Mixer: use reference instead of pointer for MixerPlugin

src/mixer/MixerAll.cxx

@@ -149,7 +149,7 @@ MultipleOutputs::SetSoftwareVolume(unsigned volume)
 		const auto mixer = ao->mixer;
 
 		if (mixer != nullptr &&
-		    mixer->plugin == &software_mixer_plugin)
+		    &mixer->plugin == &software_mixer_plugin)
 			mixer_set_volume(mixer, volume, IgnoreError());
 	}
 }

src/mixer/MixerControl.cxx

@@ -26,17 +26,13 @@
 
 Mixer *
 mixer_new(EventLoop &event_loop,
-	  const MixerPlugin *plugin, void *ao,
+	  const MixerPlugin &plugin, void *ao,
 	  const config_param &param,
 	  Error &error)
 {
-	Mixer *mixer;
+	Mixer *mixer = plugin.init(event_loop, ao, param, error);
 
-	assert(plugin != nullptr);
+	assert(mixer == nullptr || mixer->IsPlugin(plugin));
-
-	mixer = plugin->init(event_loop, ao, param, error);
-
-	assert(mixer == nullptr || mixer->IsPlugin(*plugin));
 
 	return mixer;
 }
@@ -45,13 +41,12 @@ void
 mixer_free(Mixer *mixer)
 {
 	assert(mixer != nullptr);
-	assert(mixer->plugin != nullptr);
 
 	/* mixers with the "global" flag set might still be open at
 	   this point (see mixer_auto_close()) */
 	mixer_close(mixer);
 
-	mixer->plugin->finish(mixer);
+	mixer->plugin.finish(mixer);
 }
 
 bool
@@ -60,16 +55,15 @@ mixer_open(Mixer *mixer, Error &error)
 	bool success;
 
 	assert(mixer != nullptr);
-	assert(mixer->plugin != nullptr);
 
 	const ScopeLock protect(mixer->mutex);
 
 	if (mixer->open)
 		success = true;
-	else if (mixer->plugin->open == nullptr)
+	else if (mixer->plugin.open == nullptr)
 		success = mixer->open = true;
 	else
-		success = mixer->open = mixer->plugin->open(mixer, error);
+		success = mixer->open = mixer->plugin.open(mixer, error);
 
 	mixer->failed = !success;
 
@@ -80,11 +74,10 @@ static void
 mixer_close_internal(Mixer *mixer)
 {
 	assert(mixer != nullptr);
-	assert(mixer->plugin != nullptr);
 	assert(mixer->open);
 
-	if (mixer->plugin->close != nullptr)
+	if (mixer->plugin.close != nullptr)
-		mixer->plugin->close(mixer);
+		mixer->plugin.close(mixer);
 
 	mixer->open = false;
 }
@@ -93,7 +86,6 @@ void
 mixer_close(Mixer *mixer)
 {
 	assert(mixer != nullptr);
-	assert(mixer->plugin != nullptr);
 
 	const ScopeLock protect(mixer->mutex);
 
@@ -104,7 +96,7 @@ mixer_close(Mixer *mixer)
 void
 mixer_auto_close(Mixer *mixer)
 {
-	if (!mixer->plugin->global)
+	if (!mixer->plugin.global)
 		mixer_close(mixer);
 }
 
@@ -129,14 +121,14 @@ mixer_get_volume(Mixer *mixer, Error &error)
 
 	assert(mixer != nullptr);
 
-	if (mixer->plugin->global && !mixer->failed &&
+	if (mixer->plugin.global && !mixer->failed &&
 	    !mixer_open(mixer, error))
 		return -1;
 
 	const ScopeLock protect(mixer->mutex);
 
 	if (mixer->open) {
-		volume = mixer->plugin->get_volume(mixer, error);
+		volume = mixer->plugin.get_volume(mixer, error);
 		if (volume < 0 && error.IsDefined())
 			mixer_failed(mixer);
 	} else
@@ -151,12 +143,12 @@ mixer_set_volume(Mixer *mixer, unsigned volume, Error &error)
 	assert(mixer != nullptr);
 	assert(volume <= 100);
 
-	if (mixer->plugin->global && !mixer->failed &&
+	if (mixer->plugin.global && !mixer->failed &&
 	    !mixer_open(mixer, error))
 		return false;
 
 	const ScopeLock protect(mixer->mutex);
 
 	return mixer->open &&
-		mixer->plugin->set_volume(mixer, volume, error);
+		mixer->plugin.set_volume(mixer, volume, error);
 }

src/mixer/MixerControl.hxx

@@ -32,7 +32,7 @@ struct MixerPlugin;
 struct config_param;
 
 Mixer *
-mixer_new(EventLoop &event_loop, const MixerPlugin *plugin, void *ao,
+mixer_new(EventLoop &event_loop, const MixerPlugin &plugin, void *ao,
 	  const config_param &param,
 	  Error &error);
 

src/mixer/MixerInternal.hxx

@@ -26,7 +26,7 @@
 
 class Mixer {
 public:
-	const MixerPlugin *plugin;
+	const MixerPlugin &plugin;
 
 	/**
 	 * This mutex protects all of the mixer struct, including its
@@ -47,12 +47,12 @@ public:
 
 public:
 	Mixer(const MixerPlugin &_plugin)
-		:plugin(&_plugin),
+		:plugin(_plugin),
 		 open(false),
 		 failed(false) {}
 
 	bool IsPlugin(const MixerPlugin &other) const {
-		return plugin == &other;
+		return &plugin == &other;
 	}
 };
 

src/output/Init.cxx

@@ -129,10 +129,10 @@ audio_output_load_mixer(EventLoop &event_loop, AudioOutput *ao,
 		if (plugin == nullptr)
 			return nullptr;
 
-		return mixer_new(event_loop, plugin, ao, param, error);
+		return mixer_new(event_loop, *plugin, ao, param, error);
 
 	case MIXER_TYPE_SOFTWARE:
-		mixer = mixer_new(event_loop, &software_mixer_plugin, nullptr,
+		mixer = mixer_new(event_loop, software_mixer_plugin, nullptr,
 				  config_param(),
 				  IgnoreError());
 		assert(mixer != nullptr);

test/read_mixer.cxx

@@ -116,7 +116,7 @@ int main(int argc, gcc_unused char **argv)
 	EventLoop event_loop;
 
 	Error error;
-	Mixer *mixer = mixer_new(event_loop, &alsa_mixer_plugin, nullptr,
+	Mixer *mixer = mixer_new(event_loop, alsa_mixer_plugin, nullptr,
 				 config_param(), error);
 	if (mixer == NULL) {
 		LogError(error, "mixer_new() failed");