62 lines
1.9 KiB
Python
62 lines
1.9 KiB
Python
# MicroPython uasyncio module
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# MIT license; Copyright (c) 2019-2020 Damien P. George
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from . import core
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# Event class for primitive events that can be waited on, set, and cleared
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class Event:
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def __init__(self):
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self.state = False # False=unset; True=set
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self.waiting = core.TaskQueue() # Queue of Tasks waiting on completion of this event
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def is_set(self):
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return self.state
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def set(self):
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# Event becomes set, schedule any tasks waiting on it
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# Note: This must not be called from anything except the thread running
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# the asyncio loop (i.e. neither hard or soft IRQ, or a different thread).
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while self.waiting.peek():
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core._task_queue.push_head(self.waiting.pop_head())
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self.state = True
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def clear(self):
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self.state = False
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async def wait(self):
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if not self.state:
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# Event not set, put the calling task on the event's waiting queue
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self.waiting.push_head(core.cur_task)
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# Set calling task's data to the event's queue so it can be removed if needed
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core.cur_task.data = self.waiting
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yield
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return True
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# MicroPython-extension: This can be set from outside the asyncio event loop,
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# such as other threads, IRQs or scheduler context. Implementation is a stream
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# that asyncio will poll until a flag is set.
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# Note: Unlike Event, this is self-clearing.
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try:
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import uio
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class ThreadSafeFlag(uio.IOBase):
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def __init__(self):
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self._flag = 0
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def ioctl(self, req, flags):
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if req == 3: # MP_STREAM_POLL
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return self._flag * flags
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return None
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def set(self):
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self._flag = 1
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async def wait(self):
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if not self._flag:
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yield core._io_queue.queue_read(self)
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self._flag = 0
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except ImportError:
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pass
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