codekingpro/portable-devtools

1# Access WeakSet through the weakref module.2# This code is separated-out because it is needed3# by abc.py to load everything else at startup.4 5from _weakref import ref6from types import GenericAlias7 8__all__ = ['WeakSet']9 10 11class WeakSet:12    def __init__(self, data=None):13        self.data = set()14 15        def _remove(item, selfref=ref(self)):16            self = selfref()17            if self is not None:18                self.data.discard(item)19 20        self._remove = _remove21        if data is not None:22            self.update(data)23 24    def __iter__(self):25        for itemref in self.data.copy():26            item = itemref()27            if item is not None:28                # Caveat: the iterator will keep a strong reference to29                # `item` until it is resumed or closed.30                yield item31 32    def __len__(self):33        return len(self.data)34 35    def __contains__(self, item):36        try:37            wr = ref(item)38        except TypeError:39            return False40        return wr in self.data41 42    def __reduce__(self):43        return self.__class__, (list(self),), self.__getstate__()44 45    def add(self, item):46        self.data.add(ref(item, self._remove))47 48    def clear(self):49        self.data.clear()50 51    def copy(self):52        return self.__class__(self)53 54    def pop(self):55        while True:56            try:57                itemref = self.data.pop()58            except KeyError:59                raise KeyError('pop from empty WeakSet') from None60            item = itemref()61            if item is not None:62                return item63 64    def remove(self, item):65        self.data.remove(ref(item))66 67    def discard(self, item):68        self.data.discard(ref(item))69 70    def update(self, other):71        for element in other:72            self.add(element)73 74    def __ior__(self, other):75        self.update(other)76        return self77 78    def difference(self, other):79        newset = self.copy()80        newset.difference_update(other)81        return newset82    __sub__ = difference83 84    def difference_update(self, other):85        self.__isub__(other)86    def __isub__(self, other):87        if self is other:88            self.data.clear()89        else:90            self.data.difference_update(ref(item) for item in other)91        return self92 93    def intersection(self, other):94        return self.__class__(item for item in other if item in self)95    __and__ = intersection96 97    def intersection_update(self, other):98        self.__iand__(other)99    def __iand__(self, other):100        self.data.intersection_update(ref(item) for item in other)101        return self102 103    def issubset(self, other):104        return self.data.issubset(ref(item) for item in other)105    __le__ = issubset106 107    def __lt__(self, other):108        return self.data < set(map(ref, other))109 110    def issuperset(self, other):111        return self.data.issuperset(ref(item) for item in other)112    __ge__ = issuperset113 114    def __gt__(self, other):115        return self.data > set(map(ref, other))116 117    def __eq__(self, other):118        if not isinstance(other, self.__class__):119            return NotImplemented120        return self.data == set(map(ref, other))121 122    def symmetric_difference(self, other):123        newset = self.copy()124        newset.symmetric_difference_update(other)125        return newset126    __xor__ = symmetric_difference127 128    def symmetric_difference_update(self, other):129        self.__ixor__(other)130    def __ixor__(self, other):131        if self is other:132            self.data.clear()133        else:134            self.data.symmetric_difference_update(ref(item, self._remove) for item in other)135        return self136 137    def union(self, other):138        return self.__class__(e for s in (self, other) for e in s)139    __or__ = union140 141    def isdisjoint(self, other):142        return len(self.intersection(other)) == 0143 144    def __repr__(self):145        return repr(self.data)146 147    __class_getitem__ = classmethod(GenericAlias)148