mirror of
https://github.com/KevinMidboe/python-gpiozero.git
synced 2025-10-29 17:50:37 +00:00
92 lines
2.4 KiB
Python
92 lines
2.4 KiB
Python
from __future__ import (
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unicode_literals,
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print_function,
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absolute_import,
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division,
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)
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str = type('')
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import weakref
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from collections import deque
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from threading import Thread, Event, RLock
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try:
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from statistics import median, mean
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except ImportError:
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from .compat import median, mean
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from .exc import (
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GPIOBadQueueLen,
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GPIOBadSampleWait,
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)
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_THREADS = set()
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def _threads_shutdown():
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while _THREADS:
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for t in _THREADS.copy():
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t.stop()
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class GPIOThread(Thread):
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def __init__(self, group=None, target=None, name=None, args=(), kwargs={}):
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super(GPIOThread, self).__init__(group, target, name, args, kwargs)
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self.stopping = Event()
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self.daemon = True
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def start(self):
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self.stopping.clear()
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_THREADS.add(self)
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super(GPIOThread, self).start()
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def stop(self):
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self.stopping.set()
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self.join()
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def join(self):
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super(GPIOThread, self).join()
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_THREADS.discard(self)
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class GPIOQueue(GPIOThread):
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def __init__(
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self, parent, queue_len=5, sample_wait=0.0, partial=False,
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average=median):
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assert callable(average)
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super(GPIOQueue, self).__init__(target=self.fill)
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if queue_len < 1:
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raise GPIOBadQueueLen('queue_len must be at least one')
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if sample_wait < 0:
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raise GPIOBadSampleWait('sample_wait must be 0 or greater')
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self.queue = deque(maxlen=queue_len)
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self.partial = partial
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self.sample_wait = sample_wait
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self.full = Event()
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self.parent = weakref.proxy(parent)
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self.average = average
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@property
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def value(self):
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if not self.partial:
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self.full.wait()
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try:
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return self.average(self.queue)
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except ZeroDivisionError:
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# No data == inactive value
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return 0.0
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def fill(self):
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try:
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while (not self.stopping.wait(self.sample_wait) and
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len(self.queue) < self.queue.maxlen):
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self.queue.append(self.parent._read())
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if self.partial:
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self.parent._fire_events()
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self.full.set()
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while not self.stopping.wait(self.sample_wait):
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self.queue.append(self.parent._read())
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self.parent._fire_events()
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except ReferenceError:
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# Parent is dead; time to die!
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pass
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