MixerInternal: convert to class

Makefile.am

@@ -795,7 +795,7 @@ MIXER_API_SRC = \
 	src/MixerControl.cxx src/MixerControl.hxx \
 	src/MixerType.cxx src/MixerType.hxx \
 	src/MixerAll.cxx src/MixerAll.hxx \
-	src/MixerInternal.cxx src/MixerInternal.hxx
+	src/MixerInternal.hxx
 
 libmixer_plugins_a_SOURCES = \
 	src/mixer/SoftwareMixerPlugin.cxx \
@@ -1325,7 +1325,6 @@ test_run_output_SOURCES = test/run_output.cxx \
 	src/resolver.c \
 	src/OutputInit.cxx src/OutputFinish.cxx src/OutputList.cxx \
 	src/OutputPlugin.cxx \
-	src/MixerInternal.cxx \
 	src/MixerControl.cxx \
 	src/MixerType.cxx \
 	src/FilterPlugin.cxx \
@@ -1345,7 +1344,6 @@ test_read_mixer_LDADD = \
 	$(GLIB_LIBS)
 test_read_mixer_SOURCES = test/read_mixer.cxx \
 	src/MixerControl.cxx \
-	src/MixerInternal.cxx \
 	src/FilterPlugin.cxx \
 	src/filter/VolumeFilterPlugin.cxx \
 	src/fd_util.c

src/MixerAll.cxx

@@ -40,7 +40,6 @@ static int
 output_mixer_get_volume(unsigned i)
 {
 	struct audio_output *output;
-	struct mixer *mixer;
 	int volume;
 	GError *error = NULL;
 
@@ -50,7 +49,7 @@ output_mixer_get_volume(unsigned i)
 	if (!output->enabled)
 		return -1;
 
-	mixer = output->mixer;
+	Mixer *mixer = output->mixer;
 	if (mixer == NULL)
 		return -1;
 
@@ -88,7 +87,6 @@ static bool
 output_mixer_set_volume(unsigned i, unsigned volume)
 {
 	struct audio_output *output;
-	struct mixer *mixer;
 	bool success;
 	GError *error = NULL;
 
@@ -99,7 +97,7 @@ output_mixer_set_volume(unsigned i, unsigned volume)
 	if (!output->enabled)
 		return false;
 
-	mixer = output->mixer;
+	Mixer *mixer = output->mixer;
 	if (mixer == NULL)
 		return false;
 
@@ -132,7 +130,6 @@ static int
 output_mixer_get_software_volume(unsigned i)
 {
 	struct audio_output *output;
-	struct mixer *mixer;
 
 	assert(i < audio_output_count());
 
@@ -140,8 +137,8 @@ output_mixer_get_software_volume(unsigned i)
 	if (!output->enabled)
 		return -1;
 
-	mixer = output->mixer;
-	if (mixer == NULL || mixer->plugin != &software_mixer_plugin)
+	Mixer *mixer = output->mixer;
+	if (mixer == NULL || !mixer->IsPlugin(software_mixer_plugin))
 		return -1;
 
 	return mixer_get_volume(mixer, NULL);

src/MixerControl.cxx

@@ -27,24 +27,24 @@
 #undef G_LOG_DOMAIN
 #define G_LOG_DOMAIN "mixer"
 
-struct mixer *
+Mixer *
 mixer_new(const struct mixer_plugin *plugin, void *ao,
 	  const struct config_param *param,
 	  GError **error_r)
 {
-	struct mixer *mixer;
+	Mixer *mixer;
 
 	assert(plugin != NULL);
 
 	mixer = plugin->init(ao, param, error_r);
 
-	assert(mixer == NULL || mixer->plugin == plugin);
+	assert(mixer == NULL || mixer->IsPlugin(*plugin));
 
 	return mixer;
 }
 
 void
-mixer_free(struct mixer *mixer)
+mixer_free(Mixer *mixer)
 {
 	assert(mixer != NULL);
 	assert(mixer->plugin != NULL);
@@ -60,7 +60,7 @@ mixer_free(struct mixer *mixer)
 }
 
 bool
-mixer_open(struct mixer *mixer, GError **error_r)
+mixer_open(Mixer *mixer, GError **error_r)
 {
 	bool success;
 
@@ -84,7 +84,7 @@ mixer_open(struct mixer *mixer, GError **error_r)
 }
 
 static void
-mixer_close_internal(struct mixer *mixer)
+mixer_close_internal(Mixer *mixer)
 {
 	assert(mixer != NULL);
 	assert(mixer->plugin != NULL);
@@ -97,7 +97,7 @@ mixer_close_internal(struct mixer *mixer)
 }
 
 void
-mixer_close(struct mixer *mixer)
+mixer_close(Mixer *mixer)
 {
 	assert(mixer != NULL);
 	assert(mixer->plugin != NULL);
@@ -111,7 +111,7 @@ mixer_close(struct mixer *mixer)
 }
 
 void
-mixer_auto_close(struct mixer *mixer)
+mixer_auto_close(Mixer *mixer)
 {
 	if (!mixer->plugin->global)
 		mixer_close(mixer);
@@ -122,7 +122,7 @@ mixer_auto_close(struct mixer *mixer)
  * calling this function.
  */
 static void
-mixer_failed(struct mixer *mixer)
+mixer_failed(Mixer *mixer)
 {
 	assert(mixer->open);
 
@@ -132,7 +132,7 @@ mixer_failed(struct mixer *mixer)
 }
 
 int
-mixer_get_volume(struct mixer *mixer, GError **error_r)
+mixer_get_volume(Mixer *mixer, GError **error_r)
 {
 	int volume;
 
@@ -161,7 +161,7 @@ mixer_get_volume(struct mixer *mixer, GError **error_r)
 }
 
 bool
-mixer_set_volume(struct mixer *mixer, unsigned volume, GError **error_r)
+mixer_set_volume(Mixer *mixer, unsigned volume, GError **error_r)
 {
 	bool success;
 

src/MixerControl.hxx

@@ -27,7 +27,7 @@
 
 #include "gerror.h"
 
-struct mixer;
+class Mixer;
 struct mixer_plugin;
 struct config_param;
 
@@ -35,32 +35,32 @@ struct config_param;
 extern "C" {
 #endif
 
-struct mixer *
+Mixer *
 mixer_new(const struct mixer_plugin *plugin, void *ao,
 	  const struct config_param *param,
 	  GError **error_r);
 
 void
-mixer_free(struct mixer *mixer);
+mixer_free(Mixer *mixer);
 
 bool
-mixer_open(struct mixer *mixer, GError **error_r);
+mixer_open(Mixer *mixer, GError **error_r);
 
 void
-mixer_close(struct mixer *mixer);
+mixer_close(Mixer *mixer);
 
 /**
  * Close the mixer unless the plugin's "global" flag is set.  This is
  * called when the #audio_output is closed.
  */
 void
-mixer_auto_close(struct mixer *mixer);
+mixer_auto_close(Mixer *mixer);
 
 int
-mixer_get_volume(struct mixer *mixer, GError **error_r);
+mixer_get_volume(Mixer *mixer, GError **error_r);
 
 bool
-mixer_set_volume(struct mixer *mixer, unsigned volume, GError **error_r);
+mixer_set_volume(Mixer *mixer, unsigned volume, GError **error_r);
 
 #ifdef __cplusplus
 }

src/MixerInternal.cxx

-/*
- * 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"
-
-#undef G_LOG_DOMAIN
-#define G_LOG_DOMAIN "mixer"
-
-void
-mixer_init(struct mixer *mixer, const struct mixer_plugin *plugin)
-{
-	mixer->plugin = plugin;
-	mixer->mutex = g_mutex_new();
-	mixer->open = false;
-	mixer->failed = false;
-}

src/MixerInternal.hxx

@@ -25,7 +25,8 @@
 
 #include <glib.h>
 
-struct mixer {
+class Mixer {
+public:
 	const struct mixer_plugin *plugin;
 
 	/**
@@ -44,9 +45,17 @@ struct mixer {
 	 * automatically?
 	 */
 	bool failed;
-};
 
-void
-mixer_init(struct mixer *mixer, const struct mixer_plugin *plugin);
+public:
+	Mixer(const mixer_plugin &_plugin)
+		:plugin(&_plugin),
+		 mutex(g_mutex_new()),
+		 open(false),
+		 failed(false) {}
+
+	bool IsPlugin(const mixer_plugin &other) const {
+		return plugin == &other;
+	}
+};
 
 #endif

src/MixerPlugin.hxx

@@ -32,7 +32,7 @@
 #include <stdbool.h>
 
 struct config_param;
-struct mixer;
+class Mixer;
 
 struct mixer_plugin {
 	/**
@@ -45,13 +45,13 @@ struct mixer_plugin {
 	 * NULL to ignore errors
 	 * @return a mixer object, or NULL on error
 	 */
-	struct mixer *(*init)(void *ao, const struct config_param *param,
-			      GError **error_r);
+	Mixer *(*init)(void *ao, const struct config_param *param,
+		       GError **error_r);
 
 	/**
 	 * Finish and free mixer data
          */
-	void (*finish)(struct mixer *data);
+	void (*finish)(Mixer *data);
 
 	/**
 	 * Open mixer device
@@ -60,12 +60,12 @@ struct mixer_plugin {
 	 * NULL to ignore errors
 	 * @return true on success, false on error
 	 */
-	bool (*open)(struct mixer *data, GError **error_r);
+	bool (*open)(Mixer *data, GError **error_r);
 
 	/**
 	 * Close mixer device
 	 */
-	void (*close)(struct mixer *data);
+	void (*close)(Mixer *data);
 
 	/**
 	 * Reads the current volume.
@@ -75,7 +75,7 @@ struct mixer_plugin {
 	 * @return the current volume (0..100 including) or -1 if
 	 * unavailable or on error (error_r set, mixer will be closed)
 	 */
-	int (*get_volume)(struct mixer *mixer, GError **error_r);
+	int (*get_volume)(Mixer *mixer, GError **error_r);
 
 	/**
 	 * Sets the volume.
@@ -85,7 +85,7 @@ struct mixer_plugin {
 	 * @param volume the new volume (0..100 including)
 	 * @return true on success, false on error
 	 */
-	bool (*set_volume)(struct mixer *mixer, unsigned volume,
+	bool (*set_volume)(Mixer *mixer, unsigned volume,
 			   GError **error_r);
 
 	/**

src/OutputCommand.cxx

@@ -64,7 +64,6 @@ bool
 audio_output_disable_index(unsigned idx)
 {
 	struct audio_output *ao;
-	struct mixer *mixer;
 
 	if (idx >= audio_output_count())
 		return false;
@@ -76,7 +75,7 @@ audio_output_disable_index(unsigned idx)
 	ao->enabled = false;
 	idle_add(IDLE_OUTPUT);
 
-	mixer = ao->mixer;
+	Mixer *mixer = ao->mixer;
 	if (mixer != NULL) {
 		mixer_close(mixer);
 		idle_add(IDLE_MIXER);

src/OutputInit.cxx

@@ -96,14 +96,14 @@ audio_output_mixer_type(const struct config_param *param)
 						  "hardware"));
 }
 
-static struct mixer *
+static Mixer *
 audio_output_load_mixer(struct audio_output *ao,
 			const struct config_param *param,
 			const struct mixer_plugin *plugin,
 			Filter &filter_chain,
 			GError **error_r)
 {
-	struct mixer *mixer;
+	Mixer *mixer;
 
 	switch (audio_output_mixer_type(param)) {
 	case MIXER_TYPE_NONE:

src/filter/ReplayGainFilterPlugin.cxx

@@ -43,7 +43,7 @@ class ReplayGainFilter final : public Filter {
 	 * If set, then this hardware mixer is used for applying
 	 * replay gain, instead of the software volume library.
 	 */
-	struct mixer *mixer;
+	Mixer *mixer;
 
 	/**
 	 * The base volume level for scale=1.0, between 1 and 100
@@ -80,7 +80,7 @@ public:
 		replay_gain_info_init(&info);
 	}
 
-	void SetMixer(struct mixer *_mixer, unsigned _base) {
+	void SetMixer(Mixer *_mixer, unsigned _base) {
 		assert(_mixer == NULL || (_base > 0 && _base <= 100));
 
 		mixer = _mixer;
@@ -217,7 +217,7 @@ const struct filter_plugin replay_gain_filter_plugin = {
 };
 
 void
-replay_gain_filter_set_mixer(Filter *_filter, struct mixer *mixer,
+replay_gain_filter_set_mixer(Filter *_filter, Mixer *mixer,
 			     unsigned base)
 {
 	ReplayGainFilter *filter = (ReplayGainFilter *)_filter;

src/filter/ReplayGainFilterPlugin.hxx

@@ -23,7 +23,7 @@
 #include "replay_gain_info.h"
 
 class Filter;
-struct mixer;
+class Mixer;
 
 /**
  * Enables or disables the hardware mixer for applying replay gain.
@@ -34,7 +34,7 @@ struct mixer;
  * (including).
  */
 void
-replay_gain_filter_set_mixer(Filter *_filter, struct mixer *mixer,
+replay_gain_filter_set_mixer(Filter *_filter, Mixer *mixer,
 			     unsigned base);
 
 /**

src/mixer/AlsaMixerPlugin.cxx

@@ -45,7 +45,7 @@ private:
 	virtual void DispatchSockets() override;
 };
 
-class AlsaMixer final : public mixer {
+class AlsaMixer final : public Mixer {
 	const char *device;
 	const char *control;
 	unsigned int index;
@@ -59,9 +59,7 @@ class AlsaMixer final : public mixer {
 	AlsaMixerMonitor *monitor;
 
 public:
-	AlsaMixer() {
-		mixer_init(this, &alsa_mixer_plugin);
-	}
+	AlsaMixer():Mixer(alsa_mixer_plugin) {}
 
 	void Configure(const config_param *param);
 	bool Setup(GError **error_r);
@@ -150,7 +148,7 @@ AlsaMixer::Configure(const config_param *param)
 					  VOLUME_MIXER_ALSA_INDEX_DEFAULT);
 }
 
-static struct mixer *
+static Mixer *
 alsa_mixer_init(G_GNUC_UNUSED void *ao, const struct config_param *param,
 		G_GNUC_UNUSED GError **error_r)
 {
@@ -161,7 +159,7 @@ alsa_mixer_init(G_GNUC_UNUSED void *ao, const struct config_param *param,
 }
 
 static void
-alsa_mixer_finish(struct mixer *data)
+alsa_mixer_finish(Mixer *data)
 {
 	AlsaMixer *am = (AlsaMixer *)data;
 
@@ -254,7 +252,7 @@ AlsaMixer::Open(GError **error_r)
 }
 
 static bool
-alsa_mixer_open(struct mixer *data, GError **error_r)
+alsa_mixer_open(Mixer *data, GError **error_r)
 {
 	AlsaMixer *am = (AlsaMixer *)data;
 
@@ -273,7 +271,7 @@ AlsaMixer::Close()
 }
 
 static void
-alsa_mixer_close(struct mixer *data)
+alsa_mixer_close(Mixer *data)
 {
 	AlsaMixer *am = (AlsaMixer *)data;
 	am->Close();
@@ -319,7 +317,7 @@ AlsaMixer::GetVolume(GError **error_r)
 }
 
 static int
-alsa_mixer_get_volume(struct mixer *mixer, GError **error_r)
+alsa_mixer_get_volume(Mixer *mixer, GError **error_r)
 {
 	AlsaMixer *am = (AlsaMixer *)mixer;
 	return am->GetVolume(error_r);
@@ -355,7 +353,7 @@ AlsaMixer::SetVolume(unsigned volume, GError **error_r)
 }
 
 static bool
-alsa_mixer_set_volume(struct mixer *mixer, unsigned volume, GError **error_r)
+alsa_mixer_set_volume(Mixer *mixer, unsigned volume, GError **error_r)
 {
 	AlsaMixer *am = (AlsaMixer *)mixer;
 	return am->SetVolume(volume, error_r);

src/mixer/OssMixerPlugin.cxx

@@ -40,7 +40,7 @@
 
 #define VOLUME_MIXER_OSS_DEFAULT		"/dev/mixer"
 
-class OssMixer : public mixer {
+class OssMixer : public Mixer {
 	const char *device;
 	const char *control;
 
@@ -48,9 +48,7 @@ class OssMixer : public mixer {
 	int volume_control;
 
 public:
-	OssMixer() {
-		mixer_init(this, &oss_mixer_plugin);
-	}
+	OssMixer():Mixer(oss_mixer_plugin) {}
 
 	bool Configure(const config_param *param, GError **error_r);
 	bool Open(GError **error_r);
@@ -104,7 +102,7 @@ OssMixer::Configure(const config_param *param, GError **error_r)
 	return true;
 }
 
-static struct mixer *
+static Mixer *
 oss_mixer_init(G_GNUC_UNUSED void *ao, const struct config_param *param,
 	       GError **error_r)
 {
@@ -119,7 +117,7 @@ oss_mixer_init(G_GNUC_UNUSED void *ao, const struct config_param *param,
 }
 
 static void
-oss_mixer_finish(struct mixer *data)
+oss_mixer_finish(Mixer *data)
 {
 	OssMixer *om = (OssMixer *) data;
 
@@ -135,7 +133,7 @@ OssMixer::Close()
 }
 
 static void
-oss_mixer_close(struct mixer *data)
+oss_mixer_close(Mixer *data)
 {
 	OssMixer *om = (OssMixer *) data;
 	om->Close();
@@ -176,7 +174,7 @@ OssMixer::Open(GError **error_r)
 }
 
 static bool
-oss_mixer_open(struct mixer *data, GError **error_r)
+oss_mixer_open(Mixer *data, GError **error_r)
 {
 	OssMixer *om = (OssMixer *) data;
 
@@ -211,7 +209,7 @@ OssMixer::GetVolume(GError **error_r)
 }
 
 static int
-oss_mixer_get_volume(struct mixer *mixer, GError **error_r)
+oss_mixer_get_volume(Mixer *mixer, GError **error_r)
 {
 	OssMixer *om = (OssMixer *)mixer;
 	return om->GetVolume(error_r);
@@ -240,7 +238,7 @@ OssMixer::SetVolume(unsigned volume, GError **error_r)
 }
 
 static bool
-oss_mixer_set_volume(struct mixer *mixer, unsigned volume, GError **error_r)
+oss_mixer_set_volume(Mixer *mixer, unsigned volume, GError **error_r)
 {
 	OssMixer *om = (OssMixer *)mixer;
 	return om->SetVolume(volume, error_r);

src/mixer/PulseMixerPlugin.cxx

@@ -39,16 +39,16 @@
 #undef G_LOG_DOMAIN
 #define G_LOG_DOMAIN "pulse_mixer"
 
-struct PulseMixer : mixer {
+struct PulseMixer final : public Mixer {
 	PulseOutput *output;
 
 	bool online;
 	struct pa_cvolume volume;
 
 	PulseMixer(PulseOutput *_output)
-		:output(_output), online(false)
+		:Mixer(pulse_mixer_plugin),
+		output(_output), online(false)
 	{
-		mixer_init(this, &pulse_mixer_plugin);
 	}
 };
 
@@ -152,7 +152,7 @@ pulse_mixer_on_change(PulseMixer *pm,
 	pulse_mixer_update(pm, context, stream);
 }
 
-static struct mixer *
+static Mixer *
 pulse_mixer_init(void *ao, G_GNUC_UNUSED const struct config_param *param,
 		 GError **error_r)
 {
@@ -172,7 +172,7 @@ pulse_mixer_init(void *ao, G_GNUC_UNUSED const struct config_param *param,
 }
 
 static void
-pulse_mixer_finish(struct mixer *data)
+pulse_mixer_finish(Mixer *data)
 {
 	PulseMixer *pm = (PulseMixer *) data;
 
@@ -182,7 +182,7 @@ pulse_mixer_finish(struct mixer *data)
 }
 
 static int
-pulse_mixer_get_volume(struct mixer *mixer, G_GNUC_UNUSED GError **error_r)
+pulse_mixer_get_volume(Mixer *mixer, G_GNUC_UNUSED GError **error_r)
 {
 	PulseMixer *pm = (PulseMixer *) mixer;
 	int ret;
@@ -199,7 +199,7 @@ pulse_mixer_get_volume(struct mixer *mixer, G_GNUC_UNUSED GError **error_r)
 }
 
 static bool
-pulse_mixer_set_volume(struct mixer *mixer, unsigned volume, GError **error_r)
+pulse_mixer_set_volume(Mixer *mixer, unsigned volume, GError **error_r)
 {
 	PulseMixer *pm = (PulseMixer *) mixer;
 	struct pa_cvolume cvolume;

src/mixer/RoarMixerPlugin.cxx

@@ -24,26 +24,24 @@
 #include "output_api.h"
 #include "output/RoarOutputPlugin.hxx"
 
-struct RoarMixer {
+struct RoarMixer final : public Mixer {
 	/** the base mixer class */
-	struct mixer base;
 	RoarOutput *self;
 
-	RoarMixer(RoarOutput *_output):self(_output) {
-		mixer_init(&base, &roar_mixer_plugin);
-	}
+	RoarMixer(RoarOutput *_output)
+		:Mixer(roar_mixer_plugin),
+		self(_output) {}
 };
 
-static struct mixer *
+static Mixer *
 roar_mixer_init(void *ao, gcc_unused const struct config_param *param,
 		gcc_unused GError **error_r)
 {
-	RoarMixer *self = new RoarMixer((RoarOutput *)ao);
-	return &self->base;
+	return new RoarMixer((RoarOutput *)ao);
 }
 
 static void
-roar_mixer_finish(struct mixer *data)
+roar_mixer_finish(Mixer *data)
 {
 	RoarMixer *self = (RoarMixer *) data;
 
@@ -51,14 +49,14 @@ roar_mixer_finish(struct mixer *data)
 }
 
 static int
-roar_mixer_get_volume(struct mixer *mixer, gcc_unused GError **error_r)
+roar_mixer_get_volume(Mixer *mixer, gcc_unused GError **error_r)
 {
 	RoarMixer *self = (RoarMixer *)mixer;
 	return roar_output_get_volume(self->self);
 }
 
 static bool
-roar_mixer_set_volume(struct mixer *mixer, unsigned volume,
+roar_mixer_set_volume(Mixer *mixer, unsigned volume,
 		      gcc_unused GError **error_r)
 {
 	RoarMixer *self = (RoarMixer *)mixer;

src/mixer/SoftwareMixerPlugin.cxx

@@ -29,18 +29,17 @@
 #include <assert.h>
 #include <math.h>
 
-struct SoftwareMixer final : public mixer {
+struct SoftwareMixer final : public Mixer {
 	Filter *filter;
 
 	unsigned volume;
 
 	SoftwareMixer()
-		:filter(filter_new(&volume_filter_plugin, nullptr, nullptr)),
-		 volume(100)
+		:Mixer(software_mixer_plugin),
+		filter(filter_new(&volume_filter_plugin, nullptr, nullptr)),
+		volume(100)
 	{
 		assert(filter != nullptr);
-
-		mixer_init(this, &software_mixer_plugin);
 	}
 
 	~SoftwareMixer() {
@@ -48,7 +47,7 @@ struct SoftwareMixer final : public mixer {
 	}
 };
 
-static struct mixer *
+static Mixer *
 software_mixer_init(G_GNUC_UNUSED void *ao,
 		    G_GNUC_UNUSED const struct config_param *param,
 		    G_GNUC_UNUSED GError **error_r)
@@ -57,7 +56,7 @@ software_mixer_init(G_GNUC_UNUSED void *ao,
 }
 
 static void
-software_mixer_finish(struct mixer *data)
+software_mixer_finish(Mixer *data)
 {
 	SoftwareMixer *sm = (SoftwareMixer *)data;
 
@@ -65,7 +64,7 @@ software_mixer_finish(struct mixer *data)
 }
 
 static int
-software_mixer_get_volume(struct mixer *mixer, G_GNUC_UNUSED GError **error_r)
+software_mixer_get_volume(Mixer *mixer, G_GNUC_UNUSED GError **error_r)
 {
 	SoftwareMixer *sm = (SoftwareMixer *)mixer;
 
@@ -73,7 +72,7 @@ software_mixer_get_volume(struct mixer *mixer, G_GNUC_UNUSED GError **error_r)
 }
 
 static bool
-software_mixer_set_volume(struct mixer *mixer, unsigned volume,
+software_mixer_set_volume(Mixer *mixer, unsigned volume,
 			  G_GNUC_UNUSED GError **error_r)
 {
 	SoftwareMixer *sm = (SoftwareMixer *)mixer;
@@ -103,11 +102,10 @@ const struct mixer_plugin software_mixer_plugin = {
 };
 
 Filter *
-software_mixer_get_filter(struct mixer *mixer)
+software_mixer_get_filter(Mixer *mixer)
 {
 	SoftwareMixer *sm = (SoftwareMixer *)mixer;
-
-	assert(sm->plugin == &software_mixer_plugin);
+	assert(sm->IsPlugin(software_mixer_plugin));
 
 	return sm->filter;
 }

src/mixer/SoftwareMixerPlugin.hxx

@@ -20,7 +20,7 @@
 #ifndef MPD_SOFTWARE_MIXER_PLUGIN_HXX
 #define MPD_SOFTWARE_MIXER_PLUGIN_HXX
 
-struct mixer;
+class Mixer;
 class Filter;
 
 /**
@@ -28,6 +28,6 @@ class Filter;
  * of this mixer plugin should install this filter.
  */
 Filter *
-software_mixer_get_filter(struct mixer *mixer);
+software_mixer_get_filter(Mixer *mixer);
 
 #endif

src/mixer/WinmmMixerPlugin.cxx

@@ -31,12 +31,12 @@
 #undef G_LOG_DOMAIN
 #define G_LOG_DOMAIN "winmm_mixer"
 
-struct WinmmMixer final : public mixer {
+struct WinmmMixer final : public Mixer {
 	WinmmOutput *output;
 
 	WinmmMixer(WinmmOutput *_output)
-		:output(_output) {
-		mixer_init(this, &winmm_mixer_plugin);
+		:Mixer(winmm_mixer_plugin),
+		output(_output) {
 	}
 };
 
@@ -59,7 +59,7 @@ winmm_volume_encode(int volume)
 	return MAKELONG(value, value);
 }
 
-static struct mixer *
+static Mixer *
 winmm_mixer_init(void *ao, G_GNUC_UNUSED const struct config_param *param,
 		 G_GNUC_UNUSED GError **error_r)
 {
@@ -69,7 +69,7 @@ winmm_mixer_init(void *ao, G_GNUC_UNUSED const struct config_param *param,
 }
 
 static void
-winmm_mixer_finish(struct mixer *data)
+winmm_mixer_finish(Mixer *data)
 {
 	WinmmMixer *wm = (WinmmMixer *)data;
 
@@ -77,7 +77,7 @@ winmm_mixer_finish(struct mixer *data)
 }
 
 static int
-winmm_mixer_get_volume(struct mixer *mixer, GError **error_r)
+winmm_mixer_get_volume(Mixer *mixer, GError **error_r)
 {
 	WinmmMixer *wm = (WinmmMixer *) mixer;
 	DWORD volume;
@@ -94,7 +94,7 @@ winmm_mixer_get_volume(struct mixer *mixer, GError **error_r)
 }
 
 static bool
-winmm_mixer_set_volume(struct mixer *mixer, unsigned volume, GError **error_r)
+winmm_mixer_set_volume(Mixer *mixer, unsigned volume, GError **error_r)
 {
 	WinmmMixer *wm = (WinmmMixer *) mixer;
 	DWORD value = winmm_volume_encode(volume);

src/output_internal.h

@@ -76,7 +76,11 @@ struct audio_output {
 	 * May be NULL if none is available, or if software volume is
 	 * configured.
 	 */
+#ifdef __cplusplus
+	class Mixer *mixer;
+#else
 	struct mixer *mixer;
+#endif
 
 	/**
 	 * Will this output receive tags from the decoder?  The

test/read_mixer.cxx

@@ -111,7 +111,6 @@ pcm_volume(G_GNUC_UNUSED void *buffer, G_GNUC_UNUSED size_t length,
 int main(int argc, G_GNUC_UNUSED char **argv)
 {
 	GError *error = NULL;
-	struct mixer *mixer;
 	bool success;
 	int volume;
 
@@ -124,7 +123,7 @@ int main(int argc, G_GNUC_UNUSED char **argv)
 
 	main_loop = new EventLoop(EventLoop::Default());
 
-	mixer = mixer_new(&alsa_mixer_plugin, NULL, NULL, &error);
+	Mixer *mixer = mixer_new(&alsa_mixer_plugin, NULL, NULL, &error);
 	if (mixer == NULL) {
 		g_printerr("mixer_new() failed: %s\n", error->message);
 		g_error_free(error);

test/run_filter.cxx

@@ -36,7 +36,7 @@
 #include <unistd.h>
 
 bool
-mixer_set_volume(G_GNUC_UNUSED struct mixer *mixer,
+mixer_set_volume(gcc_unused Mixer *mixer,
 		 G_GNUC_UNUSED unsigned volume, G_GNUC_UNUSED GError **error_r)
 {
 	return true;