rt-thread采用內核對象管理系統來訪問和管理所有內核對象.首先來看看rt-thread的內核對象是如何定義的: 1 數據結構 1.1 對象控制塊 在include/rtdef.h頭文件中可以找到內核對象有結構定義: [cpp] /** * Base structure of Kernel object */ struct rt_object { char name[RT_NAME_MAX];//名稱 rt_uint8_t type;//內核對象類型 rt_uint8_t flag;//內核對象標志 #ifdef RT_USING_MODULE void *module_id;//模塊ID #endif rt_list_t list;//內核對象鏈表節點 }; typedef struct rt_object *rt_object_t; 這裡需要注意地是,上述內核對象控制塊包含了一rt_list_t類型的成員list,這個是一鏈表節點,便於將此內核對象加入到一鏈表中,其結構如下定義: [cpp] struct rt_list_node { struct rt_list_node *next; //指向下一節點 struct rt_list_node *prev; //指向前一節點 }; typedef struct rt_list_node rt_list_t; 另內核對象類型取值有如下類型: [cpp] /** * The object type can be one of the follows with specific * macros enabled: * - Thread * - Semaphore * - Mutex * - Event * - MailBox * - MessageQueue * - MemHeap * - MemPool * - Device * - Timer * - Module * - Unknown * - Static */ enum rt_object_class_type { RT_Object_Class_Thread = 0, //線程 #ifdef RT_USING_SEMAPHORE RT_Object_Class_Semaphore, //信號量 #endif #ifdef RT_USING_MUTEX RT_Object_Class_Mutex, //互斥鎖 #endif #ifdef RT_USING_EVENT RT_Object_Class_Event, //事件 #endif #ifdef RT_USING_MAILBOX RT_Object_Class_MailBox, //郵箱 #endif #ifdef RT_USING_MESSAGEQUEUE RT_Object_Class_MessageQueue, //消息隊列 #endif #ifdef RT_USING_MEMHEAP RT_Object_Class_MemHeap, //內存堆 #endif #ifdef RT_USING_MEMPOOL RT_Object_Class_MemPool, //內存池 #endif #ifdef RT_USING_DEVICE RT_Object_Class_Device, //設備驅動 #endif RT_Object_Class_Timer, //時鐘 #ifdef RT_USING_MODULE RT_Object_Class_Module, //模塊 #endif RT_Object_Class_Unknown, //未知內核對象類型 RT_Object_Class_Static = 0x80 //rt-thread以此位標志是否為系統內核對象 }; 需要注意的是,rt-thread將內核對象的type的最高位若為1,則表示此內核對象為系統內核對象,否則非系統內核對象. 1.2 內核對象容器 RTT使用內核對象容器來管理同一類型的內核對象,並將其放入同一鏈表中,便於訪問.內核對象信息的結構如下定義: [cpp] /** * The information of the kernel object */ struct rt_object_information { enum rt_object_class_type type; //內核對象類型 rt_list_t object_list; //內核對象鏈表 rt_size_t object_size; //內核對象所占的大小 }; 1.3 內核對象管理系統 RTT中,每一類型的內核對象都會有一內核對象容器來包容,這個類型的內核對象容器實際上是用一鏈表(見1.2節所示的內核對象容器結構定義),這個鏈表將所有相同類型的內核對象鏈接起來.由於每一類型都對應著有一個這樣的內核對象容器來管理,那麼所有內核對象容器整體就叫做內核對象管理系統. RTT中,內核對象管理系統是用一個rt_object_information數組來實現的,如下: [cpp] #define _OBJ_CONTAINER_LIST_INIT(c)\//內核對象容器的鏈表初始化,這裡用一個宏來定義,鏈表的前一節點和後一節點在初始化時都指向本身所在地址 {&(rt_object_container[c].object_list), &(rt_object_container[c].object_list)} //內核對象管理系統,這裡用rt_object_information數組來實現 struct rt_object_information rt_object_container[RT_Object_Class_Unknown] = { /* initialize object container - thread */)},//線程對象信息 {RT_Object_Class_Thread, _OBJ_CONTAINER_LIST_INIT(RT_Object_Class_Thread), sizeof(struct rt_thread#ifdef RT_USING_SEMAPHORE /* initialize object container - semaphore *///信號量對象信息 {RT_Object_Class_Semaphore, _OBJ_CONTAINER_LIST_INIT(RT_Object_Class_Semaphore), sizeof(struct rt_semaphore)}, #endif #ifdef RT_USING_MUTEX /* initialize object container - mutex *///互斥鎖對象信息 {RT_Object_Class_Mutex, _OBJ_CONTAINER_LIST_INIT(RT_Object_Class_Mutex), sizeof(struct rt_mutex)}, #endif #ifdef RT_USING_EVENT /* initialize object container - event *///事件對象信息 {RT_Object_Class_Event, _OBJ_CONTAINER_LIST_INIT(RT_Object_Class_Event), sizeof(struct rt_event)}, #endif #ifdef RT_USING_MAILBOX /* initialize object container - mailbox *///郵箱對象信息 {RT_Object_Class_MailBox, _OBJ_CONTAINER_LIST_INIT(RT_Object_Class_MailBox), sizeof(struct rt_mailbox)}, #endif #ifdef RT_USING_MESSAGEQUEUE /* initialize object container - message queue *///消息隊列對象信息 {RT_Object_Class_MessageQueue, _OBJ_CONTAINER_LIST_INIT(RT_Object_Class_MessageQueue), sizeof(struct rt_messagequeue)}, #endif #ifdef RT_USING_MEMHEAP /* initialize object container - memory heap *///內存堆對象信息 {RT_Object_Class_MemHeap, _OBJ_CONTAINER_LIST_INIT(RT_Object_Class_MemHeap), sizeof(struct rt_memheap)}, #endif #ifdef RT_USING_MEMPOOL /* initialize object container - memory pool *///內存池對象信息 {RT_Object_Class_MemPool, _OBJ_CONTAINER_LIST_INIT(RT_Object_Class_MemPool), sizeof(struct rt_mempool)}, #endif #ifdef RT_USING_DEVICE /* initialize object container - device *///設備驅動對象信息 {RT_Object_Class_Device, _OBJ_CONTAINER_LIST_INIT(RT_Object_Class_Device), sizeof(struct rt_device)}, #endif /* initialize object container - timer *///時鐘對象信息 {RT_Object_Class_Timer, _OBJ_CONTAINER_LIST_INIT(RT_Object_Class_Timer), sizeof(struct rt_timer)}, #ifdef RT_USING_MODULE /* initialize object container - module *///模塊對象信息 {RT_Object_Class_Module, _OBJ_CONTAINER_LIST_INIT(RT_Object_Class_Module), sizeof(struct rt_module)}, #endif }; 2 內核對象接口 2.1 內核對象初始化 RTT提供靜態和動態兩種初始化接口,如下: 靜態初始化是將一個已經存在的且占有內存空間的對象初始化,它的接口如下: [cpp] /** * This function will initialize an object and add it to object system * management. * * @param object the specified object to be initialized. * @param type the object type. * @param name the object name. In system, the object's name must be unique. */ void rt_object_init(struct rt_object *object,//指向已存在的對象指針 enum rt_object_class_type type, //對象的類型 const char *name) //對象的名字字符串 { register rt_base_t temp; struct rt_object_information *information; //對象容器 #ifdef RT_USING_MODULE //如果使用了模塊,那麼對象容器指向本線程所包含的對象窗口,否則指向全局對象管理系統中對應的容器 /* get module object information */ information = (rt_module_self() != RT_NULL) ? &rt_module_self()->module_object[type] : &rt_object_container[type]; #else /* get object information */ information = &rt_object_container[type]; #endif /* initialize object's parameters */ /* set object type to static */ object->type = type | RT_Object_Class_Static;//設置系統對象標志 /* copy name */ rt_strncpy(object->name, name, RT_NAME_MAX);//給名字賦值 RT_OBJECT_HOOK_CALL(rt_object_attach_hook, (object));//使用鉤子函數 /* lock interrupt */ temp = rt_hw_interrupt_disable();//關中斷 /* insert object into information object list */ rt_list_insert_after(&(information->object_list), &(object->list));//將初始化的內核對象加入到對應容器中 /* unlock interrupt */ rt_hw_interrupt_enable(temp);//開中斷 } 動態初始化是指對象原本並不存在,在不內存中,需要動態為其分配內存,其接口如下: [cpp] /** * This function will allocate an object from object system * * @param type the type of object * @param name the object name. In system, the object's name must be unique. * * @return object */ rt_object_t rt_object_allocate(enum rt_object_class_type type, const char *name)//動態初始化接口只需要傳入名字和類型 { struct rt_object *object; register rt_base_t temp; struct rt_object_information *information;//對象容器 RT_DEBUG_NOT_IN_INTERRUPT; #ifdef RT_USING_MODULE//同上面那個接口一樣,獲取對象容器 /* * get module object information, * module object should be managed by kernel object container */ information = (rt_module_self() != RT_NULL && (type != RT_Object_Class_Module)) ? &rt_module_self()->module_object[type] : &rt_object_container[type]; #else /* get object information */ information = &rt_object_container[type]; #endif object = (struct rt_object *)rt_malloc(information->object_size);//為對象動態分配內存空間 if (object == RT_NULL) { /* no memory can be allocated */ return RT_NULL; } /* initialize object's parameters */ /* set object type */ object->type = type;//設置類型 /* set object flag */ object->flag = 0;//設置標志為0 #ifdef RT_USING_MODULE if (rt_module_self() != RT_NULL) { object->flag |= RT_OBJECT_FLAG_MODULE;//如果使用了模塊功能,則將flag標志設置為模塊標志 } object->module_id = (void *)rt_module_self();//設置模塊ID #endif /* copy name */ rt_strncpy(object->name, name, RT_NAME_MAX);//給名稱賦值 RT_OBJECT_HOOK_CALL(rt_object_attach_hook, (object));//使用鉤子函數 /* lock interrupt */ temp = rt_hw_interrupt_disable();//關中斷 /* insert object into information object list */ rt_list_insert_after(&(information->object_list), &(object->list));//將此對象加入對應容器 /* unlock interrupt */ rt_hw_interrupt_enable(temp);//關中斷 /* return object */ return object; } 2.2 脫離或刪除對象 如果對象是靜態初始化的,那麼對應的是脫離,如果是動態初始化的,則是刪除. 脫離接口如下: [cpp] /** * This function will detach a static object from object system, * and the memory of static object is not freed. * * @param object the specified object to be detached. */ void rt_object_detach(rt_object_t object) { register rt_base_t temp; /* object check */ RT_ASSERT(object != RT_NULL); RT_OBJECT_HOOK_CALL(rt_object_detach_hook, (object));//使用鉤子函數 /* lock interrupt */ temp = rt_hw_interrupt_disable();//關中斷 /* remove from old list */ rt_list_remove(&(object->list));//從窗口中移除 /* unlock interrupt */ rt_hw_interrupt_enable(temp);//開中斷 } 刪除接口如下: [cpp] /** * This function will delete an object and release object memory. * * @param object the specified object to be deleted. */ void rt_object_delete(rt_object_t object) { register rt_base_t temp; /* object check */ RT_ASSERT(object != RT_NULL); RT_ASSERT(!(object->type & RT_Object_Class_Static));//刪除的對象必須是非系統對象 RT_OBJECT_HOOK_CALL(rt_object_detach_hook, (object));//使用鉤子函數 /* lock interrupt */ temp = rt_hw_interrupt_disable();//關中斷 /* remove from old list */ rt_list_remove(&(object->list));//從對應的容器中移除 /* unlock interrupt */ rt_hw_interrupt_enable(temp);//開中斷 #if defined(RT_USING_MODULE) && defined(RT_USING_SLAB)//如果使用了模塊功能且采用的是SLAB動態內存管理模式 if (object->flag & RT_OBJECT_FLAG_MODULE) rt_module_free((rt_module_t)object->module_id, object);//釋放模塊ID所占空間 else #endif /* free the memory of object */ rt_free(object);//釋放內核對象所占空間 } 其中rt_list_remove會自動找到對象的前一節點和後一節點,然後刪除本身節點. 1.3 判斷是否為系統內核對象 [cpp] /** * This function will judge the object is system object or not. * Normally, the system object is a static object and the type * of object set to RT_Object_Class_Static. * * @param object the specified object to be judged. * * @return RT_TRUE if a system object, RT_FALSE for others. */ rt_bool_t rt_object_is_systemobject(rt_object_t object) { /* object check */ RT_ASSERT(object != RT_NULL); if (object->type & RT_Object_Class_Static)//RTT是通過內核對象的type的最高位是否為1來判斷此對象是否為系統內核對象的 return RT_TRUE; return RT_FALSE; } 1.4 查找內核對象 [cpp] /** * This function will find specified name object from object * container. * * @param name the specified name of object. * @param type the type of object * * @return the found object or RT_NULL if there is no this object * in object container. * * @note this function shall not be invoked in interrupt status. */ rt_object_t rt_object_find(const char *name, rt_uint8_t type) { struct rt_object *object; struct rt_list_node *node; struct rt_object_information *information; extern volatile rt_uint8_t rt_interrupt_nest; /* parameter check *///輸入系統檢查 if ((name == RT_NULL) || (type > RT_Object_Class_Unknown)) return RT_NULL; /* which is invoke in interrupt status */ if (rt_interrupt_nest != 0)//確保當前沒有中斷嵌套 RT_ASSERT(0); /* enter critical */ rt_enter_critical();//進入臨界區 /* try to find object */ information = &rt_object_container[type];//獲取對應的對象容器 for (node = information->object_list.next;//開始通過名字來掃描內核對象 node != &(information->object_list); node = node->next) { object = rt_list_entry(node, struct rt_object, list);//獲取內核對象 if (rt_strncmp(object->name, name, RT_NAME_MAX) == 0)//判斷名字是否相符 { /* leave critical */ rt_exit_critical();//退出臨界區 return object; } } /* leave critical */ rt_exit_critical();//退出臨界區 return RT_NULL; }
