Files
pretix_cgo/src/pretix/helpers/monkeypatching.py
2022-01-25 21:08:28 +01:00

57 lines
2.2 KiB
Python

#
# This file is part of pretix (Community Edition).
#
# Copyright (C) 2014-2020 Raphael Michel and contributors
# Copyright (C) 2020-2021 rami.io GmbH and contributors
#
# This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
# Public License as published by the Free Software Foundation in version 3 of the License.
#
# ADDITIONAL TERMS APPLY: Pursuant to Section 7 of the GNU Affero General Public License, additional terms are
# applicable granting you additional permissions and placing additional restrictions on your usage of this software.
# Please refer to the pretix LICENSE file to obtain the full terms applicable to this work. If you did not receive
# this file, see <https://pretix.eu/about/en/license>.
#
# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
# details.
#
# You should have received a copy of the GNU Affero General Public License along with this program. If not, see
# <https://www.gnu.org/licenses/>.
#
from datetime import datetime
def monkeypatch_vobject_performance():
"""
This works around a performance issue in the unmaintained vobject library which calls
a very expensive function for every event in a calendar. Since the slow function is
mostly used to compare timezones to UTC, not to arbitrary other timezones, we can
add a few early-out optimizations.
"""
from vobject import icalendar
old_tzinfo_eq = icalendar.tzinfo_eq
test_date = datetime(2000, 1, 1)
def new_tzinfo_eq(tzinfo1, tzinfo2, *args, **kwargs):
if tzinfo1 is None:
return tzinfo2 is None
if tzinfo2 is None:
return tzinfo1 is None
n1 = tzinfo1.tzname(test_date)
n2 = tzinfo2.tzname(test_date)
if n1 == "UTC" and n2 == "UTC":
return True
if n1 == "UTC" or n2 == "UTC":
return False
return old_tzinfo_eq(tzinfo1, tzinfo2, *args, **kwargs)
icalendar.tzinfo_eq = new_tzinfo_eq
def monkeypatch_all_at_ready():
monkeypatch_vobject_performance()