Define AudioTrack and PlayableTrack as common bases for Wave and Note

src/NoteTrack.cpp

@@ -103,8 +103,8 @@ NoteTrack::Holder TrackFactory::NewNoteTrack()
    return std::make_unique<NoteTrack>(mDirManager);
 }
 
-NoteTrack::NoteTrack(const std::shared_ptr<DirManager> &projDirManager):
-Track(projDirManager)
+NoteTrack::NoteTrack(const std::shared_ptr<DirManager> &projDirManager)
+   : NoteTrackBase(projDirManager)
 {
    SetDefaultName(_("Note Track"));
    SetName(GetDefaultName());

src/NoteTrack.h

@@ -50,7 +50,17 @@ class wxRect;
 class DirManager;
 class Alg_seq;   // from "allegro.h"
 
-class AUDACITY_DLL_API NoteTrack final : public Track {
+using NoteTrackBase =
+#ifdef EXPERIMENTAL_MIDI_OUT
+   PlayableTrack
+#else
+   AudioTrack
+#endif
+   ;
+
+class AUDACITY_DLL_API NoteTrack final
+   : public NoteTrackBase
+{
  public:
    friend class TrackArtist;
 

src/Track.h

@@ -251,6 +251,22 @@ class AUDACITY_DLL_API Track /* not final */ : public XMLTagHandler
    bool IsSyncLockSelected() const;
 };
 
+class AudioTrack /* not final */ : public Track
+{
+public:
+   AudioTrack(const std::shared_ptr<DirManager> &projDirManager)
+      : Track{ projDirManager } {}
+   AudioTrack(const Track &orig) : Track{ orig } {}
+};
+
+class PlayableTrack /* not final */ : public AudioTrack
+{
+public:
+   PlayableTrack(const std::shared_ptr<DirManager> &projDirManager)
+      : AudioTrack{ projDirManager } {}
+   PlayableTrack(const Track &orig) : AudioTrack{ orig } {}
+};
+
 class AUDACITY_DLL_API TrackListIterator /* not final */
 {
  public:

src/WaveTrack.cpp

@@ -79,7 +79,7 @@ WaveTrack::Holder TrackFactory::NewWaveTrack(sampleFormat format, double rate)
 }
 
 WaveTrack::WaveTrack(const std::shared_ptr<DirManager> &projDirManager, sampleFormat format, double rate) :
-   Track(projDirManager)
+   PlayableTrack(projDirManager)
 {
    if (format == (sampleFormat)0)
    {
@@ -116,7 +116,7 @@ WaveTrack::WaveTrack(const std::shared_ptr<DirManager> &projDirManager, sampleFo
 }
 
 WaveTrack::WaveTrack(const WaveTrack &orig):
-   Track(orig)
+   PlayableTrack(orig)
    , mpSpectrumSettings(orig.mpSpectrumSettings
       ? std::make_unique<SpectrogramSettings>(*orig.mpSpectrumSettings)
       : nullptr
@@ -141,7 +141,7 @@ WaveTrack::WaveTrack(const WaveTrack &orig):
 // Copy the track metadata but not the contents.
 void WaveTrack::Init(const WaveTrack &orig)
 {
-   Track::Init(orig);
+   PlayableTrack::Init(orig);
    mFormat = orig.mFormat;
    mRate = orig.mRate;
    mGain = orig.mGain;
@@ -171,7 +171,7 @@ void WaveTrack::Merge(const Track &orig)
       SetWaveformSettings
          (wt.mpWaveformSettings ? std::make_unique<WaveformSettings>(*wt.mpWaveformSettings) : nullptr);
    }
-   Track::Merge(orig);
+   PlayableTrack::Merge(orig);
 }
 
 WaveTrack::~WaveTrack()

src/WaveTrack.h

@@ -69,7 +69,7 @@ class Regions : public std::vector < Region > {};
 
 class Envelope;
 
-class AUDACITY_DLL_API WaveTrack final : public Track {
+class AUDACITY_DLL_API WaveTrack final : public PlayableTrack {
 
  private: