From 59100e852573cbc01b602b1637b0d4a02a863a9d Mon Sep 17 00:00:00 2001 From: Markus Heiser Date: Sat, 12 Mar 2022 15:37:45 +0100 Subject: [PATCH] [fix] add module for backward compatibility cache_property has been added in py3.8 [1] To support cache_property in py3.7 the implementation from 3.8 has been copied to compat.py. This code can be cleanup with EOL of py3.7. [1] https://docs.python.org/3/library/functools.html#functools.cached_property Signed-off-by: Markus Heiser --- searx/compat.py | 70 ++++++++++++++++++++++++++++++++++++++ searx/infopage/__init__.py | 2 +- 2 files changed, 71 insertions(+), 1 deletion(-) create mode 100644 searx/compat.py diff --git a/searx/compat.py b/searx/compat.py new file mode 100644 index 000000000..504df7da2 --- /dev/null +++ b/searx/compat.py @@ -0,0 +1,70 @@ +# SPDX-License-Identifier: AGPL-3.0-or-later +# lint: pylint +# pyright: basic +"""Module for backward compatibility. + +""" +# pylint: disable=C,R + + +try: + from functools import cached_property # pylint: disable=unused-import + +except ImportError: + + # cache_property has been added in py3.8 [1] + # + # To support cache_property in py3.7 the implementation from 3.8 has been + # copied here. This code can be cleanup with EOL of py3.7. + # + # [1] https://docs.python.org/3/library/functools.html#functools.cached_property + + from threading import RLock + + _NOT_FOUND = object() + + class cached_property: + def __init__(self, func): + self.func = func + self.attrname = None + self.__doc__ = func.__doc__ + self.lock = RLock() + + def __set_name__(self, owner, name): + if self.attrname is None: + self.attrname = name + elif name != self.attrname: + raise TypeError( + "Cannot assign the same cached_property to two different names " + f"({self.attrname!r} and {name!r})." + ) + + def __get__(self, instance, owner=None): + if instance is None: + return self + if self.attrname is None: + raise TypeError("Cannot use cached_property instance without calling __set_name__ on it.") + try: + cache = instance.__dict__ + except AttributeError: # not all objects have __dict__ (e.g. class defines slots) + msg = ( + f"No '__dict__' attribute on {type(instance).__name__!r} " + f"instance to cache {self.attrname!r} property." + ) + raise TypeError(msg) from None + val = cache.get(self.attrname, _NOT_FOUND) + if val is _NOT_FOUND: + with self.lock: + # check if another thread filled cache while we awaited lock + val = cache.get(self.attrname, _NOT_FOUND) + if val is _NOT_FOUND: + val = self.func(instance) + try: + cache[self.attrname] = val + except TypeError: + msg = ( + f"The '__dict__' attribute on {type(instance).__name__!r} instance " + f"does not support item assignment for caching {self.attrname!r} property." + ) + raise TypeError(msg) from None + return val diff --git a/searx/infopage/__init__.py b/searx/infopage/__init__.py index d7736a934..5c58193c1 100644 --- a/searx/infopage/__init__.py +++ b/searx/infopage/__init__.py @@ -23,7 +23,6 @@ __all__ = ['InfoPage', 'MistletoePage', 'InfoPageSet'] import os.path import logging -from functools import cached_property import typing import urllib.parse @@ -32,6 +31,7 @@ from flask.helpers import url_for import mistletoe from .. import get_setting +from ..compat import cached_property from ..version import GIT_URL logger = logging.getLogger('doc')