744 lines
24 KiB
Python
744 lines
24 KiB
Python
"""Future-returning APIs for coroutines."""
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# Copyright (c) PyZMQ Developers.
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# Distributed under the terms of the Modified BSD License.
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from __future__ import annotations
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import warnings
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from asyncio import Future
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from collections import deque
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from functools import partial
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from itertools import chain
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from typing import Any, Awaitable, Callable, NamedTuple, TypeVar, cast, overload
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import zmq as _zmq
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from zmq import EVENTS, POLLIN, POLLOUT
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from zmq._typing import Literal
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class _FutureEvent(NamedTuple):
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future: Future
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kind: str
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kwargs: dict
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msg: Any
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timer: Any
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# These are incomplete classes and need a Mixin for compatibility with an eventloop
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# defining the following attributes:
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#
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# _Future
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# _READ
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# _WRITE
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# _default_loop()
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class _Async:
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"""Mixin for common async logic"""
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_current_loop: Any = None
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_Future: type[Future]
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def _get_loop(self) -> Any:
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"""Get event loop
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Notice if event loop has changed,
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and register init_io_state on activation of a new event loop
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"""
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if self._current_loop is None:
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self._current_loop = self._default_loop()
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self._init_io_state(self._current_loop)
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return self._current_loop
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current_loop = self._default_loop()
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if current_loop is not self._current_loop:
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# warn? This means a socket is being used in multiple loops!
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self._current_loop = current_loop
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self._init_io_state(current_loop)
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return current_loop
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def _default_loop(self) -> Any:
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raise NotImplementedError("Must be implemented in a subclass")
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def _init_io_state(self, loop=None) -> None:
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pass
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class _AsyncPoller(_Async, _zmq.Poller):
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"""Poller that returns a Future on poll, instead of blocking."""
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_socket_class: type[_AsyncSocket]
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_READ: int
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_WRITE: int
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raw_sockets: list[Any]
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def _watch_raw_socket(self, loop: Any, socket: Any, evt: int, f: Callable) -> None:
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"""Schedule callback for a raw socket"""
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raise NotImplementedError()
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def _unwatch_raw_sockets(self, loop: Any, *sockets: Any) -> None:
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"""Unschedule callback for a raw socket"""
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raise NotImplementedError()
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def poll(self, timeout=-1) -> Awaitable[list[tuple[Any, int]]]: # type: ignore
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"""Return a Future for a poll event"""
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future = self._Future()
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if timeout == 0:
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try:
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result = super().poll(0)
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except Exception as e:
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future.set_exception(e)
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else:
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future.set_result(result)
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return future
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loop = self._get_loop()
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# register Future to be called as soon as any event is available on any socket
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watcher = self._Future()
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# watch raw sockets:
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raw_sockets: list[Any] = []
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def wake_raw(*args):
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if not watcher.done():
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watcher.set_result(None)
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watcher.add_done_callback(
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lambda f: self._unwatch_raw_sockets(loop, *raw_sockets)
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)
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wrapped_sockets: list[_AsyncSocket] = []
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def _clear_wrapper_io(f):
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for s in wrapped_sockets:
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s._clear_io_state()
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for socket, mask in self.sockets:
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if isinstance(socket, _zmq.Socket):
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if not isinstance(socket, self._socket_class):
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# it's a blocking zmq.Socket, wrap it in async
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socket = self._socket_class.from_socket(socket)
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wrapped_sockets.append(socket)
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if mask & _zmq.POLLIN:
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socket._add_recv_event('poll', future=watcher)
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if mask & _zmq.POLLOUT:
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socket._add_send_event('poll', future=watcher)
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else:
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raw_sockets.append(socket)
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evt = 0
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if mask & _zmq.POLLIN:
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evt |= self._READ
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if mask & _zmq.POLLOUT:
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evt |= self._WRITE
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self._watch_raw_socket(loop, socket, evt, wake_raw)
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def on_poll_ready(f):
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if future.done():
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return
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if watcher.cancelled():
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try:
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future.cancel()
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except RuntimeError:
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# RuntimeError may be called during teardown
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pass
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return
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if watcher.exception():
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future.set_exception(watcher.exception())
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else:
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try:
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result = super(_AsyncPoller, self).poll(0)
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except Exception as e:
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future.set_exception(e)
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else:
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future.set_result(result)
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watcher.add_done_callback(on_poll_ready)
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if wrapped_sockets:
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watcher.add_done_callback(_clear_wrapper_io)
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if timeout is not None and timeout > 0:
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# schedule cancel to fire on poll timeout, if any
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def trigger_timeout():
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if not watcher.done():
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watcher.set_result(None)
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timeout_handle = loop.call_later(1e-3 * timeout, trigger_timeout)
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def cancel_timeout(f):
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if hasattr(timeout_handle, 'cancel'):
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timeout_handle.cancel()
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else:
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loop.remove_timeout(timeout_handle)
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future.add_done_callback(cancel_timeout)
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def cancel_watcher(f):
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if not watcher.done():
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watcher.cancel()
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future.add_done_callback(cancel_watcher)
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return future
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class _NoTimer:
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@staticmethod
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def cancel():
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pass
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T = TypeVar("T", bound="_AsyncSocket")
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class _AsyncSocket(_Async, _zmq.Socket[Future]):
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# Warning : these class variables are only here to allow to call super().__setattr__.
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# They be overridden at instance initialization and not shared in the whole class
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_recv_futures = None
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_send_futures = None
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_state = 0
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_shadow_sock: _zmq.Socket
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_poller_class = _AsyncPoller
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_fd = None
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def __init__(
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self,
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context=None,
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socket_type=-1,
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io_loop=None,
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_from_socket: _zmq.Socket | None = None,
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**kwargs,
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) -> None:
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if isinstance(context, _zmq.Socket):
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context, _from_socket = (None, context)
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if _from_socket is not None:
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super().__init__(shadow=_from_socket.underlying) # type: ignore
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self._shadow_sock = _from_socket
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else:
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super().__init__(context, socket_type, **kwargs) # type: ignore
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self._shadow_sock = _zmq.Socket.shadow(self.underlying)
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if io_loop is not None:
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warnings.warn(
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f"{self.__class__.__name__}(io_loop) argument is deprecated in pyzmq 22.2."
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" The currently active loop will always be used.",
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DeprecationWarning,
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stacklevel=3,
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)
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self._recv_futures = deque()
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self._send_futures = deque()
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self._state = 0
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self._fd = self._shadow_sock.FD
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@classmethod
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def from_socket(cls: type[T], socket: _zmq.Socket, io_loop: Any = None) -> T:
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"""Create an async socket from an existing Socket"""
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return cls(_from_socket=socket, io_loop=io_loop)
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def close(self, linger: int | None = None) -> None:
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if not self.closed and self._fd is not None:
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event_list: list[_FutureEvent] = list(
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chain(self._recv_futures or [], self._send_futures or [])
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)
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for event in event_list:
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if not event.future.done():
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try:
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event.future.cancel()
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except RuntimeError:
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# RuntimeError may be called during teardown
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pass
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self._clear_io_state()
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super().close(linger=linger)
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close.__doc__ = _zmq.Socket.close.__doc__
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def get(self, key):
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result = super().get(key)
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if key == EVENTS:
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self._schedule_remaining_events(result)
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return result
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get.__doc__ = _zmq.Socket.get.__doc__
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@overload # type: ignore
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def recv_multipart(
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self, flags: int = 0, *, track: bool = False
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) -> Awaitable[list[bytes]]: ...
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@overload
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def recv_multipart(
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self, flags: int = 0, *, copy: Literal[True], track: bool = False
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) -> Awaitable[list[bytes]]: ...
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@overload
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def recv_multipart(
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self, flags: int = 0, *, copy: Literal[False], track: bool = False
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) -> Awaitable[list[_zmq.Frame]]: # type: ignore
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...
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@overload
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def recv_multipart(
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self, flags: int = 0, copy: bool = True, track: bool = False
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) -> Awaitable[list[bytes] | list[_zmq.Frame]]: ...
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def recv_multipart(
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self, flags: int = 0, copy: bool = True, track: bool = False
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) -> Awaitable[list[bytes] | list[_zmq.Frame]]:
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"""Receive a complete multipart zmq message.
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Returns a Future whose result will be a multipart message.
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"""
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return self._add_recv_event(
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'recv_multipart', dict(flags=flags, copy=copy, track=track)
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)
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@overload # type: ignore
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def recv(self, flags: int = 0, *, track: bool = False) -> Awaitable[bytes]: ...
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@overload
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def recv(
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self, flags: int = 0, *, copy: Literal[True], track: bool = False
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) -> Awaitable[bytes]: ...
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@overload
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def recv(
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self, flags: int = 0, *, copy: Literal[False], track: bool = False
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) -> Awaitable[_zmq.Frame]: ...
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def recv( # type: ignore
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self, flags: int = 0, copy: bool = True, track: bool = False
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) -> Awaitable[bytes | _zmq.Frame]:
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"""Receive a single zmq frame.
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Returns a Future, whose result will be the received frame.
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Recommend using recv_multipart instead.
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"""
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return self._add_recv_event('recv', dict(flags=flags, copy=copy, track=track))
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def send_multipart( # type: ignore
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self, msg_parts: Any, flags: int = 0, copy: bool = True, track=False, **kwargs
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) -> Awaitable[_zmq.MessageTracker | None]:
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"""Send a complete multipart zmq message.
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Returns a Future that resolves when sending is complete.
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"""
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kwargs['flags'] = flags
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kwargs['copy'] = copy
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kwargs['track'] = track
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return self._add_send_event('send_multipart', msg=msg_parts, kwargs=kwargs)
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def send( # type: ignore
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self,
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data: Any,
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flags: int = 0,
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copy: bool = True,
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track: bool = False,
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**kwargs: Any,
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) -> Awaitable[_zmq.MessageTracker | None]:
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"""Send a single zmq frame.
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Returns a Future that resolves when sending is complete.
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Recommend using send_multipart instead.
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"""
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kwargs['flags'] = flags
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kwargs['copy'] = copy
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kwargs['track'] = track
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kwargs.update(dict(flags=flags, copy=copy, track=track))
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return self._add_send_event('send', msg=data, kwargs=kwargs)
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def _deserialize(self, recvd, load):
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"""Deserialize with Futures"""
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f = self._Future()
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def _chain(_):
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"""Chain result through serialization to recvd"""
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if f.done():
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# chained future may be cancelled, which means nobody is going to get this result
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# if it's an error, that's no big deal (probably zmq.Again),
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# but if it's a successful recv, this is a dropped message!
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if not recvd.cancelled() and recvd.exception() is None:
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warnings.warn(
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# is there a useful stacklevel?
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# ideally, it would point to where `f.cancel()` was called
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f"Future {f} completed while awaiting {recvd}. A message has been dropped!",
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RuntimeWarning,
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)
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return
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if recvd.exception():
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f.set_exception(recvd.exception())
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else:
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buf = recvd.result()
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try:
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loaded = load(buf)
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except Exception as e:
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f.set_exception(e)
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else:
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f.set_result(loaded)
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recvd.add_done_callback(_chain)
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def _chain_cancel(_):
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"""Chain cancellation from f to recvd"""
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if recvd.done():
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return
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if f.cancelled():
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recvd.cancel()
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f.add_done_callback(_chain_cancel)
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return f
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def poll(self, timeout=None, flags=_zmq.POLLIN) -> Awaitable[int]: # type: ignore
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"""poll the socket for events
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returns a Future for the poll results.
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"""
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if self.closed:
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raise _zmq.ZMQError(_zmq.ENOTSUP)
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p = self._poller_class()
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p.register(self, flags)
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poll_future = cast(Future, p.poll(timeout))
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future = self._Future()
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def unwrap_result(f):
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if future.done():
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return
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if poll_future.cancelled():
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try:
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future.cancel()
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except RuntimeError:
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# RuntimeError may be called during teardown
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pass
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return
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if f.exception():
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future.set_exception(poll_future.exception())
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else:
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evts = dict(poll_future.result())
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future.set_result(evts.get(self, 0))
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if poll_future.done():
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# hook up result if already done
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unwrap_result(poll_future)
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else:
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poll_future.add_done_callback(unwrap_result)
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def cancel_poll(future):
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"""Cancel underlying poll if request has been cancelled"""
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if not poll_future.done():
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try:
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poll_future.cancel()
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except RuntimeError:
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# RuntimeError may be called during teardown
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pass
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future.add_done_callback(cancel_poll)
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return future
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# overrides only necessary for updated types
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def recv_string(self, *args, **kwargs) -> Awaitable[str]: # type: ignore
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return super().recv_string(*args, **kwargs) # type: ignore
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def send_string( # type: ignore
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self, s: str, flags: int = 0, encoding: str = 'utf-8'
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) -> Awaitable[None]:
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return super().send_string(s, flags=flags, encoding=encoding) # type: ignore
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def _add_timeout(self, future, timeout):
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"""Add a timeout for a send or recv Future"""
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def future_timeout():
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if future.done():
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# future already resolved, do nothing
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return
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# raise EAGAIN
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future.set_exception(_zmq.Again())
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return self._call_later(timeout, future_timeout)
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def _call_later(self, delay, callback):
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"""Schedule a function to be called later
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Override for different IOLoop implementations
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Tornado and asyncio happen to both have ioloop.call_later
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with the same signature.
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"""
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return self._get_loop().call_later(delay, callback)
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@staticmethod
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def _remove_finished_future(future, event_list, event=None):
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"""Make sure that futures are removed from the event list when they resolve
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Avoids delaying cleanup until the next send/recv event,
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which may never come.
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"""
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# "future" instance is shared between sockets, but each socket has its own event list.
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if not event_list:
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return
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# only unconsumed events (e.g. cancelled calls)
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# will be present when this happens
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try:
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event_list.remove(event)
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except ValueError:
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# usually this will have been removed by being consumed
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return
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def _add_recv_event(self, kind, kwargs=None, future=None):
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"""Add a recv event, returning the corresponding Future"""
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f = future or self._Future()
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if kind.startswith('recv') and kwargs.get('flags', 0) & _zmq.DONTWAIT:
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# short-circuit non-blocking calls
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recv = getattr(self._shadow_sock, kind)
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try:
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r = recv(**kwargs)
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except Exception as e:
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f.set_exception(e)
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else:
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f.set_result(r)
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return f
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timer = _NoTimer
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if hasattr(_zmq, 'RCVTIMEO'):
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timeout_ms = self._shadow_sock.rcvtimeo
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if timeout_ms >= 0:
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timer = self._add_timeout(f, timeout_ms * 1e-3)
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# we add it to the list of futures before we add the timeout as the
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# timeout will remove the future from recv_futures to avoid leaks
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_future_event = _FutureEvent(f, kind, kwargs, msg=None, timer=timer)
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self._recv_futures.append(_future_event)
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if self._shadow_sock.get(EVENTS) & POLLIN:
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# recv immediately, if we can
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self._handle_recv()
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if self._recv_futures and _future_event in self._recv_futures:
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# Don't let the Future sit in _recv_events after it's done
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# no need to register this if we've already been handled
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# (i.e. immediately-resolved recv)
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f.add_done_callback(
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partial(
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self._remove_finished_future,
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event_list=self._recv_futures,
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event=_future_event,
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)
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)
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self._add_io_state(POLLIN)
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return f
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def _add_send_event(self, kind, msg=None, kwargs=None, future=None):
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"""Add a send event, returning the corresponding Future"""
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f = future or self._Future()
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# attempt send with DONTWAIT if no futures are waiting
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# short-circuit for sends that will resolve immediately
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# only call if no send Futures are waiting
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if kind in ('send', 'send_multipart') and not self._send_futures:
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flags = kwargs.get('flags', 0)
|
|
nowait_kwargs = kwargs.copy()
|
|
nowait_kwargs['flags'] = flags | _zmq.DONTWAIT
|
|
|
|
# short-circuit non-blocking calls
|
|
send = getattr(self._shadow_sock, kind)
|
|
# track if the send resolved or not
|
|
# (EAGAIN if DONTWAIT is not set should proceed with)
|
|
finish_early = True
|
|
try:
|
|
r = send(msg, **nowait_kwargs)
|
|
except _zmq.Again as e:
|
|
if flags & _zmq.DONTWAIT:
|
|
f.set_exception(e)
|
|
else:
|
|
# EAGAIN raised and DONTWAIT not requested,
|
|
# proceed with async send
|
|
finish_early = False
|
|
except Exception as e:
|
|
f.set_exception(e)
|
|
else:
|
|
f.set_result(r)
|
|
|
|
if finish_early:
|
|
# short-circuit resolved, return finished Future
|
|
# schedule wake for recv if there are any receivers waiting
|
|
if self._recv_futures:
|
|
self._schedule_remaining_events()
|
|
return f
|
|
|
|
timer = _NoTimer
|
|
if hasattr(_zmq, 'SNDTIMEO'):
|
|
timeout_ms = self._shadow_sock.get(_zmq.SNDTIMEO)
|
|
if timeout_ms >= 0:
|
|
timer = self._add_timeout(f, timeout_ms * 1e-3)
|
|
|
|
# we add it to the list of futures before we add the timeout as the
|
|
# timeout will remove the future from recv_futures to avoid leaks
|
|
_future_event = _FutureEvent(f, kind, kwargs=kwargs, msg=msg, timer=timer)
|
|
self._send_futures.append(_future_event)
|
|
# Don't let the Future sit in _send_futures after it's done
|
|
f.add_done_callback(
|
|
partial(
|
|
self._remove_finished_future,
|
|
event_list=self._send_futures,
|
|
event=_future_event,
|
|
)
|
|
)
|
|
|
|
self._add_io_state(POLLOUT)
|
|
return f
|
|
|
|
def _handle_recv(self):
|
|
"""Handle recv events"""
|
|
if not self._shadow_sock.get(EVENTS) & POLLIN:
|
|
# event triggered, but state may have been changed between trigger and callback
|
|
return
|
|
f = None
|
|
while self._recv_futures:
|
|
f, kind, kwargs, _, timer = self._recv_futures.popleft()
|
|
# skip any cancelled futures
|
|
if f.done():
|
|
f = None
|
|
else:
|
|
break
|
|
|
|
if not self._recv_futures:
|
|
self._drop_io_state(POLLIN)
|
|
|
|
if f is None:
|
|
return
|
|
|
|
timer.cancel()
|
|
|
|
if kind == 'poll':
|
|
# on poll event, just signal ready, nothing else.
|
|
f.set_result(None)
|
|
return
|
|
elif kind == 'recv_multipart':
|
|
recv = self._shadow_sock.recv_multipart
|
|
elif kind == 'recv':
|
|
recv = self._shadow_sock.recv
|
|
else:
|
|
raise ValueError(f"Unhandled recv event type: {kind!r}")
|
|
|
|
kwargs['flags'] |= _zmq.DONTWAIT
|
|
try:
|
|
result = recv(**kwargs)
|
|
except Exception as e:
|
|
f.set_exception(e)
|
|
else:
|
|
f.set_result(result)
|
|
|
|
def _handle_send(self):
|
|
if not self._shadow_sock.get(EVENTS) & POLLOUT:
|
|
# event triggered, but state may have been changed between trigger and callback
|
|
return
|
|
f = None
|
|
while self._send_futures:
|
|
f, kind, kwargs, msg, timer = self._send_futures.popleft()
|
|
# skip any cancelled futures
|
|
if f.done():
|
|
f = None
|
|
else:
|
|
break
|
|
|
|
if not self._send_futures:
|
|
self._drop_io_state(POLLOUT)
|
|
|
|
if f is None:
|
|
return
|
|
|
|
timer.cancel()
|
|
|
|
if kind == 'poll':
|
|
# on poll event, just signal ready, nothing else.
|
|
f.set_result(None)
|
|
return
|
|
elif kind == 'send_multipart':
|
|
send = self._shadow_sock.send_multipart
|
|
elif kind == 'send':
|
|
send = self._shadow_sock.send
|
|
else:
|
|
raise ValueError(f"Unhandled send event type: {kind!r}")
|
|
|
|
kwargs['flags'] |= _zmq.DONTWAIT
|
|
try:
|
|
result = send(msg, **kwargs)
|
|
except Exception as e:
|
|
f.set_exception(e)
|
|
else:
|
|
f.set_result(result)
|
|
|
|
# event masking from ZMQStream
|
|
def _handle_events(self, fd=0, events=0):
|
|
"""Dispatch IO events to _handle_recv, etc."""
|
|
if self._shadow_sock.closed:
|
|
return
|
|
|
|
zmq_events = self._shadow_sock.get(EVENTS)
|
|
if zmq_events & _zmq.POLLIN:
|
|
self._handle_recv()
|
|
if zmq_events & _zmq.POLLOUT:
|
|
self._handle_send()
|
|
self._schedule_remaining_events()
|
|
|
|
def _schedule_remaining_events(self, events=None):
|
|
"""Schedule a call to handle_events next loop iteration
|
|
|
|
If there are still events to handle.
|
|
"""
|
|
# edge-triggered handling
|
|
# allow passing events in, in case this is triggered by retrieving events,
|
|
# so we don't have to retrieve it twice.
|
|
if self._state == 0:
|
|
# not watching for anything, nothing to schedule
|
|
return
|
|
if events is None:
|
|
events = self._shadow_sock.get(EVENTS)
|
|
if events & self._state:
|
|
self._call_later(0, self._handle_events)
|
|
|
|
def _add_io_state(self, state):
|
|
"""Add io_state to poller."""
|
|
if self._state != state:
|
|
state = self._state = self._state | state
|
|
self._update_handler(self._state)
|
|
|
|
def _drop_io_state(self, state):
|
|
"""Stop poller from watching an io_state."""
|
|
if self._state & state:
|
|
self._state = self._state & (~state)
|
|
self._update_handler(self._state)
|
|
|
|
def _update_handler(self, state):
|
|
"""Update IOLoop handler with state.
|
|
|
|
zmq FD is always read-only.
|
|
"""
|
|
# ensure loop is registered and init_io has been called
|
|
# if there are any events to watch for
|
|
if state:
|
|
self._get_loop()
|
|
self._schedule_remaining_events()
|
|
|
|
def _init_io_state(self, loop=None):
|
|
"""initialize the ioloop event handler"""
|
|
if loop is None:
|
|
loop = self._get_loop()
|
|
loop.add_handler(self._shadow_sock, self._handle_events, self._READ)
|
|
self._call_later(0, self._handle_events)
|
|
|
|
def _clear_io_state(self):
|
|
"""unregister the ioloop event handler
|
|
|
|
called once during close
|
|
"""
|
|
fd = self._shadow_sock
|
|
if self._shadow_sock.closed:
|
|
fd = self._fd
|
|
if self._current_loop is not None:
|
|
self._current_loop.remove_handler(fd)
|