapsed_secs % 60
elapsed_secs /= 60
hours = elapsed_secs
return '%s%02d:%02d:%02d' % ('-' if negative else '',
hours, mins, secs)
def TimeString(time_value=None, time_separator=':', milliseconds=True):
"""Returns a time as a string.
The format is like ISO8601 but with milliseconds:
time_value: A datetime.datetime object, time in seconds since the epoch,
or None for current time.
time_separator: Separator for time components.
milliseconds: Whether to include milliseconds.
if isinstance(time_value, datetime.datetime):
t = DatetimeToUnixtime(time_value)
t = time_value or time.time()
ret = time.strftime(
'%Y-%m-%dT%H' + time_separator + '%M' + time_separator + '%S',
if milliseconds:
ret += '.%03d' % int((t - int(t)) * 1000)
ret += 'Z'
return ret
def TimedUUID():
"""Returns a UUID that is roughly sorted by time.
The first 8 hexits are replaced by the current time in 100ths of a
second, mod 2**32. This will roll over once every 490 days, but it
will cause UUIDs to be sorted by time in the vast majority of cases
(handy for ls'ing directories); and it still contains far more than
enough randomness to remain unique.
return ('%08x' % (int(time.time() * 100) & 0xFFFFFFFF) +
EPOCH_ZERO = datetime.datetime(1970, 1, 1)
EPOCH_ZERO_WITH_TZINFO = datetime.datetime(1970, 1, 1, tzinfo=TZUTC())
def DatetimeToUnixtime(obj):
"""Converts datetime.datetime to Unix time.
The function will use the time zone info if obj has; otherwise, it will treat
obj as in Coordinated Universal Time (UTC).
if not isinstance(obj, datetime.datetime):
raise ValueError('Expected datetime.datetime but found %s' % type(obj))
if obj.tzinfo is not None:
return (obj - EPOCH_ZERO_WITH_TZINFO).total_seconds()
return (obj - EPOCH_ZERO).total_seconds()