path: root/src/decoder/flac_plugin.c

/*
 * Copyright (C) 2003-2009 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" /* must be first for large file support */
#include "_flac_common.h"
#include "flac_compat.h"
#include "flac_metadata.h"

#if defined(FLAC_API_VERSION_CURRENT) && FLAC_API_VERSION_CURRENT > 7
#include "_ogg_common.h"
#endif

#include <glib.h>

#include <assert.h>
#include <unistd.h>

#include <sys/stat.h>
#include <sys/types.h>

#ifdef HAVE_CUE /* libcue */
#include "../cue/cue_tag.h"
#endif

/* this code was based on flac123, from flac-tools */

static FLAC__StreamDecoderReadStatus
flac_read_cb(G_GNUC_UNUSED const FLAC__StreamDecoder *fd,
	     FLAC__byte buf[], flac_read_status_size_t *bytes,
	     void *fdata)
{
	struct flac_data *data = fdata;
	size_t r;

	r = decoder_read(data->decoder, data->input_stream,
			 (void *)buf, *bytes);
	*bytes = r;

	if (r == 0) {
		if (decoder_get_command(data->decoder) != DECODE_COMMAND_NONE ||
		    input_stream_eof(data->input_stream))
			return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM;
		else
			return FLAC__STREAM_DECODER_READ_STATUS_ABORT;
	}

	return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE;
}

static FLAC__StreamDecoderSeekStatus
flac_seek_cb(G_GNUC_UNUSED const FLAC__StreamDecoder *fd,
	     FLAC__uint64 offset, void *fdata)
{
	struct flac_data *data = (struct flac_data *) fdata;

	if (!input_stream_seek(data->input_stream, offset, SEEK_SET))
		return FLAC__STREAM_DECODER_SEEK_STATUS_ERROR;

	return FLAC__STREAM_DECODER_SEEK_STATUS_OK;
}

static FLAC__StreamDecoderTellStatus
flac_tell_cb(G_GNUC_UNUSED const FLAC__StreamDecoder *fd,
	     FLAC__uint64 * offset, void *fdata)
{
	struct flac_data *data = (struct flac_data *) fdata;

	*offset = (long)(data->input_stream->offset);

	return FLAC__STREAM_DECODER_TELL_STATUS_OK;
}

static FLAC__StreamDecoderLengthStatus
flac_length_cb(G_GNUC_UNUSED const FLAC__StreamDecoder *fd,
	       FLAC__uint64 * length, void *fdata)
{
	struct flac_data *data = (struct flac_data *) fdata;

	if (data->input_stream->size < 0)
		return FLAC__STREAM_DECODER_LENGTH_STATUS_UNSUPPORTED;

	*length = (size_t) (data->input_stream->size);

	return FLAC__STREAM_DECODER_LENGTH_STATUS_OK;
}

static FLAC__bool
flac_eof_cb(G_GNUC_UNUSED const FLAC__StreamDecoder *fd, void *fdata)
{
	struct flac_data *data = (struct flac_data *) fdata;

	return (decoder_get_command(data->decoder) != DECODE_COMMAND_NONE &&
		decoder_get_command(data->decoder) != DECODE_COMMAND_SEEK) ||
		input_stream_eof(data->input_stream);
}

static void
flac_error_cb(G_GNUC_UNUSED const FLAC__StreamDecoder *fd,
	      FLAC__StreamDecoderErrorStatus status, void *fdata)
{
	flac_error_common_cb("flac", status, (struct flac_data *) fdata);
}

#if !defined(FLAC_API_VERSION_CURRENT) || FLAC_API_VERSION_CURRENT <= 7
static void flacPrintErroredState(FLAC__SeekableStreamDecoderState state)
{
	const char *str = ""; /* "" to silence compiler warning */
	switch (state) {
	case FLAC__SEEKABLE_STREAM_DECODER_OK:
	case FLAC__SEEKABLE_STREAM_DECODER_SEEKING:
	case FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM:
		return;
	case FLAC__SEEKABLE_STREAM_DECODER_MEMORY_ALLOCATION_ERROR:
		str = "allocation error";
		break;
	case FLAC__SEEKABLE_STREAM_DECODER_READ_ERROR:
		str = "read error";
		break;
	case FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR:
		str = "seek error";
		break;
	case FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR:
		str = "seekable stream error";
		break;
	case FLAC__SEEKABLE_STREAM_DECODER_ALREADY_INITIALIZED:
		str = "decoder already initialized";
		break;
	case FLAC__SEEKABLE_STREAM_DECODER_INVALID_CALLBACK:
		str = "invalid callback";
		break;
	case FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED:
		str = "decoder uninitialized";
	}

	g_warning("%s\n", str);
}
#else /* FLAC_API_VERSION_CURRENT >= 7 */
static void flacPrintErroredState(FLAC__StreamDecoderState state)
{
	const char *str = ""; /* "" to silence compiler warning */
	switch (state) {
	case FLAC__STREAM_DECODER_SEARCH_FOR_METADATA:
	case FLAC__STREAM_DECODER_READ_METADATA:
	case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
	case FLAC__STREAM_DECODER_READ_FRAME:
	case FLAC__STREAM_DECODER_END_OF_STREAM:
		return;
	case FLAC__STREAM_DECODER_OGG_ERROR:
		str = "error in the Ogg layer";
		break;
	case FLAC__STREAM_DECODER_SEEK_ERROR:
		str = "seek error";
		break;
	case FLAC__STREAM_DECODER_ABORTED:
		str = "decoder aborted by read";
		break;
	case FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR:
		str = "allocation error";
		break;
	case FLAC__STREAM_DECODER_UNINITIALIZED:
		str = "decoder uninitialized";
	}

	g_warning("%s\n", str);
}
#endif /* FLAC_API_VERSION_CURRENT >= 7 */

static void flacMetadata(G_GNUC_UNUSED const FLAC__StreamDecoder * dec,
			 const FLAC__StreamMetadata * block, void *vdata)
{
	flac_metadata_common_cb(block, (struct flac_data *) vdata);
}

static FLAC__StreamDecoderWriteStatus
flac_write_cb(const FLAC__StreamDecoder *dec, const FLAC__Frame *frame,
	      const FLAC__int32 *const buf[], void *vdata)
{
	FLAC__uint32 samples = frame->header.blocksize;
	struct flac_data *data = (struct flac_data *) vdata;
	float timeChange;
	FLAC__uint64 newPosition = 0;

	timeChange = ((float)samples) / frame->header.sample_rate;
	data->time += timeChange;

	FLAC__stream_decoder_get_decode_position(dec, &newPosition);
	if (data->position && newPosition >= data->position) {
		assert(timeChange >= 0);

		data->bit_rate =
		    ((newPosition - data->position) * 8.0 / timeChange)
		    / 1000 + 0.5;
	}
	data->position = newPosition;

	return flac_common_write(data, frame, buf);
}

static struct tag *
flac_tag_load(const char *file, const char *char_tnum)
{
	struct tag *tag;
	FLAC__Metadata_SimpleIterator *it;
	FLAC__StreamMetadata *block = NULL;

	it = FLAC__metadata_simple_iterator_new();
	if (!FLAC__metadata_simple_iterator_init(it, file, 1, 0)) {
		const char *err;
		FLAC_API FLAC__Metadata_SimpleIteratorStatus s;

		s = FLAC__metadata_simple_iterator_status(it);

		switch (s) { /* slightly more human-friendly messages: */
		case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ILLEGAL_INPUT:
			err = "illegal input";
			break;
		case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_ERROR_OPENING_FILE:
			err = "error opening file";
			break;
		case FLAC__METADATA_SIMPLE_ITERATOR_STATUS_NOT_A_FLAC_FILE:
			err = "not a FLAC file";
			break;
		default:
			err = FLAC__Metadata_SimpleIteratorStatusString[s];
		}
		g_debug("Reading '%s' metadata gave the following error: %s\n",
			file, err);
		FLAC__metadata_simple_iterator_delete(it);
		return NULL;
	}

	tag = tag_new();
	do {
		block = FLAC__metadata_simple_iterator_get_block(it);
		if (!block)
			break;

		flac_tag_apply_metadata(tag, char_tnum, block);
		FLAC__metadata_object_delete(block);
	} while (FLAC__metadata_simple_iterator_next(it));

	FLAC__metadata_simple_iterator_delete(it);

	if (!tag_is_defined(tag)) {
		tag_free(tag);
		tag = NULL;
	}

	return tag;
}

#if defined(FLAC_API_VERSION_CURRENT) && FLAC_API_VERSION_CURRENT > 7

static struct tag *
flac_cue_tag_load(const char *file)
{
	struct tag* tag = NULL;
	char* char_tnum = NULL;
	char* ptr = NULL;
	unsigned int tnum = 0;
	unsigned int sample_rate = 0;
	FLAC__uint64 track_time = 0;
#ifdef HAVE_CUE /* libcue */
	FLAC__StreamMetadata* vc;
	char* cs_filename;
	FILE* cs_file;
#endif /* libcue */
	FLAC__StreamMetadata* si = FLAC__metadata_object_new(FLAC__METADATA_TYPE_STREAMINFO);
	FLAC__StreamMetadata* cs;

	tnum = flac_vtrack_tnum(file);
	char_tnum = g_strdup_printf("%u", tnum);

	ptr = strrchr(file, '/');
	*ptr = '\0';

#ifdef HAVE_CUE /* libcue */
	if (FLAC__metadata_get_tags(file, &vc))
	{
		for (unsigned i = 0; i < vc->data.vorbis_comment.num_comments;
		     i++)
		{
			if ((ptr = (char*)vc->data.vorbis_comment.comments[i].entry) != NULL)
			{
				if (g_ascii_strncasecmp(ptr, "cuesheet", 8) == 0)
				{
					while (*(++ptr) != '=');
					tag = cue_tag_string(   ++ptr,
								tnum);
				}
			}
		}

		FLAC__metadata_object_delete(vc);
	}

	if (tag == NULL) {
		cs_filename = g_strconcat(file, ".cue", NULL);

		cs_file = fopen(cs_filename, "rt");
		g_free(cs_filename);

		if (cs_file != NULL) {
			tag = cue_tag_file(cs_file, tnum);
			fclose(cs_file);
		}
	}
#endif /* libcue */

	if (tag == NULL)
		tag = flac_tag_load(file, char_tnum);

	if (char_tnum != NULL) {
		tag_add_item(tag, TAG_TRACK, char_tnum);
		g_free(char_tnum);
	}

	if (FLAC__metadata_get_streaminfo(file, si))
	{
		sample_rate = si->data.stream_info.sample_rate;
		FLAC__metadata_object_delete(si);
	}

	if (FLAC__metadata_get_cuesheet(file, &cs))
	{
		if (cs->data.cue_sheet.tracks != NULL
				&& (tnum <= cs->data.cue_sheet.num_tracks - 1))
		{
			track_time = cs->data.cue_sheet.tracks[tnum].offset
				- cs->data.cue_sheet.tracks[tnum - 1].offset;
		}
		FLAC__metadata_object_delete(cs);
	}

	if (sample_rate != 0)
	{
		tag->time = (unsigned int)(track_time/sample_rate);
	}

	return tag;
}

#endif /* FLAC_API_VERSION_CURRENT >= 7 */

static struct tag *
flac_tag_dup(const char *file)
{
#if defined(FLAC_API_VERSION_CURRENT) && FLAC_API_VERSION_CURRENT > 7
	struct stat st;

	if (stat(file, &st) < 0)
		return flac_cue_tag_load(file);
	else
#endif /* FLAC_API_VERSION_CURRENT >= 7 */
		return flac_tag_load(file, NULL);
}

static void
flac_decoder_loop(struct flac_data *data, FLAC__StreamDecoder *flac_dec,
		  FLAC__uint64 t_start, FLAC__uint64 t_end)
{
	struct decoder *decoder = data->decoder;
	enum decoder_command cmd;

	while (true) {
		if (data->tag != NULL && !tag_is_empty(data->tag)) {
			cmd = decoder_tag(data->decoder, data->input_stream,
					  data->tag);
			tag_free(data->tag);
			data->tag = tag_new();
		} else
			cmd = decoder_get_command(decoder);

		if (cmd == DECODE_COMMAND_SEEK) {
			FLAC__uint64 seek_sample = t_start +
				decoder_seek_where(decoder) *
				data->audio_format.sample_rate;
			if (seek_sample >= t_start &&
			    (t_end == 0 || seek_sample <= t_end) &&
			    FLAC__stream_decoder_seek_absolute(flac_dec, seek_sample)) {
				data->next_frame = seek_sample;
				data->time = (float)(seek_sample - t_start) /
					data->audio_format.sample_rate;
				data->position = 0;
				decoder_command_finished(decoder);
			} else
				decoder_seek_error(decoder);
		} else if (cmd == DECODE_COMMAND_STOP ||
			   FLAC__stream_decoder_get_state(flac_dec) == FLAC__STREAM_DECODER_END_OF_STREAM)
			break;

		if (t_end != 0 && data->next_frame >= t_end)
			/* end of this sub track */
			break;

		if (!FLAC__stream_decoder_process_single(flac_dec)) {
			cmd = decoder_get_command(decoder);
			if (cmd != DECODE_COMMAND_SEEK)
				break;
		}
	}

	if (cmd != DECODE_COMMAND_STOP) {
		flacPrintErroredState(FLAC__stream_decoder_get_state(flac_dec));
		FLAC__stream_decoder_finish(flac_dec);
	}
}

static void
flac_decode_internal(struct decoder * decoder,
		     struct input_stream *input_stream,
		     bool is_ogg)
{
	FLAC__StreamDecoder *flac_dec;
	struct flac_data data;
	const char *err = NULL;

	if (!(flac_dec = FLAC__stream_decoder_new()))
		return;
	flac_data_init(&data, decoder, input_stream);
	data.tag = tag_new();

#if defined(FLAC_API_VERSION_CURRENT) && FLAC_API_VERSION_CURRENT > 7
        if(!FLAC__stream_decoder_set_metadata_respond(flac_dec, FLAC__METADATA_TYPE_VORBIS_COMMENT))
        {
                g_debug("Failed to set metadata respond\n");
        }
#endif

	if (is_ogg) {
#if defined(FLAC_API_VERSION_CURRENT) && FLAC_API_VERSION_CURRENT > 7
		FLAC__StreamDecoderInitStatus status =
			FLAC__stream_decoder_init_ogg_stream(flac_dec,
							     flac_read_cb,
							     flac_seek_cb,
							     flac_tell_cb,
							     flac_length_cb,
							     flac_eof_cb,
							     flac_write_cb,
							     flacMetadata,
							     flac_error_cb,
							     (void *)&data);
		if (status != FLAC__STREAM_DECODER_INIT_STATUS_OK) {
			err = "doing Ogg init()";
			goto fail;
		}
#else
		goto fail;
#endif
	} else {
		FLAC__StreamDecoderInitStatus status =
			FLAC__stream_decoder_init_stream(flac_dec,
							 flac_read_cb,
							 flac_seek_cb,
							 flac_tell_cb,
							 flac_length_cb,
							 flac_eof_cb,
							 flac_write_cb,
							 flacMetadata,
							 flac_error_cb,
							 (void *)&data);
		if (status != FLAC__STREAM_DECODER_INIT_STATUS_OK) {
			err = "doing init()";
			goto fail;
		}
	}

	if (!FLAC__stream_decoder_process_until_end_of_metadata(flac_dec)) {
		err = "problem reading metadata";
		goto fail;
	}

	if (!audio_format_valid(&data.audio_format)) {
		g_warning("Invalid audio format: %u:%u:%u\n",
			  data.audio_format.sample_rate,
			  data.audio_format.bits,
			  data.audio_format.channels);
		goto fail;
	}

	decoder_initialized(decoder, &data.audio_format,
			    input_stream->seekable, data.total_time);

	flac_decoder_loop(&data, flac_dec, 0, 0);

fail:
	flac_data_deinit(&data);
	FLAC__stream_decoder_delete(flac_dec);

	if (err)
		g_warning("%s\n", err);
}

static void
flac_decode(struct decoder * decoder, struct input_stream *input_stream)
{
	flac_decode_internal(decoder, input_stream, false);
}

#if defined(FLAC_API_VERSION_CURRENT) && FLAC_API_VERSION_CURRENT > 7

/**
 * @brief Decode a flac file with embedded cue sheets
 * @param const char* fname filename on fs
 */
static void
flac_container_decode(struct decoder* decoder,
		     const char* fname,
		     bool is_ogg)
{
	unsigned int tnum = 0;
	FLAC__uint64 t_start = 0;
	FLAC__uint64 t_end = 0;
	FLAC__uint64 track_time = 0;
	FLAC__StreamMetadata* cs = NULL;

	FLAC__StreamDecoder *flac_dec;
	FLAC__StreamDecoderInitStatus init_status;
	struct flac_data data;
	const char *err = NULL;

	char* pathname = g_strdup(fname);
	char* slash = strrchr(pathname, '/');
	*slash = '\0';

	tnum = flac_vtrack_tnum(fname);

	cs = FLAC__metadata_object_new(FLAC__METADATA_TYPE_CUESHEET);

	FLAC__metadata_get_cuesheet(pathname, &cs);

	if (cs != NULL)
	{
		if (cs->data.cue_sheet.tracks != NULL
				&& (tnum <= cs->data.cue_sheet.num_tracks - 1))
		{
			t_start = cs->data.cue_sheet.tracks[tnum - 1].offset;
			t_end = cs->data.cue_sheet.tracks[tnum].offset;
			track_time = cs->data.cue_sheet.tracks[tnum].offset
				- cs->data.cue_sheet.tracks[tnum - 1].offset;
		}

		FLAC__metadata_object_delete(cs);
	}
	else
	{
		g_free(pathname);
		return;
	}

	if (!(flac_dec = FLAC__stream_decoder_new()))
	{
		g_free(pathname);
		return;
	}

	flac_data_init(&data, decoder, NULL);

#if defined(FLAC_API_VERSION_CURRENT) && FLAC_API_VERSION_CURRENT > 7
        if(!FLAC__stream_decoder_set_metadata_respond(flac_dec, FLAC__METADATA_TYPE_VORBIS_COMMENT))
        {
                g_debug("Failed to set metadata respond\n");
        }
#endif

	init_status = is_ogg
		? FLAC__stream_decoder_init_ogg_file(flac_dec, pathname,
						     flac_write_cb,
						     flacMetadata,
						     flac_error_cb,
						     &data)
		: FLAC__stream_decoder_init_file(flac_dec,
						 pathname, flac_write_cb,
						 flacMetadata, flac_error_cb,
						 &data);
	g_free(pathname);
	if (init_status != FLAC__STREAM_DECODER_INIT_STATUS_OK) {
		err = "doing init()";
		goto fail;
	}

	if (!FLAC__stream_decoder_process_until_end_of_metadata(flac_dec))
	{
		err = "problem reading metadata";
		goto fail;
	}

	if (!audio_format_valid(&data.audio_format))
	{
		g_warning("Invalid audio format: %u:%u:%u\n",
			  data.audio_format.sample_rate,
			  data.audio_format.bits,
			  data.audio_format.channels);
		goto fail;
	}

	// set track time (order is important: after stream init)
	data.total_time = ((float)track_time / (float)data.audio_format.sample_rate);
	data.position = 0;

	decoder_initialized(decoder, &data.audio_format,
			    true, data.total_time);

	// seek to song start (order is important: after decoder init)
	FLAC__stream_decoder_seek_absolute(flac_dec, (FLAC__uint64)t_start);
	data.next_frame = t_start;

	flac_decoder_loop(&data, flac_dec, t_start, t_end);

fail:
	flac_data_deinit(&data);
	FLAC__stream_decoder_delete(flac_dec);

	if (err)
		g_warning("%s\n", err);
}

/**
 * @brief Open a flac file for decoding
 * @param const char* fname filename on fs
 */
static void
flac_filedecode_internal(struct decoder* decoder,
		     const char* fname,
		     bool is_ogg)
{
	FLAC__StreamDecoder *flac_dec;
	struct flac_data data;
	const char *err = NULL;
	unsigned int flac_err_state = 0;

	if (!(flac_dec = FLAC__stream_decoder_new()))
		return;

	flac_data_init(&data, decoder, NULL);

#if defined(FLAC_API_VERSION_CURRENT) && FLAC_API_VERSION_CURRENT > 7
        if(!FLAC__stream_decoder_set_metadata_respond(flac_dec, FLAC__METADATA_TYPE_VORBIS_COMMENT))
        {
                g_debug("Failed to set metadata respond\n");
        }
#endif


	if (is_ogg)
	{
		if (	(flac_err_state = FLAC__stream_decoder_init_ogg_file(	flac_dec,
										fname,
										flac_write_cb,
										flacMetadata,
										flac_error_cb,
										(void*) &data	))
			== FLAC__STREAM_DECODER_INIT_STATUS_ERROR_OPENING_FILE)
		{
			flac_container_decode(decoder, fname, is_ogg);
		}
		else if (flac_err_state != FLAC__STREAM_DECODER_INIT_STATUS_OK)
		{
			err = "doing Ogg init()";
			goto fail;
		}
	}
	else
	{
		if (	(flac_err_state = FLAC__stream_decoder_init_file(	flac_dec,
										fname,
										flac_write_cb,
										flacMetadata,
										flac_error_cb,
										(void*) &data	))
			== FLAC__STREAM_DECODER_INIT_STATUS_ERROR_OPENING_FILE)
		{
			flac_container_decode(decoder, fname, is_ogg);
		}
		else if (flac_err_state != FLAC__STREAM_DECODER_INIT_STATUS_OK)
		{
			err = "doing init()";
			goto fail;
		}
	}

	if (!FLAC__stream_decoder_process_until_end_of_metadata(flac_dec))
	{
		err = "problem reading metadata";
		goto fail;
	}

	if (!audio_format_valid(&data.audio_format))
	{
		g_warning("Invalid audio format: %u:%u:%u\n",
			  data.audio_format.sample_rate,
			  data.audio_format.bits,
			  data.audio_format.channels);
		goto fail;
	}

	decoder_initialized(decoder, &data.audio_format,
			    true, data.total_time);

	flac_decoder_loop(&data, flac_dec, 0, 0);

fail:
	flac_data_deinit(&data);
	FLAC__stream_decoder_delete(flac_dec);

	if (err)
		g_warning("%s\n", err);
}

/**
 * @brief	wrapper function for
 * 		flac_filedecode_internal method
 * 		for decoding without ogg
 */
static void
flac_filedecode(struct decoder *decoder, const char *fname)
{
	struct stat st;

	if (stat(fname, &st) < 0) {
		flac_container_decode(decoder, fname, false);
	} else 
		flac_filedecode_internal(decoder, fname, false);
}

#endif /* FLAC_API_VERSION_CURRENT >= 7 */

#ifndef HAVE_OGGFLAC

static bool
oggflac_init(G_GNUC_UNUSED const struct config_param *param)
{
#if defined(FLAC_API_VERSION_CURRENT) && FLAC_API_VERSION_CURRENT > 7
	return !!FLAC_API_SUPPORTS_OGG_FLAC;
#else
	/* disable oggflac when libflac is too old */
	return false;
#endif
}

#if defined(FLAC_API_VERSION_CURRENT) && FLAC_API_VERSION_CURRENT > 7

static struct tag *
oggflac_tag_dup(const char *file)
{
	struct tag *ret = NULL;
	FLAC__Metadata_Iterator *it;
	FLAC__StreamMetadata *block;
	FLAC__Metadata_Chain *chain = FLAC__metadata_chain_new();

	if (!(FLAC__metadata_chain_read_ogg(chain, file)))
		goto out;
	it = FLAC__metadata_iterator_new();
	FLAC__metadata_iterator_init(it, chain);

	ret = tag_new();
	do {
		if (!(block = FLAC__metadata_iterator_get_block(it)))
			break;

		flac_tag_apply_metadata(ret, NULL, block);
	} while (FLAC__metadata_iterator_next(it));
	FLAC__metadata_iterator_delete(it);

	if (!tag_is_defined(ret)) {
		tag_free(ret);
		ret = NULL;
	}

out:
	FLAC__metadata_chain_delete(chain);
	return ret;
}

static void
oggflac_decode(struct decoder *decoder, struct input_stream *input_stream)
{
	if (ogg_stream_type_detect(input_stream) != FLAC)
		return;

	/* rewind the stream, because ogg_stream_type_detect() has
	   moved it */
	input_stream_seek(input_stream, 0, SEEK_SET);

	flac_decode_internal(decoder, input_stream, true);
}

static const char *const oggflac_suffixes[] = { "ogg", "oga", NULL };
static const char *const oggflac_mime_types[] = {
	"audio/x-flac+ogg",
	"application/ogg",
	"application/x-ogg",
	NULL
};

#endif /* FLAC_API_VERSION_CURRENT >= 7 */

const struct decoder_plugin oggflac_decoder_plugin = {
	.name = "oggflac",
	.init = oggflac_init,
#if defined(FLAC_API_VERSION_CURRENT) && FLAC_API_VERSION_CURRENT > 7
	.stream_decode = oggflac_decode,
	.tag_dup = oggflac_tag_dup,
	.suffixes = oggflac_suffixes,
	.mime_types = oggflac_mime_types
#endif
};

#endif /* HAVE_OGGFLAC */

static const char *const flac_suffixes[] = { "flac", NULL };
static const char *const flac_mime_types[] = {
	"audio/x-flac", "application/x-flac", NULL
};

const struct decoder_plugin flac_decoder_plugin = {
	.name = "flac",
	.stream_decode = flac_decode,
#if defined(FLAC_API_VERSION_CURRENT) && FLAC_API_VERSION_CURRENT > 7
	.file_decode = flac_filedecode,
#endif /* FLAC_API_VERSION_CURRENT >= 7 */
	.tag_dup = flac_tag_dup,
	.suffixes = flac_suffixes,
	.mime_types = flac_mime_types,
#if defined(FLAC_API_VERSION_CURRENT) && FLAC_API_VERSION_CURRENT > 7
	.container_scan = flac_cue_track,
#endif /* FLAC_API_VERSION_CURRENT >= 7 */
};