+++ /dev/null
-# 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
-
-__all__ = ['WeakSet']
-
-
-class _IterationGuard:
- # This context manager registers itself in the current iterators of the
- # weak container, such as to delay all removals until the context manager
- # exits.
- # This technique should be relatively thread-safe (since sets are).
-
- def __init__(self, weakcontainer):
- # Don't create cycles
- self.weakcontainer = ref(weakcontainer)
-
- def __enter__(self):
- w = self.weakcontainer()
- if w is not None:
- w._iterating.add(self)
- return self
-
- def __exit__(self, e, t, b):
- w = self.weakcontainer()
- if w is not None:
- s = w._iterating
- s.remove(self)
- if not s:
- w._commit_removals()
-
-
-class WeakSet:
- def __init__(self, data=None):
- self.data = set()
- def _remove(item, selfref=ref(self)):
- self = selfref()
- if self is not None:
- if self._iterating:
- self._pending_removals.append(item)
- else:
- self.data.discard(item)
- self._remove = _remove
- # A list of keys to be removed
- self._pending_removals = []
- self._iterating = set()
- if data is not None:
- self.update(data)
-
- def _commit_removals(self):
- l = self._pending_removals
- discard = self.data.discard
- while l:
- discard(l.pop())
-
- def __iter__(self):
- with _IterationGuard(self):
- for itemref in self.data:
- 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) - len(self._pending_removals)
-
- 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),),
- getattr(self, '__dict__', None))
-
- def add(self, item):
- if self._pending_removals:
- self._commit_removals()
- self.data.add(ref(item, self._remove))
-
- def clear(self):
- if self._pending_removals:
- self._commit_removals()
- self.data.clear()
-
- def copy(self):
- return self.__class__(self)
-
- def pop(self):
- if self._pending_removals:
- self._commit_removals()
- while True:
- try:
- itemref = self.data.pop()
- except KeyError:
- raise KeyError('pop from empty WeakSet')
- item = itemref()
- if item is not None:
- return item
-
- def remove(self, item):
- if self._pending_removals:
- self._commit_removals()
- self.data.remove(ref(item))
-
- def discard(self, item):
- if self._pending_removals:
- self._commit_removals()
- self.data.discard(ref(item))
-
- def update(self, other):
- if self._pending_removals:
- self._commit_removals()
- 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._pending_removals:
- self._commit_removals()
- 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):
- if self._pending_removals:
- self._commit_removals()
- 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(ref(item) for item in 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(ref(item) for item in other)
-
- def __eq__(self, other):
- if not isinstance(other, self.__class__):
- return NotImplemented
- return self.data == set(ref(item) for item in 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._pending_removals:
- self._commit_removals()
- 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
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