| 4 | from functools import partial |
| 5 | |
| 6 | class CmdThread(Thread): |
| 7 | def __init__(self): |
| 8 | Thread.__init__(self) |
| 9 | self._queue = Queue() |
| 10 | self._status = 'NORMAL' |
| 11 | self._statusLock = Lock() |
| 12 | self._possibleStatus = ('NORMAL', 'SLEEPING', 'DONE') |
| 13 | self._condition = Condition(self._statusLock) |
| 14 | self.daemon = True |
| 15 | self.start() |
| 16 | |
| 17 | def run(self): |
| 18 | while True: |
| 19 | self._condition.acquire() |
| 20 | if self._status == 'DONE': |
| 21 | self._condition.release() |
| 22 | break |
| 23 | |
| 24 | if self._status == 'SLEEPING': |
| 25 | self._condition.wait() # this function will release the lock when going to sleep |
| 26 | self._condition.release() |
| 27 | continue |
| 28 | self._condition.release() |
| 29 | |
| 30 | try: |
| 31 | task = self._queue.get_nowait() |
| 32 | except Empty: |
| 33 | self._condition.acquire() |
| 34 | self._status = 'SLEEPING' |
| 35 | self._condition.wait() |
| 36 | # Here, we don't change the status to 'NORMAL' here |
| 37 | # The status is supposed to be changed by the waker |
| 38 | # Before this command thread wakes up. |
| 39 | self._condition.release() |
| 40 | continue |
| 41 | |
| 42 | if callable(task): |
| 43 | try: |
| 44 | print 'perform task.' |
| 45 | task() |
| 46 | except Exception: |
| 47 | self._statusLock.acquire() |
| 48 | self._status = 'DONE' |
| 49 | self._statusLock.release() |
| 50 | raise |
| 51 | else: |
| 52 | # you can define the task interface here. |
| 53 | pass |
| 54 | |
| 55 | |
| 56 | def addCmd(self, callableObj, *args, **argd): |
| 57 | """ non-blocking call. |
| 58 | """ |
| 59 | assert(callable(callableObj)) |
| 60 | |
| 61 | self._condition.acquire() |
| 62 | if self._status == 'DONE': |
| 63 | self._condition.release() |