158 lines
4.9 KiB
Python
158 lines
4.9 KiB
Python
import asyncio
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import logging
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from concurrent.futures import Future
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from typing import List, Optional, TypeVar
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from reactivex import abc, typing
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from reactivex.disposable import (
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CompositeDisposable,
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Disposable,
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SingleAssignmentDisposable,
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)
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from .asyncioscheduler import AsyncIOScheduler
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_TState = TypeVar("_TState")
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log = logging.getLogger("Rx")
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class AsyncIOThreadSafeScheduler(AsyncIOScheduler):
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"""A scheduler that schedules work via the asyncio mainloop. This is a
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subclass of AsyncIOScheduler which uses the threadsafe asyncio methods.
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"""
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def schedule(
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self, action: typing.ScheduledAction[_TState], state: Optional[_TState] = None
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) -> abc.DisposableBase:
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"""Schedules an action to be executed.
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Args:
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action: Action to be executed.
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state: [Optional] state to be given to the action function.
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Returns:
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The disposable object used to cancel the scheduled action
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(best effort).
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"""
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sad = SingleAssignmentDisposable()
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def interval() -> None:
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sad.disposable = self.invoke_action(action, state=state)
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handle = self._loop.call_soon_threadsafe(interval)
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def dispose() -> None:
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if self._on_self_loop_or_not_running():
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handle.cancel()
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return
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future: "Future[int]" = Future()
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def cancel_handle() -> None:
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handle.cancel()
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future.set_result(0)
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self._loop.call_soon_threadsafe(cancel_handle)
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future.result()
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return CompositeDisposable(sad, Disposable(dispose))
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def schedule_relative(
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self,
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duetime: typing.RelativeTime,
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action: typing.ScheduledAction[_TState],
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state: Optional[_TState] = None,
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) -> abc.DisposableBase:
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"""Schedules an action to be executed after duetime.
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Args:
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duetime: Relative time after which to execute the action.
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action: Action to be executed.
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state: [Optional] state to be given to the action function.
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Returns:
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The disposable object used to cancel the scheduled action
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(best effort).
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"""
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seconds = self.to_seconds(duetime)
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if seconds <= 0:
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return self.schedule(action, state=state)
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sad = SingleAssignmentDisposable()
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def interval() -> None:
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sad.disposable = self.invoke_action(action, state=state)
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# the operations on the list used here are atomic, so there is no
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# need to protect its access with a lock
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handle: List[asyncio.Handle] = []
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def stage2() -> None:
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handle.append(self._loop.call_later(seconds, interval))
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handle.append(self._loop.call_soon_threadsafe(stage2))
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def dispose() -> None:
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def do_cancel_handles() -> None:
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try:
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handle.pop().cancel()
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handle.pop().cancel()
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except Exception:
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pass
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if self._on_self_loop_or_not_running():
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do_cancel_handles()
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return
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future: "Future[int]" = Future()
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def cancel_handle() -> None:
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do_cancel_handles()
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future.set_result(0)
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self._loop.call_soon_threadsafe(cancel_handle)
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future.result()
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return CompositeDisposable(sad, Disposable(dispose))
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def schedule_absolute(
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self,
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duetime: typing.AbsoluteTime,
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action: typing.ScheduledAction[_TState],
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state: Optional[_TState] = None,
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) -> abc.DisposableBase:
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"""Schedules an action to be executed at duetime.
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Args:
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duetime: Absolute time at which to execute the action.
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action: Action to be executed.
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state: [Optional] state to be given to the action function.
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Returns:
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The disposable object used to cancel the scheduled action
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(best effort).
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"""
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duetime = self.to_datetime(duetime)
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return self.schedule_relative(duetime - self.now, action, state=state)
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def _on_self_loop_or_not_running(self) -> bool:
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"""
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Returns True if either self._loop is not running, or we're currently
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executing on self._loop. In both cases, waiting for a future to be
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resolved on the loop would result in a deadlock.
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"""
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if not self._loop.is_running():
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return True
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current_loop = None
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try:
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# In python 3.7 there asyncio.get_running_loop() is prefered.
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current_loop = asyncio.get_event_loop()
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except RuntimeError:
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# If there is no loop in current thread at all, and it is not main
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# thread, we get error like:
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# RuntimeError: There is no current event loop in thread 'Thread-1'
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pass
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return self._loop == current_loop
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