rt_event_recv bug

发布于 2020-12-01 16:31:12 浏览：1876 订阅该版

rt_event_recv 源码中 为了不出现重复代码，逻辑写的有些复杂，可以优化，用goto 或许会更清晰一些 ，或者适量的重复代码也可以让代码的阅读性更好。 比如能正常接收时直接处理返回。而不是用if else 拖到最后。
```
rt_err_t rt_event_recv(rt_event_t event,rt_uint32_t   set,rt_uint8_t option,rt_int32_t timeout,rt_uint32_t *recved)
{
    struct rt_thread *thread;
    register rt_ubase_t level;
    register rt_base_t status;

RT_DEBUG_IN_THREAD_CONTEXT;

/* parameter check */
    RT_ASSERT(event != RT_NULL);
    RT_ASSERT(rt_object_get_type(&event->parent.parent) == RT_Object_Class_Event);

if (set == 0)
        return -RT_ERROR;

/* initialize status */
    status = -RT_ERROR;
    /* get current thread */
    thread = rt_thread_self();
    /* reset thread error */
    thread->error = RT_EOK;

RT_OBJECT_HOOK_CALL(rt_object_trytake_hook, (&(event->parent.parent)));

/* disable interrupt */
    level = rt_hw_interrupt_disable();

/* check event set */

/*判断触发模式*/
    if (option & RT_EVENT_FLAG_AND){	
	/*判断事件触发条件是否满足或者大于 获取的逻辑与的要求 */
        if ((event->set & set) == set)
            status = RT_EOK;
    }
    else if (option & RT_EVENT_FLAG_OR){
    /*判断事件触发条件是否满足获取要求某一个条件 */
        if (event->set & set)
            status = RT_EOK;
    }
    else{
        /* either RT_EVENT_FLAG_AND or RT_EVENT_FLAG_OR should be set */
        RT_ASSERT(0);
    }

/*达到触发条件*/
    if (status == RT_EOK)
	{
        /* set received event */
	/*设置接受到的事件条件*/
        if (recved)
            *recved = (event->set & set);

/* received event */
		/*如果条件触发是一次性的则将此条件清除*/
        if (option & RT_EVENT_FLAG_CLEAR)
            event->set &= ~set;
    }
    else if (timeout == 0) /*未达到触发条件，且 不等待*/
    {
        /* no waiting */
        thread->error = -RT_ETIMEOUT;
    }
    else /*未达到触发条件，但是超时等待*/
    {
        /* fill thread event info */
        thread->event_set  = set;
        thread->event_info = option;

/* put thread to suspended thread list */
		/*未达到触发条件 ，且设置超时等待，则将线程挂入事件等待链表，然后设置并启动线程定时器*/
        rt_ipc_list_suspend(&(event->parent.suspend_thread),
                            thread,
                            event->parent.parent.flag);

/* if there is a waiting timeout, active thread timer */
        if (timeout > 0)
        {
            /* reset the timeout of thread timer and start it */
            rt_timer_control(&(thread->thread_timer),
                             RT_TIMER_CTRL_SET_TIME,
                             &timeout);
            rt_timer_start(&(thread->thread_timer));
        }

/* enable interrupt */
        rt_hw_interrupt_enable(level);

/* do a schedule */
		/*线程进入等待，切换任务，此处会挂起*/
        rt_schedule();

if (thread->error != RT_EOK)
        {
            /* return error */
            return thread->error;
        }

/* received an event, disable interrupt to protect */
        level = rt_hw_interrupt_disable();

/* set received event */
        if (recved)
            *recved = thread->event_set;
    }

/* enable interrupt */
    rt_hw_interrupt_enable(level);

RT_OBJECT_HOOK_CALL(rt_object_take_hook, (&(event->parent.parent)));

return thread->error;
}
RTM_EXPORT(rt_event_recv);
```

修改成这样是否会更好?

```
rt_err_t rt_event_recv(rt_event_t event,rt_uint32_t   set,rt_uint8_t option, rt_int32_t timeout,rt_uint32_t *recved)
{
    struct rt_thread *thread;
    register rt_ubase_t level;
    register rt_base_t status;

RT_DEBUG_IN_THREAD_CONTEXT;

/* parameter check */
    RT_ASSERT(event != RT_NULL);
    RT_ASSERT(rt_object_get_type(&event->parent.parent) == RT_Object_Class_Event);

if (set == 0)
        return -RT_ERROR;

/* initialize status */
    status = -RT_ERROR;
    /* get current thread */
    thread = rt_thread_self();
    /* reset thread error */
    thread->error = RT_EOK;

RT_OBJECT_HOOK_CALL(rt_object_trytake_hook, (&(event->parent.parent)));

/* disable interrupt */
    level = rt_hw_interrupt_disable();

/* check event set */

/*判断触发模式*/
    if ((option & RT_EVENT_FLAG_AND)  && ((event->set & set) == set) ||  /*判断事件触发条件是否满足获取要求某一个条件 */
		(option & RT_EVENT_FLAG_OR) && (event->set & set))		/*判断事件触发条件是否满足或者大于 获取的逻辑与的要求 */
            status = RT_EOK;
    else
          RT_ASSERT(0); /* either RT_EVENT_FLAG_AND or RT_EVENT_FLAG_OR should be set */
      
 
/*达到触发条件*/
    if (status == RT_EOK){
		thread->event_set = (event->set & set);
		goto _EXIT_OK;
    }

if (timeout == 0) /*未达到触发条件，且 不等待*/
    {
        /* no waiting */
        thread->error = -RT_ETIMEOUT;
		goto _EXIT_ERR;
    }
       /*未达到触发条件，但是超时等待*/
  
    /* fill thread event info */
    thread->event_set  = set;
    thread->event_info = option;

/* put thread to suspended thread list */
	/*未达到触发条件 ，且设置超时等待，则将线程挂入事件等待链表，然后设置并启动线程定时器*/
    rt_ipc_list_suspend(&(event->parent.suspend_thread),
                        thread,
                        event->parent.parent.flag);

/* if there is a waiting timeout, active thread timer */
	/*这个地方 难道timeout 不是一定大于0 吗？*/
    if (timeout > 0)
    {
        /* reset the timeout of thread timer and start it */
        rt_timer_control(&(thread->thread_timer),
                         RT_TIMER_CTRL_SET_TIME,
                         &timeout);
        rt_timer_start(&(thread->thread_timer));
    }

/* enable interrupt */
    rt_hw_interrupt_enable(level);

/* do a schedule */
	/*线程进入等待，切换任务，此处会挂起*/
    rt_schedule();

//此处为什么要判断这个 ，不是很明白
    if (thread->error != RT_EOK)
    {
        /* return error */
        return thread->error;
    }

/* received an event, disable interrupt to protect */
    level = rt_hw_interrupt_disable();

_EXIT_OK:
		
/*设置接受到的事件条件*/
	if (recved)
		*recved = (event->set & set);
	/* received event */
	/*如果条件触发是一次性的则将此条件清除*/
	if (option & RT_EVENT_FLAG_CLEAR)
		event->set &= ~set;
_EXIT_ERR:	
    rt_hw_interrupt_enable(level);

RT_OBJECT_HOOK_CALL(rt_object_take_hook, (&(event->parent.parent)));

return thread->error;
}
```