xref: /third_party/python/Doc/includes/custom4.c (revision 7db96d56) 
1#define PY_SSIZE_T_CLEAN
2#include <Python.h>
3#include "structmember.h"
4
5typedef struct {
6    PyObject_HEAD
7    PyObject *first; /* first name */
8    PyObject *last;  /* last name */
9    int number;
10} CustomObject;
11
12static int
13Custom_traverse(CustomObject *self, visitproc visit, void *arg)
14{
15    Py_VISIT(self->first);
16    Py_VISIT(self->last);
17    return 0;
18}
19
20static int
21Custom_clear(CustomObject *self)
22{
23    Py_CLEAR(self->first);
24    Py_CLEAR(self->last);
25    return 0;
26}
27
28static void
29Custom_dealloc(CustomObject *self)
30{
31    PyObject_GC_UnTrack(self);
32    Custom_clear(self);
33    Py_TYPE(self)->tp_free((PyObject *) self);
34}
35
36static PyObject *
37Custom_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
38{
39    CustomObject *self;
40    self = (CustomObject *) type->tp_alloc(type, 0);
41    if (self != NULL) {
42        self->first = PyUnicode_FromString("");
43        if (self->first == NULL) {
44            Py_DECREF(self);
45            return NULL;
46        }
47        self->last = PyUnicode_FromString("");
48        if (self->last == NULL) {
49            Py_DECREF(self);
50            return NULL;
51        }
52        self->number = 0;
53    }
54    return (PyObject *) self;
55}
56
57static int
58Custom_init(CustomObject *self, PyObject *args, PyObject *kwds)
59{
60    static char *kwlist[] = {"first", "last", "number", NULL};
61    PyObject *first = NULL, *last = NULL, *tmp;
62
63    if (!PyArg_ParseTupleAndKeywords(args, kwds, "|UUi", kwlist,
64                                     &first, &last,
65                                     &self->number))
66        return -1;
67
68    if (first) {
69        tmp = self->first;
70        Py_INCREF(first);
71        self->first = first;
72        Py_DECREF(tmp);
73    }
74    if (last) {
75        tmp = self->last;
76        Py_INCREF(last);
77        self->last = last;
78        Py_DECREF(tmp);
79    }
80    return 0;
81}
82
83static PyMemberDef Custom_members[] = {
84    {"number", T_INT, offsetof(CustomObject, number), 0,
85     "custom number"},
86    {NULL}  /* Sentinel */
87};
88
89static PyObject *
90Custom_getfirst(CustomObject *self, void *closure)
91{
92    Py_INCREF(self->first);
93    return self->first;
94}
95
96static int
97Custom_setfirst(CustomObject *self, PyObject *value, void *closure)
98{
99    if (value == NULL) {
100        PyErr_SetString(PyExc_TypeError, "Cannot delete the first attribute");
101        return -1;
102    }
103    if (!PyUnicode_Check(value)) {
104        PyErr_SetString(PyExc_TypeError,
105                        "The first attribute value must be a string");
106        return -1;
107    }
108    Py_INCREF(value);
109    Py_CLEAR(self->first);
110    self->first = value;
111    return 0;
112}
113
114static PyObject *
115Custom_getlast(CustomObject *self, void *closure)
116{
117    Py_INCREF(self->last);
118    return self->last;
119}
120
121static int
122Custom_setlast(CustomObject *self, PyObject *value, void *closure)
123{
124    if (value == NULL) {
125        PyErr_SetString(PyExc_TypeError, "Cannot delete the last attribute");
126        return -1;
127    }
128    if (!PyUnicode_Check(value)) {
129        PyErr_SetString(PyExc_TypeError,
130                        "The last attribute value must be a string");
131        return -1;
132    }
133    Py_INCREF(value);
134    Py_CLEAR(self->last);
135    self->last = value;
136    return 0;
137}
138
139static PyGetSetDef Custom_getsetters[] = {
140    {"first", (getter) Custom_getfirst, (setter) Custom_setfirst,
141     "first name", NULL},
142    {"last", (getter) Custom_getlast, (setter) Custom_setlast,
143     "last name", NULL},
144    {NULL}  /* Sentinel */
145};
146
147static PyObject *
148Custom_name(CustomObject *self, PyObject *Py_UNUSED(ignored))
149{
150    return PyUnicode_FromFormat("%S %S", self->first, self->last);
151}
152
153static PyMethodDef Custom_methods[] = {
154    {"name", (PyCFunction) Custom_name, METH_NOARGS,
155     "Return the name, combining the first and last name"
156    },
157    {NULL}  /* Sentinel */
158};
159
160static PyTypeObject CustomType = {
161    PyVarObject_HEAD_INIT(NULL, 0)
162    .tp_name = "custom4.Custom",
163    .tp_doc = PyDoc_STR("Custom objects"),
164    .tp_basicsize = sizeof(CustomObject),
165    .tp_itemsize = 0,
166    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC,
167    .tp_new = Custom_new,
168    .tp_init = (initproc) Custom_init,
169    .tp_dealloc = (destructor) Custom_dealloc,
170    .tp_traverse = (traverseproc) Custom_traverse,
171    .tp_clear = (inquiry) Custom_clear,
172    .tp_members = Custom_members,
173    .tp_methods = Custom_methods,
174    .tp_getset = Custom_getsetters,
175};
176
177static PyModuleDef custommodule = {
178    PyModuleDef_HEAD_INIT,
179    .m_name = "custom4",
180    .m_doc = "Example module that creates an extension type.",
181    .m_size = -1,
182};
183
184PyMODINIT_FUNC
185PyInit_custom4(void)
186{
187    PyObject *m;
188    if (PyType_Ready(&CustomType) < 0)
189        return NULL;
190
191    m = PyModule_Create(&custommodule);
192    if (m == NULL)
193        return NULL;
194
195    Py_INCREF(&CustomType);
196    if (PyModule_AddObject(m, "Custom", (PyObject *) &CustomType) < 0) {
197        Py_DECREF(&CustomType);
198        Py_DECREF(m);
199        return NULL;
200    }
201
202    return m;
203}
204