bindings: python: add support for controlled execution

Provide __enter__ and __exit__ callbacks for Chip so that it can be
used with the 'with' statement.

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>

2 files changed, 37 insertions, 0 deletions

diff --git a/bindings/python/examples/gpiod_tests.py b/bindings/python/examples/gpiod_tests.py
index 3fd3cb2b..91ea9612 100755
--- a/bindings/python/examples/gpiod_tests.py
+++ b/bindings/python/examples/gpiod_tests.py
@@ -102,6 +102,14 @@ def chip_use_after_close():
 
 add_test('Use a GPIO chip after closing it', chip_use_after_close)
 
+def chip_with_statement():
+    with gpiod.Chip('gpiochip0') as chip:
+        print('Chip name in controlled execution: {}'.format(chip.name()))
+        line = chip.get_line(3)
+        print('Got line from chip in controlled execution: {}'.format(line.name()))
+
+add_test('Use a GPIO chip in controlled execution', chip_with_statement)
+
 def chip_info():
     chip = gpiod.Chip('gpiochip0')
     print('name: {}'.format(chip.name()))
diff --git a/bindings/python/gpiodmodule.c b/bindings/python/gpiodmodule.c
index 1bf8de7b..86760450 100644
--- a/bindings/python/gpiodmodule.c
+++ b/bindings/python/gpiodmodule.c
@@ -1315,6 +1315,23 @@ static PyObject *gpiod_Chip_close(gpiod_ChipObject *self)
 	Py_RETURN_NONE;
 }
 
+PyDoc_STRVAR(gpiod_Chip_enter_doc,
+"Controlled execution enter callback.");
+
+static PyObject *gpiod_Chip_enter(gpiod_ChipObject *chip)
+{
+	Py_INCREF(chip);
+	return (PyObject *)chip;
+}
+
+PyDoc_STRVAR(gpiod_Chip_exit_doc,
+"Controlled execution exit callback.");
+
+static PyObject *gpiod_Chip_exit(gpiod_ChipObject *chip)
+{
+	return PyObject_CallMethod((PyObject *)chip, "close", "");
+}
+
 static bool gpiod_ChipIsClosed(gpiod_ChipObject *chip)
 {
 	if (!chip->chip) {
@@ -1665,6 +1682,18 @@ static PyMethodDef gpiod_Chip_methods[] = {
 		.ml_doc = gpiod_Chip_close_doc,
 	},
 	{
+		.ml_name = "__enter__",
+		.ml_meth = (PyCFunction)gpiod_Chip_enter,
+		.ml_flags = METH_NOARGS,
+		.ml_doc = gpiod_Chip_enter_doc,
+	},
+	{
+		.ml_name = "__exit__",
+		.ml_meth = (PyCFunction)gpiod_Chip_exit,
+		.ml_flags = METH_VARARGS,
+		.ml_doc = gpiod_Chip_exit_doc,
+	},
+	{
 		.ml_name = "name",
 		.ml_meth = (PyCFunction)gpiod_Chip_name,
 		.ml_flags = METH_NOARGS,