/* Cell object implementation */

#include "Python.h"

#include "pycore_cell.h"          // PyCell_GetRef()

#include "pycore_modsupport.h"    // _PyArg_NoKeywords()

#include "pycore_object.h"

#define _PyCell_CAST(op) _Py_CAST(PyCellObject*, (op))

PyObject *

PyCell_New(PyObject *obj)

{

    PyCellObject *op;

    op = (PyCellObject *)PyObject_GC_New(PyCellObject, &PyCell_Type);

    if (op == NULL)

        return NULL;

    op->ob_ref = Py_XNewRef(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;

    }

    return PyCell_GetRef((PyCellObject *)op);

}

int

PyCell_Set(PyObject *op, PyObject *value)

{

    if (!PyCell_Check(op)) {

        PyErr_BadInternalCall();

        return -1;

    }

    PyCell_SetTakeRef((PyCellObject *)op, Py_XNewRef(value));

    return 0;

}

static void

cell_dealloc(PyObject *self)

{

    PyCellObject *op = _PyCell_CAST(self);

    _PyObject_GC_UNTRACK(op);

    Py_XDECREF(op->ob_ref);

    PyObject_GC_Del(op);

}

static PyObject *

cell_compare_impl(PyObject *a, PyObject *b, int op)

{

    if (a != NULL && b != NULL) {

        return PyObject_RichCompare(a, b, op);

    }

    else {

        Py_RETURN_RICHCOMPARE(b == NULL, a == NULL, 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;

    }

    PyObject *a_ref = PyCell_GetRef((PyCellObject *)a);

    PyObject *b_ref = PyCell_GetRef((PyCellObject *)b);

    /* compare cells by contents; empty cells come before anything else */

    PyObject *res = cell_compare_impl(a_ref, b_ref, op);

    Py_XDECREF(a_ref);

    Py_XDECREF(b_ref);

    return res;

}

static PyObject *

cell_repr(PyObject *self)

{

    PyObject *ref = PyCell_GetRef((PyCellObject *)self);

    if (ref == NULL) {

        return PyUnicode_FromFormat("<cell at %p: empty>", self);

    }

    PyObject *res = PyUnicode_FromFormat("<cell at %p: %.80s object at %p>",

                                         self, Py_TYPE(ref)->tp_name, ref);

    Py_DECREF(ref);

    return res;

}

static int

cell_traverse(PyObject *self, visitproc visit, void *arg)

{

    PyCellObject *op = _PyCell_CAST(self);

    Py_VISIT(op->ob_ref);

    return 0;

}

static int

cell_clear(PyObject *self)

{

    PyCellObject *op = _PyCell_CAST(self);

    Py_CLEAR(op->ob_ref);

    return 0;

}

static PyObject *

cell_get_contents(PyObject *self, void *closure)

{

    PyCellObject *op = _PyCell_CAST(self);

    PyObject *res = PyCell_GetRef(op);

    if (res == NULL) {

        PyErr_SetString(PyExc_ValueError, "Cell is empty");

        return NULL;

    }

    return res;

}

static int

cell_set_contents(PyObject *self, PyObject *obj, void *Py_UNUSED(ignored))

{

    PyCellObject *cell = _PyCell_CAST(self);

    Py_XINCREF(obj);

    PyCell_SetTakeRef((PyCellObject *)cell, obj);

    return 0;

}

static PyGetSetDef cell_getsetlist[] = {

    {"cell_contents", cell_get_contents, cell_set_contents, NULL},

    {NULL} /* sentinel */

};

PyTypeObject PyCell_Type = {

    PyVarObject_HEAD_INIT(&PyType_Type, 0)

    "cell",

    sizeof(PyCellObject),

    0,

    cell_dealloc,                               /* tp_dealloc */

    0,                                          /* tp_vectorcall_offset */

    0,                                          /* tp_getattr */

    0,                                          /* tp_setattr */

    0,                                          /* tp_as_async */

    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 */

    cell_traverse,                              /* tp_traverse */

    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 */

    cell_new,                                   /* tp_new */

    0,                                          /* tp_free */

};