Python内建对象(Python 源码剖析第一章)

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原文链接：http://www.cnblogs.com/zhtf2014/archive/2010/11/11/1874548.html

文章标签：

#python

本文深入探讨了Python中对象的内部结构，包括引用计数、类型信息、变长对象的大小，以及PyTypeObject结构体的详细字段说明，揭示了Python对象机制的核心原理。

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PyObject

1 #define PyObject_HEAD                   \
2     _PyObject_HEAD_EXTRA                \
3     Py_ssize_t ob_refcnt;               \
4     struct _typeobject *ob_type;
5
6 typedef struct _object {
7     PyObject_HEAD
8 } PyObject;

　　Python里对象机制的核心其实非常简单，一个是引用计数，一个是类型信息。

PyVarObject

1 #define PyObject_VAR_HEAD               \
2     PyObject_HEAD                       \
3     Py_ssize_t ob_size; /* Number of items in variable part */
4 #define Py_INVALID_SIZE (Py_ssize_t)-1
5
6 typedef struct {
7     PyObject_VAR_HEAD
8 } PyVarObject;

　　变长对象多了ob_size表明元素的个数。

PyTypeObject

1 typedef struct _typeobject {
2     PyObject_VAR_HEAD
3     const char *tp_name; /* For printing, in format "<module>.<name>" */
4     Py_ssize_t tp_basicsize, tp_itemsize; /* For allocation */
5
6     /* Methods to implement standard operations */
7
8     destructor tp_dealloc;
9     printfunc tp_print;
10     getattrfunc tp_getattr;
11     setattrfunc tp_setattr;
12     cmpfunc tp_compare;
13     reprfunc tp_repr;
14
15     /* Method suites for standard classes */
16
17     PyNumberMethods *tp_as_number;
18     PySequenceMethods *tp_as_sequence;
19     PyMappingMethods *tp_as_mapping;
20
21     /* More standard operations (here for binary compatibility) */
22
23     hashfunc tp_hash;
24     ternaryfunc tp_call;
25     reprfunc tp_str;
26     getattrofunc tp_getattro;
27     setattrofunc tp_setattro;
28
29     /* Functions to access object as input/output buffer */
30     PyBufferProcs *tp_as_buffer;
31
32     /* Flags to define presence of optional/expanded features */
33     long tp_flags;
34
35     const char *tp_doc; /* Documentation string */
36
37     /* Assigned meaning in release 2.0 */
38     /* call function for all accessible objects */
39     traverseproc tp_traverse;
40
41     /* delete references to contained objects */
42     inquiry tp_clear;
43
44     /* Assigned meaning in release 2.1 */
45     /* rich comparisons */
46     richcmpfunc tp_richcompare;
47
48     /* weak reference enabler */
49     Py_ssize_t tp_weaklistoffset;
50
51     /* Added in release 2.2 */
52     /* Iterators */
53     getiterfunc tp_iter;
54     iternextfunc tp_iternext;
55
56     /* Attribute descriptor and subclassing stuff */
57     struct PyMethodDef *tp_methods;
58     struct PyMemberDef *tp_members;
59     struct PyGetSetDef *tp_getset;
60     struct _typeobject *tp_base;
61     PyObject *tp_dict;
62     descrgetfunc tp_descr_get;
63     descrsetfunc tp_descr_set;
64     Py_ssize_t tp_dictoffset;
65     initproc tp_init;
66     allocfunc tp_alloc;
67     newfunc tp_new;
68     freefunc tp_free; /* Low-level free-memory routine */
69     inquiry tp_is_gc; /* For PyObject_IS_GC */
70     PyObject *tp_bases;
71     PyObject *tp_mro; /* method resolution order */
72     PyObject *tp_cache;
73     PyObject *tp_subclasses;
74     PyObject *tp_weaklist;
75     destructor tp_del;
76
77     /* Type attribute cache version tag. Added in version 2.6 */
78     unsigned int tp_version_tag;
79
80 #ifdef COUNT_ALLOCS
81     /* these must be last and never explicitly initialized */
82     Py_ssize_t tp_allocs;
83     Py_ssize_t tp_frees;
84     Py_ssize_t tp_maxalloc;
85     struct _typeobject *tp_prev;
86     struct _typeobject *tp_next;
87 #endif
88 } PyTypeObject;
89

转载于:https://www.cnblogs.com/zhtf2014/archive/2010/11/11/1874548.html