Define virtual Track::PasteInto to simplfy Paste...

... Also making EditMenus not dependent on TimeTrack

src/LabelTrack.cpp

@@ -85,6 +85,13 @@ LabelTrack::LabelTrack(const LabelTrack &orig) :
    }
 }
 
+Track::Holder LabelTrack::PasteInto( AudacityProject & ) const
+{
+   auto pNewTrack = std::make_shared<LabelTrack>();
+   pNewTrack->Paste(0.0, this);
+   return pNewTrack;
+}
+
 template<typename IntervalType>
 static IntervalType DoMakeInterval(const LabelStruct &label, size_t index)
 {

src/LabelTrack.h

@@ -155,6 +155,8 @@ public:
    int FindNextLabel(const SelectedRegion& currentSelection);
    int FindPrevLabel(const SelectedRegion& currentSelection);
 
+   Track::Holder PasteInto( AudacityProject & ) const override;
+
    struct IntervalData final : Track::IntervalData {
       size_t index;
       explicit IntervalData(size_t index) : index{index} {};

src/NoteTrack.cpp

@@ -683,6 +683,13 @@ QuantizedTimeAndBeat NoteTrack::NearestBeatTime( double time ) const
    return { seq_time + GetOffset(), beat };
 }
 
+Track::Holder NoteTrack::PasteInto( AudacityProject & ) const
+{
+   auto pNewTrack = std::make_shared<NoteTrack>();
+   pNewTrack->Paste(0.0, this);
+   return pNewTrack;
+}
+
 auto NoteTrack::GetIntervals() const -> ConstIntervals
 {
    ConstIntervals results;

src/NoteTrack.h

@@ -185,6 +185,8 @@ public:
          mVisibleChannels = CHANNEL_BIT(c);
    }
 
+   Track::Holder PasteInto( AudacityProject & ) const override;
+
    ConstIntervals GetIntervals() const override;
    Intervals GetIntervals() override;
 

src/TimeTrack.cpp

@@ -136,6 +136,18 @@ bool TimeTrack::SupportsBasicEditing() const
    return false;
 }
 
+Track::Holder TimeTrack::PasteInto( AudacityProject &project ) const
+{
+   // Maintain uniqueness of the time track!
+   std::shared_ptr<TimeTrack> pNewTrack;
+   if( auto pTrack = *TrackList::Get( project ).Any<TimeTrack>().begin() )
+      pNewTrack = pTrack->SharedPointer<TimeTrack>();
+   else
+      pNewTrack = std::make_shared<TimeTrack>( &ViewInfo::Get( project ) );
+   pNewTrack->Paste(0.0, this);
+   return pNewTrack;
+}
+
 Track::Holder TimeTrack::Cut( double t0, double t1 )
 {
    auto result = Copy( t0, t1, false );

src/TimeTrack.h

@@ -42,6 +42,8 @@ class TimeTrack final : public Track {
 
    bool SupportsBasicEditing() const override;
 
+   Holder PasteInto( AudacityProject & ) const override;
+
    Holder Cut( double t0, double t1 ) override;
    Holder Copy( double t0, double t1, bool forClipboard ) const override;
    void Clear(double t0, double t1) override;

src/Track.h

@@ -321,6 +321,12 @@ class AUDACITY_DLL_API Track /* not final */
    //! Whether this track type implements cut-copy-paste; by default, true
    virtual bool SupportsBasicEditing() const;
 
+   using Holder = std::shared_ptr<Track>;
+
+   //! Find or create the destination track for a paste, maybe in a different project
+   /*! @return A smart pointer to the track; its `use_count()` can tell whether it is new */
+   virtual Holder PasteInto( AudacityProject & ) const = 0;
+
    //! Report times on the track where important intervals begin and end, for UI to snap to
    /*!
    Some intervals may be empty, and no ordering of the intervals is assumed.
@@ -393,7 +399,6 @@ private:
 
    void Init(const Track &orig);
 
-   using Holder = std::shared_ptr<Track>;
    // public nonvirtual duplication function that invokes Clone():
    virtual Holder Duplicate() const;
 

src/WaveTrack.cpp

@@ -334,6 +334,15 @@ static Container MakeIntervals(const std::vector<WaveClipHolder> &clips)
    return result;
 }
 
+Track::Holder WaveTrack::PasteInto( AudacityProject &project ) const
+{
+   auto &trackFactory = WaveTrackFactory::Get( project );
+   auto &pSampleBlockFactory = trackFactory.GetSampleBlockFactory();
+   auto pNewTrack = EmptyCopy( pSampleBlockFactory );
+   pNewTrack->Paste(0.0, this);
+   return pNewTrack;
+}
+
 auto WaveTrack::GetIntervals() const -> ConstIntervals
 {
    return MakeIntervals<ConstIntervals>( mClips );

src/WaveTrack.h

@@ -537,6 +537,8 @@ private:
       std::shared_ptr<WaveClip> pClip;
    };
 
+   Track::Holder PasteInto( AudacityProject & ) const override;
+
    ConstIntervals GetIntervals() const override;
    Intervals GetIntervals() override;
 

src/menus/EditMenus.cpp

@@ -11,7 +11,6 @@
 #include "../ProjectSettings.h"
 #include "../ProjectWindow.h"
 #include "../SelectUtilities.h"
-#include "../TimeTrack.h"
 #include "../TrackPanel.h"
 #include "../TrackPanelAx.h"
 #include "../UndoManager.h"
@@ -76,8 +75,6 @@ bool DoPasteText(AudacityProject &project)
 bool DoPasteNothingSelected(AudacityProject &project)
 {
    auto &tracks = TrackList::Get( project );
-   auto &trackFactory = WaveTrackFactory::Get( project );
-   auto &pSampleBlockFactory = trackFactory.GetSampleBlockFactory();
    auto &selectedRegion = ViewInfo::Get( project ).selectedRegion;
    auto &viewInfo = ViewInfo::Get( project );
    auto &window = ProjectWindow::Get( project );
@@ -94,44 +91,18 @@ bool DoPasteNothingSelected(AudacityProject &project)
 
       Track* pFirstNewTrack = NULL;
       for (auto pClip : clipTrackRange) {
-         Track::Holder uNewTrack;
-         Track *pNewTrack;
-         pClip->TypeSwitch(
-            [&](const WaveTrack *wc) {
-               uNewTrack = wc->EmptyCopy( pSampleBlockFactory );
-               pNewTrack = uNewTrack.get();
-            },
-#ifdef USE_MIDI
-            [&](const NoteTrack *) {
-               uNewTrack = std::make_shared<NoteTrack>(),
-               pNewTrack = uNewTrack.get();
-            },
-#endif
-            [&](const LabelTrack *) {
-               uNewTrack = std::make_shared<LabelTrack>(),
-               pNewTrack = uNewTrack.get();
-            },
-            [&](const TimeTrack *) {
-               // Maintain uniqueness of the time track!
-               pNewTrack = *tracks.Any<TimeTrack>().begin();
-               if (!pNewTrack)
-                  uNewTrack = std::make_shared<TimeTrack>( &viewInfo ),
-                  pNewTrack = uNewTrack.get();
-            }
-         );
-
+         auto pNewTrack = pClip->PasteInto( project );
+         bool newTrack = (pNewTrack.use_count() == 1);
          wxASSERT(pClip);
 
-         pNewTrack->Paste(0.0, pClip);
-
          if (!pFirstNewTrack)
-            pFirstNewTrack = pNewTrack;
+            pFirstNewTrack = pNewTrack.get();
 
          pNewTrack->SetSelected(true);
-         if (uNewTrack)
-            FinishCopy(pClip, uNewTrack, tracks);
+         if (newTrack)
+            FinishCopy(pClip, pNewTrack, tracks);
          else
-            Track::FinishCopy(pClip, pNewTrack);
+            Track::FinishCopy(pClip, pNewTrack.get());
       }
 
       // Select some pasted samples, which is probably impossible to get right