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/*
* atexit - allow programmer to define multiple exit functions to be executed
* upon normal program termination.
*
* Translated from atexit.py by Collin Winter.
+ Copyright 2007 Python Software Foundation.
*/
#include "Python.h"
#include "pycore_initconfig.h" // _PyStatus_NO_MEMORY
#include "pycore_interp.h" // PyInterpreterState.atexit
#include "pycore_pystate.h" // _PyInterpreterState_GET
/* ===================================================================== */
/* Callback machinery. */
static inline struct atexit_state*
get_atexit_state(void)
{
PyInterpreterState *interp = _PyInterpreterState_GET();
return &interp->atexit;
}
static void
atexit_delete_cb(struct atexit_state *state, int i)
{
atexit_callback *cb = state->callbacks[i];
state->callbacks[i] = NULL;
Py_DECREF(cb->func);
Py_DECREF(cb->args);
Py_XDECREF(cb->kwargs);
PyMem_Free(cb);
}
/* Clear all callbacks without calling them */
static void
atexit_cleanup(struct atexit_state *state)
{
atexit_callback *cb;
for (int i = 0; i < state->ncallbacks; i++) {
cb = state->callbacks[i];
if (cb == NULL)
continue;
atexit_delete_cb(state, i);
}
state->ncallbacks = 0;
}
PyStatus
_PyAtExit_Init(PyInterpreterState *interp)
{
struct atexit_state *state = &interp->atexit;
// _PyAtExit_Init() must only be called once
assert(state->callbacks == NULL);
state->callback_len = 32;
state->ncallbacks = 0;
state->callbacks = PyMem_New(atexit_callback*, state->callback_len);
if (state->callbacks == NULL) {
return _PyStatus_NO_MEMORY();
}
return _PyStatus_OK();
}
void
_PyAtExit_Fini(PyInterpreterState *interp)
{
struct atexit_state *state = &interp->atexit;
atexit_cleanup(state);
PyMem_Free(state->callbacks);
state->callbacks = NULL;
}
static void
atexit_callfuncs(struct atexit_state *state)
{
assert(!PyErr_Occurred());
if (state->ncallbacks == 0) {
return;
}
for (int i = state->ncallbacks - 1; i >= 0; i--) {
atexit_callback *cb = state->callbacks[i];
if (cb == NULL) {
continue;
}
// bpo-46025: Increment the refcount of cb->func as the call itself may unregister it
PyObject* the_func = Py_NewRef(cb->func);
PyObject *res = PyObject_Call(cb->func, cb->args, cb->kwargs);
if (res == NULL) {
_PyErr_WriteUnraisableMsg("in atexit callback", the_func);
}
else {
Py_DECREF(res);
}
Py_DECREF(the_func);
}
atexit_cleanup(state);
assert(!PyErr_Occurred());
}
void
_PyAtExit_Call(PyInterpreterState *interp)
{
struct atexit_state *state = &interp->atexit;
atexit_callfuncs(state);
}
/* ===================================================================== */
/* Module methods. */
PyDoc_STRVAR(atexit_register__doc__,
"register(func, *args, **kwargs) -> func\n\
\n\
Register a function to be executed upon normal program termination\n\
\n\
func - function to be called at exit\n\
args - optional arguments to pass to func\n\
kwargs - optional keyword arguments to pass to func\n\
\n\
func is returned to facilitate usage as a decorator.");
static PyObject *
atexit_register(PyObject *module, PyObject *args, PyObject *kwargs)
{
if (PyTuple_GET_SIZE(args) == 0) {
PyErr_SetString(PyExc_TypeError,
"register() takes at least 1 argument (0 given)");
return NULL;
}
PyObject *func = PyTuple_GET_ITEM(args, 0);
if (!PyCallable_Check(func)) {
PyErr_SetString(PyExc_TypeError,
"the first argument must be callable");
return NULL;
}
struct atexit_state *state = get_atexit_state();
if (state->ncallbacks >= state->callback_len) {
atexit_callback **r;
state->callback_len += 16;
size_t size = sizeof(atexit_callback*) * (size_t)state->callback_len;
r = (atexit_callback**)PyMem_Realloc(state->callbacks, size);
if (r == NULL) {
return PyErr_NoMemory();
}
state->callbacks = r;
}
atexit_callback *callback = PyMem_Malloc(sizeof(atexit_callback));
if (callback == NULL) {
return PyErr_NoMemory();
}
callback->args = PyTuple_GetSlice(args, 1, PyTuple_GET_SIZE(args));
if (callback->args == NULL) {
PyMem_Free(callback);
return NULL;
}
callback->func = Py_NewRef(func);
callback->kwargs = Py_XNewRef(kwargs);
state->callbacks[state->ncallbacks++] = callback;
return Py_NewRef(func);
}
PyDoc_STRVAR(atexit_run_exitfuncs__doc__,
"_run_exitfuncs() -> None\n\
\n\
Run all registered exit functions.\n\
\n\
If a callback raises an exception, it is logged with sys.unraisablehook.");
static PyObject *
atexit_run_exitfuncs(PyObject *module, PyObject *unused)
{
struct atexit_state *state = get_atexit_state();
atexit_callfuncs(state);
Py_RETURN_NONE;
}
PyDoc_STRVAR(atexit_clear__doc__,
"_clear() -> None\n\
\n\
Clear the list of previously registered exit functions.");
static PyObject *
atexit_clear(PyObject *module, PyObject *unused)
{
atexit_cleanup(get_atexit_state());
Py_RETURN_NONE;
}
PyDoc_STRVAR(atexit_ncallbacks__doc__,
"_ncallbacks() -> int\n\
\n\
Return the number of registered exit functions.");
static PyObject *
atexit_ncallbacks(PyObject *module, PyObject *unused)
{
struct atexit_state *state = get_atexit_state();
return PyLong_FromSsize_t(state->ncallbacks);
}
PyDoc_STRVAR(atexit_unregister__doc__,
"unregister(func) -> None\n\
\n\
Unregister an exit function which was previously registered using\n\
atexit.register\n\
\n\
func - function to be unregistered");
static PyObject *
atexit_unregister(PyObject *module, PyObject *func)
{
struct atexit_state *state = get_atexit_state();
for (int i = 0; i < state->ncallbacks; i++)
{
atexit_callback *cb = state->callbacks[i];
if (cb == NULL) {
continue;
}
int eq = PyObject_RichCompareBool(cb->func, func, Py_EQ);
if (eq < 0) {
return NULL;
}
if (eq) {
atexit_delete_cb(state, i);
}
}
Py_RETURN_NONE;
}
static PyMethodDef atexit_methods[] = {
{"register", (PyCFunction)(void(*)(void)) atexit_register, METH_VARARGS|METH_KEYWORDS,
atexit_register__doc__},
{"_clear", (PyCFunction) atexit_clear, METH_NOARGS,
atexit_clear__doc__},
{"unregister", (PyCFunction) atexit_unregister, METH_O,
atexit_unregister__doc__},
{"_run_exitfuncs", (PyCFunction) atexit_run_exitfuncs, METH_NOARGS,
atexit_run_exitfuncs__doc__},
{"_ncallbacks", (PyCFunction) atexit_ncallbacks, METH_NOARGS,
atexit_ncallbacks__doc__},
{NULL, NULL} /* sentinel */
};
/* ===================================================================== */
/* Initialization function. */
PyDoc_STRVAR(atexit__doc__,
"allow programmer to define multiple exit functions to be executed\n\
upon normal program termination.\n\
\n\
Two public functions, register and unregister, are defined.\n\
");
static struct PyModuleDef atexitmodule = {
PyModuleDef_HEAD_INIT,
.m_name = "atexit",
.m_doc = atexit__doc__,
.m_size = 0,
.m_methods = atexit_methods,
};
PyMODINIT_FUNC
PyInit_atexit(void)
{
return PyModuleDef_Init(&atexitmodule);
}
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