summaryrefslogtreecommitdiffstats
path: root/Objects/cellobject.c
blob: 4e359f889fdc81ce24b3f5a2816ef7f5146ee9f3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
/* Cell object implementation */

#include "Python.h"
#include "pycore_object.h"
#include "pycore_pymem.h"
#include "pycore_pystate.h"

PyObject *
PyCell_New(PyObject *obj)
{
    PyCellObject *op;

    op = (PyCellObject *)PyObject_GC_New(PyCellObject, &PyCell_Type);
    if (op == NULL)
        return NULL;
    op->ob_ref = obj;
    Py_XINCREF(obj);

    _PyObject_GC_TRACK(op);
    return (PyObject *)op;
}

PyDoc_STRVAR(cell_new_doc,
"cell([contents])\n"
"--\n"
"\n"
"Create a new cell object.\n"
"\n"
"  contents\n"
"    the contents of the cell. If not specified, the cell will be empty,\n"
"    and \n further attempts to access its cell_contents attribute will\n"
"    raise a ValueError.");


static PyObject *
cell_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
{
    PyObject *return_value = NULL;
    PyObject *obj = NULL;

    if (!_PyArg_NoKeywords("cell", kwargs)) {
        goto exit;
    }
    /* min = 0: we allow the cell to be empty */
    if (!PyArg_UnpackTuple(args, "cell", 0, 1, &obj)) {
        goto exit;
    }
    return_value = PyCell_New(obj);

exit:
    return return_value;
}

PyObject *
PyCell_Get(PyObject *op)
{
    if (!PyCell_Check(op)) {
        PyErr_BadInternalCall();
        return NULL;
    }
    Py_XINCREF(((PyCellObject*)op)->ob_ref);
    return PyCell_GET(op);
}

int
PyCell_Set(PyObject *op, PyObject *obj)
{
    PyObject* oldobj;
    if (!PyCell_Check(op)) {
        PyErr_BadInternalCall();
        return -1;
    }
    oldobj = PyCell_GET(op);
    Py_XINCREF(obj);
    PyCell_SET(op, obj);
    Py_XDECREF(oldobj);
    return 0;
}

static void
cell_dealloc(PyCellObject *op)
{
    _PyObject_GC_UNTRACK(op);
    Py_XDECREF(op->ob_ref);
    PyObject_GC_Del(op);
}

static PyObject *
cell_richcompare(PyObject *a, PyObject *b, int op)
{
    /* neither argument should be NULL, unless something's gone wrong */
    assert(a != NULL && b != NULL);

    /* both arguments should be instances of PyCellObject */
    if (!PyCell_Check(a) || !PyCell_Check(b)) {
        Py_RETURN_NOTIMPLEMENTED;
    }

    /* compare cells by contents; empty cells come before anything else */
    a = ((PyCellObject *)a)->ob_ref;
    b = ((PyCellObject *)b)->ob_ref;
    if (a != NULL && b != NULL)
        return PyObject_RichCompare(a, b, op);

    Py_RETURN_RICHCOMPARE(b == NULL, a == NULL, op);
}

static PyObject *
cell_repr(PyCellObject *op)
{
    if (op->ob_ref == NULL)
        return PyUnicode_FromFormat("<cell at %p: empty>", op);

    return PyUnicode_FromFormat("<cell at %p: %.80s object at %p>",
                               op, op->ob_ref->ob_type->tp_name,
                               op->ob_ref);
}

static int
cell_traverse(PyCellObject *op, visitproc visit, void *arg)
{
    Py_VISIT(op->ob_ref);
    return 0;
}

static int
cell_clear(PyCellObject *op)
{
    Py_CLEAR(op->ob_ref);
    return 0;
}

static PyObject *
cell_get_contents(PyCellObject *op, void *closure)
{
    if (op->ob_ref == NULL)
    {
        PyErr_SetString(PyExc_ValueError, "Cell is empty");
        return NULL;
    }
    Py_INCREF(op->ob_ref);
    return op->ob_ref;
}

static int
cell_set_contents(PyCellObject *op, PyObject *obj, void *Py_UNUSED(ignored))
{
    Py_XINCREF(obj);
    Py_XSETREF(op->ob_ref, obj);
    return 0;
}

static PyGetSetDef cell_getsetlist[] = {
    {"cell_contents", (getter)cell_get_contents,
                      (setter)cell_set_contents, NULL},
    {NULL} /* sentinel */
};

PyTypeObject PyCell_Type = {
    PyVarObject_HEAD_INIT(&PyType_Type, 0)
    "cell",
    sizeof(PyCellObject),
    0,
    (destructor)cell_dealloc,                   /* tp_dealloc */
    0,                                          /* tp_print */
    0,                                          /* tp_getattr */
    0,                                          /* tp_setattr */
    0,                                          /* tp_reserved */
    (reprfunc)cell_repr,                        /* tp_repr */
    0,                                          /* tp_as_number */
    0,                                          /* tp_as_sequence */
    0,                                          /* tp_as_mapping */
    0,                                          /* tp_hash */
    0,                                          /* tp_call */
    0,                                          /* tp_str */
    PyObject_GenericGetAttr,                    /* tp_getattro */
    0,                                          /* tp_setattro */
    0,                                          /* tp_as_buffer */
    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,    /* tp_flags */
    cell_new_doc,                               /* tp_doc */
    (traverseproc)cell_traverse,                /* tp_traverse */
    (inquiry)cell_clear,                        /* tp_clear */
    cell_richcompare,                           /* tp_richcompare */
    0,                                          /* tp_weaklistoffset */
    0,                                          /* tp_iter */
    0,                                          /* tp_iternext */
    0,                                          /* tp_methods */
    0,                                          /* tp_members */
    cell_getsetlist,                            /* tp_getset */
    0,                                          /* tp_base */
    0,                                          /* tp_dict */
    0,                                          /* tp_descr_get */
    0,                                          /* tp_descr_set */
    0,                                          /* tp_dictoffset */
    0,                                          /* tp_init */
    0,                                          /* tp_alloc */
    (newfunc)cell_new,                          /* tp_new */
    0,                                          /* tp_free */
};