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"""Object Utilities."""
__all__ = ('cached_property',)
try:
from functools import _NOT_FOUND, cached_property as _cached_property
except ImportError:
# TODO: Remove this fallback once we drop support for Python < 3.8
from cached_property import threaded_cached_property as _cached_property
_NOT_FOUND = object()
class cached_property(_cached_property):
def __init__(self, fget=None, fset=None, fdel=None):
super().__init__(fget)
self.__set = fset
self.__del = fdel
if not hasattr(self, 'attrname'):
# This is a backport so we set this ourselves.
self.attrname = self.func.__name__
def __get__(self, instance, owner=None):
# TODO: Remove this after we drop support for Python<3.8
# or fix the signature in the cached_property package
return super().__get__(instance, owner)
def __set__(self, instance, value):
if instance is None:
return self
with self.lock:
if self.__set is not None:
value = self.__set(instance, value)
cache = instance.__dict__
cache[self.attrname] = value
def __delete__(self, instance):
if instance is None:
return self
with self.lock:
value = instance.__dict__.pop(self.attrname, _NOT_FOUND)
if self.__del and value is not _NOT_FOUND:
self.__del(instance, value)
def setter(self, fset):
return self.__class__(self.func, fset, self.__del)
def deleter(self, fdel):
return self.__class__(self.func, self.__set, fdel)
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