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- import abc
- import functools
- import weakref
-
- from . import exc as async_exc
-
-
- class ReversibleProxy:
- # weakref.ref(async proxy object) -> weakref.ref(sync proxied object)
- _proxy_objects = {}
-
- def _assign_proxied(self, target):
- if target is not None:
- target_ref = weakref.ref(target, ReversibleProxy._target_gced)
- proxy_ref = weakref.ref(
- self,
- functools.partial(ReversibleProxy._target_gced, target_ref),
- )
- ReversibleProxy._proxy_objects[target_ref] = proxy_ref
-
- return target
-
- @classmethod
- def _target_gced(cls, ref, proxy_ref=None):
- cls._proxy_objects.pop(ref, None)
-
- @classmethod
- def _regenerate_proxy_for_target(cls, target):
- raise NotImplementedError()
-
- @classmethod
- def _retrieve_proxy_for_target(cls, target, regenerate=True):
- try:
- proxy_ref = cls._proxy_objects[weakref.ref(target)]
- except KeyError:
- pass
- else:
- proxy = proxy_ref()
- if proxy is not None:
- return proxy
-
- if regenerate:
- return cls._regenerate_proxy_for_target(target)
- else:
- return None
-
-
- class StartableContext(abc.ABC):
- @abc.abstractmethod
- async def start(self, is_ctxmanager=False):
- pass
-
- def __await__(self):
- return self.start().__await__()
-
- async def __aenter__(self):
- return await self.start(is_ctxmanager=True)
-
- @abc.abstractmethod
- async def __aexit__(self, type_, value, traceback):
- pass
-
- def _raise_for_not_started(self):
- raise async_exc.AsyncContextNotStarted(
- "%s context has not been started and object has not been awaited."
- % (self.__class__.__name__)
- )
-
-
- class ProxyComparable(ReversibleProxy):
- def __hash__(self):
- return id(self)
-
- def __eq__(self, other):
- return (
- isinstance(other, self.__class__)
- and self._proxied == other._proxied
- )
-
- def __ne__(self, other):
- return (
- not isinstance(other, self.__class__)
- or self._proxied != other._proxied
- )
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