1 /* Cell object implementation */
2
3 #include "Python.h"
4
5 PyObject *
PyCell_New(PyObject * obj)6 PyCell_New(PyObject *obj)
7 {
8 PyCellObject *op;
9
10 op = (PyCellObject *)PyObject_GC_New(PyCellObject, &PyCell_Type);
11 if (op == NULL)
12 return NULL;
13 op->ob_ref = obj;
14 Py_XINCREF(obj);
15
16 _PyObject_GC_TRACK(op);
17 return (PyObject *)op;
18 }
19
20 PyObject *
PyCell_Get(PyObject * op)21 PyCell_Get(PyObject *op)
22 {
23 if (!PyCell_Check(op)) {
24 PyErr_BadInternalCall();
25 return NULL;
26 }
27 Py_XINCREF(((PyCellObject*)op)->ob_ref);
28 return PyCell_GET(op);
29 }
30
31 int
PyCell_Set(PyObject * op,PyObject * obj)32 PyCell_Set(PyObject *op, PyObject *obj)
33 {
34 PyObject* oldobj;
35 if (!PyCell_Check(op)) {
36 PyErr_BadInternalCall();
37 return -1;
38 }
39 oldobj = PyCell_GET(op);
40 Py_XINCREF(obj);
41 PyCell_SET(op, obj);
42 Py_XDECREF(oldobj);
43 return 0;
44 }
45
46 static void
cell_dealloc(PyCellObject * op)47 cell_dealloc(PyCellObject *op)
48 {
49 _PyObject_GC_UNTRACK(op);
50 Py_XDECREF(op->ob_ref);
51 PyObject_GC_Del(op);
52 }
53
54 #define TEST_COND(cond) ((cond) ? Py_True : Py_False)
55
56 static PyObject *
cell_richcompare(PyObject * a,PyObject * b,int op)57 cell_richcompare(PyObject *a, PyObject *b, int op)
58 {
59 int result;
60 PyObject *v;
61
62 /* neither argument should be NULL, unless something's gone wrong */
63 assert(a != NULL && b != NULL);
64
65 /* both arguments should be instances of PyCellObject */
66 if (!PyCell_Check(a) || !PyCell_Check(b)) {
67 v = Py_NotImplemented;
68 Py_INCREF(v);
69 return v;
70 }
71
72 /* compare cells by contents; empty cells come before anything else */
73 a = ((PyCellObject *)a)->ob_ref;
74 b = ((PyCellObject *)b)->ob_ref;
75 if (a != NULL && b != NULL)
76 return PyObject_RichCompare(a, b, op);
77
78 result = (b == NULL) - (a == NULL);
79 switch (op) {
80 case Py_EQ:
81 v = TEST_COND(result == 0);
82 break;
83 case Py_NE:
84 v = TEST_COND(result != 0);
85 break;
86 case Py_LE:
87 v = TEST_COND(result <= 0);
88 break;
89 case Py_GE:
90 v = TEST_COND(result >= 0);
91 break;
92 case Py_LT:
93 v = TEST_COND(result < 0);
94 break;
95 case Py_GT:
96 v = TEST_COND(result > 0);
97 break;
98 default:
99 PyErr_BadArgument();
100 return NULL;
101 }
102 Py_INCREF(v);
103 return v;
104 }
105
106 static PyObject *
cell_repr(PyCellObject * op)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, op->ob_ref->ob_type->tp_name,
114 op->ob_ref);
115 }
116
117 static int
cell_traverse(PyCellObject * op,visitproc visit,void * arg)118 cell_traverse(PyCellObject *op, visitproc visit, void *arg)
119 {
120 Py_VISIT(op->ob_ref);
121 return 0;
122 }
123
124 static int
cell_clear(PyCellObject * op)125 cell_clear(PyCellObject *op)
126 {
127 Py_CLEAR(op->ob_ref);
128 return 0;
129 }
130
131 static PyObject *
cell_get_contents(PyCellObject * op,void * closure)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 PyGetSetDef cell_getsetlist[] = {
144 {"cell_contents", (getter)cell_get_contents, NULL},
145 {NULL} /* sentinel */
146 };
147
148 PyTypeObject PyCell_Type = {
149 PyVarObject_HEAD_INIT(&PyType_Type, 0)
150 "cell",
151 sizeof(PyCellObject),
152 0,
153 (destructor)cell_dealloc, /* tp_dealloc */
154 0, /* tp_print */
155 0, /* tp_getattr */
156 0, /* tp_setattr */
157 0, /* tp_reserved */
158 (reprfunc)cell_repr, /* tp_repr */
159 0, /* tp_as_number */
160 0, /* tp_as_sequence */
161 0, /* tp_as_mapping */
162 0, /* tp_hash */
163 0, /* tp_call */
164 0, /* tp_str */
165 PyObject_GenericGetAttr, /* tp_getattro */
166 0, /* tp_setattro */
167 0, /* tp_as_buffer */
168 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
169 0, /* tp_doc */
170 (traverseproc)cell_traverse, /* tp_traverse */
171 (inquiry)cell_clear, /* tp_clear */
172 cell_richcompare, /* tp_richcompare */
173 0, /* tp_weaklistoffset */
174 0, /* tp_iter */
175 0, /* tp_iternext */
176 0, /* tp_methods */
177 0, /* tp_members */
178 cell_getsetlist, /* tp_getset */
179 };
180