bindings: python: add support for 'default_val' in Line.request()

Until now Line.request() only took 'default_vals' argument which was
passed down directly to LineBulk.request() internally. This meant that
even when requesting a single line in output mode, the default value
had to be passed in a sequence.

Add support for the 'default_val' argument which makes it possible to
specify the default value as an integer. The previous 'default_vals'
argument is still supported, but the two cannot be passed at the same
time.

Documentation for default_vals is removed, as it's now deprecated for
Line.request().

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

diff --git a/bindings/python/gpiodmodule.c b/bindings/python/gpiodmodule.c
index e6ac3a67c368adadaee6a57672556f5a281fe666..ec28553c2a1fc900e66e58d651cba6c46bca6efc 100644 (file)
--- a/bindings/python/gpiodmodule.c
+++ b/bindings/python/gpiodmodule.c
@@ -403,18 +403,55 @@ PyDoc_STRVAR(gpiod_Line_request_doc,
 "    Type of the request.\n"
 "  flags\n"
 "    Other configuration flags.\n"
-"  default_vals\n"
-"    Default value of this line (as a sequence, example: default_vals=[ 1 ]).");
+"  default_val\n"
+"    Default value of this line."
+"\n"
+"Note: default_vals argument (sequence of default values passed down to\n"
+"LineBulk.request()) is still supported for backward compatibility but is\n"
+"now deprecated when requesting single lines.");
 
-/*
- * TODO: add support for 'default_val' argument which will allow users to pass
- * a single default value directly rather than wrapping it in a sequence.
- */
 static PyObject *gpiod_Line_request(gpiod_LineObject *self,
                                    PyObject *args, PyObject *kwds)
 {
+       PyObject *ret, *def_val, *def_vals;
        gpiod_LineBulkObject *bulk_obj;
-       PyObject *ret;
+       int rv;
+
+       def_val = PyDict_GetItemString(kwds, "default_val");
+       def_vals = PyDict_GetItemString(kwds, "default_vals");
+
+       if (def_val && def_vals) {
+               PyErr_SetString(PyExc_TypeError,
+                               "Cannot pass both default_val and default_vals arguments at the same time");
+               return NULL;
+       }
+
+       if (def_val) {
+               /*
+                * If default_val was passed as a single value, we wrap it
+                * in a tuple and add it to the kwds dictionary to be passed
+                * down to LineBulk.request(). We also remove the 'default_val'
+                * entry from kwds.
+                *
+                * I'm not sure if it's allowed to modify the kwds dictionary
+                * but it doesn't seem to cause any problems. If it does then
+                * we can simply copy the dictionary before calling
+                * LineBulk.request().
+                */
+               rv = PyDict_DelItemString(kwds, "default_val");
+               if (rv)
+                       return NULL;
+
+               def_vals = Py_BuildValue("(O)", def_val);
+               if (!def_vals)
+                       return NULL;
+
+               rv = PyDict_SetItemString(kwds, "default_vals", def_vals);
+               if (rv) {
+                       Py_DECREF(def_vals);
+                       return NULL;
+               }
+       }
 
        bulk_obj = gpiod_LineToLineBulk(self);
        if (!bulk_obj)