C++ VALID_TASK函数代码示例

void
isc_task_sendanddetach(isc_task_t **taskp, isc_event_t **eventp) {
	isc_boolean_t idle1, idle2;
	isc_task_t *task;

	/*
	 * Send '*event' to '*taskp' and then detach '*taskp' from its
	 * task.
	 */

	REQUIRE(taskp != NULL);
	task = *taskp;
	REQUIRE(VALID_TASK(task));

	XTRACE("isc_task_sendanddetach");

	LOCK(&task->lock);
	idle1 = task_send(task, eventp);
	idle2 = task_detach(task);
	UNLOCK(&task->lock);

	/*
	 * If idle1, then idle2 shouldn't be true as well since we're holding
	 * the task lock, and thus the task cannot switch from ready back to
	 * idle.
	 */
	INSIST(!(idle1 && idle2));

	if (idle1 || idle2)
		task_ready(task);

	*taskp = NULL;
}

isc_boolean_t
isc_task_exiting(isc_task_t *t) {
	isc__task_t *task = (isc__task_t *)t;

	REQUIRE(VALID_TASK(task));
	return (TASK_SHUTTINGDOWN(task));
}

ISC_TASKFUNC_SCOPE const char *
isc__task_getname(isc_task_t *task0) {
	isc__task_t *task = (isc__task_t *)task0;

	REQUIRE(VALID_TASK(task));

	return (task->name);
}

ISC_TASKFUNC_SCOPE void *
isc__task_gettag(isc_task_t *task0) {
	isc__task_t *task = (isc__task_t *)task0;

	REQUIRE(VALID_TASK(task));

	return (task->tag);
}

ISC_TASKFUNC_SCOPE void
isc__task_getcurrenttime(isc_task_t *task0, isc_stdtime_t *t) {
	isc__task_t *task = (isc__task_t *)task0;

	REQUIRE(VALID_TASK(task));
	REQUIRE(t != NULL);

	LOCK(&task->lock);
	*t = task->now;
	UNLOCK(&task->lock);
}

ISC_TASKFUNC_SCOPE void
isc__taskmgr_setexcltask(isc_taskmgr_t *mgr0, isc_task_t *task0) {
	isc__taskmgr_t *mgr = (isc__taskmgr_t *) mgr0;
	isc__task_t *task = (isc__task_t *) task0;

	REQUIRE(VALID_MANAGER(mgr));
	REQUIRE(VALID_TASK(task));
	if (mgr->excl != NULL)
		isc__task_detach((isc_task_t **) &mgr->excl);
	isc__task_attach(task0, (isc_task_t **) &mgr->excl);
}

void
isc_task_getcurrenttime(isc_task_t *task, isc_stdtime_t *t) {
	REQUIRE(VALID_TASK(task));
	REQUIRE(t != NULL);

	LOCK(&task->lock);

	*t = task->now;

	UNLOCK(&task->lock);
}

void
isc_task_setname(isc_task_t *task, const char *name, void *tag) {

	/*
	 * Name 'task'.
	 */

	REQUIRE(VALID_TASK(task));

	LOCK(&task->lock);
	memset(task->name, 0, sizeof(task->name));
	strncpy(task->name, name, sizeof(task->name) - 1);
	task->tag = tag;
	UNLOCK(&task->lock);
}

void
isc_task_shutdown(isc_task_t *task) {
	isc_boolean_t was_idle;

	/*
	 * Shutdown 'task'.
	 */

	REQUIRE(VALID_TASK(task));

	LOCK(&task->lock);
	was_idle = task_shutdown(task);
	UNLOCK(&task->lock);

	if (was_idle)
		task_ready(task);
}

void
isc_task_attach(isc_task_t *source, isc_task_t **targetp) {

	/*
	 * Attach *targetp to source.
	 */

	REQUIRE(VALID_TASK(source));
	REQUIRE(targetp != NULL && *targetp == NULL);

	XTTRACE(source, "isc_task_attach");

	LOCK(&source->lock);
	source->references++;
	UNLOCK(&source->lock);

	*targetp = source;
}

ISC_TASKFUNC_SCOPE isc_boolean_t
isc__task_purgeevent(isc_task_t *task0, isc_event_t *event) {
	isc__task_t *task = (isc__task_t *)task0;
	isc_event_t *curr_event, *next_event;

	/*
	 * Purge 'event' from a task's event queue.
	 *
	 * XXXRTH:  WARNING:  This method may be removed before beta.
	 */

	REQUIRE(VALID_TASK(task));

	/*
	 * If 'event' is on the task's event queue, it will be purged,
	 * unless it is marked as unpurgeable.  'event' does not have to be
	 * on the task's event queue; in fact, it can even be an invalid
	 * pointer.  Purging only occurs if the event is actually on the task's
	 * event queue.
	 *
	 * Purging never changes the state of the task.
	 */

	LOCK(&task->lock);
	for (curr_event = HEAD(task->events);
	     curr_event != NULL;
	     curr_event = next_event) {
		next_event = NEXT(curr_event, ev_link);
		if (curr_event == event && PURGE_OK(event)) {
			DEQUEUE(task->events, curr_event, ev_link);
			break;
		}
	}
	UNLOCK(&task->lock);

	if (curr_event == NULL)
		return (ISC_FALSE);

	isc_event_free(&curr_event);

	return (ISC_TRUE);
}

ISC_TASKFUNC_SCOPE void
isc__task_send(isc_task_t *task0, isc_event_t **eventp) {
	isc__task_t *task = (isc__task_t *)task0;
	isc_boolean_t was_idle;

	/*
	 * Send '*event' to 'task'.
	 */

	REQUIRE(VALID_TASK(task));

	XTRACE("isc_task_send");

	/*
	 * We're trying hard to hold locks for as short a time as possible.
	 * We're also trying to hold as few locks as possible.  This is why
	 * some processing is deferred until after the lock is released.
	 */
	LOCK(&task->lock);
	was_idle = task_send(task, eventp);
	UNLOCK(&task->lock);

	if (was_idle) {
		/*
		 * We need to add this task to the ready queue.
		 *
		 * We've waited until now to do it because making a task
		 * ready requires locking the manager.  If we tried to do
		 * this while holding the task lock, we could deadlock.
		 *
		 * We've changed the state to ready, so no one else will
		 * be trying to add this task to the ready queue.  The
		 * only way to leave the ready state is by executing the
		 * task.  It thus doesn't matter if events are added,
		 * removed, or a shutdown is started in the interval
		 * between the time we released the task lock, and the time
		 * we add the task to the ready queue.
		 */
		task_ready(task);
	}
}

static unsigned int
dequeue_events(isc_task_t *task, void *sender, isc_eventtype_t first,
	       isc_eventtype_t last, void *tag,
	       isc_eventlist_t *events, isc_boolean_t purging)
{
	isc_event_t *event, *next_event;
	unsigned int count = 0;

	REQUIRE(VALID_TASK(task));
	REQUIRE(last >= first);

	XTRACE("dequeue_events");

	/*
	 * Events matching 'sender', whose type is >= first and <= last, and
	 * whose tag is 'tag' will be dequeued.  If 'purging', matching events
	 * which are marked as unpurgable will not be dequeued.
	 *
	 * sender == NULL means "any sender", and tag == NULL means "any tag".
	 */

	LOCK(&task->lock);

	for (event = HEAD(task->events); event != NULL; event = next_event) {
		next_event = NEXT(event, ev_link);
		if (event->ev_type >= first && event->ev_type <= last &&
		    (sender == NULL || event->ev_sender == sender) &&
		    (tag == NULL || event->ev_tag == tag) &&
		    (!purging || PURGE_OK(event))) {
			DEQUEUE(task->events, event, ev_link);
			ENQUEUE(*events, event, ev_link);
			count++;
		}
	}

	UNLOCK(&task->lock);

	return (count);
}

ISC_TASKFUNC_SCOPE isc_result_t
isc__task_onshutdown(isc_task_t *task0, isc_taskaction_t action,
		     const void *arg)
{
	isc__task_t *task = (isc__task_t *)task0;
	isc_boolean_t disallowed = ISC_FALSE;
	isc_result_t result = ISC_R_SUCCESS;
	isc_event_t *event;

	/*
	 * Send a shutdown event with action 'action' and argument 'arg' when
	 * 'task' is shutdown.
	 */

	REQUIRE(VALID_TASK(task));
	REQUIRE(action != NULL);

	event = isc_event_allocate(task->manager->mctx,
				   NULL,
				   ISC_TASKEVENT_SHUTDOWN,
				   action,
				   arg,
				   sizeof(*event));
	if (event == NULL)
		return (ISC_R_NOMEMORY);

	LOCK(&task->lock);
	if (TASK_SHUTTINGDOWN(task)) {
		disallowed = ISC_TRUE;
		result = ISC_R_SHUTTINGDOWN;
	} else
		ENQUEUE(task->on_shutdown, event, ev_link);
	UNLOCK(&task->lock);

	if (disallowed)
		isc_mem_put(task->manager->mctx, event, sizeof(*event));

	return (result);
}

void
isc_task_detach(isc_task_t **taskp) {
	isc_task_t *task;
	isc_boolean_t was_idle;

	/*
	 * Detach *taskp from its task.
	 */

	REQUIRE(taskp != NULL);
	task = *taskp;
	REQUIRE(VALID_TASK(task));

	XTRACE("isc_task_detach");

	LOCK(&task->lock);
	was_idle = task_detach(task);
	UNLOCK(&task->lock);

	if (was_idle)
		task_ready(task);

	*taskp = NULL;
}