Objects/cellobject.c

   1 /* Cell object implementation */
   2
   3 #include "Python.h"
   4
   5 PyObject *
   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 *
  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
  32 PyCell_Set(PyObject *op, PyObject *obj)
  33 {
  34         if (!PyCell_Check(op)) {
  35                 PyErr_BadInternalCall();
  36                 return -1;
  37         }
  38         Py_XDECREF(((PyCellObject*)op)->ob_ref);
  39         Py_XINCREF(obj);
  40         PyCell_SET(op, obj);
  41         return 0;
  42 }
  43
  44 static void
  45 cell_dealloc(PyCellObject *op)
  46 {
  47         _PyObject_GC_UNTRACK(op);
  48         Py_XDECREF(op->ob_ref);
  49         PyObject_GC_Del(op);
  50 }
  51
  52 static int
  53 cell_compare(PyCellObject *a, PyCellObject *b)
  54 {
  55         if (a->ob_ref == NULL) {
  56                 if (b->ob_ref == NULL)
  57                         return 0;
  58                 return -1;
  59         } else if (b->ob_ref == NULL)
  60                 return 1;
  61         return PyObject_Compare(a->ob_ref, b->ob_ref);
  62 }
  63
  64 static PyObject *
  65 cell_repr(PyCellObject *op)
  66 {
  67         if (op->ob_ref == NULL)
  68                 return PyString_FromFormat("<cell at %p: empty>", op);
  69
  70         return PyString_FromFormat("<cell at %p: %.80s object at %p>",
  71                                    op, op->ob_ref->ob_type->tp_name,
  72                                    op->ob_ref);
  73 }
  74
  75 static int
  76 cell_traverse(PyCellObject *op, visitproc visit, void *arg)
  77 {
  78         Py_VISIT(op->ob_ref);
  79         return 0;
  80 }
  81
  82 static int
  83 cell_clear(PyCellObject *op)
  84 {
  85         Py_CLEAR(op->ob_ref);
  86         return 0;
  87 }
  88
  89 static PyObject *
  90 cell_get_contents(PyCellObject *op, void *closure)
  91 {
  92         if (op->ob_ref == NULL)
  93         {
  94                 PyErr_SetString(PyExc_ValueError, "Cell is empty");
  95                 return NULL;
  96         }
  97         Py_INCREF(op->ob_ref);
  98         return op->ob_ref;
  99 }
 100
 101 static PyGetSetDef cell_getsetlist[] = {
 102         {"cell_contents", (getter)cell_get_contents, NULL},
 103         {NULL} /* sentinel */
 104 };
 105
 106 PyTypeObject PyCell_Type = {
 107         PyObject_HEAD_INIT(&PyType_Type)
 108         0,
 109         "cell",
 110         sizeof(PyCellObject),
 111         0,
 112         (destructor)cell_dealloc,               /* tp_dealloc */
 113         0,                                      /* tp_print */
 114         0,                                      /* tp_getattr */
 115         0,                                      /* tp_setattr */
 116         (cmpfunc)cell_compare,                  /* tp_compare */
 117         (reprfunc)cell_repr,                    /* tp_repr */
 118         0,                                      /* tp_as_number */
 119         0,                                      /* tp_as_sequence */
 120         0,                                      /* tp_as_mapping */
 121         0,                                      /* tp_hash */
 122         0,                                      /* tp_call */
 123         0,                                      /* tp_str */
 124         PyObject_GenericGetAttr,                /* tp_getattro */
 125         0,                                      /* tp_setattro */
 126         0,                                      /* tp_as_buffer */
 127         Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
 128         0,                                      /* tp_doc */
 129         (traverseproc)cell_traverse,            /* tp_traverse */
 130         (inquiry)cell_clear,                    /* tp_clear */
 131         0,                                      /* tp_richcompare */
 132         0,                                      /* tp_weaklistoffset */
 133         0,                                      /* tp_iter */
 134         0,                                      /* tp_iternext */
 135         0,                                      /* tp_methods */
 136         0,                                      /* tp_members */
 137         cell_getsetlist,                        /* tp_getset */
 138 };