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