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         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
  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 static int
  55 cell_compare(PyCellObject *a, PyCellObject *b)
  56 {
  57         /* Py3K warning for comparisons  */
  58         if (PyErr_WarnPy3k("cell comparisons not supported in 3.x",
  59                            1) < 0) {
  60                 return -2;
  61         }
  62
  63         if (a->ob_ref == NULL) {
  64                 if (b->ob_ref == NULL)
  65                         return 0;
  66                 return -1;
  67         } else if (b->ob_ref == NULL)
  68                 return 1;
  69         return PyObject_Compare(a->ob_ref, b->ob_ref);
  70 }
  71
  72 static PyObject *
  73 cell_repr(PyCellObject *op)
  74 {
  75         if (op->ob_ref == NULL)
  76                 return PyString_FromFormat("<cell at %p: empty>", op);
  77
  78         return PyString_FromFormat("<cell at %p: %.80s object at %p>",
  79                                    op, op->ob_ref->ob_type->tp_name,
  80                                    op->ob_ref);
  81 }
  82
  83 static int
  84 cell_traverse(PyCellObject *op, visitproc visit, void *arg)
  85 {
  86         Py_VISIT(op->ob_ref);
  87         return 0;
  88 }
  89
  90 static int
  91 cell_clear(PyCellObject *op)
  92 {
  93         Py_CLEAR(op->ob_ref);
  94         return 0;
  95 }
  96
  97 static PyObject *
  98 cell_get_contents(PyCellObject *op, void *closure)
  99 {
 100         if (op->ob_ref == NULL)
 101         {
 102                 PyErr_SetString(PyExc_ValueError, "Cell is empty");
 103                 return NULL;
 104         }
 105         Py_INCREF(op->ob_ref);
 106         return op->ob_ref;
 107 }
 108
 109 static PyGetSetDef cell_getsetlist[] = {
 110         {"cell_contents", (getter)cell_get_contents, NULL},
 111         {NULL} /* sentinel */
 112 };
 113
 114 PyTypeObject PyCell_Type = {
 115         PyVarObject_HEAD_INIT(&PyType_Type, 0)
 116         "cell",
 117         sizeof(PyCellObject),
 118         0,
 119         (destructor)cell_dealloc,               /* tp_dealloc */
 120         0,                                      /* tp_print */
 121         0,                                      /* tp_getattr */
 122         0,                                      /* tp_setattr */
 123         (cmpfunc)cell_compare,                  /* tp_compare */
 124         (reprfunc)cell_repr,                    /* tp_repr */
 125         0,                                      /* tp_as_number */
 126         0,                                      /* tp_as_sequence */
 127         0,                                      /* tp_as_mapping */
 128         0,                                      /* tp_hash */
 129         0,                                      /* tp_call */
 130         0,                                      /* tp_str */
 131         PyObject_GenericGetAttr,                /* tp_getattro */
 132         0,                                      /* tp_setattro */
 133         0,                                      /* tp_as_buffer */
 134         Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
 135         0,                                      /* tp_doc */
 136         (traverseproc)cell_traverse,            /* tp_traverse */
 137         (inquiry)cell_clear,                    /* tp_clear */
 138         0,                                      /* tp_richcompare */
 139         0,                                      /* tp_weaklistoffset */
 140         0,                                      /* tp_iter */
 141         0,                                      /* tp_iternext */
 142         0,                                      /* tp_methods */
 143         0,                                      /* tp_members */
 144         cell_getsetlist,                        /* tp_getset */
 145 };