from __future__ import generators
import threading
class SpawnedGenerator(threading.Thread):
"Class to spawn a generator."
def __init__(self, generator, queueSize=0):
"Initialise the spawned generator from a generator."
threading.Thread.__init__(self)
self.generator = generator
self.queueSize = queueSize
def stop(self):
"Request a stop."
self.stopRequested = 1
def run(self):
"Called in a separate thread by Thread.start()."
queue = self.queue
try:
it = iter(self.generator)
while 1:
next = it.next()
queue.put((1, next)) # will raise StopIteration
if self.stopRequested:
raise StopIteration, "stop requested"
except:
queue.put((0, sys.exc_info()))
def __call__(self):
"Yield results obtained from the generator."
self.queue = queue = Queue.Queue(self.queueSize)
self.stopRequested = 0
self.start() # run() will stuff the queue in a separate Thread
keepGoing, item = queue.get()
while keepGoing:
yield item
keepGoing, item = queue.get()
# if keepGoing is false, item is exc_info() result
self.exc_info = item # stash it for the curious
type, value, traceback = item
if isinstance(type, StopIteration):
return
else:
raise type, value, traceback
def __iter__(self):
"Return an iterator for our executed self."
return iter(self())
