RT thread analysis - object container implementation and function

Catalog

1 Preface

2 Relevant data structure

2.1 object

1） type

2） data structure

2.3 Containers

1） data structure

2） Container definition _object_container[]

2.3 Object container link graph

3 Get object container rt_object_get_information()

4  Object initialization rt_object_init()

5  Object delete rt_object_delete()

6 Look for objects rt_object_find()

7 summary

---

1 Preface

         In kernel , All data structures are treated as one object , Include ： Threads 、 Semaphore 、 The mutex 、 event 、 mailbox 、 Message queue 、 Memory heap 、 Memory pool 、 Equipment and timers . For the convenience of management , When the user or kernel creates an object , The object will be put into the container . The container is a global array in the kernel , Record the information of all objects .

2 Relevant data structure

2.1 object

1） type

enum rt_object_class_type
{
    RT_Object_Class_Null          = 0x00,      /**< The object is not used. */
    RT_Object_Class_Thread        = 0x01,      /**< The object is a thread. */
    RT_Object_Class_Semaphore     = 0x02,      /**< The object is a semaphore. */
    RT_Object_Class_Mutex         = 0x03,      /**< The object is a mutex. */
    RT_Object_Class_Event         = 0x04,      /**< The object is a event. */
    RT_Object_Class_MailBox       = 0x05,      /**< The object is a mail box. */
    RT_Object_Class_MessageQueue  = 0x06,      /**< The object is a message queue. */
    RT_Object_Class_MemHeap       = 0x07,      /**< The object is a memory heap. */
    RT_Object_Class_MemPool       = 0x08,      /**< The object is a memory pool. */
    RT_Object_Class_Device        = 0x09,      /**< The object is a device. */
    RT_Object_Class_Timer         = 0x0a,      /**< The object is a timer. */
    RT_Object_Class_Module        = 0x0b,      /**< The object is a module. */
    RT_Object_Class_Unknown       = 0x0c,      /**< The object is unknown. */
    RT_Object_Class_Static        = 0x80       /**< The object is a static object. */
};

2） data structure

struct rt_object
{
    // Object name , Use string representation , Length from RT_NAME_MAX decision 
    char       name[RT_NAME_MAX];  
    // object type                                                             
    rt_uint8_t type;
    // Object state                                     
    rt_uint8_t flag; 
    // Intrusive linked list , Link the object to the container                                    
    rt_list_t  list;                                    
};
typedef struct rt_object *rt_object_t; 

2.3 Containers

         The global structure array is used in the kernel (rt_object_information _object_container[]) To define the container . Each container holds objects of the same type , Save its information , Use a linked list to link all objects for easy management .

1） data structure

struct rt_object_information
{
    // The object type under the container 
    enum rt_object_class_type type;
    // Link all objects under the container                     
    rt_list_t                 object_list;  
    // Its object size             
    rt_size_t                 object_size;             
};

2） Container definition _object_container[]

//2.1)  Containers are represented by arrays , The following is to define the sequence numbers of different objects in the array 
enum rt_object_info_type
{
    RT_Object_Info_Thread = 0,                         /**< The object is a thread. */
#ifdef RT_USING_SEMAPHORE
    RT_Object_Info_Semaphore,                          /**< The object is a semaphore. */
#endif
#ifdef RT_USING_MUTEX
    RT_Object_Info_Mutex,                              /**< The object is a mutex. */
#endif
#ifdef RT_USING_EVENT
    RT_Object_Info_Event,                              /**< The object is a event. */
#endif
#ifdef RT_USING_MAILBOX
    RT_Object_Info_MailBox,                            /**< The object is a mail box. */
#endif
#ifdef RT_USING_MESSAGEQUEUE
    RT_Object_Info_MessageQueue,                       /**< The object is a message queue. */
#endif
#ifdef RT_USING_MEMHEAP
    RT_Object_Info_MemHeap,                            /**< The object is a memory heap */
#endif
#ifdef RT_USING_MEMPOOL
    RT_Object_Info_MemPool,                            /**< The object is a memory pool. */
#endif
#ifdef RT_USING_DEVICE
    RT_Object_Info_Device,                             /**< The object is a device */
#endif
    RT_Object_Info_Timer,                              /**< The object is a timer. */
#ifdef RT_USING_MODULE
    RT_Object_Info_Module,                             /**< The object is a module. */
#endif
    RT_Object_Info_Unknown,                            /**< The object is unknown. */
};

//2.2)  Each container holds objects of the same type , such as _object_container[0] Are storage objects RT_Object_Class_Thread, Then use the linked list object_list Link all objects 
#define _OBJ_CONTAINER_LIST_INIT(c)     \
    {&(_object_container[c].object_list), &(_object_container[c].object_list)}
static struct rt_object_information _object_container[RT_Object_Info_Unknown] =
{
    /* initialize object container - thread */
    {RT_Object_Class_Thread, _OBJ_CONTAINER_LIST_INIT(RT_Object_Info_Thread), sizeof(struct rt_thread)},
#ifdef RT_USING_SEMAPHORE
    /* initialize object container - semaphore */
    {RT_Object_Class_Semaphore, _OBJ_CONTAINER_LIST_INIT(RT_Object_Info_Semaphore), sizeof(struct rt_semaphore)},
#endif
#ifdef RT_USING_MUTEX
    /* initialize object container - mutex */
    {RT_Object_Class_Mutex, _OBJ_CONTAINER_LIST_INIT(RT_Object_Info_Mutex), sizeof(struct rt_mutex)},
#endif
#ifdef RT_USING_EVENT
    /* initialize object container - event */
    {RT_Object_Class_Event, _OBJ_CONTAINER_LIST_INIT(RT_Object_Info_Event), sizeof(struct rt_event)},
#endif
#ifdef RT_USING_MAILBOX
    /* initialize object container - mailbox */
    {RT_Object_Class_MailBox, _OBJ_CONTAINER_LIST_INIT(RT_Object_Info_MailBox), sizeof(struct rt_mailbox)},
#endif
#ifdef RT_USING_MESSAGEQUEUE
    /* initialize object container - message queue */
    {RT_Object_Class_MessageQueue, _OBJ_CONTAINER_LIST_INIT(RT_Object_Info_MessageQueue), sizeof(struct rt_messagequeue)},
#endif
#ifdef RT_USING_MEMHEAP
    /* initialize object container - memory heap */
    {RT_Object_Class_MemHeap, _OBJ_CONTAINER_LIST_INIT(RT_Object_Info_MemHeap), sizeof(struct rt_memheap)},
#endif
#ifdef RT_USING_MEMPOOL
    /* initialize object container - memory pool */
    {RT_Object_Class_MemPool, _OBJ_CONTAINER_LIST_INIT(RT_Object_Info_MemPool), sizeof(struct rt_mempool)},
#endif
#ifdef RT_USING_DEVICE
    /* initialize object container - device */
    {RT_Object_Class_Device, _OBJ_CONTAINER_LIST_INIT(RT_Object_Info_Device), sizeof(struct rt_device)},
#endif
    /* initialize object container - timer */
    {RT_Object_Class_Timer, _OBJ_CONTAINER_LIST_INIT(RT_Object_Info_Timer), sizeof(struct rt_timer)},
#ifdef RT_USING_MODULE
    /* initialize object container - module */
    {RT_Object_Class_Module, _OBJ_CONTAINER_LIST_INIT(RT_Object_Info_Module), sizeof(struct rt_dlmodule)},
#endif
};

2.3 Object container link graph

3 Get object container rt_object_get_information()

struct rt_object_information* rt_object_get_information(enum rt_object_class_type type)
{
    int index;
    
    // Traverse container array _object_container[], Find the object container by type 
    for (index = 0; index < RT_Object_Info_Unknown; index ++)
        if (_object_container[index].type == type) 
            return &_object_container[index];

    return RT_NULL;
}

4  Object initialization rt_object_init()

void rt_object_init(struct rt_object         *object,
                    enum rt_object_class_type type,
                    const char               *name)
{
    //1  By object type , Find the container 
    information = rt_object_get_information(type);
    
    //2  Traverse all objects under the container , If it is consistent with the object to be initialized , Enter assertion 
    //PS: The function of this error check ？？？
    for (node  = information->object_list.next;
        node != &(information->object_list);
        node  = node->next)
    {
        struct rt_object *obj;

        obj = rt_list_entry(node, struct rt_object, list);
        if (obj) /* skip warning when disable debug */
        {
            RT_ASSERT(obj != object);
        }
    }
    
    //3  Set static tags 
    object->type = type | RT_Object_Class_Static;
    
    //4  Set object name 
    rt_strncpy(object->name, name, RT_NAME_MAX);
    
    //5  Insert the object into the end of the container list 
    rt_list_insert_after(&(information->object_list), &(object->list));
}

5  Object delete rt_object_delete()

void rt_object_delete(rt_object_t object)
{
    //1  Reset object type 
    object->type = RT_Object_Class_Null;
    
    //2  Remove objects from the container list 
    rt_list_remove(&(object->list));
    
    //3  Free object memory 
    RT_KERNEL_FREE(object);
}

6 Look for objects rt_object_find()

rt_object_t rt_object_find(const char *name, rt_uint8_t type)
{
    //1  Find the corresponding container by type 
    information = rt_object_get_information((enum rt_object_class_type)type);
    
    //2  Context detection , This function is not allowed to call 
    RT_DEBUG_NOT_IN_INTERRUPT;
}

7 summary

• Every data structure in the kernel is abstracted as an object rt_object, Include ： Threads 、 Semaphore 、 The mutex 、 event 、 mailbox 、 Message queue 、 Memory heap 、 Memory pool 、 Equipment and timers .
• In actual use , Object properties can be inherited
• The kernel maintains containers using global struct arrays , Each member of the array manages all objects of the same type , It is convenient to query the information of each object at any time