1 files changed, 336 insertions, 0 deletions
diff --git a/src/mixer/AlsaMixerPlugin.cxx b/src/mixer/AlsaMixerPlugin.cxx
new file mode 100644
index 00000000..d75016c0
--- /dev/null
+++ b/src/mixer/AlsaMixerPlugin.cxx
@@ -0,0 +1,336 @@
+/*
+ * Copyright (C) 2003-2013 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "MixerInternal.hxx"
+#include "output_api.h"
+#include "GlobalEvents.hxx"
+#include "Main.hxx"
+#include "event/MultiSocketMonitor.hxx"
+
+#include <algorithm>
+
+#include <glib.h>
+#include <alsa/asoundlib.h>
+
+#define VOLUME_MIXER_ALSA_DEFAULT		"default"
+#define VOLUME_MIXER_ALSA_CONTROL_DEFAULT	"PCM"
+#define VOLUME_MIXER_ALSA_INDEX_DEFAULT		0
+
+class AlsaMixerMonitor final : private MultiSocketMonitor {
+	snd_mixer_t *const mixer;
+
+public:
+	AlsaMixerMonitor(EventLoop &_loop, snd_mixer_t *_mixer)
+		:MultiSocketMonitor(_loop), mixer(_mixer) {}
+
+private:
+	virtual void PrepareSockets(gcc_unused gint *timeout_r) override;
+	virtual void DispatchSockets() override;
+};
+
+struct alsa_mixer {
+	/** the base mixer class */
+	struct mixer base;
+
+	const char *device;
+	const char *control;
+	unsigned int index;
+
+	snd_mixer_t *handle;
+	snd_mixer_elem_t *elem;
+	long volume_min;
+	long volume_max;
+	int volume_set;
+
+	AlsaMixerMonitor *monitor;
+};
+
+/**
+ * The quark used for GError.domain.
+ */
+static inline GQuark
+alsa_mixer_quark(void)
+{
+	return g_quark_from_static_string("alsa_mixer");
+}
+
+void
+AlsaMixerMonitor::PrepareSockets(gcc_unused gint *timeout_r)
+{
+	int count = snd_mixer_poll_descriptors_count(mixer);
+	if (count < 0)
+		count = 0;
+
+	struct pollfd *pfds = g_new(struct pollfd, count);
+	count = snd_mixer_poll_descriptors(mixer, pfds, count);
+	if (count < 0)
+		count = 0;
+
+	struct pollfd *end = pfds + count;
+
+	UpdateSocketList([pfds, end](int fd) -> unsigned {
+			auto i = std::find_if(pfds, end, [fd](const struct pollfd &pfd){
+					return pfd.fd == fd;
+				});
+			if (i == end)
+				return 0;
+
+			auto events = i->events;
+			i->events = 0;
+			return events;
+		});
+
+	for (auto i = pfds; i != end; ++i)
+		if (i->events != 0)
+			AddSocket(i->fd, i->events);
+
+	g_free(pfds);
+}
+
+void
+AlsaMixerMonitor::DispatchSockets()
+{
+	snd_mixer_handle_events(mixer);
+}
+
+/*
+ * libasound callbacks
+ *
+ */
+
+static int
+alsa_mixer_elem_callback(G_GNUC_UNUSED snd_mixer_elem_t *elem, unsigned mask)
+{
+	if (mask & SND_CTL_EVENT_MASK_VALUE)
+		GlobalEvents::Emit(GlobalEvents::MIXER);
+
+	return 0;
+}
+
+/*
+ * mixer_plugin methods
+ *
+ */
+
+static struct mixer *
+alsa_mixer_init(G_GNUC_UNUSED void *ao, const struct config_param *param,
+		G_GNUC_UNUSED GError **error_r)
+{
+	struct alsa_mixer *am = g_new(struct alsa_mixer, 1);
+
+	mixer_init(&am->base, &alsa_mixer_plugin);
+
+	am->device = config_get_block_string(param, "mixer_device",
+					     VOLUME_MIXER_ALSA_DEFAULT);
+	am->control = config_get_block_string(param, "mixer_control",
+					      VOLUME_MIXER_ALSA_CONTROL_DEFAULT);
+	am->index = config_get_block_unsigned(param, "mixer_index",
+					      VOLUME_MIXER_ALSA_INDEX_DEFAULT);
+
+	return &am->base;
+}
+
+static void
+alsa_mixer_finish(struct mixer *data)
+{
+	struct alsa_mixer *am = (struct alsa_mixer *)data;
+
+	g_free(am);
+
+	/* free libasound's config cache */
+	snd_config_update_free_global();
+}
+
+G_GNUC_PURE
+static snd_mixer_elem_t *
+alsa_mixer_lookup_elem(snd_mixer_t *handle, const char *name, unsigned idx)
+{
+	for (snd_mixer_elem_t *elem = snd_mixer_first_elem(handle);
+	     elem != NULL; elem = snd_mixer_elem_next(elem)) {
+		if (snd_mixer_elem_get_type(elem) == SND_MIXER_ELEM_SIMPLE &&
+		    g_ascii_strcasecmp(snd_mixer_selem_get_name(elem),
+				       name) == 0 &&
+		    snd_mixer_selem_get_index(elem) == idx)
+			return elem;
+	}
+
+	return NULL;
+}
+
+static bool
+alsa_mixer_setup(struct alsa_mixer *am, GError **error_r)
+{
+	int err;
+
+	if ((err = snd_mixer_attach(am->handle, am->device)) < 0) {
+		g_set_error(error_r, alsa_mixer_quark(), err,
+			    "failed to attach to %s: %s",
+			    am->device, snd_strerror(err));
+		return false;
+	}
+
+	if ((err = snd_mixer_selem_register(am->handle, NULL,
+		    NULL)) < 0) {
+		g_set_error(error_r, alsa_mixer_quark(), err,
+			    "snd_mixer_selem_register() failed: %s",
+			    snd_strerror(err));
+		return false;
+	}
+
+	if ((err = snd_mixer_load(am->handle)) < 0) {
+		g_set_error(error_r, alsa_mixer_quark(), err,
+			    "snd_mixer_load() failed: %s\n",
+			    snd_strerror(err));
+		return false;
+	}
+
+	am->elem = alsa_mixer_lookup_elem(am->handle, am->control, am->index);
+	if (am->elem == NULL) {
+		g_set_error(error_r, alsa_mixer_quark(), 0,
+			    "no such mixer control: %s", am->control);
+		return false;
+	}
+
+	snd_mixer_selem_get_playback_volume_range(am->elem,
+						  &am->volume_min,
+						  &am->volume_max);
+
+	snd_mixer_elem_set_callback(am->elem, alsa_mixer_elem_callback);
+
+	am->monitor = new AlsaMixerMonitor(*main_loop, am->handle);
+
+	return true;
+}
+
+static bool
+alsa_mixer_open(struct mixer *data, GError **error_r)
+{
+	struct alsa_mixer *am = (struct alsa_mixer *)data;
+	int err;
+
+	am->volume_set = -1;
+
+	err = snd_mixer_open(&am->handle, 0);
+	if (err < 0) {
+		g_set_error(error_r, alsa_mixer_quark(), err,
+			    "snd_mixer_open() failed: %s", snd_strerror(err));
+		return false;
+	}
+
+	if (!alsa_mixer_setup(am, error_r)) {
+		snd_mixer_close(am->handle);
+		return false;
+	}
+
+	return true;
+}
+
+static void
+alsa_mixer_close(struct mixer *data)
+{
+	struct alsa_mixer *am = (struct alsa_mixer *)data;
+
+	assert(am->handle != NULL);
+
+	delete am->monitor;
+
+	snd_mixer_elem_set_callback(am->elem, NULL);
+	snd_mixer_close(am->handle);
+}
+
+static int
+alsa_mixer_get_volume(struct mixer *mixer, GError **error_r)
+{
+	struct alsa_mixer *am = (struct alsa_mixer *)mixer;
+	int err;
+	int ret;
+	long level;
+
+	assert(am->handle != NULL);
+
+	err = snd_mixer_handle_events(am->handle);
+	if (err < 0) {
+		g_set_error(error_r, alsa_mixer_quark(), err,
+			    "snd_mixer_handle_events() failed: %s",
+			    snd_strerror(err));
+		return false;
+	}
+
+	err = snd_mixer_selem_get_playback_volume(am->elem,
+						  SND_MIXER_SCHN_FRONT_LEFT,
+						  &level);
+	if (err < 0) {
+		g_set_error(error_r, alsa_mixer_quark(), err,
+			    "failed to read ALSA volume: %s",
+			    snd_strerror(err));
+		return false;
+	}
+
+	ret = ((am->volume_set / 100.0) * (am->volume_max - am->volume_min)
+	       + am->volume_min) + 0.5;
+	if (am->volume_set > 0 && ret == level) {
+		ret = am->volume_set;
+	} else {
+		ret = (int)(100 * (((float)(level - am->volume_min)) /
+				   (am->volume_max - am->volume_min)) + 0.5);
+	}
+
+	return ret;
+}
+
+static bool
+alsa_mixer_set_volume(struct mixer *mixer, unsigned volume, GError **error_r)
+{
+	struct alsa_mixer *am = (struct alsa_mixer *)mixer;
+	float vol;
+	long level;
+	int err;
+
+	assert(am->handle != NULL);
+
+	vol = volume;
+
+	am->volume_set = vol + 0.5;
+
+	level = (long)(((vol / 100.0) * (am->volume_max - am->volume_min) +
+			am->volume_min) + 0.5);
+	level = level > am->volume_max ? am->volume_max : level;
+	level = level < am->volume_min ? am->volume_min : level;
+
+	err = snd_mixer_selem_set_playback_volume_all(am->elem, level);
+	if (err < 0) {
+		g_set_error(error_r, alsa_mixer_quark(), err,
+			    "failed to set ALSA volume: %s",
+			    snd_strerror(err));
+		return false;
+	}
+
+	return true;
+}
+
+const struct mixer_plugin alsa_mixer_plugin = {
+	alsa_mixer_init,
+	alsa_mixer_finish,
+	alsa_mixer_open,
+	alsa_mixer_close,
+	alsa_mixer_get_volume,
+	alsa_mixer_set_volume,
+	true,
+};