mixer: migrate to C++ exceptions

src/mixer/plugins/AlsaMixerPlugin.cxx

@@ -26,8 +26,8 @@
 #include "util/ASCII.hxx"
 #include "util/ReusableArray.hxx"
 #include "util/Clamp.hxx"
-#include "util/Error.hxx"
 #include "util/Domain.hxx"
+#include "util/RuntimeError.hxx"
 #include "Log.hxx"
 
 #include <algorithm>
@@ -82,13 +82,13 @@ public:
 	virtual ~AlsaMixer();
 
 	void Configure(const ConfigBlock &block);
-	bool Setup(Error &error);
+	void Setup();
 
 	/* 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;
+	void Open() override;
+	void Close() override;
+	int GetVolume() override;
+	void SetVolume(unsigned volume) override;
 };
 
 static constexpr Domain alsa_mixer_domain("alsa_mixer");
@@ -148,8 +148,11 @@ alsa_mixer_elem_callback(snd_mixer_elem_t *elem, unsigned mask)
 		snd_mixer_elem_get_callback_private(elem);
 
 	if (mask & SND_CTL_EVENT_MASK_VALUE) {
-		int volume = mixer.GetVolume(IgnoreError());
-		mixer.listener.OnMixerVolumeChanged(mixer, volume);
+		try {
+			int volume = mixer.GetVolume();
+			mixer.listener.OnMixerVolumeChanged(mixer, volume);
+		} catch (const std::runtime_error &) {
+		}
 	}
 
 	return 0;
@@ -174,8 +177,7 @@ AlsaMixer::Configure(const ConfigBlock &block)
 static Mixer *
 alsa_mixer_init(EventLoop &event_loop, gcc_unused AudioOutput &ao,
 		MixerListener &listener,
-		const ConfigBlock &block,
-		gcc_unused Error &error)
+		const ConfigBlock &block)
 {
 	AlsaMixer *am = new AlsaMixer(event_loop, listener);
 	am->Configure(block);
@@ -205,39 +207,26 @@ alsa_mixer_lookup_elem(snd_mixer_t *handle, const char *name, unsigned idx)
 	return nullptr;
 }
 
-inline bool
-AlsaMixer::Setup(Error &error)
+inline void
+AlsaMixer::Setup()
 {
 	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_attach(handle, device)) < 0)
+		throw FormatRuntimeError("failed to attach to %s: %s",
+					 device, snd_strerror(err));
 
-	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_selem_register(handle, nullptr, nullptr)) < 0)
+		throw FormatRuntimeError("snd_mixer_selem_register() failed: %s",
+					 snd_strerror(err));
 
-	if ((err = snd_mixer_load(handle)) < 0) {
-		error.Format(alsa_mixer_domain, err,
-			     "snd_mixer_load() failed: %s\n",
-			     snd_strerror(err));
-		return false;
-	}
+	if ((err = snd_mixer_load(handle)) < 0)
+		throw FormatRuntimeError("snd_mixer_load() failed: %s\n",
+					 snd_strerror(err));
 
 	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;
-	}
+	if (elem == nullptr)
+		throw FormatRuntimeError("no such mixer control: %s", control);
 
 	snd_mixer_selem_get_playback_volume_range(elem, &volume_min,
 						  &volume_max);
@@ -246,33 +235,29 @@ AlsaMixer::Setup(Error &error)
 	snd_mixer_elem_set_callback(elem, alsa_mixer_elem_callback);
 
 	monitor = new AlsaMixerMonitor(event_loop, handle);
-
-	return true;
 }
 
-inline bool
-AlsaMixer::Open(Error &error)
+void
+AlsaMixer::Open()
 {
 	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 (err < 0)
+		throw FormatRuntimeError("snd_mixer_open() failed: %s",
+					 snd_strerror(err));
 
-	if (!Setup(error)) {
+	try {
+		Setup();
+	} catch (...) {
 		snd_mixer_close(handle);
-		return false;
+		throw;
 	}
-
-	return true;
 }
 
-inline void
+void
 AlsaMixer::Close()
 {
 	assert(handle != nullptr);
@@ -283,8 +268,8 @@ AlsaMixer::Close()
 	snd_mixer_close(handle);
 }
 
-inline int
-AlsaMixer::GetVolume(Error &error)
+int
+AlsaMixer::GetVolume()
 {
 	int err;
 	int ret;
@@ -293,22 +278,16 @@ AlsaMixer::GetVolume(Error &error)
 	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;
-	}
+	if (err < 0)
+		throw FormatRuntimeError("snd_mixer_handle_events() failed: %s",
+					 snd_strerror(err));
 
 	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;
-	}
+	if (err < 0)
+		throw FormatRuntimeError("failed to read ALSA volume: %s",
+					 snd_strerror(err));
 
 	ret = ((volume_set / 100.0) * (volume_max - volume_min)
 	       + volume_min) + 0.5;
@@ -322,8 +301,8 @@ AlsaMixer::GetVolume(Error &error)
 	return ret;
 }
 
-inline bool
-AlsaMixer::SetVolume(unsigned volume, Error &error)
+void
+AlsaMixer::SetVolume(unsigned volume)
 {
 	float vol;
 	long level;
@@ -340,14 +319,9 @@ AlsaMixer::SetVolume(unsigned volume, Error &error)
 	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;
+	if (err < 0)
+		throw FormatRuntimeError("failed to set ALSA volume: %s",
+					 snd_strerror(err));
 }
 
 const MixerPlugin alsa_mixer_plugin = {