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/*
* Copyright 2003-2019 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_DATABASE_INTERFACE_HXX
#define MPD_DATABASE_INTERFACE_HXX
#include "Visitor.hxx"
#include "tag/Type.h"
#include "util/Compiler.h"
#include <chrono>
#include <string>
struct DatabasePlugin;
struct DatabaseStats;
struct DatabaseSelection;
struct LightSong;
template<typename Key> class RecursiveMap;
template<typename T> struct ConstBuffer;
class Database {
const DatabasePlugin &plugin;
protected:
Database(const DatabasePlugin &_plugin) noexcept
:plugin(_plugin) {}
public:
/**
* Free instance data.
*/
virtual ~Database() noexcept = default;
const DatabasePlugin &GetPlugin() const noexcept {
return plugin;
}
/**
* Open the database. Read it into memory if applicable.
*
* Throws on error (e.g. #DatabaseError).
*/
virtual void Open() {
}
/**
* Close the database, free allocated memory.
*/
virtual void Close() noexcept {}
/**
* Look up a song (including tag data) in the database. When
* you don't need this anymore, call ReturnSong().
*
* Throws on error. "Not found" is an error that throws
* DatabaseErrorCode::NOT_FOUND.
*
* @param uri_utf8 the URI of the song within the music
* directory (UTF-8)
* @return a pointer that must be released with ReturnSong()
*/
virtual const LightSong *GetSong(const char *uri_utf8) const = 0;
/**
* Mark the song object as "unused". Call this on objects
* returned by GetSong().
*/
virtual void ReturnSong(const LightSong *song) const noexcept = 0;
/**
* Visit the selected entities.
*
* Throws on error.
*/
virtual void Visit(const DatabaseSelection &selection,
VisitDirectory visit_directory,
VisitSong visit_song,
VisitPlaylist visit_playlist) const = 0;
void Visit(const DatabaseSelection &selection,
VisitDirectory visit_directory,
VisitSong visit_song) const {
Visit(selection, visit_directory, visit_song, VisitPlaylist());
}
void Visit(const DatabaseSelection &selection,
VisitSong visit_song) const {
return Visit(selection, VisitDirectory(), visit_song);
}
/**
* Collect unique values of the given tag types. Each item in
* the #tag_types parameter results in one nesting level in
* the return value.
*
* Throws on error.
*/
virtual RecursiveMap<std::string> CollectUniqueTags(const DatabaseSelection &selection,
ConstBuffer<TagType> tag_types) const = 0;
/**
* Throws on error.
*/
virtual DatabaseStats GetStats(const DatabaseSelection &selection) const = 0;
/**
* Update the database.
*
* Throws on error.
*
* @return the job id or 0 if not implemented
*/
virtual unsigned Update(gcc_unused const char *uri_utf8,
gcc_unused bool discard) {
/* not implemented: return 0 */
return 0;
}
/**
* Returns the time stamp of the last database update.
* Returns a negative value if that is not not known/available.
*/
gcc_pure
virtual std::chrono::system_clock::time_point GetUpdateStamp() const noexcept = 0;
};
#endif
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