179 lines
4.5 KiB
Python
179 lines
4.5 KiB
Python
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from __future__ import print_function
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import threading, traceback
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class StoppableThread(threading.Thread):
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"""A thread which can be required to stop.
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The thread run() method should periodically call the shouldRun()
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method if this yields False, the finish() should be called before returning.
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This is really only feasible by sub-classing.
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>>> class TestThread(StoppableThread):
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... def __init__(self):
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... super(TestThread,self).__init__()
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... self.E=threading.Event()
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... def run(self):
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... try:
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... import time
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... self.E.set()
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... while self.shouldRun():
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... time.sleep(0.01)
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... finally:
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... self.finish()
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>>> T = TestThread()
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>>> T.start()
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>>> T.E.wait()
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True
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>>> T.join()
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>>> T.is_alive()
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False
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"""
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def __init__(self, max=0):
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super(StoppableThread, self).__init__()
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self._run, self._stop = False, False
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self._sevt, self._lock = threading.Event(), threading.Lock()
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def running(self):
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with self._lock:
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return self._run and not self._stop
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def start(self):
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with self._lock:
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assert not self._stop
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self._run = True
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self._sevt.clear()
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super(StoppableThread, self).start()
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def join(self):
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with self._lock:
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if not self._run:
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return
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self._stop = True
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self._sevt.wait()
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super(StoppableThread, self).join()
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def shouldRun(self):
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with self._lock:
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return not self._stop
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def finish(self):
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with self._lock:
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self._run = self._stop = False
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self._sevt.set()
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def run(self, *args, **kws):
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try:
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super(StoppableThread, self).start(*args, **kws)
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finally:
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self.finish()
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class Worker(threading.Thread):
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"""A threaded work queue.
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>>> w = Worker()
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>>> w = Worker()
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>>> w.start()
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>>> w.join()
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>>> import threading
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>>> E = threading.Event()
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>>> w = Worker()
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>>> w.start()
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>>> w.add(E.set)
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>>> E.wait(1.0)
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True
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>>> w.join()
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"""
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def __init__(self, max=0):
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super(Worker, self).__init__()
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self._run, self._stop = False, None
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self._lock = threading.Lock()
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self._update = threading.Condition(self._lock)
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self.maxQ, self._Q = max, []
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def running(self):
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with self._lock:
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return self._run and not self._stop
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def start(self):
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with self._lock:
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if self._run or self._stop:
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return
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super(Worker, self).start()
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self._run = True
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def join(self, flush=True):
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self._update.acquire()
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try:
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if self._stop:
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raise RuntimeError("Someone else is already trying to stop me")
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self._stop = threading.Event()
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self._update.notify()
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self._update.release()
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try:
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self._stop.wait()
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finally:
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self._update.acquire()
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self._stop = None
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assert not self._run
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if flush:
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self._Q = []
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finally:
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self._update.release()
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def __len__(self):
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with self._lock:
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return len(self._Q)
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def add(self, func, args=(), kws={}):
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with self._lock:
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if not self._run or self._stop:
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return
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elif self.maxQ>0 and len(self._Q)>=self.maxQ:
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raise RuntimeError('Worker queue full')
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self._Q.append((func,args,kws))
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self._update.notify()
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def run(self):
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self._update.acquire()
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try:
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assert self._run
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while True:
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while self._stop is None and len(self._Q)==0:
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self._update.wait()
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if self._stop is not None:
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break
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F, A, K = self._Q.pop(0)
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self._update.release()
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try:
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F(*A,**K)
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except:
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print('Error running',F,A,K)
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traceback.print_exc()
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finally:
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self._update.acquire()
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self._run = False
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self._stop.set()
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finally:
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self._update.release()
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if __name__=='__main__':
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import doctest
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doctest.testmod()
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