[libgpiod][PATCH 7/9] bindings: python: migrate the gpiod._ext module to multi-phase init

[Vincent Fazio <vfazio@gmail.com>]

Single-phase initialization has been classified as legacy within CPython
documentation [0] with multi-phase being its successor [1].

As such, switch to the new methodology.

[0]: https://docs.python.org/3/c-api/extension-modules.html#legacy-single-phase-initialization
[1]: https://docs.python.org/3/c-api/extension-modules.html#multi-phase-initialization

Signed-off-by: Vincent Fazio <vfazio@gmail.com>
---
 bindings/python/gpiod/ext/module.c | 68 +++++++++++++++---------------
 1 file changed, 33 insertions(+), 35 deletions(-)

diff --git a/bindings/python/gpiod/ext/module.c b/bindings/python/gpiod/ext/module.c
index 25c252a..71fa3c2 100644
--- a/bindings/python/gpiod/ext/module.c
+++ b/bindings/python/gpiod/ext/module.c
@@ -135,12 +135,6 @@ static PyMethodDef module_methods[] = {
 	{ }
 };
 
-static PyModuleDef module_def = {
-	PyModuleDef_HEAD_INIT,
-	.m_name = "gpiod._ext",
-	.m_methods = module_methods,
-};
-
 extern PyTypeObject chip_type;
 extern PyTypeObject line_config_type;
 extern PyTypeObject line_settings_type;
@@ -154,53 +148,57 @@ static PyTypeObject *types[] = {
 	NULL,
 };
 
-PyMODINIT_FUNC PyInit__ext(void)
+static int module_exec(PyObject* module)
 {
 	const struct module_const *modconst;
-	PyObject *module, *all;
+	PyObject *all;
 	PyTypeObject **type;
 	int ret;
 
-	module = PyModule_Create(&module_def);
-	if (!module)
-		return NULL;
-
 	ret = PyModule_AddStringConstant(module, "api_version",
 					 gpiod_api_version());
-	if (ret) {
-		Py_DECREF(module);
-		return NULL;
-	}
+
+	if (ret < 0)
+		return -1;
 
 	all = PyList_New(0);
-	if (!all) {
-		Py_DECREF(module);
-		return NULL;
-	}
+	if (!all)
+		return -1;
 
 	ret = PyModule_AddObjectRef(module, "__all__", all);
 	Py_DECREF(all);
-	if (ret) {
-		Py_DECREF(module);
-		return NULL;
-	}
+	if (ret)
+		return -1;
 
 	for (type = types; *type; type++) {
 		ret = PyModule_AddType(module, *type);
-		if (ret) {
-			Py_DECREF(module);
-			return NULL;
-		}
+		if (ret < 0)
+			return -1;
 	}
 
 	for (modconst = module_constants; modconst->name; modconst++) {
-		ret = PyModule_AddIntConstant(module,
-					      modconst->name, modconst->val);
-		if (ret) {
-			Py_DECREF(module);
-			return NULL;
-		}
+		ret = PyModule_AddIntConstant(module, modconst->name,
+					      modconst->val);
+		if (ret < 0)
+			return -1;
 	}
 
-	return module;
+	return 0;
+}
+
+static struct PyModuleDef_Slot module_slots[] = {
+	{Py_mod_exec, module_exec},
+	{0, NULL},
+};
+
+static PyModuleDef module_def = {
+	PyModuleDef_HEAD_INIT,
+	.m_name = "gpiod._ext",
+	.m_methods = module_methods,
+	.m_slots = module_slots,
+};
+
+PyMODINIT_FUNC PyInit__ext(void)
+{
+	return PyModuleDef_Init(&module_def);
 }
-- 
2.43.0