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bpo-40429: Refactor super_init() #19776

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Merged
vstinner merged 1 commit into from
Apr 29, 2020
Merged

bpo-40429: Refactor super_init() #19776

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149 changes: 85 additions & 64 deletions Objects/typeobject.c
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Original file line number Diff line number Diff line change
Expand Up @@ -8014,6 +8014,83 @@ super_descr_get(PyObject *self, PyObject *obj, PyObject *type)
}
}

static int
super_init_without_args(PyFrameObject *f, PyCodeObject *co,
PyTypeObject **type_p, PyObject **obj_p)
{
if (co->co_argcount == 0) {
PyErr_SetString(PyExc_RuntimeError,
"super(): no arguments");
return -1;
}

PyObject *obj = f->f_localsplus[0];
Py_ssize_t i, n;
if (obj == NULL && co->co_cell2arg) {
/* The first argument might be a cell. */
n = PyTuple_GET_SIZE(co->co_cellvars);
for (i = 0; i < n; i++) {
if (co->co_cell2arg[i] == 0) {
PyObject *cell = f->f_localsplus[co->co_nlocals + i];
assert(PyCell_Check(cell));
obj = PyCell_GET(cell);
break;
}
}
}
if (obj == NULL) {
PyErr_SetString(PyExc_RuntimeError,
"super(): arg[0] deleted");
return -1;
}

if (co->co_freevars == NULL) {
n = 0;
}
else {
assert(PyTuple_Check(co->co_freevars));
n = PyTuple_GET_SIZE(co->co_freevars);
}

PyTypeObject *type = NULL;
for (i = 0; i < n; i++) {
PyObject *name = PyTuple_GET_ITEM(co->co_freevars, i);
assert(PyUnicode_Check(name));
if (_PyUnicode_EqualToASCIIId(name, &PyId___class__)) {
Py_ssize_t index = co->co_nlocals +
PyTuple_GET_SIZE(co->co_cellvars) + i;
PyObject *cell = f->f_localsplus[index];
if (cell == NULL || !PyCell_Check(cell)) {
PyErr_SetString(PyExc_RuntimeError,
"super(): bad __class__ cell");
return -1;
}
type = (PyTypeObject *) PyCell_GET(cell);
if (type == NULL) {
PyErr_SetString(PyExc_RuntimeError,
"super(): empty __class__ cell");
return -1;
}
if (!PyType_Check(type)) {
PyErr_Format(PyExc_RuntimeError,
"super(): __class__ is not a type (%s)",
Py_TYPE(type)->tp_name);
return -1;
}
break;
}
}
if (type == NULL) {
PyErr_SetString(PyExc_RuntimeError,
"super(): __class__ cell not found");
return -1;
}

*type_p = type;
*obj_p = obj;
return 0;
}

static int
super_init(PyObject *self, PyObject *args, PyObject *kwds)
{
Expand All @@ -8030,75 +8107,19 @@ super_init(PyObject *self, PyObject *args, PyObject *kwds)
if (type == NULL) {
/* Call super(), without args -- fill in from __class__
and first local variable on the stack. */
PyFrameObject *f;
Py_ssize_t i, n;
f = PyThreadState_GetFrame(_PyThreadState_GET());
PyThreadState *tstate = _PyThreadState_GET();
PyFrameObject *f = PyThreadState_GetFrame(tstate);
if (f == NULL) {
PyErr_SetString(PyExc_RuntimeError,
"super(): no current frame");
return -1;
}
PyCodeObject *co = PyFrame_GetCode(f);
Py_DECREF(co); // use a borrowed reference
if (co->co_argcount == 0) {
PyErr_SetString(PyExc_RuntimeError,
"super(): no arguments");
return -1;
}
obj = f->f_localsplus[0];
if (obj == NULL && co->co_cell2arg) {
/* The first argument might be a cell. */
n = PyTuple_GET_SIZE(co->co_cellvars);
for (i = 0; i < n; i++) {
if (co->co_cell2arg[i] == 0) {
PyObject *cell = f->f_localsplus[co->co_nlocals + i];
assert(PyCell_Check(cell));
obj = PyCell_GET(cell);
break;
}
}
}
if (obj == NULL) {
PyErr_SetString(PyExc_RuntimeError,
"super(): arg[0] deleted");
return -1;
}
if (co->co_freevars == NULL)
n = 0;
else {
assert(PyTuple_Check(co->co_freevars));
n = PyTuple_GET_SIZE(co->co_freevars);
}
for (i = 0; i < n; i++) {
PyObject *name = PyTuple_GET_ITEM(co->co_freevars, i);
assert(PyUnicode_Check(name));
if (_PyUnicode_EqualToASCIIId(name, &PyId___class__)) {
Py_ssize_t index = co->co_nlocals +
PyTuple_GET_SIZE(co->co_cellvars) + i;
PyObject *cell = f->f_localsplus[index];
if (cell == NULL || !PyCell_Check(cell)) {
PyErr_SetString(PyExc_RuntimeError,
"super(): bad __class__ cell");
return -1;
}
type = (PyTypeObject *) PyCell_GET(cell);
if (type == NULL) {
PyErr_SetString(PyExc_RuntimeError,
"super(): empty __class__ cell");
return -1;
}
if (!PyType_Check(type)) {
PyErr_Format(PyExc_RuntimeError,
"super(): __class__ is not a type (%s)",
Py_TYPE(type)->tp_name);
return -1;
}
break;
}
}
if (type == NULL) {
PyErr_SetString(PyExc_RuntimeError,
"super(): __class__ cell not found");

PyCodeObject *code = PyFrame_GetCode(f);
int res = super_init_without_args(f, code, &type, &obj);
Py_DECREF(code);

if (res < 0) {
return -1;
}
}
Expand Down