1 /* Cell object implementation */
2
3 #include "Python.h"
4 #include "pycore_object.h"
5
6 PyObject *
7 PyCell_New(PyObject *obj)
8 {
9 PyCellObject *op;
10
11 op = (PyCellObject *)PyObject_GC_New(PyCellObject, &PyCell_Type);
12 if (op == NULL)
13 return NULL;
14 op->ob_ref = obj;
15 Py_XINCREF(obj);
16
17 _PyObject_GC_TRACK(op);
18 return (PyObject *)op;
19 }
20
21 PyDoc_STRVAR(cell_new_doc,
22 "cell([contents])\n"
23 "--\n"
24 "\n"
25 "Create a new cell object.\n"
26 "\n"
27 " contents\n"
28 " the contents of the cell. If not specified, the cell will be empty,\n"
29 " and \n further attempts to access its cell_contents attribute will\n"
30 " raise a ValueError.");
31
32
33 static PyObject *
34 cell_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
35 {
36 PyObject *return_value = NULL;
37 PyObject *obj = NULL;
38
39 if (!_PyArg_NoKeywords("cell", kwargs)) {
40 goto exit;
41 }
42 /* min = 0: we allow the cell to be empty */
43 if (!PyArg_UnpackTuple(args, "cell", 0, 1, &obj)) {
44 goto exit;
45 }
46 return_value = PyCell_New(obj);
47
48 exit:
49 return return_value;
50 }
51
52 PyObject *
53 PyCell_Get(PyObject *op)
54 {
55 if (!PyCell_Check(op)) {
56 PyErr_BadInternalCall();
57 return NULL;
58 }
59 Py_XINCREF(((PyCellObject*)op)->ob_ref);
60 return PyCell_GET(op);
61 }
62
63 int
64 PyCell_Set(PyObject *op, PyObject *obj)
65 {
66 PyObject* oldobj;
67 if (!PyCell_Check(op)) {
68 PyErr_BadInternalCall();
69 return -1;
70 }
71 oldobj = PyCell_GET(op);
72 Py_XINCREF(obj);
73 PyCell_SET(op, obj);
74 Py_XDECREF(oldobj);
75 return 0;
76 }
77
78 static void
79 cell_dealloc(PyCellObject *op)
80 {
81 _PyObject_GC_UNTRACK(op);
82 Py_XDECREF(op->ob_ref);
83 PyObject_GC_Del(op);
84 }
85
86 static PyObject *
87 cell_richcompare(PyObject *a, PyObject *b, int op)
88 {
89 /* neither argument should be NULL, unless something's gone wrong */
90 assert(a != NULL && b != NULL);
91
92 /* both arguments should be instances of PyCellObject */
93 if (!PyCell_Check(a) || !PyCell_Check(b)) {
94 Py_RETURN_NOTIMPLEMENTED;
95 }
96
97 /* compare cells by contents; empty cells come before anything else */
98 a = ((PyCellObject *)a)->ob_ref;
99 b = ((PyCellObject *)b)->ob_ref;
100 if (a != NULL && b != NULL)
101 return PyObject_RichCompare(a, b, op);
102
103 Py_RETURN_RICHCOMPARE(b == NULL, a == NULL, op);
104 }
105
106 static PyObject *
107 cell_repr(PyCellObject *op)
108 {
109 if (op->ob_ref == NULL)
110 return PyUnicode_FromFormat("<cell at %p: empty>", op);
111
112 return PyUnicode_FromFormat("<cell at %p: %.80s object at %p>",
113 op, Py_TYPE(op->ob_ref)->tp_name,
114 op->ob_ref);
115 }
116
117 static int
118 cell_traverse(PyCellObject *op, visitproc visit, void *arg)
119 {
120 Py_VISIT(op->ob_ref);
121 return 0;
122 }
123
124 static int
125 cell_clear(PyCellObject *op)
126 {
127 Py_CLEAR(op->ob_ref);
128 return 0;
129 }
130
131 static PyObject *
132 cell_get_contents(PyCellObject *op, void *closure)
133 {
134 if (op->ob_ref == NULL)
135 {
136 PyErr_SetString(PyExc_ValueError, "Cell is empty");
137 return NULL;
138 }
139 Py_INCREF(op->ob_ref);
140 return op->ob_ref;
141 }
142
143 static int
144 cell_set_contents(PyCellObject *op, PyObject *obj, void *Py_UNUSED(ignored))
145 {
146 Py_XINCREF(obj);
147 Py_XSETREF(op->ob_ref, obj);
148 return 0;
149 }
150
151 static PyGetSetDef cell_getsetlist[] = {
152 {"cell_contents", (getter)cell_get_contents,
153 (setter)cell_set_contents, NULL},
154 {NULL} /* sentinel */
155 };
156
157 PyTypeObject PyCell_Type = {
158 PyVarObject_HEAD_INIT(&PyType_Type, 0)
159 "cell",
160 sizeof(PyCellObject),
161 0,
162 (destructor)cell_dealloc, /* tp_dealloc */
163 0, /* tp_vectorcall_offset */
164 0, /* tp_getattr */
165 0, /* tp_setattr */
166 0, /* tp_as_async */
167 (reprfunc)cell_repr, /* tp_repr */
168 0, /* tp_as_number */
169 0, /* tp_as_sequence */
170 0, /* tp_as_mapping */
171 0, /* tp_hash */
172 0, /* tp_call */
173 0, /* tp_str */
174 PyObject_GenericGetAttr, /* tp_getattro */
175 0, /* tp_setattro */
176 0, /* tp_as_buffer */
177 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
178 cell_new_doc, /* tp_doc */
179 (traverseproc)cell_traverse, /* tp_traverse */
180 (inquiry)cell_clear, /* tp_clear */
181 cell_richcompare, /* tp_richcompare */
182 0, /* tp_weaklistoffset */
183 0, /* tp_iter */
184 0, /* tp_iternext */
185 0, /* tp_methods */
186 0, /* tp_members */
187 cell_getsetlist, /* tp_getset */
188 0, /* tp_base */
189 0, /* tp_dict */
190 0, /* tp_descr_get */
191 0, /* tp_descr_set */
192 0, /* tp_dictoffset */
193 0, /* tp_init */
194 0, /* tp_alloc */
195 (newfunc)cell_new, /* tp_new */
196 0, /* tp_free */
197 };