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cpython/Lib/_weakrefset.py
Raymond Hettinger 93fa608626 Moved WeakSet into a bootstap module use by abc.py.
This makes it possible to use ABCs in weakref.py
(which will be done in a later checkin).
2008-02-05 00:20:01 +00:00

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