/* 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_vectorcall_offset */

    0,                                          /* tp_getattr */

    0,                                          /* tp_setattr */

    0,                                          /* tp_as_async */

    (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 */

};