cpython/Lib/_weakrefset.py

147 lines
4.2 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 __len__(self):
return sum(x() is not None for x in self.data)
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:
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):
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)
def __ior__(self, other):
self.update(other)
return self
# 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 difference(self, other):
return self._apply(other, self.data.difference)
__sub__ = difference
def difference_update(self, other):
if self is other:
self.data.clear()
else:
self.data.difference_update(ref(item) for item in 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._apply(other, self.data.intersection)
__and__ = intersection
def intersection_update(self, other):
self.data.intersection_update(ref(item) for item in 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)
__lt__ = issubset
def __le__(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)
__gt__ = issuperset
def __ge__(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):
return self._apply(other, self.data.symmetric_difference)
__xor__ = symmetric_difference
def symmetric_difference_update(self, other):
if self is other:
self.data.clear()
else:
self.data.symmetric_difference_update(ref(item) for item in other)
def __ixor__(self, other):
if self is other:
self.data.clear()
else:
self.data.symmetric_difference_update(ref(item) for item in other)
return self
def union(self, other):
return self._apply(other, self.data.union)
__or__ = union
def isdisjoint(self, other):
return len(self.intersection(other)) == 0