# object.h

## \_PyObject\_HEAD\_EXTRA

```
# 调试的时候定义双链表
#define _PyObject_HEAD_EXTRA            \
    struct _object *_ob_next;           \
    struct _object *_ob_prev;
```

## \_typeobject/PyTypeObject结构体

类型定义结构体

* PyObject\_VAR\_HEAD是可变长对象定义

  `define PyObject_VAR_HEAD PyVarObject ob_base;`
* 创建对象时分配内存空间大小的变量， `tp_basicsize`基本的大小，和`tp_itemsize`里面元素的大小

```c
typedef struct _typeobject {
    PyObject_VAR_HEAD
    const char *tp_name; /* For printing, in format "<module>.<name>" */
    Py_ssize_t tp_basicsize, tp_itemsize; /* For allocation */

    destructor tp_dealloc;
    printfunc tp_print;
    getattrfunc tp_getattr;
    setattrfunc tp_setattr;
    PyAsyncMethods *tp_as_async;
    reprfunc tp_repr;
..........
    //各种类型的操作集结构体

    PyNumberMethods *tp_as_number;
    PySequenceMethods *tp_as_sequence;
    PyMappingMethods *tp_as_mapping;
    ........
//  结构体定义指针函数
    hashfunc tp_hash;
    ternaryfunc tp_call;
    reprfunc tp_str;
    getattrofunc tp_getattro;
    setattrofunc tp_setattro;
    inquiry tp_is_gc; /* For PyObject_IS_GC */
} PyTypeObject;
```

## \_object/PyObject结构体

* PyObject包含\_PyObject\_HEAD\_EXTRA头用于调试
* ob\_refcnt引用计数，用于垃圾回收
* ob\_type类型结构体指针，定义类型

```c
# 初级对象 
typedef struct _object {
    _PyObject_HEAD_EXTRA
    Py_ssize_t ob_refcnt;
    struct _typeobject *ob_type;
} PyObject;
```

## PyVarObject结构体

其直接是一个PyObject和一个描述元素数量多int组成

```
// 变长对象
typedef struct {
    PyObject ob_base;
    Py_ssize_t ob_size; /* Number of items in variable part */
} PyVarObject;
```

## 垃圾回收

```
/*
#ifdef Py_REF_DEBUG
765 PyAPI_DATA(Py_ssize_t) _Py_RefTotal;
769 #define _Py_INC_REFTOTAL        _Py_RefTotal++
770 #define _Py_DEC_REFTOTAL        _Py_RefTotal--
771 #define _Py_REF_DEBUG_COMMA     ,
*/

//增加引用计数
#define Py_INCREF(op) (                         \
    ((PyObject *)(op))->ob_refcnt++)


//减少引用计数
#define Py_DECREF(op)                                   \
    do {                                                \
        PyObject *_py_decref_tmp = (PyObject *)(op);    \
        if (--(_py_decref_tmp)->ob_refcnt != 0)         \
            _Py_CHECK_REFCNT(_py_decref_tmp)            \
        else                                            \
            _Py_Dealloc(_py_decref_tmp);                \
    } while (0)

// 销毁函数
PyAPI_FUNC(void) _Py_Dealloc(PyObject *);
```

## PyNumberMethods

对数字类对象的操作结构体

```c
typedef struct {
    /*
    定义了作为一个数值对象支持的操作. 如果一个对象被视为数值对象(如整型), 
    那么它的 tp_as_number.nb_add 就要有对该对象进行加法操作的具体行为
    */

//typedef PyObject * (*binaryfunc)(PyObject *, PyObject *); 
//二元操作，对两个PyObject进行操作，返回一个PyObject
    binaryfunc nb_add;
    binaryfunc nb_subtract;
    binaryfunc nb_multiply;
    binaryfunc nb_remainder;
    binaryfunc nb_divmod;
//  ternaryfunc，三元操作
    ternaryfunc nb_power;
//  unaryfunc，一元操作
    unaryfunc nb_negative;
    unaryfunc nb_positive;
    unaryfunc nb_absolute;
.......
    binaryfunc nb_matrix_multiply;
    binaryfunc nb_inplace_matrix_multiply;
} PyNumberMethods;
```

## PySequenceMethods

序列类型list。。操作

## PyMappingMethods

字典类型dict。。操作

## PyAsyncMethods

异步操作。。。

很多。。。

## 一些宏函数

```c
#define Py_REFCNT(ob)           (((PyObject*)(ob))->ob_refcnt)
#define Py_TYPE(ob)             (((PyObject*)(ob))->ob_type)
#define Py_SIZE(ob)             (((PyVarObject*)(ob))->ob_size)
```


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