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cpython/Lib/_weakrefset.py
Kumar Aditya cd0f9d111a
gh-89967: make WeakKeyDictionary and WeakValueDictionary thread safe (#125325)
Make `WeakKeyDictionary` and `WeakValueDictionary` thread safe by copying the underlying the dict before iterating over it.
2024-10-13 21:05:05 +05:30

148 lines
3.9 KiB
Python

# Access WeakSet through the weakref module.
# This code is separated-out because it is needed
# by abc.py to load everything else at startup.
from _weakref import ref
from types import GenericAlias
__all__ = ['WeakSet']
class WeakSet:
def __init__(self, data=None):
self.data = set()
def _remove(item, selfref=ref(self)):
self = selfref()
if self is not None:
self.data.discard(item)
self._remove = _remove
if data is not None:
self.update(data)
def __iter__(self):
for itemref in self.data.copy():
item = itemref()
if item is not None:
# Caveat: the iterator will keep a strong reference to
# `item` until it is resumed or closed.
yield item
def __len__(self):
return len(self.data)
def __contains__(self, item):
try:
wr = ref(item)
except TypeError:
return False
return wr in self.data
def __reduce__(self):
return self.__class__, (list(self),), self.__getstate__()
def add(self, item):
self.data.add(ref(item, self._remove))
def clear(self):
self.data.clear()
def copy(self):
return self.__class__(self)
def pop(self):
while True:
try:
itemref = self.data.pop()
except KeyError:
raise KeyError('pop from empty WeakSet') from None
item = itemref()
if item is not None:
return item
def remove(self, item):
self.data.remove(ref(item))
def discard(self, item):
self.data.discard(ref(item))
def update(self, other):
for element in other:
self.add(element)
def __ior__(self, other):
self.update(other)
return self
def difference(self, other):
newset = self.copy()
newset.difference_update(other)
return newset
__sub__ = difference
def difference_update(self, other):
self.__isub__(other)
def __isub__(self, other):
if self is other:
self.data.clear()
else:
self.data.difference_update(ref(item) for item in other)
return self
def intersection(self, other):
return self.__class__(item for item in other if item in self)
__and__ = intersection
def intersection_update(self, other):
self.__iand__(other)
def __iand__(self, other):
self.data.intersection_update(ref(item) for item in other)
return self
def issubset(self, other):
return self.data.issubset(ref(item) for item in other)
__le__ = issubset
def __lt__(self, other):
return self.data < set(map(ref, other))
def issuperset(self, other):
return self.data.issuperset(ref(item) for item in other)
__ge__ = issuperset
def __gt__(self, other):
return self.data > set(map(ref, other))
def __eq__(self, other):
if not isinstance(other, self.__class__):
return NotImplemented
return self.data == set(map(ref, other))
def symmetric_difference(self, other):
newset = self.copy()
newset.symmetric_difference_update(other)
return newset
__xor__ = symmetric_difference
def symmetric_difference_update(self, other):
self.__ixor__(other)
def __ixor__(self, other):
if self is other:
self.data.clear()
else:
self.data.symmetric_difference_update(ref(item, self._remove) for item in other)
return self
def union(self, other):
return self.__class__(e for s in (self, other) for e in s)
__or__ = union
def isdisjoint(self, other):
return len(self.intersection(other)) == 0
def __repr__(self):
return repr(self.data)
__class_getitem__ = classmethod(GenericAlias)