eliminate g_error() usage

Replaced all occurrences of g_error() with MPD_ERROR() located in a new header
file 'mpd_error.h'. This macro uses g_critical() to print the error message
and then exits gracefully in contrast to g_error() which would internally call
abort() to produce a core dump.

The macro name is distinctive and allows to find all places with dubious error
handling. The long-term goal is to get rid of MPD_ERROR() altogether. To
facilitate the eventual removal of this macro it was added in a new header
file rather than to an existing header file.

This fixes #2995 and #3007.

3 files changed, 11 insertions, 8 deletions

diff --git a/src/output/shout_plugin.c b/src/output/shout_plugin.c
index a8b409be2..d1466eb3a 100644
--- a/src/output/shout_plugin.c
+++ b/src/output/shout_plugin.c
@@ -21,6 +21,7 @@
 #include "output_api.h"
 #include "encoder_plugin.h"
 #include "encoder_list.h"
+#include "mpd_error.h"
 
 #include <shout/shout.h>
 #include <glib.h>
@@ -101,8 +102,8 @@ static void free_shout_data(struct shout_data *sd)
 #define check_block_param(name) {		  \
 		block_param = config_get_block_param(param, name);	\
 		if (!block_param) {					\
-			g_error("no \"%s\" defined for shout device defined at line " \
-				"%i\n", name, param->line);		\
+			MPD_ERROR("no \"%s\" defined for shout device defined at line " \
+				  "%i\n", name, param->line);		\
 		}							\
 	}
 
diff --git a/src/output_all.c b/src/output_all.c
index dbd5a6ce6..3f582dcb4 100644
--- a/src/output_all.c
+++ b/src/output_all.c
@@ -26,6 +26,7 @@
 #include "pipe.h"
 #include "buffer.h"
 #include "player_control.h"
+#include "mpd_error.h"
 
 #ifndef NDEBUG
 #include "chunk.h"
@@ -122,17 +123,17 @@ audio_output_all_init(void)
 
 		if (!audio_output_init(output, param, &error)) {
 			if (param != NULL)
-				g_error("line %i: %s",
-					param->line, error->message);
+				MPD_ERROR("line %i: %s",
+					  param->line, error->message)
 			else
-				g_error("%s", error->message);
+				MPD_ERROR("%s", error->message);
 		}
 
 		/* require output names to be unique: */
 		for (j = 0; j < i; j++) {
 			if (!strcmp(output->name, audio_outputs[j].name)) {
-				g_error("output devices with identical "
-					"names: %s\n", output->name);
+				MPD_ERROR("output devices with identical "
+					  "names: %s\n", output->name);
 			}
 		}
 	}
diff --git a/src/output_thread.c b/src/output_thread.c
index df9d7801b..c10a1552f 100644
--- a/src/output_thread.c
+++ b/src/output_thread.c
@@ -28,6 +28,7 @@
 #include "filter_plugin.h"
 #include "filter/convert_filter_plugin.h"
 #include "filter/replay_gain_filter_plugin.h"
+#include "mpd_error.h"
 
 #include <glib.h>
 
@@ -629,5 +630,5 @@ void audio_output_thread_start(struct audio_output *ao)
 	assert(ao->command == AO_COMMAND_NONE);
 
 	if (!(ao->thread = g_thread_create(audio_output_task, ao, true, &e)))
-		g_error("Failed to spawn output task: %s\n", e->message);
+		MPD_ERROR("Failed to spawn output task: %s\n", e->message);
 }