parserbase.h

/* This file is part of Clementine.
   Copyright 2010, David Sansome <me@davidsansome.com>

   Clementine 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 3 of the License, or
   (at your option) any later version.

   Clementine 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 Clementine.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef PARSERBASE_H
#define PARSERBASE_H

#include <QDir>
#include <QObject>

#include "core/song.h"
#include "playlist/playlist.h"

class LibraryBackendInterface;

class ParserBase : public QObject {
  Q_OBJECT

 public:
  ParserBase(LibraryBackendInterface* library, QObject* parent = nullptr);

  virtual QString name() const = 0;
  virtual QStringList file_extensions() const = 0;
  virtual QString mime_type() const { return QString(); }

  virtual bool TryMagic(const QByteArray& data) const = 0;

  // Loads all songs from playlist found at path 'playlist_path' in directory
  // 'dir'.
  // The 'device' argument is an opened and ready to read from representation of
  // this playlist.
  // This method might not return all of the songs found in the playlist. Any
  // playlist
  // parser may decide to leave out some entries if it finds them incomplete or
  // invalid.
  // This means that the final resulting SongList should be considered valid (at
  // least
  // from the parser's point of view).
  virtual SongList Load(QIODevice* device, const QString& playlist_path = "",
                        const QDir& dir = QDir()) const = 0;
  virtual void Save(
      const SongList& songs, QIODevice* device, const QDir& dir = QDir(),
      Playlist::Path path_type = Playlist::Path_Automatic) const = 0;

 signals:
  void Error(const QString& msg) const;

 protected:
  // Loads a song.  If filename_or_url is a URL (with a scheme other than
  // "file") then it is set on the song and the song marked as a stream.
  // If it is a filename or a file:// URL then it is made absolute and canonical
  // and set as a file:// url on the song.  Also sets the song's metadata by
  // searching in the Library, or loading from the file as a fallback.
  // This function should always be used when loading a playlist.
  Song LoadSong(const QString& filename_or_url, qint64 beginning,
                const QDir& dir) const;
  void LoadSong(const QString& filename_or_url, qint64 beginning,
                const QDir& dir, Song* song) const;

  // If the URL is a file:// URL then returns its path, absolute or relative to
  // the directory depending on the path_type option.
  // Otherwise returns the URL as is.
  // This function should always be used when saving a playlist.
  QString URLOrFilename(const QUrl& url, const QDir& dir,
                        Playlist::Path path_type) const;

 private:
  LibraryBackendInterface* library_;
};

#endif  // PARSERBASE_H