def acquire( self, timeout: Optional[Union[float, datetime.timedelta]] = None ) -> Awaitable[_ReleasingContextManager]: """Decrement the counter. Returns an awaitable. Block if the counter is zero and wait for a `.release`. The awaitable raises `.TimeoutError` after the deadline. """ waiter = Future() # type: Future[_ReleasingContextManager] if self._value > 0: self._value -= 1 waiter.set_result(_ReleasingContextManager(self)) else: self._waiters.append(waiter) if timeout: def on_timeout() -> None: if not waiter.done(): waiter.set_exception(gen.TimeoutError()) self._garbage_collect() io_loop = ioloop.IOLoop.current() timeout_handle = io_loop.add_timeout(timeout, on_timeout) waiter.add_done_callback( lambda _: io_loop.remove_timeout(timeout_handle)) return waiter
def wait( self, timeout: Optional[Union[float, datetime.timedelta]] = None ) -> Awaitable[None]: """Block until the internal flag is true. Returns an awaitable, which raises `tornado.util.TimeoutError` after a timeout. """ fut = Future() # type: Future[None] if self._value: fut.set_result(None) return fut self._waiters.add(fut) fut.add_done_callback(lambda fut: self._waiters.remove(fut)) if timeout is None: return fut else: timeout_fut = gen.with_timeout(timeout, fut) # This is a slightly clumsy workaround for the fact that # gen.with_timeout doesn't cancel its futures. Cancelling # fut will remove it from the waiters list. timeout_fut.add_done_callback(lambda tf: fut.cancel() if not fut.done() else None) return timeout_fut
def _set_timeout(future: Future, timeout: Union[None, float, datetime.timedelta]) -> None: if timeout: def on_timeout() -> None: if not future.done(): future.set_exception(gen.TimeoutError()) io_loop = ioloop.IOLoop.current() timeout_handle = io_loop.add_timeout(timeout, on_timeout) future.add_done_callback( lambda _: io_loop.remove_timeout(timeout_handle))
def wait( self, timeout: Optional[Union[float, datetime.timedelta]] = None ) -> Awaitable[bool]: """Wait for `.notify`. Returns a `.Future` that resolves ``True`` if the condition is notified, or ``False`` after a timeout. """ waiter = Future() # type: Future[bool] self._waiters.append(waiter) if timeout: def on_timeout() -> None: if not waiter.done(): future_set_result_unless_cancelled(waiter, False) self._garbage_collect() io_loop = ioloop.IOLoop.current() timeout_handle = io_loop.add_timeout(timeout, on_timeout) waiter.add_done_callback( lambda _: io_loop.remove_timeout(timeout_handle)) return waiter