Source code for cup.thread

#!/usr/bin/env python
# -*- coding: utf-8 -*
# Copyright: [CUP] - See LICENSE for details.
# Author: Zhaominghao, Guannan Ma
    cup thread module

__all__ = ['async_raise', 'CupThread', 'RWLock']

import threading
import time
import ctypes

import cup

[docs]def async_raise(tid, exctype): """ Raises an exception in the threads with id tid :param tid: thread id in python :param exctype: exception class, e.g. IOError """ return ctypes.pythonapi.PyThreadState_SetAsyncExc( tid, ctypes.py_object(exctype) )
[docs]class CupThread(threading.Thread): """ CupThread is a sub-class inherited from threading.Thread; .. HINT:: CupThread has 3 more methods: 1. raise_exc, to send a raise-exception signal to the thread,\ TRY to let the thread raise an exception. 2. get_my_tid, get thread id 3. terminate, to stop the thread .. CAUTION:: Notice if a thread in busy running under kernel-sysmode, it may not response to the signals! Thus, it may not raise any exception/terminate even though cup has send a CupThread signal! """
[docs] def get_my_tid(self): """ return thread id """ if not self.isAlive(): cup.log.warn('the thread is not active') return None # do we have it cached? if hasattr(self, '_thread_id'): # pylint: disable=E0203 return self._thread_id # pylint: disable=W0212 # no, look for it in the _active dict for tid, tobj in threading._active.items(): if tobj is self: # pylint: disable=W0201 self._thread_id = tid return tid
[docs] def raise_exc(self, exctype): """ asynchrously send 'raise exception' signal to the thread. :param exctype: raise Exception, exctype type is class :return: return 1 on success. 0 otherwise. """ return async_raise(self.get_my_tid(), exctype)
[docs] def terminate(self, times=15): """ asynchrously terminate the thread. Return True if the termination is successful or the thread is already stopped. Return False, otherwise. :times: retry times until call for failure. """ cnt = 0 while self.isAlive(): self.raise_exc(cup.err.ThreadTermException) time.sleep(1) cnt += 1 if cnt > times: return False return True
[docs]class RWLock(object): """ Read Write Lock is a typical lock type in computer world. Code example: :: from cup import thread rwlock = thread.RWLock() # can acquire read lock rwlock.acquire_readlock() # can acquire read lock again if there has not been WRITE locked rwlock.acquire_readlock() # <-- this will succeed # rwlock.acquire_writelock() # <--- this will hang if uncommented rwlock.release_readlock() rwlock.acquire_writelock() # rwlock.acquire_readlock() # <--- this will hang if uncommented rwlock.release_writelock() """ def __init__(self): self._lock = threading.Lock() self._cond = threading.Condition(self._lock) self._rd_num = 0 self._wt_num = 0
[docs] def acquire_writelock(self, wait_time=None): """ Acquire write lock. .. IMPORTANT:: If wait_time is not None and wait_time >=0, cup will wait until wait_time passes. If the call timeouts and cannot get the lock, will raise RuntimeError """ self._cond.acquire() if self._wt_num > 0 or self._rd_num > 0: try: self._cond.wait(wait_time) except RuntimeError as error: raise RuntimeError(str(error)) self._wt_num += 1 self._cond.release()
[docs] def release_writelock(self): """ release write lock """ self._cond.acquire() self._wt_num -= 1 if self._wt_num == 0: self._cond.notify_all() self._cond.release()
[docs] def acquire_readlock(self, wait_time=None): """ Acquire readlock. :param wait_time: same to wait_time for acquire_writelock :raise: RuntimeError if after wait_time, cup still can NOT getthe lock """ self._cond.acquire() if self._wt_num > 0: try: self._cond.wait(wait_time) except RuntimeError as error: raise RuntimeError(error) self._rd_num += 1 self._cond.release()
[docs] def release_readlock(self): """ release read lock """ self._cond.acquire() self._rd_num -= 1 if self._rd_num == 0 and self._wt_num == 0: self._cond.notify() self._cond.release()
# vi:set tw=0 ts=4 sw=4 nowrap fdm=indent