objc.h

早期freebsd实现

  } ivar_list[1];                               /* Variable length 
                                                  structure. */
} IvarList, *IvarList_t;


/*
 * The compiler generates one (or more) of these structures for a class that
 * has methods defined in its specification. 
 *
 * The implementation of a class can be broken into separate pieces in a file
 * and categories can break them across modules. To handle this problem is a
 * singly linked list of methods. 
 */
typedef struct objc_method Method;
typedef Method* Method_t;
typedef struct objc_method_list {
  struct objc_method_list*  method_next;      /* This variable is used to link 
                                                a method list to another.  It 
                                                is a singly linked list. */
  int             method_count;               /* Number of methods defined in 
                                                this structure. */
  struct objc_method {
    SEL         method_name;                  /* This variable is the method's 
                                                name.  It is a char*. 
                                                  The unique integer passed to 
                                                objc_msgSend is a char* too.  
                                                It is compared against 
                                                method_name using strcmp. */
    const char* method_types;                 /* Description of the method's
                                                parameter list.  Useful for
                                                debuggers. */
    IMP         method_imp;                   /* Address of the method in the 
                                                executable. */
  } method_list[1];                           /* Variable length 
                                                structure. */
} MethodList, *MethodList_t;


/*
 * The compiler generates one of these structures for each class.  
 *
 * This structure is the definition for meta classes. By definition a meta
 * class is the class's class.  Its most relevant contribution is that its
 * method list contain the class's factory methods. 
 *
 * This structure is generated by the compiler in the executable and used by
 * the run-time during normal messaging operations.  Therefore some members
 * change type. The compiler generates "char* const" and places a string in
 * the following member variables:  class_pointer and super_class. 
 */
typedef struct objc_metaClass {     
  struct objc_metaClass*  class_pointer;      /* Pointer to Object meta class. */
  struct objc_metaClass*  super_class;        /* Pointer to meta class's
                                                super class. NULL for 
                                                Object. */
  const char*             name;               /* Name of the meta class. */
  long                    version;            /* Unknown. */
  long                    info;               /* Bit mask.  See class masks 
                                                defined above. */
  long                    instance_size;      /* Always 0 except for Object.
                                                Should be ignored. */
  IvarList_t              ivars;              /* Always NULL except for 
                                                Object.  Should be ignored. */
  MethodList_t            methods;            /* Linked List of factory methods 
                                                for the class. */
  struct record **        cache;              /* Pointer to factory method dispatch table. */
} MetaClass, *MetaClass_t;


/*
 * The compiler generates one of these structures for each class.  
 *
 * This structure is the definition for classes. 
 *
 * This structure is generated by the compiler in the executable and used by
 * the run-time during normal messaging operations.  Therefore some members
 * change type. The compiler generates "char* const" and places a string in
 * the following member variables:  super_class. 
 */
typedef struct objc_class {     
  MetaClass_t         class_pointer;          /* Pointer to the class's
                                                meta class. */
  struct objc_class*  super_class;            /* Pointer to the super 
                                                class. NULL for class 
                                                Object. */
  const char*         name;                   /* Name of the class. */
  long                version;                /* Unknown. */
  long                info;                   /* Bit mask.  See class masks 
                                                defined above. */
  long                instance_size;          /* Size in bytes of the class.  
                                                The sum of the class definition 
                                                and all super class 
                                                definitions. */
  IvarList_t          ivars;                  /* Pointer to a structure that
                                                describes the instance 
                                                variables in the class
                                                definition.  NULL indicates
                                                no instance variables.  Does
                                                not include super class
                                                variables. */
  MethodList_t        methods;                /* Linked list of instance
                                                methods defined for the 
                                                class. */
  struct record **    cache;                  /* Pointer to instance method dispatch table. */
} Class, *Class_t;


/*
 * The compiler generates one of these structures for each category.  A class
 * may have many categories and contain both instance and factory methods.  
 */
typedef struct objc_category {
  const char*   category_name;                /* Name of the category.  Name
                                                contained in the () of the
                                                category definition. */
  const char*   class_name;                   /* Name of the class to which
                                                the category belongs. */
  MethodList_t  instance_methods;             /* Linked list of instance
                                                methods defined in the 
                                                category. NULL indicates no
                                                instance methods defined. */
  MethodList_t  class_methods;                /* Linked list of factory 
                                                methods defined in the
                                                category.  NULL indicates no
                                                class methods defined. */
} Category, *Category_t;


/*
 * Structure used when a message is send to a class's super class.  The
 * compiler generates one of these structures and passes it to
 * objc_msgSuper. 
 */
typedef struct objc_super {
  id      receiver;                           /* Id of the object sending
                                                the message. */
  Class_t class;                              /* Object's super class. */
} Super, *Super_t;

/*
 * _alloc points to the function, called through class_createInstance, used
 * to allocate memory for new instances. 
 */
extern id (*_alloc)(Class_t);
/*
 * _dealloc points to the function, called through object_dispose, used to
 * free instances. 
 */
extern id (*_dealloc)(id);
/*
 * _realloc points to the function, called through object_realloc, used to
 * reallocate memory for an object 
 */
extern id (*_realloc)(id, unsigned int);

/*
 * _copy points to the function, called through object_copy, used to create
 * an exact copy of an object. 
 */
extern  id (*_copy)(id);

/*
 * _error points to the function that the run-time system calls in response
 * to an error.  By default, it prints formatted error messages to the
 * standard error stream and calls abort to produce a core file. 
 */
extern void (*_error)(id object, const char *fmt, va_list ap);


#ifdef __cplusplus
}
#endif


#endif /* not __objc_INCLUDE_GNU */