output_init: return GError on error

Do error handling with GError instead of aborting with g_error().

src/output_all.c

@@ -77,6 +77,7 @@ audio_output_all_init(void)
 {
 	const struct config_param *param = NULL;
 	unsigned int i;
+	GError *error = NULL;
 
 	notify_init(&audio_output_client_notify);
 
@@ -93,18 +94,8 @@ audio_output_all_init(void)
 		/* only allow param to be NULL if there just one audioOutput */
 		assert(param || (num_audio_outputs == 1));
 
-		if (!audio_output_init(output, param)) {
-			if (param)
-			{
-				g_error("problems configuring output device "
-					"defined at line %i\n", param->line);
-			}
-			else
-			{
-				g_error("No audio_output specified and unable to "
-					"detect a default audio output device\n");
-			}
-		}
+		if (!audio_output_init(output, param, &error))
+			g_error("line %i: %s", param->line, error->message);
 
 		/* require output names to be unique: */
 		for (j = 0; j < i; j++) {

src/output_control.h

@@ -19,6 +19,8 @@
 #ifndef MPD_OUTPUT_CONTROL_H
 #define MPD_OUTPUT_CONTROL_H
 
+#include <glib.h>
+
 #include <stddef.h>
 #include <stdbool.h>
 
@@ -27,8 +29,15 @@ struct audio_format;
 struct tag;
 struct config_param;
 
+static inline GQuark
+audio_output_quark(void)
+{
+	return g_quark_from_static_string("audio_output");
+}
+
 bool
-audio_output_init(struct audio_output *ao, const struct config_param *param);
+audio_output_init(struct audio_output *ao, const struct config_param *param,
+		  GError **error);
 
 bool
 audio_output_open(struct audio_output *ao,

src/output_init.c

@@ -42,7 +42,7 @@
 }
 
 static const struct audio_output_plugin *
-audio_output_detect(void)
+audio_output_detect(GError **error)
 {
 	const struct audio_output_plugin *plugin;
 	unsigned i;
@@ -59,17 +59,19 @@ audio_output_detect(void)
 			return plugin;
 	}
 
+	g_set_error(error, audio_output_quark(), 0,
+		    "Unable to detect an audio device");
 	return NULL;
 }
 
 bool
-audio_output_init(struct audio_output *ao, const struct config_param *param)
+audio_output_init(struct audio_output *ao, const struct config_param *param,
+		  GError **error)
 {
 	const char *name = NULL;
 	char *format = NULL;
 	struct block_param *bp = NULL;
 	const struct audio_output_plugin *plugin = NULL;
-	GError *error = NULL;
 
 	if (param) {
 		const char *type = NULL;
@@ -80,18 +82,18 @@ audio_output_init(struct audio_output *ao, const struct config_param *param)
 
 		plugin = audio_output_plugin_get(type);
 		if (plugin == NULL) {
-			g_error("couldn't find audio output plugin for type "
-				"\"%s\" at line %i\n", type, param->line);
+			g_set_error(error, audio_output_quark(), 0,
+				    "No such audio output plugin: %s",
+				    type);
+			return false;
 		}
 	} else {
 		g_warning("No \"%s\" defined in config file\n",
 			  CONF_AUDIO_OUTPUT);
 
-		plugin = audio_output_detect();
-		if (plugin == NULL) {
-			g_warning("Unable to detect an audio device");
+		plugin = audio_output_detect(error);
+		if (plugin == NULL)
 			return false;
-		}
 
 		g_message("Successfully detected a %s audio device",
 			  plugin->name);
@@ -111,10 +113,9 @@ audio_output_init(struct audio_output *ao, const struct config_param *param)
 		bool ret;
 
 		ret = audio_format_parse(&ao->config_audio_format, format,
-					 &error);
+					 error);
 		if (!ret)
-			g_error("error parsing format at line %i: %s",
-				bp->line, error->message);
+			return false;
 	} else
 		audio_format_clear(&ao->config_audio_format);
 
@@ -124,14 +125,9 @@ audio_output_init(struct audio_output *ao, const struct config_param *param)
 
 	ao->data = ao_plugin_init(plugin,
 				  format ? &ao->config_audio_format : NULL,
-				  param, &error);
-	if (ao->data == NULL) {
-		g_warning("Failed to initialize \"%s\" [%s]: %s",
-			  ao->name, ao->plugin->name,
-			  error->message);
-		g_error_free(error);
+				  param, error);
+	if (ao->data == NULL)
 		return false;
-	}
 
 	return true;
 }