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
