output_all: add basic GError support

Makefile.am

@@ -795,6 +795,7 @@ OUTPUT_API_SRC = \
 	src/output_list.c \
 	src/output_all.c \
 	src/output_thread.c \
+	src/output_error.h \
 	src/output_control.c \
 	src/output_state.c \
 	src/output_print.c \

src/output_all.c

@@ -19,6 +19,7 @@
 
 #include "config.h"
 #include "output_all.h"
+#include "output_error.h"
 #include "output_internal.h"
 #include "output_control.h"
 #include "chunk.h"
@@ -270,7 +271,7 @@ audio_output_all_update(void)
 }
 
 bool
-audio_output_all_play(struct music_chunk *chunk)
+audio_output_all_play(struct music_chunk *chunk, GError **error_r)
 {
 	bool ret;
 	unsigned int i;
@@ -281,8 +282,12 @@ audio_output_all_play(struct music_chunk *chunk)
 	assert(music_chunk_check_format(chunk, &input_audio_format));
 
 	ret = audio_output_all_update();
-	if (!ret)
+	if (!ret) {
+		/* TODO: obtain real error */
+		g_set_error(error_r, output_quark(), 0,
+			    "Failed to open audio output");
 		return false;
+	}
 
 	music_pipe_push(g_mp, chunk);
 
@@ -294,7 +299,8 @@ audio_output_all_play(struct music_chunk *chunk)
 
 bool
 audio_output_all_open(const struct audio_format *audio_format,
-		      struct music_buffer *buffer)
+		      struct music_buffer *buffer,
+		      GError **error_r)
 {
 	bool ret = false, enabled = false;
 	unsigned int i;
@@ -334,7 +340,12 @@ audio_output_all_open(const struct audio_format *audio_format,
 	}
 
 	if (!enabled)
-		g_warning("All audio outputs are disabled");
+		g_set_error(error_r, output_quark(), 0,
+			    "All audio outputs are disabled");
+	else if (!ret)
+		/* TODO: obtain real error */
+		g_set_error(error_r, output_quark(), 0,
+			    "Failed to open audio output");
 
 	if (!ret)
 		/* close all devices if there was an error */

src/output_all.h

@@ -26,6 +26,8 @@
 #ifndef OUTPUT_ALL_H
 #define OUTPUT_ALL_H
 
+#include "gerror.h"
+
 #include <stdbool.h>
 #include <stddef.h>
 
@@ -84,7 +86,8 @@ audio_output_all_enable_disable(void);
  */
 bool
 audio_output_all_open(const struct audio_format *audio_format,
-		      struct music_buffer *buffer);
+		      struct music_buffer *buffer,
+		      GError **error_r);
 
 /**
  * Closes all audio outputs.
@@ -108,7 +111,7 @@ audio_output_all_release(void);
  * (all closed then)
  */
 bool
-audio_output_all_play(struct music_chunk *chunk);
+audio_output_all_play(struct music_chunk *chunk, GError **error_r);
 
 /**
  * Checks if the output devices have drained their music pipe, and

src/output_error.h

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2003-2012 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_OUTPUT_ERROR_H
+#define MPD_OUTPUT_ERROR_H
+
+#include <glib.h>
+
+/**
+ * Quark for GError.domain.
+ */
+G_GNUC_CONST
+static inline GQuark
+output_quark(void)
+{
+	return g_quark_from_static_string("output");
+}
+
+#endif

src/player_thread.c

@@ -305,7 +305,9 @@ player_open_output(struct player *player)
 	assert(pc->state == PLAYER_STATE_PLAY ||
 	       pc->state == PLAYER_STATE_PAUSE);
 
-	if (audio_output_all_open(&player->play_audio_format, player_buffer)) {
+	GError *error = NULL;
+	if (audio_output_all_open(&player->play_audio_format, player_buffer,
+				  &error)) {
 		player->output_open = true;
 		player->paused = false;
 
@@ -315,6 +317,9 @@ player_open_output(struct player *player)
 
 		return true;
 	} else {
+		g_warning("%s", error->message);
+		g_error_free(error);
+
 		player->output_open = false;
 
 		/* pause: the user may resume playback as soon as an
@@ -429,7 +434,11 @@ player_send_silence(struct player *player)
 	chunk->length = num_frames * frame_size;
 	memset(chunk->data, 0, chunk->length);
 
-	if (!audio_output_all_play(chunk)) {
+	GError *error = NULL;
+	if (!audio_output_all_play(chunk, &error)) {
+		g_warning("%s", error->message);
+		g_error_free(error);
+
 		music_buffer_return(player_buffer, chunk);
 		return false;
 	}
@@ -650,7 +659,8 @@ update_song_tag(struct song *song, const struct tag *new_tag)
 static bool
 play_chunk(struct player_control *pc,
 	   struct song *song, struct music_chunk *chunk,
-	   const struct audio_format *format)
+	   const struct audio_format *format,
+	   GError **error_r)
 {
 	assert(music_chunk_check_format(chunk, format));
 
@@ -668,7 +678,7 @@ play_chunk(struct player_control *pc,
 
 	/* send the chunk to the audio outputs */
 
-	if (!audio_output_all_play(chunk))
+	if (!audio_output_all_play(chunk, error_r))
 		return false;
 
 	pc->total_play_time += (double)chunk->length /
@@ -783,8 +793,12 @@ play_next_chunk(struct player *player)
 
 	/* play the current chunk */
 
+	GError *error = NULL;
 	if (!play_chunk(player->pc, player->song, chunk,
-			&player->play_audio_format)) {
+			&player->play_audio_format, &error)) {
+		g_warning("%s", error->message);
+		g_error_free(error);
+
 		music_buffer_return(player_buffer, chunk);
 
 		player_lock(pc);