112 lines
3.1 KiB
Python
112 lines
3.1 KiB
Python
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# 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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__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:
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item = itemref()
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if item is not None:
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yield item
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def __contains__(self, item):
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return ref(item) in self.data
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def __reduce__(self):
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return (self.__class__, (list(self),),
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getattr(self, '__dict__', None))
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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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itemref = self.data.pop()
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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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if isinstance(other, self.__class__):
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self.data.update(other.data)
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else:
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for element in other:
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self.add(element)
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__ior__ = update
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# Helper functions for simple delegating methods.
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def _apply(self, other, method):
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if not isinstance(other, self.__class__):
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other = self.__class__(other)
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newdata = method(other.data)
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newset = self.__class__()
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newset.data = newdata
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return newset
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def _apply_mutate(self, other, method):
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if not isinstance(other, self.__class__):
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other = self.__class__(other)
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method(other)
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def difference(self, other):
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return self._apply(other, self.data.difference)
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__sub__ = difference
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def difference_update(self, other):
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self._apply_mutate(self, self.data.difference_update)
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__isub__ = difference_update
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def intersection(self, other):
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return self._apply(other, self.data.intersection)
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__and__ = intersection
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def intersection_update(self, other):
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self._apply_mutate(self, self.data.intersection_update)
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__iand__ = intersection_update
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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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__lt__ = issubset
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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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__gt__ = issuperset
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def symmetric_difference(self, other):
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return self._apply(other, self.data.symmetric_difference)
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__xor__ = symmetric_difference
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def symmetric_difference_update(self, other):
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self._apply_mutate(other, self.data.symmetric_difference_update)
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__ixor__ = symmetric_difference_update
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def union(self, other):
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self._apply_mutate(other, self.data.union)
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__or__ = union
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