strawberry-audio-player-windows-mac-linux/src/core/urlhandler.h

/*
 * Strawberry Music Player
 * This file was part of Clementine.
 * Copyright 2010, David Sansome <me@davidsansome.com>
 *
 * Strawberry 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.
 *
 * Strawberry 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 Strawberry.  If not, see <http://www.gnu.org/licenses/>.
 * 
 */

#ifndef URLHANDLER_H
#define URLHANDLER_H

#include "config.h"

#include <QtGlobal>
#include <QObject>
#include <QString>
#include <QUrl>
#include <QIcon>

class UrlHandler : public QObject {
  Q_OBJECT

 public:
  explicit UrlHandler(QObject *parent = nullptr);

  // The URL scheme that this handler handles.
  virtual QString scheme() const = 0;
  virtual QIcon icon() const;

  // Returned by StartLoading() and LoadNext(), indicates what the player should do when it wants to load a URL.
  struct LoadResult {
    enum Type {
      // There wasn't a track available, and the player should move on to the next playlist item.
      NoMoreTracks,

      // There might be another track available but the handler needs to do some work (eg. fetching a remote playlist) to find out.
      // AsyncLoadComplete will be emitted later with the same original_url.
      WillLoadAsynchronously,

      // There was a track available.  Its url is in media_url.
      TrackAvailable,
    };

    LoadResult(const QUrl &original_url = QUrl(), Type type = NoMoreTracks, const QUrl &media_url = QUrl(), qint64 length_nanosec_ = -1);

    // The url that the playlist item has in Url().
    // Might be something unplayable like lastfm://...
    QUrl original_url_;

    Type type_;

    // The actual url to something that gstreamer can play.
    QUrl media_url_;

    // Track length, if we are able to get it only now
    qint64 length_nanosec_;
  };

  // Called by the Player when a song starts loading - gives the handler a chance to do something clever to get a playable track.
  virtual LoadResult StartLoading(const QUrl &url) { return LoadResult(url); }

  // Called by the player when a song finishes - gives the handler a chance to get another track to play.
  virtual LoadResult LoadNext(const QUrl &url) { return LoadResult(url); }

  // Functions to be warned when something happen to a track handled by UrlHandler.
  virtual void TrackAboutToEnd() {};
  virtual void TrackSkipped() {};

signals:
  void AsyncLoadComplete(const UrlHandler::LoadResult &result);
};

#endif  // URLHANDLER_H