test/ContainerScan: new debug program

Makefile.am

@@ -1644,6 +1644,7 @@ noinst_PROGRAMS = \
 	test/run_decoder \
 	test/read_tags \
 	test/ReadApeTags \
+	test/ContainerScan \
 	test/run_filter \
 	test/run_output \
 	test/run_convert \
@@ -1930,6 +1931,25 @@ test_ReadApeTags_SOURCES = \
 	src/Log.cxx src/LogBackend.cxx \
 	test/ReadApeTags.cxx
 
+test_ContainerScan_LDADD = \
+	$(DECODER_LIBS) \
+	libpcm.a \
+	$(INPUT_LIBS) \
+	$(ARCHIVE_LIBS) \
+	$(TAG_LIBS) \
+	libconf.a \
+	libbasic.a \
+	libevent.a \
+	libthread.a \
+	$(FS_LIBS) \
+	$(ICU_LDADD) \
+	libsystem.a \
+	libutil.a
+test_ContainerScan_SOURCES = test/ContainerScan.cxx \
+	src/Log.cxx src/LogBackend.cxx \
+	src/ReplayGainInfo.cxx \
+	$(DECODER_SRC)
+
 if ENABLE_ID3TAG
 test_dump_rva2_LDADD = \
 	$(TAG_LIBS) \

test/ContainerScan.cxx

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2003-2016 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.
+ */
+
+#include "config.h"
+#include "Log.hxx"
+#include "decoder/DecoderList.hxx"
+#include "decoder/DecoderPlugin.hxx"
+#include "fs/Path.hxx"
+#include "fs/io/StdioOutputStream.hxx"
+#include "fs/io/BufferedOutputStream.hxx"
+#include "util/UriUtil.hxx"
+
+#include <stdexcept>
+
+#include <assert.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+static const DecoderPlugin *
+FindContainerDecoderPlugin(const char *suffix)
+{
+	return decoder_plugins_find([suffix](const DecoderPlugin &plugin){
+			return plugin.container_scan != nullptr &&
+				plugin.SupportsSuffix(suffix);
+		});
+}
+
+static const DecoderPlugin *
+FindContainerDecoderPlugin(Path path)
+{
+	const auto utf8 = path.ToUTF8();
+	if (utf8.empty())
+		return nullptr;
+
+	UriSuffixBuffer suffix_buffer;
+	const char *const suffix = uri_get_suffix(utf8.c_str(), suffix_buffer);
+	if (suffix == nullptr)
+		return nullptr;
+
+	return FindContainerDecoderPlugin(suffix);
+}
+
+int main(int argc, char **argv)
+try {
+	if (argc != 2) {
+		fprintf(stderr, "Usage: ContainerScan PATH\n");
+		return EXIT_FAILURE;
+	}
+
+	const Path path = Path::FromFS(argv[1]);
+
+	decoder_plugin_init_all();
+
+	const auto *plugin = FindContainerDecoderPlugin(path);
+	if (plugin == nullptr) {
+		fprintf(stderr, "No decoder found for this file\n");
+		return EXIT_FAILURE;
+	}
+
+	const auto v = plugin->container_scan(path);
+	if (v.empty()) {
+		fprintf(stderr, "File is not a container\n");
+		return EXIT_FAILURE;
+	}
+
+	StdioOutputStream sos(stdout);
+	BufferedOutputStream bos(sos);
+
+	for (const auto &song : v)
+		bos.Format("%s\n", song.c_str());
+
+	bos.Flush();
+
+	decoder_plugin_deinit_all();
+
+	return EXIT_SUCCESS;
+} catch (const std::exception &e) {
+	LogError(e);
+	return EXIT_FAILURE;
+}