mpd/src/tag/Fallback.hxx

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/*
* Copyright 2003-2018 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_TAG_FALLBACK_HXX
#define MPD_TAG_FALLBACK_HXX
#include <utility>
template<typename F>
bool
ApplyTagFallback(TagType type, F &&f) noexcept
{
if (type == TAG_ALBUM_ARTIST_SORT) {
/* fall back to "AlbumArtist", "ArtistSort" and
"Artist" if no "AlbumArtistSort" was found */
if (f(TAG_ALBUM_ARTIST))
return true;
return ApplyTagFallback(TAG_ARTIST_SORT, std::forward<F>(f));
}
if (type == TAG_ALBUM_ARTIST || type == TAG_ARTIST_SORT)
/* fall back to "Artist" if no
"AlbumArtist"/"ArtistSort" was found */
return f(TAG_ARTIST);
return false;
}
template<typename F>
bool
ApplyTagWithFallback(TagType type, F &&f) noexcept
{
return f(type) || ApplyTagFallback(type, std::forward<F>(f));
}
#endif