| 34 | |
| 35 | |
| 36 | class WeakSet: |
| 37 | def __init__(self, data=None): |
| 38 | self.data = set() |
| 39 | def _remove(item, selfref=ref(self)): |
| 40 | self = selfref() |
| 41 | if self is not None: |
| 42 | if self._iterating: |
| 43 | self._pending_removals.append(item) |
| 44 | else: |
| 45 | self.data.discard(item) |
| 46 | self._remove = _remove |
| 47 | # A list of keys to be removed |
| 48 | self._pending_removals = [] |
| 49 | self._iterating = set() |
| 50 | if data is not None: |
| 51 | self.update(data) |
| 52 | |
| 53 | def _commit_removals(self): |
| 54 | pop = self._pending_removals.pop |
| 55 | discard = self.data.discard |
| 56 | while True: |
| 57 | try: |
| 58 | item = pop() |
| 59 | except IndexError: |
| 60 | return |
| 61 | discard(item) |
| 62 | |
| 63 | def __iter__(self): |
| 64 | with _IterationGuard(self): |
| 65 | for itemref in self.data: |
| 66 | item = itemref() |
| 67 | if item is not None: |
| 68 | # Caveat: the iterator will keep a strong reference to |
| 69 | # `item` until it is resumed or closed. |
| 70 | yield item |
| 71 | |
| 72 | def __len__(self): |
| 73 | return len(self.data) - len(self._pending_removals) |
| 74 | |
| 75 | def __contains__(self, item): |
| 76 | try: |
| 77 | wr = ref(item) |
| 78 | except TypeError: |
| 79 | return False |
| 80 | return wr in self.data |
| 81 | |
| 82 | def __reduce__(self): |
| 83 | return self.__class__, (list(self),), self.__getstate__() |
| 84 | |
| 85 | def add(self, item): |
| 86 | if self._pending_removals: |
| 87 | self._commit_removals() |
| 88 | self.data.add(ref(item, self._remove)) |
| 89 | |
| 90 | def clear(self): |
| 91 | if self._pending_removals: |
| 92 | self._commit_removals() |
| 93 | self.data.clear() |
no outgoing calls
no test coverage detected