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cd0f9d111a
Make `WeakKeyDictionary` and `WeakValueDictionary` thread safe by copying the underlying the dict before iterating over it.
148 lines
3.9 KiB
Python
148 lines
3.9 KiB
Python
# Access WeakSet through the weakref module.
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# This code is separated-out because it is needed
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# by abc.py to load everything else at startup.
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from _weakref import ref
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from types import GenericAlias
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__all__ = ['WeakSet']
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class WeakSet:
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def __init__(self, data=None):
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self.data = set()
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def _remove(item, selfref=ref(self)):
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self = selfref()
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if self is not None:
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self.data.discard(item)
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self._remove = _remove
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if data is not None:
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self.update(data)
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def __iter__(self):
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for itemref in self.data.copy():
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item = itemref()
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if item is not None:
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# Caveat: the iterator will keep a strong reference to
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# `item` until it is resumed or closed.
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yield item
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def __len__(self):
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return len(self.data)
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def __contains__(self, item):
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try:
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wr = ref(item)
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except TypeError:
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return False
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return wr in self.data
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def __reduce__(self):
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return self.__class__, (list(self),), self.__getstate__()
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def add(self, item):
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self.data.add(ref(item, self._remove))
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def clear(self):
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self.data.clear()
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def copy(self):
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return self.__class__(self)
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def pop(self):
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while True:
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try:
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itemref = self.data.pop()
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except KeyError:
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raise KeyError('pop from empty WeakSet') from None
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item = itemref()
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if item is not None:
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return item
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def remove(self, item):
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self.data.remove(ref(item))
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def discard(self, item):
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self.data.discard(ref(item))
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def update(self, other):
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for element in other:
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self.add(element)
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def __ior__(self, other):
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self.update(other)
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return self
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def difference(self, other):
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newset = self.copy()
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newset.difference_update(other)
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return newset
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__sub__ = difference
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def difference_update(self, other):
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self.__isub__(other)
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def __isub__(self, other):
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if self is other:
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self.data.clear()
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else:
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self.data.difference_update(ref(item) for item in other)
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return self
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def intersection(self, other):
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return self.__class__(item for item in other if item in self)
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__and__ = intersection
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def intersection_update(self, other):
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self.__iand__(other)
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def __iand__(self, other):
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self.data.intersection_update(ref(item) for item in other)
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return self
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def issubset(self, other):
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return self.data.issubset(ref(item) for item in other)
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__le__ = issubset
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def __lt__(self, other):
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return self.data < set(map(ref, other))
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def issuperset(self, other):
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return self.data.issuperset(ref(item) for item in other)
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__ge__ = issuperset
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def __gt__(self, other):
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return self.data > set(map(ref, other))
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def __eq__(self, other):
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if not isinstance(other, self.__class__):
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return NotImplemented
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return self.data == set(map(ref, other))
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def symmetric_difference(self, other):
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newset = self.copy()
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newset.symmetric_difference_update(other)
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return newset
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__xor__ = symmetric_difference
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def symmetric_difference_update(self, other):
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self.__ixor__(other)
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def __ixor__(self, other):
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if self is other:
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self.data.clear()
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else:
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self.data.symmetric_difference_update(ref(item, self._remove) for item in other)
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return self
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def union(self, other):
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return self.__class__(e for s in (self, other) for e in s)
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__or__ = union
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def isdisjoint(self, other):
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return len(self.intersection(other)) == 0
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def __repr__(self):
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return repr(self.data)
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__class_getitem__ = classmethod(GenericAlias)
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