class TimeoutGuard(Guard):
"""
Timeout spawns a timer thread, when posted. If removed
before timeout, then the timer thread is cancelled.
"""
def __init__(self, seconds, action=None):
self.seconds = seconds
self.posted = (None, None)
self.s = Scheduler()
self.p = None
self.g = (self, action)
# Timer expired, offer an active Channel Request
def expire(self):
op, req = self.posted
if op == READ:
ChannelReq(self.p, msg=None).offer(req)
elif op == WRITE:
req.offer(ChannelReq(self.p))
def post_read(self, reader):
self.posted = (READ, reader)
# Start process
self.p = Process(self.expire)
self.p.start()
self.p.setstate(ACTIVE)
# Put process on the scheduler timer queue
self.s.timer_wait(self.p, self.seconds)
def post_write(self, writer):
self.posted = (WRITE, writer)
# Start process
self.p = Process(self.expire)
self.p.start()
self.p.setstate(ACTIVE)
# Put process on the scheduler timer queue
self.s.timer_wait(self.p, self.seconds)
def remove_read(self, req):
self.s.timer_cancel(self.p)
def remove_write(self, req):
self.s.timer_cancel(self.p)
def process(self):
p = Process(self.empty)
p.start()
p.setstate(ACTIVE)
return p