POCO中Event同步对象的POSIX实现

POCO1.4.1p1中Event同步对象的POSIX实现不够严谨，WIN32实现直接采用windows提供的event对象，而POSIX下采用条件变量模拟事件，但是没有考虑到cancellation point的问题，可能导致程序行为异常，下面代码注释的pthread_cleanup_push和pthread_cleanup_pop是我加上的，项目中放开这两个注释后暂时未重现异常问题。

 

void EventImpl::waitImpl(){//pthread_cleanup_push(pthread_mutex_unlock, &_mutex);if (pthread_mutex_lock(&_mutex))throw SystemException("wait for event failed (lock)"); while (!_state) {if (pthread_cond_wait(&_cond, &_mutex)){pthread_mutex_unlock(&_mutex);throw SystemException("wait for event failed");}}if (_auto)_state = false;pthread_mutex_unlock(&_mutex);//pthread_cleanup_pop(0);}bool EventImpl::waitImpl(long milliseconds){int rc = 0;struct timespec abstime;#if defined(__VMS)struct timespec delta;delta.tv_sec = milliseconds / 1000;delta.tv_nsec = (milliseconds % 1000)*1000000;pthread_get_expiration_np(&delta, &abstime);#elif defined(POCO_VXWORKS)clock_gettime(CLOCK_REALTIME, &abstime);abstime.tv_sec += milliseconds / 1000;abstime.tv_nsec += (milliseconds % 1000)*1000000;if (abstime.tv_nsec >= 1000000000){abstime.tv_nsec -= 1000000000;abstime.tv_sec++;}#elsestruct timeval tv;gettimeofday(&tv, NULL);abstime.tv_sec = tv.tv_sec + milliseconds / 1000;abstime.tv_nsec = tv.tv_usec*1000 + (milliseconds % 1000)*1000000;if (abstime.tv_nsec >= 1000000000){abstime.tv_nsec -= 1000000000;abstime.tv_sec++;}#endif//pthread_cleanup_push(pthread_mutex_unlock, &_mutex);if (pthread_mutex_lock(&_mutex) != 0)throw SystemException("wait for event failed (lock)"); while (!_state) {if ((rc = pthread_cond_timedwait(&_cond, &_mutex, &abstime))){if (rc == ETIMEDOUT) break;pthread_mutex_unlock(&_mutex);throw SystemException("cannot wait for event");}}if (rc == 0 && _auto) _state = false;pthread_mutex_unlock(&_mutex);//pthread_cleanup_pop(0);return rc == 0;}