From 891a30eb080e73ffcb50e753afac5281a39daa48 Mon Sep 17 00:00:00 2001
From: Paul Donohue <git@PaulSD.com>
Date: Fri, 21 Oct 2016 12:04:57 -0400
Subject: [PATCH] Add Mixer.handleevents() to acknowledge events identified by
 select.poll

---
 alsaaudio.c          | 34 ++++++++++++++++++++++++++++++++++
 doc/libalsaaudio.rst |  6 ++++++
 2 files changed, 40 insertions(+)

diff --git a/alsaaudio.c b/alsaaudio.c
index 6dd8199..a04e4bd 100644
--- a/alsaaudio.c
+++ b/alsaaudio.c
@@ -2116,6 +2116,38 @@ PyDoc_STRVAR(polldescriptors_doc,
 Return a list of file descriptors and event masks\n\
 suitable for use with poll to monitor changes on this mixer.");
 
+static PyObject *
+alsamixer_handleevents(alsamixer_t *self, PyObject *args)
+{
+    int handled;
+
+    if (!PyArg_ParseTuple(args,":handleevents"))
+        return NULL;
+
+    if (!self->handle)
+    {
+        PyErr_SetString(ALSAAudioError, "Mixer is closed");
+        return NULL;
+    }
+
+    handled = snd_mixer_handle_events(self->handle);
+    if (handled < 0)
+    {
+        PyErr_Format(ALSAAudioError, "%s [%s]", snd_strerror(handled),
+                     self->cardname);
+        return NULL;
+    }
+
+    return PyLong_FromLong(handled);
+}
+
+PyDoc_STRVAR(handleevents_doc,
+"handleevents() -> int\n\
+\n\
+Acknowledge events on the polldescriptors() file descriptors\n\
+to prevent subsequent polls from returning the same events again.\n\
+Returns the number of events that were acknowledged.");
+
 static PyMethodDef alsamixer_methods[] = {
     {"cardname", (PyCFunction)alsamixer_cardname, METH_VARARGS,
      mixer_cardname_doc},
@@ -2138,6 +2170,8 @@ static PyMethodDef alsamixer_methods[] = {
     {"setrec", (PyCFunction)alsamixer_setrec, METH_VARARGS, setrec_doc},
     {"polldescriptors", (PyCFunction)alsamixer_polldescriptors, METH_VARARGS,
      polldescriptors_doc},
+    {"handleevents", (PyCFunction)alsamixer_handleevents, METH_VARARGS,
+     handleevents_doc},
 
     {NULL, NULL}
 };
diff --git a/doc/libalsaaudio.rst b/doc/libalsaaudio.rst
index 67592bf..8fc3b87 100644
--- a/doc/libalsaaudio.rst
+++ b/doc/libalsaaudio.rst
@@ -476,6 +476,12 @@ Mixer objects have the following methods:
    Returns a tuple of (file descriptor, eventmask) that can be used to
    wait for changes on the mixer with *select.poll*.
 
+.. method:: Mixer.handleevents()
+
+   Acknowledge events on the *polldescriptors* file descriptors
+   to prevent subsequent polls from returning the same events again.
+   Returns the number of events that were acknowledged.
+
 **A rant on the ALSA Mixer API**
 
 The ALSA mixer API is extremely complicated - and hardly documented at all.