util/Error: new error passing library

Replaces GLib's GError.

19 files changed, 187 insertions, 250 deletions

diff --git a/test/DumpDatabase.cxx b/test/DumpDatabase.cxx
index e788d625a..cf86d91ff 100644
--- a/test/DumpDatabase.cxx
+++ b/test/DumpDatabase.cxx
@@ -27,6 +27,7 @@
 #include "conf.h"
 #include "Tag.hxx"
 #include "fs/Path.hxx"
+#include "util/Error.hxx"
 
 #include <iostream>
 using std::cout;
@@ -46,14 +47,14 @@ my_log_func(const gchar *log_domain, gcc_unused GLogLevelFlags log_level,
 }
 
 static bool
-DumpDirectory(const Directory &directory, GError **)
+DumpDirectory(const Directory &directory, Error &)
 {
 	cout << "D " << directory.path << endl;
 	return true;
 }
 
 static bool
-DumpSong(Song &song, GError **)
+DumpSong(Song &song, Error &)
 {
 	cout << "S " << song.parent->path << "/" << song.uri << endl;
 	return true;
@@ -61,7 +62,7 @@ DumpSong(Song &song, GError **)
 
 static bool
 DumpPlaylist(const PlaylistInfo &playlist,
-	     const Directory &directory, GError **)
+	     const Directory &directory, Error &)
 {
 	cout << "P " << directory.path << "/" << playlist.name.c_str() << endl;
 	return true;
@@ -70,8 +71,6 @@ DumpPlaylist(const PlaylistInfo &playlist,
 int
 main(int argc, char **argv)
 {
-	GError *error = nullptr;
-
 	if (argc != 3) {
 		cerr << "Usage: DumpDatabase CONFIG PLUGIN" << endl;
 		return 1;
@@ -98,9 +97,9 @@ main(int argc, char **argv)
 
 	config_global_init();
 
-	if (!ReadConfigFile(config_path, &error)) {
-		cerr << error->message << endl;
-		g_error_free(error);
+	Error error;
+	if (!ReadConfigFile(config_path, error)) {
+		cerr << error.GetMessage() << endl;
 		return EXIT_FAILURE;
 	}
 
@@ -113,29 +112,26 @@ main(int argc, char **argv)
 	if (path != nullptr)
 		param.AddBlockParam("path", path->value, path->line);
 
-	Database *db = plugin->create(param, &error);
+	Database *db = plugin->create(param, error);
 
 	if (db == nullptr) {
-		cerr << error->message << endl;
-		g_error_free(error);
+		cerr << error.GetMessage() << endl;
 		return EXIT_FAILURE;
 	}
 
-	if (!db->Open(&error)) {
+	if (!db->Open(error)) {
 		delete db;
-		cerr << error->message << endl;
-		g_error_free(error);
+		cerr << error.GetMessage() << endl;
 		return EXIT_FAILURE;
 	}
 
 	const DatabaseSelection selection("", true);
 
 	if (!db->Visit(selection, DumpDirectory, DumpSong, DumpPlaylist,
-		       &error)) {
+		       error)) {
 		db->Close();
 		delete db;
-		cerr << error->message << endl;
-		g_error_free(error);
+		cerr << error.GetMessage() << endl;
 		return EXIT_FAILURE;
 	}
 
diff --git a/test/dump_playlist.cxx b/test/dump_playlist.cxx
index 768eee367..c3cdf638f 100644
--- a/test/dump_playlist.cxx
+++ b/test/dump_playlist.cxx
@@ -30,6 +30,7 @@
 #include "PlaylistRegistry.hxx"
 #include "PlaylistPlugin.hxx"
 #include "fs/Path.hxx"
+#include "util/Error.hxx"
 
 #include <glib.h>
 
@@ -84,7 +85,8 @@ decoder_read(gcc_unused struct decoder *decoder,
 	     struct input_stream *is,
 	     void *buffer, size_t length)
 {
-	return input_stream_lock_read(is, buffer, length, NULL);
+	Error error;
+	return input_stream_lock_read(is, buffer, length, error);
 }
 
 void
@@ -139,7 +141,6 @@ int main(int argc, char **argv)
 {
 	const char *uri;
 	struct input_stream *is = NULL;
-	GError *error = NULL;
 	struct playlist_provider *playlist;
 	Song *song;
 
@@ -162,18 +163,18 @@ int main(int argc, char **argv)
 	/* initialize MPD */
 
 	config_global_init();
-	if (!ReadConfigFile(config_path, &error)) {
-		g_printerr("%s\n", error->message);
-		g_error_free(error);
+
+	Error error;
+	if (!ReadConfigFile(config_path, error)) {
+		g_printerr("%s\n", error.GetMessage());
 		return 1;
 	}
 
 	io_thread_init();
 	io_thread_start();
 
-	if (!input_stream_global_init(&error)) {
-		g_warning("%s", error->message);
-		g_error_free(error);
+	if (!input_stream_global_init(error)) {
+		g_warning("%s", error.GetMessage());
 		return 2;
 	}
 
@@ -189,12 +190,11 @@ int main(int argc, char **argv)
 	if (playlist == NULL) {
 		/* open the stream and wait until it becomes ready */
 
-		is = input_stream_open(uri, mutex, cond, &error);
+		is = input_stream_open(uri, mutex, cond, error);
 		if (is == NULL) {
-			if (error != NULL) {
-				g_warning("%s", error->message);
-				g_error_free(error);
-			} else
+			if (error.IsDefined())
+				g_warning("%s", error.GetMessage());
+			else
 				g_printerr("input_stream_open() failed\n");
 			return 2;
 		}
diff --git a/test/dump_rva2.cxx b/test/dump_rva2.cxx
index 9dbb018d6..95a55eb43 100644
--- a/test/dump_rva2.cxx
+++ b/test/dump_rva2.cxx
@@ -23,6 +23,7 @@
 #include "replay_gain_info.h"
 #include "conf.h"
 #include "Tag.hxx"
+#include "util/Error.hxx"
 
 #include <id3tag.h>
 
@@ -51,8 +52,6 @@ Tag::~Tag() {}
 
 int main(int argc, char **argv)
 {
-	GError *error = NULL;
-
 #ifdef HAVE_LOCALE_H
 	/* initialize locale */
 	setlocale(LC_CTYPE,"");
@@ -65,12 +64,12 @@ int main(int argc, char **argv)
 
 	const char *path = argv[1];
 
-	struct id3_tag *tag = tag_id3_load(path, &error);
+	Error error;
+	struct id3_tag *tag = tag_id3_load(path, error);
 	if (tag == NULL) {
-		if (error != NULL) {
-			g_printerr("%s\n", error->message);
-			g_error_free(error);
-		} else
+		if (error.IsDefined())
+			g_printerr("%s\n", error.GetMessage());
+		else
 			g_printerr("No ID3 tag found\n");
 
 		return EXIT_FAILURE;
diff --git a/test/dump_text_file.cxx b/test/dump_text_file.cxx
index 165a6493c..a9f8c95a2 100644
--- a/test/dump_text_file.cxx
+++ b/test/dump_text_file.cxx
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2003-2011 The Music Player Daemon Project
+ * Copyright (C) 2003-2013 The Music Player Daemon Project
  * http://www.musicpd.org
  *
  * This program is free software; you can redistribute it and/or modify
@@ -24,6 +24,7 @@
 #include "conf.h"
 #include "stdbin.h"
 #include "TextInputStream.hxx"
+#include "util/Error.hxx"
 
 #ifdef ENABLE_ARCHIVE
 #include "ArchiveList.hxx"
@@ -56,7 +57,7 @@ dump_text_file(TextInputStream &is)
 static int
 dump_input_stream(struct input_stream *is)
 {
-	GError *error = NULL;
+	Error error;
 
 	input_stream_lock(is);
 
@@ -64,9 +65,8 @@ dump_input_stream(struct input_stream *is)
 
 	input_stream_wait_ready(is);
 
-	if (!input_stream_check(is, &error)) {
-		g_warning("%s", error->message);
-		g_error_free(error);
+	if (!input_stream_check(is, error)) {
+		g_warning("%s", error.GetMessage());
 		input_stream_unlock(is);
 		return EXIT_FAILURE;
 	}
@@ -80,9 +80,8 @@ dump_input_stream(struct input_stream *is)
 	}
 	input_stream_lock(is);
 
-	if (!input_stream_check(is, &error)) {
-		g_warning("%s", error->message);
-		g_error_free(error);
+	if (!input_stream_check(is, error)) {
+		g_warning("%s", error.GetMessage());
 		input_stream_unlock(is);
 		return EXIT_FAILURE;
 	}
@@ -94,7 +93,6 @@ dump_input_stream(struct input_stream *is)
 
 int main(int argc, char **argv)
 {
-	GError *error = NULL;
 	struct input_stream *is;
 	int ret;
 
@@ -122,9 +120,9 @@ int main(int argc, char **argv)
 	archive_plugin_init_all();
 #endif
 
-	if (!input_stream_global_init(&error)) {
-		g_warning("%s", error->message);
-		g_error_free(error);
+	Error error;
+	if (!input_stream_global_init(error)) {
+		g_warning("%s", error.GetMessage());
 		return 2;
 	}
 
@@ -133,15 +131,14 @@ int main(int argc, char **argv)
 	Mutex mutex;
 	Cond cond;
 
-	is = input_stream_open(argv[1], mutex, cond, &error);
+	is = input_stream_open(argv[1], mutex, cond, error);
 	if (is != NULL) {
 		ret = dump_input_stream(is);
 		input_stream_close(is);
 	} else {
-		if (error != NULL) {
-			g_warning("%s", error->message);
-			g_error_free(error);
-		} else
+		if (error.IsDefined())
+			g_warning("%s", error.GetMessage());
+		else
 			g_printerr("input_stream_open() failed\n");
 		ret = 2;
 	}
diff --git a/test/read_conf.cxx b/test/read_conf.cxx
index 79f3eca54..55ff8c068 100644
--- a/test/read_conf.cxx
+++ b/test/read_conf.cxx
@@ -20,6 +20,7 @@
 #include "config.h"
 #include "conf.h"
 #include "fs/Path.hxx"
+#include "util/Error.hxx"
 
 #include <glib.h>
 
@@ -50,10 +51,9 @@ int main(int argc, char **argv)
 
 	config_global_init();
 
-	GError *error = NULL;
-	if (!ReadConfigFile(config_path, &error)) {
-		g_printerr("%s:", error->message);
-		g_error_free(error);
+	Error error;
+	if (!ReadConfigFile(config_path, error)) {
+		g_printerr("%s:", error.GetMessage());
 		return 1;
 	}
 
diff --git a/test/read_mixer.cxx b/test/read_mixer.cxx
index 0cc84c9b9..8426443ae 100644
--- a/test/read_mixer.cxx
+++ b/test/read_mixer.cxx
@@ -26,6 +26,7 @@
 #include "Main.hxx"
 #include "event/Loop.hxx"
 #include "ConfigData.hxx"
+#include "util/Error.hxx"
 
 #include <glib.h>
 
@@ -63,7 +64,7 @@ pulse_output_clear_mixer(gcc_unused PulseOutput *po,
 bool
 pulse_output_set_volume(gcc_unused PulseOutput *po,
 			gcc_unused const struct pa_cvolume *volume,
-			gcc_unused GError **error_r)
+			gcc_unused Error &error)
 {
 	return false;
 }
@@ -111,8 +112,6 @@ pcm_volume(gcc_unused void *buffer, gcc_unused size_t length,
 
 int main(int argc, gcc_unused char **argv)
 {
-	GError *error = NULL;
-	bool success;
 	int volume;
 
 	if (argc != 2) {
@@ -126,23 +125,21 @@ int main(int argc, gcc_unused char **argv)
 
 	main_loop = new EventLoop(EventLoop::Default());
 
+	Error error;
 	Mixer *mixer = mixer_new(&alsa_mixer_plugin, nullptr,
-				 config_param(), &error);
+				 config_param(), error);
 	if (mixer == NULL) {
-		g_printerr("mixer_new() failed: %s\n", error->message);
-		g_error_free(error);
+		g_printerr("mixer_new() failed: %s\n", error.GetMessage());
 		return 2;
 	}
 
-	success = mixer_open(mixer, &error);
-	if (!success) {
+	if (!mixer_open(mixer, error)) {
 		mixer_free(mixer);
-		g_printerr("failed to open the mixer: %s\n", error->message);
-		g_error_free(error);
+		g_printerr("failed to open the mixer: %s\n", error.GetMessage());
 		return 2;
 	}
 
-	volume = mixer_get_volume(mixer, &error);
+	volume = mixer_get_volume(mixer, error);
 	mixer_close(mixer);
 	mixer_free(mixer);
 
@@ -151,10 +148,9 @@ int main(int argc, gcc_unused char **argv)
 	assert(volume >= -1 && volume <= 100);
 
 	if (volume < 0) {
-		if (error != NULL) {
+		if (error.IsDefined()) {
 			g_printerr("failed to read volume: %s\n",
-				   error->message);
-			g_error_free(error);
+				   error.GetMessage());
 		} else
 			g_printerr("failed to read volume\n");
 		return 2;
diff --git a/test/read_tags.cxx b/test/read_tags.cxx
index d72721324..8e45be930 100644
--- a/test/read_tags.cxx
+++ b/test/read_tags.cxx
@@ -27,6 +27,7 @@
 #include "TagHandler.hxx"
 #include "TagId3.hxx"
 #include "ApeTag.hxx"
+#include "util/Error.hxx"
 
 #include <glib.h>
 
@@ -70,7 +71,8 @@ decoder_read(gcc_unused struct decoder *decoder,
 	     struct input_stream *is,
 	     void *buffer, size_t length)
 {
-	return input_stream_lock_read(is, buffer, length, NULL);
+	Error error;
+	return input_stream_lock_read(is, buffer, length, error);
 }
 
 void
@@ -140,7 +142,6 @@ static const struct tag_handler print_handler = {
 
 int main(int argc, char **argv)
 {
-	GError *error = NULL;
 	const char *decoder_name, *path;
 	const struct decoder_plugin *plugin;
 
@@ -164,9 +165,9 @@ int main(int argc, char **argv)
 	io_thread_init();
 	io_thread_start();
 
-	if (!input_stream_global_init(&error)) {
-		g_warning("%s", error->message);
-		g_error_free(error);
+	Error error;
+	if (!input_stream_global_init(error)) {
+		g_warning("%s", error.GetMessage());
 		return 2;
 	}
 
@@ -185,12 +186,11 @@ int main(int argc, char **argv)
 		Cond cond;
 
 		struct input_stream *is =
-			input_stream_open(path, mutex, cond, &error);
+			input_stream_open(path, mutex, cond, error);
 
 		if (is == NULL) {
 			g_printerr("Failed to open %s: %s\n",
-				   path, error->message);
-			g_error_free(error);
+				   path, error.GetMessage());
 			return 1;
 		}
 
@@ -201,13 +201,11 @@ int main(int argc, char **argv)
 			input_stream_update(is);
 		}
 
-		if (!input_stream_check(is, &error)) {
+		if (!input_stream_check(is, error)) {
 			mutex.unlock();
 
 			g_printerr("Failed to read %s: %s\n",
-				   path, error->message);
-			g_error_free(error);
-
+				   path, error.GetMessage());
 			return EXIT_FAILURE;
 		}
 
diff --git a/test/run_convert.cxx b/test/run_convert.cxx
index 37e2c8734..72e457338 100644
--- a/test/run_convert.cxx
+++ b/test/run_convert.cxx
@@ -29,6 +29,7 @@
 #include "pcm/PcmConvert.hxx"
 #include "conf.h"
 #include "util/fifo_buffer.h"
+#include "util/Error.hxx"
 #include "stdbin.h"
 
 #include <glib.h>
@@ -56,7 +57,6 @@ config_get_string(gcc_unused enum ConfigOption option,
 
 int main(int argc, char **argv)
 {
-	GError *error = NULL;
 	AudioFormat in_audio_format, out_audio_format;
 	const void *output;
 	ssize_t nbytes;
@@ -69,18 +69,19 @@ int main(int argc, char **argv)
 
 	g_log_set_default_handler(my_log_func, NULL);
 
+	Error error;
 	if (!audio_format_parse(in_audio_format, argv[1],
-				false, &error)) {
+				false, error)) {
 		g_printerr("Failed to parse audio format: %s\n",
-			   error->message);
+			   error.GetMessage());
 		return 1;
 	}
 
 	AudioFormat out_audio_format_mask;
 	if (!audio_format_parse(out_audio_format_mask, argv[2],
-				true, &error)) {
+				true, error)) {
 		g_printerr("Failed to parse audio format: %s\n",
-			   error->message);
+			   error.GetMessage());
 		return 1;
 	}
 
@@ -113,9 +114,9 @@ int main(int argc, char **argv)
 		fifo_buffer_consume(buffer, length);
 
 		output = state.Convert(in_audio_format, src, length,
-				       out_audio_format, &length, &error);
+				       out_audio_format, &length, error);
 		if (output == NULL) {
-			g_printerr("Failed to convert: %s\n", error->message);
+			g_printerr("Failed to convert: %s\n", error.GetMessage());
 			return 2;
 		}
 
diff --git a/test/run_decoder.cxx b/test/run_decoder.cxx
index c7ef92cf8..fb06c637a 100644
--- a/test/run_decoder.cxx
+++ b/test/run_decoder.cxx
@@ -24,6 +24,7 @@
 #include "InputInit.hxx"
 #include "InputLegacy.hxx"
 #include "AudioFormat.hxx"
+#include "util/Error.hxx"
 #include "stdbin.h"
 
 #include <glib.h>
@@ -91,7 +92,8 @@ decoder_read(gcc_unused struct decoder *decoder,
 	     struct input_stream *is,
 	     void *buffer, size_t length)
 {
-	return input_stream_lock_read(is, buffer, length, NULL);
+	Error error;
+	return input_stream_lock_read(is, buffer, length, error);
 }
 
 void
@@ -144,7 +146,6 @@ decoder_mixramp(gcc_unused struct decoder *decoder,
 
 int main(int argc, char **argv)
 {
-	GError *error = NULL;
 	const char *decoder_name;
 	struct decoder decoder;
 
@@ -165,9 +166,9 @@ int main(int argc, char **argv)
 	io_thread_init();
 	io_thread_start();
 
-	if (!input_stream_global_init(&error)) {
-		g_warning("%s", error->message);
-		g_error_free(error);
+	Error error;
+	if (!input_stream_global_init(error)) {
+		g_warning("%s", error.GetMessage());
 		return 2;
 	}
 
@@ -189,12 +190,11 @@ int main(int argc, char **argv)
 		Cond cond;
 
 		struct input_stream *is =
-			input_stream_open(decoder.uri, mutex, cond, &error);
+			input_stream_open(decoder.uri, mutex, cond, error);
 		if (is == NULL) {
-			if (error != NULL) {
-				g_warning("%s", error->message);
-				g_error_free(error);
-			} else
+			if (error.IsDefined())
+				g_warning("%s", error.GetMessage());
+			else
 				g_printerr("input_stream_open() failed\n");
 
 			return 1;
diff --git a/test/run_encoder.cxx b/test/run_encoder.cxx
index b7d64e40a..46edc9618 100644
--- a/test/run_encoder.cxx
+++ b/test/run_encoder.cxx
@@ -23,6 +23,7 @@
 #include "AudioFormat.hxx"
 #include "AudioParser.hxx"
 #include "conf.h"
+#include "util/Error.hxx"
 #include "stdbin.h"
 
 #include <glib.h>
@@ -43,8 +44,6 @@ encoder_to_stdout(Encoder &encoder)
 
 int main(int argc, char **argv)
 {
-	GError *error = NULL;
-	bool ret;
 	const char *encoder_name;
 	static char buffer[32768];
 
@@ -71,11 +70,11 @@ int main(int argc, char **argv)
 	config_param param;
 	param.AddBlockParam("quality", "5.0", -1);
 
-	const auto encoder = encoder_init(*plugin, param, &error);
+	Error error;
+	const auto encoder = encoder_init(*plugin, param, error);
 	if (encoder == NULL) {
 		g_printerr("Failed to initialize encoder: %s\n",
-			   error->message);
-		g_error_free(error);
+			   error.GetMessage());
 		return 1;
 	}
 
@@ -83,20 +82,16 @@ int main(int argc, char **argv)
 
 	AudioFormat audio_format(44100, SampleFormat::S16, 2);
 	if (argc > 2) {
-		ret = audio_format_parse(audio_format, argv[2],
-					 false, &error);
-		if (!ret) {
+		if (!audio_format_parse(audio_format, argv[2], false, error)) {
 			g_printerr("Failed to parse audio format: %s\n",
-				   error->message);
-			g_error_free(error);
+				   error.GetMessage());
 			return 1;
 		}
 	}
 
-	if (!encoder_open(encoder, audio_format, &error)) {
+	if (!encoder_open(encoder, audio_format, error)) {
 		g_printerr("Failed to open encoder: %s\n",
-			   error->message);
-		g_error_free(error);
+			   error.GetMessage());
 		return 1;
 	}
 
@@ -106,22 +101,18 @@ int main(int argc, char **argv)
 
 	ssize_t nbytes;
 	while ((nbytes = read(0, buffer, sizeof(buffer))) > 0) {
-		ret = encoder_write(encoder, buffer, nbytes, &error);
-		if (!ret) {
+		if (!encoder_write(encoder, buffer, nbytes, error)) {
 			g_printerr("encoder_write() failed: %s\n",
-				   error->message);
-			g_error_free(error);
+				   error.GetMessage());
 			return 1;
 		}
 
 		encoder_to_stdout(*encoder);
 	}
 
-	ret = encoder_end(encoder, &error);
-	if (!ret) {
+	if (!encoder_end(encoder, error)) {
 		g_printerr("encoder_flush() failed: %s\n",
-			   error->message);
-		g_error_free(error);
+			   error.GetMessage());
 		return 1;
 	}
 
diff --git a/test/run_filter.cxx b/test/run_filter.cxx
index e39626ea5..62f8dde31 100644
--- a/test/run_filter.cxx
+++ b/test/run_filter.cxx
@@ -27,6 +27,8 @@
 #include "pcm/PcmVolume.hxx"
 #include "MixerControl.hxx"
 #include "stdbin.h"
+#include "util/Error.hxx"
+#include "system/FatalError.hxx"
 
 #include <glib.h>
 
@@ -37,7 +39,7 @@
 
 bool
 mixer_set_volume(gcc_unused Mixer *mixer,
-		 gcc_unused unsigned volume, gcc_unused GError **error_r)
+		 gcc_unused unsigned volume, gcc_unused Error &error)
 {
 	return true;
 }
@@ -70,7 +72,6 @@ static Filter *
 load_filter(const char *name)
 {
 	const struct config_param *param;
-	GError *error = NULL;
 
 	param = find_named_config_block(CONF_AUDIO_FILTER, name);
 	if (param == NULL) {
@@ -78,10 +79,10 @@ load_filter(const char *name)
 		return nullptr;
 	}
 
-	Filter *filter = filter_configured_new(*param, &error);
+	Error error;
+	Filter *filter = filter_configured_new(*param, error);
 	if (filter == NULL) {
-		g_printerr("Failed to load filter: %s\n", error->message);
-		g_error_free(error);
+		g_printerr("Failed to load filter: %s\n", error.GetMessage());
 		return NULL;
 	}
 
@@ -91,8 +92,7 @@ load_filter(const char *name)
 int main(int argc, char **argv)
 {
 	struct audio_format_string af_string;
-	bool success;
-	GError *error = NULL;
+	Error error2;
 	char buffer[4096];
 
 	if (argc < 3 || argc > 4) {
@@ -115,21 +115,16 @@ int main(int argc, char **argv)
 	/* read configuration file (mpd.conf) */
 
 	config_global_init();
-	if (!ReadConfigFile(config_path, &error)) {
-		g_printerr("%s:", error->message);
-		g_error_free(error);
-		return 1;
-	}
+	if (!ReadConfigFile(config_path, error2))
+		FatalError(error2);
 
 	/* parse the audio format */
 
 	if (argc > 3) {
-		success = audio_format_parse(audio_format, argv[3],
-					     false, &error);
-		if (!success) {
+		Error error;
+		if (!audio_format_parse(audio_format, argv[3], false, error)) {
 			g_printerr("Failed to parse audio format: %s\n",
-				   error->message);
-			g_error_free(error);
+				   error.GetMessage());
 			return 1;
 		}
 	}
@@ -142,11 +137,10 @@ int main(int argc, char **argv)
 
 	/* open the filter */
 
-	const AudioFormat out_audio_format =
-		filter->Open(audio_format, &error);
+	Error error;
+	const AudioFormat out_audio_format = filter->Open(audio_format, error);
 	if (!out_audio_format.IsDefined()) {
-		g_printerr("Failed to open filter: %s\n", error->message);
-		g_error_free(error);
+		g_printerr("Failed to open filter: %s\n", error.GetMessage());
 		delete filter;
 		return 1;
 	}
@@ -166,9 +160,9 @@ int main(int argc, char **argv)
 			break;
 
 		dest = filter->FilterPCM(buffer, (size_t)nbytes,
-					 &length, &error);
+					 &length, error);
 		if (dest == NULL) {
-			g_printerr("Filter failed: %s\n", error->message);
+			g_printerr("Filter failed: %s\n", error.GetMessage());
 			filter->Close();
 			delete filter;
 			return 1;
diff --git a/test/run_inotify.cxx b/test/run_inotify.cxx
index e8ca4c8bd..459d0c504 100644
--- a/test/run_inotify.cxx
+++ b/test/run_inotify.cxx
@@ -20,6 +20,7 @@
 #include "config.h"
 #include "InotifySource.hxx"
 #include "event/Loop.hxx"
+#include "util/Error.hxx"
 
 #include <glib.h>
 
@@ -51,7 +52,6 @@ my_inotify_callback(gcc_unused int wd, unsigned mask,
 
 int main(int argc, char **argv)
 {
-	GError *error = NULL;
 	const char *path;
 
 	if (argc != 2) {
@@ -63,20 +63,19 @@ int main(int argc, char **argv)
 
 	event_loop = new EventLoop(EventLoop::Default());
 
+	Error error;
 	InotifySource *source = InotifySource::Create(*event_loop,
 						      my_inotify_callback,
-						      nullptr, &error);
+						      nullptr, error);
 	if (source == NULL) {
-		g_warning("%s", error->message);
-		g_error_free(error);
+		g_warning("%s", error.GetMessage());
 		return 2;
 	}
 
-	int descriptor = source->Add(path, IN_MASK, &error);
+	int descriptor = source->Add(path, IN_MASK, error);
 	if (descriptor < 0) {
 		delete source;
-		g_warning("%s", error->message);
-		g_error_free(error);
+		g_warning("%s", error.GetMessage());
 		return 2;
 	}
 
diff --git a/test/run_input.cxx b/test/run_input.cxx
index 494bcd823..3c74ab509 100644
--- a/test/run_input.cxx
+++ b/test/run_input.cxx
@@ -26,6 +26,7 @@
 #include "InputStream.hxx"
 #include "InputInit.hxx"
 #include "IOThread.hxx"
+#include "util/Error.hxx"
 
 #ifdef ENABLE_ARCHIVE
 #include "ArchiveList.hxx"
@@ -49,7 +50,7 @@ my_log_func(const gchar *log_domain, gcc_unused GLogLevelFlags log_level,
 static int
 dump_input_stream(struct input_stream *is)
 {
-	GError *error = NULL;
+	Error error;
 	char buffer[4096];
 	size_t num_read;
 	ssize_t num_written;
@@ -60,9 +61,8 @@ dump_input_stream(struct input_stream *is)
 
 	input_stream_wait_ready(is);
 
-	if (!input_stream_check(is, &error)) {
-		g_warning("%s", error->message);
-		g_error_free(error);
+	if (!input_stream_check(is, error)) {
+		g_warning("%s", error.GetMessage());
 		input_stream_unlock(is);
 		return EXIT_FAILURE;
 	}
@@ -83,12 +83,10 @@ dump_input_stream(struct input_stream *is)
 		}
 
 		num_read = input_stream_read(is, buffer, sizeof(buffer),
-					     &error);
+					     error);
 		if (num_read == 0) {
-			if (error != NULL) {
-				g_warning("%s", error->message);
-				g_error_free(error);
-			}
+			if (error.IsDefined())
+				g_warning("%s", error.GetMessage());
 
 			break;
 		}
@@ -98,9 +96,8 @@ dump_input_stream(struct input_stream *is)
 			break;
 	}
 
-	if (!input_stream_check(is, &error)) {
-		g_warning("%s", error->message);
-		g_error_free(error);
+	if (!input_stream_check(is, error)) {
+		g_warning("%s", error.GetMessage());
 		input_stream_unlock(is);
 		return EXIT_FAILURE;
 	}
@@ -112,7 +109,7 @@ dump_input_stream(struct input_stream *is)
 
 int main(int argc, char **argv)
 {
-	GError *error = NULL;
+	Error error;
 	struct input_stream *is;
 	int ret;
 
@@ -140,9 +137,8 @@ int main(int argc, char **argv)
 	archive_plugin_init_all();
 #endif
 
-	if (!input_stream_global_init(&error)) {
-		g_warning("%s", error->message);
-		g_error_free(error);
+	if (!input_stream_global_init(error)) {
+		g_warning("%s", error.GetMessage());
 		return 2;
 	}
 
@@ -151,15 +147,14 @@ int main(int argc, char **argv)
 	Mutex mutex;
 	Cond cond;
 
-	is = input_stream_open(argv[1], mutex, cond, &error);
+	is = input_stream_open(argv[1], mutex, cond, error);
 	if (is != NULL) {
 		ret = dump_input_stream(is);
 		input_stream_close(is);
 	} else {
-		if (error != NULL) {
-			g_warning("%s", error->message);
-			g_error_free(error);
-		} else
+		if (error.IsDefined())
+			g_warning("%s", error.GetMessage());
+		else
 			g_printerr("input_stream_open() failed\n");
 		ret = 2;
 	}
diff --git a/test/run_normalize.cxx b/test/run_normalize.cxx
index 5b51f4631..3193fefd2 100644
--- a/test/run_normalize.cxx
+++ b/test/run_normalize.cxx
@@ -27,6 +27,7 @@
 #include "AudioCompress/compress.h"
 #include "AudioParser.hxx"
 #include "AudioFormat.hxx"
+#include "util/Error.hxx"
 #include "stdbin.h"
 
 #include <glib.h>
@@ -37,8 +38,6 @@
 
 int main(int argc, char **argv)
 {
-	GError *error = NULL;
-	bool ret;
 	struct Compressor *compressor;
 	static char buffer[4096];
 	ssize_t nbytes;
@@ -50,11 +49,10 @@ int main(int argc, char **argv)
 
 	AudioFormat audio_format(48000, SampleFormat::S16, 2);
 	if (argc > 1) {
-		ret = audio_format_parse(audio_format, argv[1],
-					 false, &error);
-		if (!ret) {
+		Error error;
+		if (!audio_format_parse(audio_format, argv[1], false, error)) {
 			g_printerr("Failed to parse audio format: %s\n",
-				   error->message);
+				   error.GetMessage());
 			return 1;
 		}
 	}
diff --git a/test/run_output.cxx b/test/run_output.cxx
index 6bf4ebced..59c1a543e 100644
--- a/test/run_output.cxx
+++ b/test/run_output.cxx
@@ -33,6 +33,7 @@
 #include "FilterRegistry.hxx"
 #include "PlayerControl.hxx"
 #include "stdbin.h"
+#include "util/Error.hxx"
 
 #include <glib.h>
 
@@ -48,21 +49,6 @@ GlobalEvents::Emit(gcc_unused Event event)
 {
 }
 
-PcmConvert::PcmConvert() {}
-PcmConvert::~PcmConvert() {}
-
-const void *
-PcmConvert::Convert(gcc_unused const AudioFormat src_format,
-		    gcc_unused const void *src, gcc_unused size_t src_size,
-		    gcc_unused const AudioFormat dest_format,
-		    gcc_unused size_t *dest_size_r,
-		    gcc_unused GError **error_r)
-{
-	g_set_error(error_r, pcm_convert_quark(), 0,
-		    "Not implemented");
-	return NULL;
-}
-
 const struct filter_plugin *
 filter_plugin_by_name(gcc_unused const char *name)
 {
@@ -92,7 +78,6 @@ static struct audio_output *
 load_audio_output(const char *name)
 {
 	const struct config_param *param;
-	GError *error = NULL;
 
 	param = find_named_config_block(CONF_AUDIO_OUTPUT, name);
 	if (param == NULL) {
@@ -102,12 +87,11 @@ load_audio_output(const char *name)
 
 	static struct player_control dummy_player_control(32, 4);
 
+	Error error;
 	struct audio_output *ao =
-		audio_output_new(*param, &dummy_player_control, &error);
-	if (ao == NULL) {
-		g_printerr("%s\n", error->message);
-		g_error_free(error);
-	}
+		audio_output_new(*param, &dummy_player_control, error);
+	if (ao == nullptr)
+		g_printerr("%s\n", error.GetMessage());
 
 	return ao;
 }
@@ -117,19 +101,17 @@ run_output(struct audio_output *ao, AudioFormat audio_format)
 {
 	/* open the audio output */
 
-	GError *error = NULL;
-	if (!ao_plugin_enable(ao, &error)) {
+	Error error;
+	if (!ao_plugin_enable(ao, error)) {
 		g_printerr("Failed to enable audio output: %s\n",
-			   error->message);
-		g_error_free(error);
+			   error.GetMessage());
 		return false;
 	}
 
-	if (!ao_plugin_open(ao, audio_format, &error)) {
+	if (!ao_plugin_open(ao, audio_format, error)) {
 		ao_plugin_disable(ao);
 		g_printerr("Failed to open audio output: %s\n",
-			   error->message);
-		g_error_free(error);
+			   error.GetMessage());
 		return false;
 	}
 
@@ -157,13 +139,12 @@ run_output(struct audio_output *ao, AudioFormat audio_format)
 		if (play_length > 0) {
 			size_t consumed = ao_plugin_play(ao,
 							 buffer, play_length,
-							 &error);
+							 error);
 			if (consumed == 0) {
 				ao_plugin_close(ao);
 				ao_plugin_disable(ao);
 				g_printerr("Failed to play: %s\n",
-					   error->message);
-				g_error_free(error);
+					   error.GetMessage());
 				return false;
 			}
 
@@ -182,8 +163,7 @@ run_output(struct audio_output *ao, AudioFormat audio_format)
 
 int main(int argc, char **argv)
 {
-	bool success;
-	GError *error = NULL;
+	Error error;
 
 	if (argc < 3 || argc > 4) {
 		g_printerr("Usage: run_output CONFIG NAME [FORMAT] <IN\n");
@@ -201,9 +181,8 @@ int main(int argc, char **argv)
 	/* read configuration file (mpd.conf) */
 
 	config_global_init();
-	if (!ReadConfigFile(config_path, &error)) {
-		g_printerr("%s:", error->message);
-		g_error_free(error);
+	if (!ReadConfigFile(config_path, error)) {
+		g_printerr("%s\n", error.GetMessage());
 		return 1;
 	}
 
@@ -221,19 +200,16 @@ int main(int argc, char **argv)
 	/* parse the audio format */
 
 	if (argc > 3) {
-		success = audio_format_parse(audio_format, argv[3],
-					     false, &error);
-		if (!success) {
+		if (!audio_format_parse(audio_format, argv[3], false, error)) {
 			g_printerr("Failed to parse audio format: %s\n",
-				   error->message);
-			g_error_free(error);
+				   error.GetMessage());
 			return 1;
 		}
 	}
 
 	/* do it */
 
-	success = run_output(ao, audio_format);
+	bool success = run_output(ao, audio_format);
 
 	/* cleanup and exit */
 
diff --git a/test/run_resolver.cxx b/test/run_resolver.cxx
index bb7f6deaa..559e12934 100644
--- a/test/run_resolver.cxx
+++ b/test/run_resolver.cxx
@@ -19,6 +19,9 @@
 
 #include "config.h"
 #include "system/Resolver.hxx"
+#include "util/Error.hxx"
+
+#include <glib.h>
 
 #ifdef WIN32
 #include <ws2tcpip.h>
@@ -37,23 +40,21 @@ int main(int argc, char **argv)
 		return EXIT_FAILURE;
 	}
 
-	GError *error = NULL;
+	Error error;
 	struct addrinfo *ai =
 		resolve_host_port(argv[1], 80, AI_PASSIVE, SOCK_STREAM,
-				  &error);
+				  error);
 	if (ai == NULL) {
-		g_printerr("%s\n", error->message);
-		g_error_free(error);
+		g_warning("%s", error.GetMessage());
 		return EXIT_FAILURE;
 	}
 
 	for (const struct addrinfo *i = ai; i != NULL; i = i->ai_next) {
 		char *p = sockaddr_to_string(i->ai_addr, i->ai_addrlen,
-					     &error);
+					     error);
 		if (p == NULL) {
 			freeaddrinfo(ai);
-			g_printerr("%s\n", error->message);
-			g_error_free(error);
+			g_warning("%s", error.GetMessage());
 			return EXIT_FAILURE;
 		}
 
diff --git a/test/software_volume.cxx b/test/software_volume.cxx
index d3b47d74a..19a0be88c 100644
--- a/test/software_volume.cxx
+++ b/test/software_volume.cxx
@@ -27,6 +27,7 @@
 #include "pcm/PcmVolume.hxx"
 #include "AudioParser.hxx"
 #include "AudioFormat.hxx"
+#include "util/Error.hxx"
 #include "stdbin.h"
 
 #include <glib.h>
@@ -36,8 +37,6 @@
 
 int main(int argc, char **argv)
 {
-	GError *error = NULL;
-	bool ret;
 	static char buffer[4096];
 	ssize_t nbytes;
 
@@ -46,13 +45,12 @@ int main(int argc, char **argv)
 		return 1;
 	}
 
+	Error error;
 	AudioFormat audio_format(48000, SampleFormat::S16, 2);
 	if (argc > 1) {
-		ret = audio_format_parse(audio_format, argv[1],
-					 false, &error);
-		if (!ret) {
+		if (!audio_format_parse(audio_format, argv[1], false, error)) {
 			g_printerr("Failed to parse audio format: %s\n",
-				   error->message);
+				   error.GetMessage());
 			return 1;
 		}
 	}
diff --git a/test/test_vorbis_encoder.cxx b/test/test_vorbis_encoder.cxx
index 12e17a785..3d1ac535b 100644
--- a/test/test_vorbis_encoder.cxx
+++ b/test/test_vorbis_encoder.cxx
@@ -24,8 +24,7 @@
 #include "conf.h"
 #include "stdbin.h"
 #include "Tag.hxx"
-
-#include <glib.h>
+#include "util/Error.hxx"
 
 #include <stddef.h>
 #include <unistd.h>
@@ -56,27 +55,27 @@ main(gcc_unused int argc, gcc_unused char **argv)
 	config_param param;
 	param.AddBlockParam("quality", "5.0", -1);
 
-	const auto encoder = encoder_init(*plugin, param, NULL);
+	const auto encoder = encoder_init(*plugin, param, IgnoreError());
 	assert(encoder != NULL);
 
 	/* open the encoder */
 
 	AudioFormat audio_format(44100, SampleFormat::S16, 2);
-	success = encoder_open(encoder, audio_format, NULL);
+	success = encoder_open(encoder, audio_format, IgnoreError());
 	assert(success);
 
 	encoder_to_stdout(*encoder);
 
 	/* write a block of data */
 
-	success = encoder_write(encoder, zero, sizeof(zero), NULL);
+	success = encoder_write(encoder, zero, sizeof(zero), IgnoreError());
 	assert(success);
 
 	encoder_to_stdout(*encoder);
 
 	/* write a tag */
 
-	success = encoder_pre_tag(encoder, NULL);
+	success = encoder_pre_tag(encoder, IgnoreError());
 	assert(success);
 
 	encoder_to_stdout(*encoder);
@@ -85,19 +84,19 @@ main(gcc_unused int argc, gcc_unused char **argv)
 	tag.AddItem(TAG_ARTIST, "Foo");
 	tag.AddItem(TAG_TITLE, "Bar");
 
-	success = encoder_tag(encoder, &tag, NULL);
+	success = encoder_tag(encoder, &tag, IgnoreError());
 	assert(success);
 
 	encoder_to_stdout(*encoder);
 
 	/* write another block of data */
 
-	success = encoder_write(encoder, zero, sizeof(zero), NULL);
+	success = encoder_write(encoder, zero, sizeof(zero), IgnoreError());
 	assert(success);
 
 	/* finish */
 
-	success = encoder_end(encoder, NULL);
+	success = encoder_end(encoder, IgnoreError());
 	assert(success);
 
 	encoder_to_stdout(*encoder);
diff --git a/test/visit_archive.cxx b/test/visit_archive.cxx
index 047ef4d6d..b059f16f9 100644
--- a/test/visit_archive.cxx
+++ b/test/visit_archive.cxx
@@ -28,6 +28,7 @@
 #include "ArchiveFile.hxx"
 #include "ArchiveVisitor.hxx"
 #include "fs/Path.hxx"
+#include "util/Error.hxx"
 
 #include <glib.h>
 
@@ -54,7 +55,7 @@ class MyArchiveVisitor final : public ArchiveVisitor {
 int
 main(int argc, char **argv)
 {
-	GError *error = nullptr;
+	Error error;
 
 	if (argc != 3) {
 		fprintf(stderr, "Usage: visit_archive PLUGIN PATH\n");
@@ -81,9 +82,8 @@ main(int argc, char **argv)
 
 	archive_plugin_init_all();
 
-	if (!input_stream_global_init(&error)) {
-		g_warning("%s", error->message);
-		g_error_free(error);
+	if (!input_stream_global_init(error)) {
+		fprintf(stderr, "%s", error.GetMessage());
 		return 2;
 	}
 
@@ -97,14 +97,13 @@ main(int argc, char **argv)
 
 	int result = EXIT_SUCCESS;
 
-	ArchiveFile *file = archive_file_open(plugin, path.c_str(), &error);
+	ArchiveFile *file = archive_file_open(plugin, path.c_str(), error);
 	if (file != nullptr) {
 		MyArchiveVisitor visitor;
 		file->Visit(visitor);
 		file->Close();
 	} else {
-		fprintf(stderr, "%s\n", error->message);
-		g_error_free(error);
+		fprintf(stderr, "%s", error.GetMessage());
 		result = EXIT_FAILURE;
 	}