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/***************************************************************************
begin : Thu Aug 19 2004
copyright : (C) 2002 - 2004 by Michael Pyne
email : [email protected]
***************************************************************************/
/***************************************************************************
* *
* 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. *
* *
***************************************************************************/
#ifndef _TRACKSEQUENCEITERATOR_H
#define _TRACKSEQUENCEITERATOR_H
#include "playlistitem.h"
#include "playlistsearch.h"
class Playlist;
/**
* This abstract class defines an interface to be used by TrackSequenceManager,
* to iterate over the items in a playlist. Implement this class in a subclass
* in order to define your own ordering for playlist sequences. For an example,
* see the UpcomingPlaylist class.
*
* @author Michael Pyne <[email protected]>
* @see UpcomingPlaylist
* @see TrackSequenceManager
*/
class TrackSequenceIterator
{
public:
/**
* Default constructor.
*/
TrackSequenceIterator();
/**
* Default copy constructor.
*
* @param other the TrackSequenceIterator we are copying
*/
TrackSequenceIterator(const TrackSequenceIterator & other);
/**
* Default destructor.
*/
virtual ~TrackSequenceIterator();
/**
* This function moves the current item to the next track. You must
* reimplement this function in your subclasses.
*/
virtual void advance() = 0;
/**
* This function moves the current item to the previous track. This may
* not always make sense, and the history functionality of the Playlist
* class currently overrides this. You must reimplement this function in
* your subclass.
*/
virtual void backup() = 0;
/**
* This function returns the current PlaylistItem, or 0 if the iterator is
* not pointing at any PlaylistItem.
*
* @return current track
*/
virtual PlaylistItem *current() const { return m_current; }
/**
* This function creates a perfect copy of the object it is called on, to
* avoid the C++ slicing problem. When you reimplement this function, you
* should change the return type to the name of the subclass.
*
* @return pointer to a copy of the object
*/
virtual TrackSequenceIterator *clone() const = 0;
/**
* This function is called by the TrackSequenceManager when current() returns
* 0, if the TrackSequenceManager has a playlist defined. This function
* should choose an appropriate starting track and set it as the current
* item. This function must be reimplemented in subclasses.
*
* @param playlist the playlist to iterate over
*/
virtual void prepareToPlay(Playlist *playlist) = 0;
/**
* This function is called whenever the current playlist changes, such as
* having a new search applied, items added/removed, etc. If you need to
* update internal state, you should do so without affecting the current
* playing item. Default implementation does nothing.
*/
virtual void playlistChanged();
/**
* This function is called by the manager when \p item is about to be
* removed. Subclasses should ensure that they're not still holding a
* pointer to the item. The default implementation does nothing.
*
* @param item the item about to be removed.
*/
virtual void itemAboutToDie(const PlaylistItem *item);
/**
* This function is called by the TrackSequenceManager is some situations,
* such as when playback is being stopped. If you subclass needs to reset
* any internal data members, do so in this function. This function must
* be reimplemented in subclasses.
*/
virtual void reset() = 0;
/**
* This function is a public mutator to set the current item.
*
* @param current the new current item
*/
virtual void setCurrent(PlaylistItem *current);
private:
PlaylistItem::Pointer m_current; ///< the current item
};
/**
* This is the default iterator for JuK, supporting normal, random, and album
* random playback with or without looping.
*
* @author Michael Pyne <[email protected]>
*/
class DefaultSequenceIterator : public TrackSequenceIterator
{
public:
/**
* Default constructor.
*/
DefaultSequenceIterator();
/**
* Default copy constructor.
*
* @param other the DefaultSequenceIterator to copy.
*/
DefaultSequenceIterator(const DefaultSequenceIterator &other);
/**
* Default destructor.
*/
virtual ~DefaultSequenceIterator();
/**
* This function advances to the next item in the current sequence. The
* algorithm used depends on what playback mode is selected.
*/
virtual void advance();
/**
* This function moves to the previous item in the playlist. This occurs
* no matter what playback mode is selected.
*/
virtual void backup();
/**
* This function prepares the class for iterator. If no random play mode
* is selected, the first item in the given playlist is the starting item.
* Otherwise, an item is randomly picked to be the starting item.
*
* @param playlist The playlist to initialize for.
*/
virtual void prepareToPlay(Playlist *playlist);
/**
* This function clears all internal state, including any random play lists,
* and what the current album is.
*/
virtual void reset();
/**
* This function recalculates the random lists, and is should be called
* whenever its current playlist changes (at least for searches).
*/
virtual void playlistChanged();
/**
* Called when \p item is about to be removed. This function ensures that
* it isn't remaining in the random play list.
*/
virtual void itemAboutToDie(const PlaylistItem *item);
/**
* This function sets the current item, and initializes any internal lists
* that may be needed for playback.
*
* @param current The new current item.
*/
virtual void setCurrent(PlaylistItem *current);
/**
* This function returns a perfect copy of the object it is called on, to
* get around the C++ slicing problem.
*
* @return A copy of the object the method is called on.
*/
virtual DefaultSequenceIterator *clone() const;
private:
/**
* Reinitializes the internal random play list based on the playlist given
* by \p p. The currently playing item, if any, is automatically removed
* from the list.
*
* @param p The Playlist to read items from. If p is 0, the playlist of
* the currently playing item is used instead.
*/
void refillRandomList(Playlist *p = 0);
void initAlbumSearch(PlaylistItem *searchItem);
private:
PlaylistItemList m_randomItems;
PlaylistSearch m_albumSearch;
};
#endif /* _TRACKSEQUENCEITERATOR_H */
// vim: set et sw=4:
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