cpython/Objects/cellobject.c
Lisa Roach 64505a1f6c bpo-30486: Allow setting cell value (#1840)
The cell_contents attribute of the cell object is now writable.
2017-06-08 14:43:26 +03:00

189 lines
4.9 KiB
C

/* Cell object implementation */
#include "Python.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;
}
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);
}
#define TEST_COND(cond) ((cond) ? Py_True : Py_False)
static PyObject *
cell_richcompare(PyObject *a, PyObject *b, int op)
{
int result;
PyObject *v;
/* 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)) {
v = Py_NotImplemented;
Py_INCREF(v);
return v;
}
/* 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);
result = (b == NULL) - (a == NULL);
switch (op) {
case Py_EQ:
v = TEST_COND(result == 0);
break;
case Py_NE:
v = TEST_COND(result != 0);
break;
case Py_LE:
v = TEST_COND(result <= 0);
break;
case Py_GE:
v = TEST_COND(result >= 0);
break;
case Py_LT:
v = TEST_COND(result < 0);
break;
case Py_GT:
v = TEST_COND(result > 0);
break;
default:
PyErr_BadArgument();
return NULL;
}
Py_INCREF(v);
return v;
}
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;
}
int
cell_set_contents(PyCellObject *op, PyObject *obj)
{
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 */
0, /* 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 */
};