Files
pyDevSup/python/devsup/util.py
Michael Davidsaver 641921664b use Queue for worker
2013-04-07 10:05:50 -04:00

138 lines
3.4 KiB
Python

from __future__ import print_function
import threading, traceback
try:
import Queue as queue
except ImportError:
import queue
class StoppableThread(threading.Thread):
"""A thread which can be requested to stop.
The thread run() method should periodically call the shouldRun()
method and return if this yields False.
>>> class TestThread(StoppableThread):
... def __init__(self):
... super(TestThread,self).__init__()
... self.E=threading.Event()
... def run(self):
... import time
... self.cur = threading.current_thread()
... self.E.set()
... while self.shouldRun():
... time.sleep(0.01)
>>> T = TestThread()
>>> T.start()
>>> T.E.wait(1.0)
True
>>> T.cur is T
True
>>> T.join()
>>> T.is_alive()
False
"""
def __init__(self, max=0):
super(StoppableThread, self).__init__()
self.__stop = True
self.__lock = threading.Lock()
def start(self):
with self.__lock:
self.__stop = False
super(StoppableThread, self).start()
def join(self):
with self.__lock:
self.__stop = True
super(StoppableThread, self).join()
def shouldRun(self):
with self.__lock:
return not self.__stop
class Worker(threading.Thread):
"""A threaded work queue.
>>> w = Worker()
>>> w = Worker()
>>> w.start()
>>> w.join()
>>> import threading
>>> E = threading.Event()
>>> w = Worker()
>>> w.start()
>>> w.add(E.set)
True
>>> E.wait(1.0)
True
>>> w.join()
"""
StopWorker = object()
def __init__(self, max=0):
super(Worker, self).__init__()
self._Q = queue.Queue(maxsize=max)
self.__stop = False
self.__lock = threading.Lock()
def join(self, flush=True):
"""Stop accepting new jobs and join the worker thread
Blocks until currently queued work is complete.
"""
with self.__lock:
self.__stop = True
self._Q.put((self.StopWorker,None,None))
super(Worker, self).join()
def __len__(self):
return self._Q.qsize()
def add(self, func, args=(), kws={}, block=True):
"""Attempt to send a job to the worker.
:returns: True if the job was queued. False if the queue is full,
or has been joined.
When ``block=True`` then this method will only return
False if the Worker has been joined.
"""
with self.__lock:
if self.__stop is True:
return False
try:
self._Q.put((func,args,kws), block)
return True
except queue.Full:
return False
def run(self):
Q = self._Q
block = True
try:
while True:
F, A, K = Q.get(block)
if F is self.StopWorker:
block = False
Q.task_done()
continue
try:
F(*A, **K)
except:
print('Error running',F,A,K)
traceback.print_exc()
finally:
Q.task_done()
except queue.Empty:
pass # We are done now
if __name__=='__main__':
import doctest
doctest.testmod()