PendingTracks.h

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/**********************************************************************
 
 Audacity: A Digital Audio Editor
 
 @file PendingTracks.h
 
 Paul Licameli
 
 **********************************************************************/
#ifndef __AUDACITY_PENDING_TRACKS__
#define __AUDACITY_PENDING_TRACKS__
 
#include "ClientData.h"
#include "Observer.h"
 
class AudacityProject;
class Channel;
class Track;
class TrackId;
class TrackList;
struct TrackListEvent;
 
class TRACK_API PendingTracks final
   : public ClientData::Base
   , public Observer::Publisher<TrackListEvent>
{
public:
   static PendingTracks &Get(AudacityProject &project);
   static const PendingTracks &Get(const AudacityProject &project);
 
   explicit PendingTracks(AudacityProject &project);
   PendingTracks(const PendingTracks&) = delete;
   PendingTracks &operator=(const PendingTracks&) = delete;
   ~PendingTracks();
 
 
   void RegisterPendingNewTracks(TrackList &&list);
 
   Channel &SubstitutePendingChangedChannel(Channel &channel) const;
   const Channel &SubstitutePendingChangedChannel(const Channel &channel) const;
 
   Track &SubstitutePendingChangedTrack(Track &track) const;
   const Track &SubstitutePendingChangedTrack(const Track &track) const;
 
   const Channel &SubstituteOriginalChannel(const Channel &channel) const;
 
   const Track &SubstituteOriginalTrack(const Track &track) const;
 
   using Updater = std::function<void(Track &dest, const Track &src)>;
 
   //
   Track* RegisterPendingChangedTrack(
      Updater updater,
      Track *src
   );
 
   void UpdatePendingTracks();
 
 
   void ClearPendingTracks(
      std::vector<std::shared_ptr<Track>> *pAdded = nullptr);
 
   //
   bool ApplyPendingTracks();
 
   bool HasPendingTracks() const;
 
private:
   std::pair<Track *, Channel *>
   DoSubstitutePendingChangedChannel(Track &track, size_t channelIndex) const;
 
   std::pair<const Track *, const Channel*>
   DoSubstituteOriginalChannel(const Track &track, size_t channelIndex) const;
 
   TrackList &mTracks;
   Observer::Subscription mTrackListSubscription;
   std::vector<Updater> mUpdaters;
   std::shared_ptr<TrackList> mPendingUpdates;
};
 
#endif