output/osx: migrate from class Error to C++ exceptions

Beware, this commit was not tested.  I don't have OS X, but I want to
prepare an API change.

src/output/plugins/OSXOutputPlugin.cxx

@@ -21,7 +21,7 @@
 #include "OSXOutputPlugin.hxx"
 #include "../OutputAPI.hxx"
 #include "util/ScopeExit.hxx"
-#include "util/Error.hxx"
+#include "util/RuntimeError.hxx"
 #include "util/Domain.hxx"
 #include "thread/Mutex.hxx"
 #include "thread/Cond.hxx"
@@ -52,8 +52,7 @@ struct OSXOutput {
 
 	boost::lockfree::spsc_queue<uint8_t> *ring_buffer;
 
-	OSXOutput()
+	OSXOutput(const ConfigBlock &block);
-		:base(osx_output_plugin) {}
 };
 
 static constexpr Domain osx_output_domain("osx_output");
@@ -80,40 +79,34 @@ osx_output_test_default_device(void)
 	return true;
 }
 
-static void
+OSXOutput::OSXOutput(const ConfigBlock &block)
-osx_output_configure(OSXOutput *oo, const ConfigBlock &block)
+	:base(osx_output_plugin, block)
 {
 	const char *device = block.GetBlockValue("device");
 
 	if (device == nullptr || 0 == strcmp(device, "default")) {
-		oo->component_subtype = kAudioUnitSubType_DefaultOutput;
+		component_subtype = kAudioUnitSubType_DefaultOutput;
-		oo->device_name = nullptr;
+		device_name = nullptr;
 	}
 	else if (0 == strcmp(device, "system")) {
-		oo->component_subtype = kAudioUnitSubType_SystemOutput;
+		component_subtype = kAudioUnitSubType_SystemOutput;
-		oo->device_name = nullptr;
+		device_name = nullptr;
 	}
 	else {
-		oo->component_subtype = kAudioUnitSubType_HALOutput;
+		component_subtype = kAudioUnitSubType_HALOutput;
 		/* XXX am I supposed to strdup() this? */
-		oo->device_name = device;
+		device_name = device;
 	}
 
-	oo->channel_map = block.GetBlockValue("channel_map");
+	channel_map = block.GetBlockValue("channel_map");
-	oo->hog_device = block.GetBlockValue("hog_device", false);
+	hog_device = block.GetBlockValue("hog_device", false);
-	oo->sync_sample_rate = block.GetBlockValue("sync_sample_rate", false);
+	sync_sample_rate = block.GetBlockValue("sync_sample_rate", false);
 }
 
 static AudioOutput *
-osx_output_init(const ConfigBlock &block, Error &error)
+osx_output_init(const ConfigBlock &block, Error &)
 {
-	OSXOutput *oo = new OSXOutput();
+	OSXOutput *oo = new OSXOutput(block);
-	if (!oo->base.Configure(block, error)) {
-		delete oo;
-		return nullptr;
-	}
-
-	osx_output_configure(oo, block);
 
 	AudioObjectPropertyAddress aopa = {
 		kAudioHardwarePropertyDefaultOutputDevice,
@@ -142,25 +135,21 @@ osx_output_finish(AudioOutput *ao)
 	delete oo;
 }
 
-static bool
+static void
 osx_output_parse_channel_map(
 	const char *device_name,
 	const char *channel_map_str,
 	SInt32 channel_map[],
-	UInt32 num_channels,
+	UInt32 num_channels)
-	Error &error)
 {
 	char *endptr;
 	unsigned int inserted_channels = 0;
 	bool want_number = true;
 
 	while (*channel_map_str) {
-		if (inserted_channels >= num_channels) {
+		if (inserted_channels >= num_channels)
-			error.Format(osx_output_domain,
+			throw FormatRuntimeError("%s: channel map contains more than %u entries or trailing garbage",
-				"%s: channel map contains more than %u entries or trailing garbage",
+						 device_name, num_channels);
-				device_name, num_channels);
-			return false;
-		}
 
 		if (!want_number && *channel_map_str == ',') {
 			++channel_map_str;
@@ -172,12 +161,9 @@ osx_output_parse_channel_map(
 			(isdigit(*channel_map_str) || *channel_map_str == '-')
 		) {
 			channel_map[inserted_channels] = strtol(channel_map_str, &endptr, 10);
-			if (channel_map[inserted_channels] < -1) {
+			if (channel_map[inserted_channels] < -1)
-				error.Format(osx_output_domain,
+				throw FormatRuntimeError("%s: channel map value %d not allowed (must be -1 or greater)",
-					"%s: channel map value %d not allowed (must be -1 or greater)",
+
-					device_name, channel_map[inserted_channels]);
-				return false;
-			}
 			channel_map_str = endptr;
 			want_number = false;
 			FormatDebug(osx_output_domain,
@@ -187,24 +173,17 @@ osx_output_parse_channel_map(
 			continue;
 		}
 
-		error.Format(osx_output_domain,
+		throw FormatRuntimeError("%s: invalid character '%c' in channel map",
-			"%s: invalid character '%c' in channel map",
+					 device_name, *channel_map_str);
-			device_name, *channel_map_str);
-		return false;
 	}
 
-	if (inserted_channels < num_channels) {
+	if (inserted_channels < num_channels)
-		error.Format(osx_output_domain,
+		throw FormatRuntimeError("%s: channel map contains less than %u entries",
-			"%s: channel map contains less than %u entries",
+					 device_name, num_channels);
-			device_name, num_channels);
-		return false;
-	}
-
-	return true;
 }
 
-static bool
+static void
-osx_output_set_channel_map(OSXOutput *oo, Error &error)
+osx_output_set_channel_map(OSXOutput *oo)
 {
 	AudioStreamBasicDescription desc;
 	OSStatus status;
@@ -221,22 +200,16 @@ osx_output_set_channel_map(OSXOutput *oo, Error &error)
 		&size);
 	if (status != noErr) {
 		osx_os_status_to_cstring(status, errormsg, sizeof(errormsg));
-		error.Format(osx_output_domain, status,
+		throw FormatRuntimeError("%s: unable to get number of output device channels: %s",
-			"%s: unable to get number of output device channels: %s",
+					 oo->device_name, errormsg);
-			oo->device_name, errormsg);
-		return false;
 	}
 
 	num_channels = desc.mChannelsPerFrame;
 	std::unique_ptr<SInt32[]> channel_map(new SInt32[num_channels]);
-	if (!osx_output_parse_channel_map(oo->device_name,
+	osx_output_parse_channel_map(oo->device_name,
-		oo->channel_map,
+				     oo->channel_map,
-		channel_map.get(),
+				     channel_map.get(),
-		num_channels,
+				     num_channels));
-		error)
-	) {
-		return false;
-	}
 
 	size = num_channels * sizeof(SInt32);
 	status = AudioUnitSetProperty(oo->au,
@@ -247,12 +220,8 @@ osx_output_set_channel_map(OSXOutput *oo, Error &error)
 		size);
 	if (status != noErr) {
 		osx_os_status_to_cstring(status, errormsg, sizeof(errormsg));
-		error.Format(osx_output_domain, status,
+		throw FormatRuntimeError("%s: unable to set channel map: %s", oo->device_name, errormsg);
-			"%s: unable to set channel map: %s", oo->device_name, errormsg);
-		return false;
 	}
-
-	return true;
 }
 
 static void
@@ -428,8 +397,8 @@ osx_output_hog_device(AudioDeviceID dev_id, bool hog)
 }
 
 
-static bool
+static void
-osx_output_set_device(OSXOutput *oo, Error &error)
+osx_output_set_device(OSXOutput *oo)
 {
 	OSStatus status;
 	UInt32 size, numdevices;
@@ -445,17 +414,15 @@ osx_output_set_device(OSXOutput *oo, Error &error)
 	};
 
 	if (oo->component_subtype != kAudioUnitSubType_HALOutput)
-		return true;
+		return;
 
 	/* how many audio devices are there? */
 	propaddr = { kAudioHardwarePropertyDevices, kAudioObjectPropertyScopeGlobal, kAudioObjectPropertyElementMaster };
 	status = AudioObjectGetPropertyDataSize(kAudioObjectSystemObject, &propaddr, 0, nullptr, &size);
 	if (status != noErr) {
 		osx_os_status_to_cstring(status, errormsg, sizeof(errormsg));
-		error.Format(osx_output_domain, status,
+		throw FormatRuntimeError("Unable to determine number of OS X audio devices: %s",
-			     "Unable to determine number of OS X audio devices: %s",
+					 errormsg);
-			     errormsg);
-		return false;
 	}
 
 	/* what are the available audio device IDs? */
@@ -464,10 +431,8 @@ osx_output_set_device(OSXOutput *oo, Error &error)
 	status = AudioObjectGetPropertyData(kAudioObjectSystemObject, &propaddr, 0, nullptr, &size, deviceids.get());
 	if (status != noErr) {
 		osx_os_status_to_cstring(status, errormsg, sizeof(errormsg));
-		error.Format(osx_output_domain, status,
+		throw FormatRuntimeError("Unable to determine OS X audio device IDs: %s",
-			     "Unable to determine OS X audio device IDs: %s",
+					 errormsg);
-			     errormsg);
-		return false;
 	}
 
 	/* which audio device matches oo->device_name? */
@@ -477,18 +442,14 @@ osx_output_set_device(OSXOutput *oo, Error &error)
 		status = AudioObjectGetPropertyData(deviceids[i], &propaddr, 0, nullptr, &size, &cfname);
 		if (status != noErr) {
 			osx_os_status_to_cstring(status, errormsg, sizeof(errormsg));
-			error.Format(osx_output_domain, status,
+			throw FormatRuntimeError("Unable to determine OS X device name "
-				     "Unable to determine OS X device name "
+						 "(device %u): %s",
-				     "(device %u): %s",
+						 (unsigned int) deviceids[i],
-				     (unsigned int) deviceids[i],
+						 errormsg);
-				     errormsg);
-			return false;
 		}
 
-		if (!CFStringGetCString(cfname, name, sizeof(name), kCFStringEncodingUTF8)) {
+		if (!CFStringGetCString(cfname, name, sizeof(name), kCFStringEncodingUTF8))
-			error.Set(osx_output_domain, "Unable to convert device name from CFStringRef to char*");
+			throw std::runtime_error("Unable to convert device name from CFStringRef to char*");
-			return false;
-		}
 
 		if (strcmp(oo->device_name, name) == 0) {
 			FormatDebug(osx_output_domain,
@@ -502,7 +463,7 @@ osx_output_set_device(OSXOutput *oo, Error &error)
 			      "Found no audio device with name '%s' "
 			      "(will use default audio device)",
 			      oo->device_name);
-		return true;
+		return;
 	}
 
 	status = AudioUnitSetProperty(oo->au,
@@ -513,10 +474,8 @@ osx_output_set_device(OSXOutput *oo, Error &error)
 				      sizeof(AudioDeviceID));
 	if (status != noErr) {
 		osx_os_status_to_cstring(status, errormsg, sizeof(errormsg));
-		error.Format(osx_output_domain, status,
+		throw FormatRuntimeError("Unable to set OS X audio output device: %s",
-			     "Unable to set OS X audio output device: %s",
+					 errormsg);
-			     errormsg);
-		return false;
 	}
 
 	oo->dev_id = deviceids[i];
@@ -524,10 +483,8 @@ osx_output_set_device(OSXOutput *oo, Error &error)
 		    "set OS X audio output device ID=%u, name=%s",
 		    (unsigned)deviceids[i], name);
 
-	if (oo->channel_map && !osx_output_set_channel_map(oo, error))
+	if (oo->channel_map)
-		return false;
+		osx_output_set_channel_map(oo);
-
-	return true;
 }
 
 
@@ -556,7 +513,7 @@ osx_render(void *vdata,
 }
 
 static bool
-osx_output_enable(AudioOutput *ao, Error &error)
+osx_output_enable(AudioOutput *ao, Error &)
 {
 	char errormsg[1024];
 	OSXOutput *oo = (OSXOutput *)ao;
@@ -569,24 +526,21 @@ osx_output_enable(AudioOutput *ao, Error &error)
 	desc.componentFlagsMask = 0;
 
 	AudioComponent comp = AudioComponentFindNext(nullptr, &desc);
-	if (comp == 0) {
+	if (comp == 0)
-		error.Set(osx_output_domain,
+		throw std::runtime_error("Error finding OS X component");
-			  "Error finding OS X component");
-		return false;
-	}
 
 	OSStatus status = AudioComponentInstanceNew(comp, &oo->au);
 	if (status != noErr) {
 		osx_os_status_to_cstring(status, errormsg, sizeof(errormsg));
-		error.Format(osx_output_domain, status,
+		throw FormatRuntimeError("Unable to open OS X component: %s",
-			     "Unable to open OS X component: %s",
+					 errormsg);
-			     errormsg);
-		return false;
 	}
 
-	if (!osx_output_set_device(oo, error)) {
+	try {
+		osx_output_set_device(oo);
+	} catch (...) {
 		AudioComponentInstanceDispose(oo->au);
-		return false;
+		throw;
 	}
 
 	if (oo->hog_device) {
@@ -621,7 +575,7 @@ osx_output_close(AudioOutput *ao)
 
 static bool
 osx_output_open(AudioOutput *ao, AudioFormat &audio_format,
-		Error &error)
+		Error &)
 {
 	char errormsg[1024];
 	OSXOutput *od = (OSXOutput *)ao;
@@ -667,11 +621,8 @@ osx_output_open(AudioOutput *ao, AudioFormat &audio_format,
 				     kAudioUnitScope_Input, 0,
 				     &od->asbd,
 				     sizeof(od->asbd));
-	if (status != noErr) {
+	if (status != noErr)
-		error.Set(osx_output_domain, status,
+		throw std::runtime_error("Unable to set format on OS X device");
-			  "Unable to set format on OS X device");
-		return false;
-	}
 
 	AURenderCallbackStruct callback;
 	callback.inputProc = osx_render;
@@ -684,28 +635,22 @@ osx_output_open(AudioOutput *ao, AudioFormat &audio_format,
 				     &callback, sizeof(callback));
 	if (status != noErr) {
 		AudioComponentInstanceDispose(od->au);
-		error.Set(osx_output_domain, status,
+		throw std::runtime_error("unable to set callback for OS X audio unit");
-			  "unable to set callback for OS X audio unit");
-		return false;
 	}
 
 	status = AudioUnitInitialize(od->au);
 	if (status != noErr) {
 		osx_os_status_to_cstring(status, errormsg, sizeof(errormsg));
-		error.Format(osx_output_domain, status,
+		throw FormatRuntimeError("Unable to initialize OS X audio unit: %s",
-			     "Unable to initialize OS X audio unit: %s",
+					 errormsg);
-			     errormsg);
-		return false;
 	}
 
 	UInt32 buffer_frame_size = 1;
 	status = osx_output_set_buffer_size(od->au, od->asbd, &buffer_frame_size);
 	if (status != noErr) {
 		osx_os_status_to_cstring(status, errormsg, sizeof(errormsg));
-		error.Format(osx_output_domain, status,
+		throw FormatRuntimeError("Unable to set frame size: %s",
-			     "Unable to set frame size: %s",
+					 errormsg);
-			     errormsg);
-		return false;
 	}
 
 	od->ring_buffer = new boost::lockfree::spsc_queue<uint8_t>(buffer_frame_size);
@@ -714,10 +659,8 @@ osx_output_open(AudioOutput *ao, AudioFormat &audio_format,
 	if (status != 0) {
 		AudioUnitUninitialize(od->au);
 		osx_os_status_to_cstring(status, errormsg, sizeof(errormsg));
-		error.Format(osx_output_domain, status,
+		throw FormatRuntimeError("unable to start audio output: %s",
-			     "unable to start audio output: %s",
+					 errormsg);
-			     errormsg);
-		return false;
 	}
 
 	return true;