1 files changed, 357 insertions, 0 deletions
diff --git a/src/mixer/plugins/AlsaMixerPlugin.cxx b/src/mixer/plugins/AlsaMixerPlugin.cxx
new file mode 100644
index 000000000..cd787182a
--- /dev/null
+++ b/src/mixer/plugins/AlsaMixerPlugin.cxx
@@ -0,0 +1,357 @@
+/*
+ * Copyright (C) 2003-2014 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 "mixer/MixerInternal.hxx"
+#include "mixer/Listener.hxx"
+#include "output/OutputAPI.hxx"
+#include "event/MultiSocketMonitor.hxx"
+#include "event/DeferredMonitor.hxx"
+#include "event/Loop.hxx"
+#include "util/ASCII.hxx"
+#include "util/ReusableArray.hxx"
+#include "util/Clamp.hxx"
+#include "util/Error.hxx"
+#include "util/Domain.hxx"
+#include "Log.hxx"
+
+#include <algorithm>
+
+#include <alsa/asoundlib.h>
+
+#define VOLUME_MIXER_ALSA_DEFAULT		"default"
+#define VOLUME_MIXER_ALSA_CONTROL_DEFAULT	"PCM"
+static constexpr unsigned VOLUME_MIXER_ALSA_INDEX_DEFAULT = 0;
+
+class AlsaMixerMonitor final : MultiSocketMonitor, DeferredMonitor {
+	snd_mixer_t *mixer;
+
+	ReusableArray<pollfd> pfd_buffer;
+
+public:
+	AlsaMixerMonitor(EventLoop &_loop, snd_mixer_t *_mixer)
+		:MultiSocketMonitor(_loop), DeferredMonitor(_loop),
+		 mixer(_mixer) {
+		DeferredMonitor::Schedule();
+	}
+
+private:
+	virtual void RunDeferred() override {
+		InvalidateSockets();
+	}
+
+	virtual int PrepareSockets() override;
+	virtual void DispatchSockets() override;
+};
+
+class AlsaMixer final : public Mixer {
+	EventLoop &event_loop;
+
+	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;
+
+public:
+	AlsaMixer(EventLoop &_event_loop, MixerListener &_listener)
+		:Mixer(alsa_mixer_plugin, _listener),
+		 event_loop(_event_loop) {}
+
+	virtual ~AlsaMixer();
+
+	void Configure(const config_param &param);
+	bool Setup(Error &error);
+
+	/* virtual methods from class Mixer */
+	virtual bool Open(Error &error) override;
+	virtual void Close() override;
+	virtual int GetVolume(Error &error) override;
+	virtual bool SetVolume(unsigned volume, Error &error) override;
+};
+
+static constexpr Domain alsa_mixer_domain("alsa_mixer");
+
+int
+AlsaMixerMonitor::PrepareSockets()
+{
+	if (mixer == nullptr) {
+		ClearSocketList();
+		return -1;
+	}
+
+	int count = snd_mixer_poll_descriptors_count(mixer);
+	if (count < 0)
+		count = 0;
+
+	struct pollfd *pfds = pfd_buffer.Get(count);
+
+	count = snd_mixer_poll_descriptors(mixer, pfds, count);
+	if (count < 0)
+		count = 0;
+
+	ReplaceSocketList(pfds, count);
+	return -1;
+}
+
+void
+AlsaMixerMonitor::DispatchSockets()
+{
+	assert(mixer != nullptr);
+
+	int err = snd_mixer_handle_events(mixer);
+	if (err < 0) {
+		FormatError(alsa_mixer_domain,
+			    "snd_mixer_handle_events() failed: %s",
+			    snd_strerror(err));
+
+		if (err == -ENODEV) {
+			/* the sound device was unplugged; disable
+			   this GSource */
+			mixer = nullptr;
+			InvalidateSockets();
+			return;
+		}
+	}
+}
+
+/*
+ * libasound callbacks
+ *
+ */
+
+static int
+alsa_mixer_elem_callback(snd_mixer_elem_t *elem, unsigned mask)
+{
+	AlsaMixer &mixer = *(AlsaMixer *)
+		snd_mixer_elem_get_callback_private(elem);
+
+	if (mask & SND_CTL_EVENT_MASK_VALUE) {
+		int volume = mixer.GetVolume(IgnoreError());
+		mixer.listener.OnMixerVolumeChanged(mixer, volume);
+	}
+
+	return 0;
+}
+
+/*
+ * mixer_plugin methods
+ *
+ */
+
+inline void
+AlsaMixer::Configure(const config_param &param)
+{
+	device = param.GetBlockValue("mixer_device",
+				     VOLUME_MIXER_ALSA_DEFAULT);
+	control = param.GetBlockValue("mixer_control",
+				      VOLUME_MIXER_ALSA_CONTROL_DEFAULT);
+	index = param.GetBlockValue("mixer_index",
+				    VOLUME_MIXER_ALSA_INDEX_DEFAULT);
+}
+
+static Mixer *
+alsa_mixer_init(EventLoop &event_loop, gcc_unused AudioOutput &ao,
+		MixerListener &listener,
+		const config_param &param,
+		gcc_unused Error &error)
+{
+	AlsaMixer *am = new AlsaMixer(event_loop, listener);
+	am->Configure(param);
+
+	return am;
+}
+
+AlsaMixer::~AlsaMixer()
+{
+	/* free libasound's config cache */
+	snd_config_update_free_global();
+}
+
+gcc_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 != nullptr; elem = snd_mixer_elem_next(elem)) {
+		if (snd_mixer_elem_get_type(elem) == SND_MIXER_ELEM_SIMPLE &&
+		    StringEqualsCaseASCII(snd_mixer_selem_get_name(elem),
+					  name) &&
+		    snd_mixer_selem_get_index(elem) == idx)
+			return elem;
+	}
+
+	return nullptr;
+}
+
+inline bool
+AlsaMixer::Setup(Error &error)
+{
+	int err;
+
+	if ((err = snd_mixer_attach(handle, device)) < 0) {
+		error.Format(alsa_mixer_domain, err,
+			     "failed to attach to %s: %s",
+			     device, snd_strerror(err));
+		return false;
+	}
+
+	if ((err = snd_mixer_selem_register(handle, nullptr,
+		    nullptr)) < 0) {
+		error.Format(alsa_mixer_domain, err,
+			     "snd_mixer_selem_register() failed: %s",
+			     snd_strerror(err));
+		return false;
+	}
+
+	if ((err = snd_mixer_load(handle)) < 0) {
+		error.Format(alsa_mixer_domain, err,
+			     "snd_mixer_load() failed: %s\n",
+			     snd_strerror(err));
+		return false;
+	}
+
+	elem = alsa_mixer_lookup_elem(handle, control, index);
+	if (elem == nullptr) {
+		error.Format(alsa_mixer_domain, 0,
+			    "no such mixer control: %s", control);
+		return false;
+	}
+
+	snd_mixer_selem_get_playback_volume_range(elem, &volume_min,
+						  &volume_max);
+
+	snd_mixer_elem_set_callback_private(elem, this);
+	snd_mixer_elem_set_callback(elem, alsa_mixer_elem_callback);
+
+	monitor = new AlsaMixerMonitor(event_loop, handle);
+
+	return true;
+}
+
+inline bool
+AlsaMixer::Open(Error &error)
+{
+	int err;
+
+	volume_set = -1;
+
+	err = snd_mixer_open(&handle, 0);
+	if (err < 0) {
+		error.Format(alsa_mixer_domain, err,
+			     "snd_mixer_open() failed: %s", snd_strerror(err));
+		return false;
+	}
+
+	if (!Setup(error)) {
+		snd_mixer_close(handle);
+		return false;
+	}
+
+	return true;
+}
+
+inline void
+AlsaMixer::Close()
+{
+	assert(handle != nullptr);
+
+	delete monitor;
+
+	snd_mixer_elem_set_callback(elem, nullptr);
+	snd_mixer_close(handle);
+}
+
+inline int
+AlsaMixer::GetVolume(Error &error)
+{
+	int err;
+	int ret;
+	long level;
+
+	assert(handle != nullptr);
+
+	err = snd_mixer_handle_events(handle);
+	if (err < 0) {
+		error.Format(alsa_mixer_domain, err,
+			     "snd_mixer_handle_events() failed: %s",
+			     snd_strerror(err));
+		return false;
+	}
+
+	err = snd_mixer_selem_get_playback_volume(elem,
+						  SND_MIXER_SCHN_FRONT_LEFT,
+						  &level);
+	if (err < 0) {
+		error.Format(alsa_mixer_domain, err,
+			     "failed to read ALSA volume: %s",
+			     snd_strerror(err));
+		return false;
+	}
+
+	ret = ((volume_set / 100.0) * (volume_max - volume_min)
+	       + volume_min) + 0.5;
+	if (volume_set > 0 && ret == level) {
+		ret = volume_set;
+	} else {
+		ret = (int)(100 * (((float)(level - volume_min)) /
+				   (volume_max - volume_min)) + 0.5);
+	}
+
+	return ret;
+}
+
+inline bool
+AlsaMixer::SetVolume(unsigned volume, Error &error)
+{
+	float vol;
+	long level;
+	int err;
+
+	assert(handle != nullptr);
+
+	vol = volume;
+
+	volume_set = vol + 0.5;
+
+	level = (long)(((vol / 100.0) * (volume_max - volume_min) +
+			volume_min) + 0.5);
+	level = Clamp(level, volume_min, volume_max);
+
+	err = snd_mixer_selem_set_playback_volume_all(elem, level);
+	if (err < 0) {
+		error.Format(alsa_mixer_domain, err,
+			     "failed to set ALSA volume: %s",
+			     snd_strerror(err));
+		return false;
+	}
+
+	return true;
+}
+
+const MixerPlugin alsa_mixer_plugin = {
+	alsa_mixer_init,
+	true,
+};