93 lines
2.7 KiB
Python
93 lines
2.7 KiB
Python
# SPDX-FileCopyrightText: 2019-2020 Damien P. George
|
|
#
|
|
# SPDX-License-Identifier: MIT
|
|
#
|
|
# MicroPython uasyncio module
|
|
# MIT license; Copyright (c) 2019-2020 Damien P. George
|
|
#
|
|
# This code comes from MicroPython, and has not been run through black or pylint there.
|
|
# Altering these files significantly would make merging difficult, so we will not use
|
|
# pylint or black.
|
|
# pylint: skip-file
|
|
# fmt: off
|
|
"""
|
|
Events
|
|
======
|
|
"""
|
|
|
|
from . import core
|
|
|
|
# Event class for primitive events that can be waited on, set, and cleared
|
|
class Event:
|
|
"""Create a new event which can be used to synchronize tasks. Events
|
|
start in the cleared state.
|
|
"""
|
|
|
|
def __init__(self):
|
|
self.state = False # False=unset; True=set
|
|
self.waiting = core.TaskQueue() # Queue of Tasks waiting on completion of this event
|
|
|
|
def is_set(self):
|
|
"""Returns ``True`` if the event is set, ``False`` otherwise."""
|
|
|
|
return self.state
|
|
|
|
def set(self):
|
|
"""Set the event. Any tasks waiting on the event will be scheduled to run.
|
|
"""
|
|
|
|
# Event becomes set, schedule any tasks waiting on it
|
|
# Note: This must not be called from anything except the thread running
|
|
# the asyncio loop (i.e. neither hard or soft IRQ, or a different thread).
|
|
while self.waiting.peek():
|
|
core._task_queue.push_head(self.waiting.pop_head())
|
|
self.state = True
|
|
|
|
def clear(self):
|
|
"""Clear the event."""
|
|
|
|
self.state = False
|
|
|
|
async def wait(self):
|
|
"""Wait for the event to be set. If the event is already set then it returns
|
|
immediately.
|
|
|
|
This is a coroutine.
|
|
"""
|
|
|
|
if not self.state:
|
|
# Event not set, put the calling task on the event's waiting queue
|
|
self.waiting.push_head(core.cur_task)
|
|
# Set calling task's data to the event's queue so it can be removed if needed
|
|
core.cur_task.data = self.waiting
|
|
await core._never()
|
|
return True
|
|
|
|
|
|
# MicroPython-extension: This can be set from outside the asyncio event loop,
|
|
# such as other threads, IRQs or scheduler context. Implementation is a stream
|
|
# that asyncio will poll until a flag is set.
|
|
# Note: Unlike Event, this is self-clearing.
|
|
try:
|
|
import uio
|
|
|
|
class ThreadSafeFlag(uio.IOBase):
|
|
def __init__(self):
|
|
self._flag = 0
|
|
|
|
def ioctl(self, req, flags):
|
|
if req == 3: # MP_STREAM_POLL
|
|
return self._flag * flags
|
|
return None
|
|
|
|
def set(self):
|
|
self._flag = 1
|
|
|
|
async def wait(self):
|
|
if not self._flag:
|
|
yield core._io_queue.queue_read(self)
|
|
self._flag = 0
|
|
|
|
except ImportError:
|
|
pass
|