All tracks allocated with make_shared, no more make_unique...

... so that we can use Track::SharedPointer without undefined behavior even on
tracks that don't yet belong to any TrackList.

Also fix the return type of function template TrackList::Add and remove some
casts.

src/LabelTrack.cpp

@@ -99,7 +99,7 @@ int LabelTrack::mFontHeight=-1;
 
 LabelTrack::Holder TrackFactory::NewLabelTrack()
 {
-   return std::make_unique<LabelTrack>(mDirManager);
+   return std::make_shared<LabelTrack>(mDirManager);
 }
 
 LabelTrack::LabelTrack(const std::shared_ptr<DirManager> &projDirManager):
@@ -1142,7 +1142,7 @@ double LabelTrack::GetEndTime() const
 
 Track::Holder LabelTrack::Duplicate() const
 {
-   return std::make_unique<LabelTrack>( *this );
+   return std::make_shared<LabelTrack>( *this );
 }
 
 void LabelTrack::SetSelected(bool s)
@@ -2489,7 +2489,7 @@ Track::Holder LabelTrack::SplitCut(double t0, double t1)
 
 Track::Holder LabelTrack::Copy(double t0, double t1, bool) const
 {
-   auto tmp = std::make_unique<LabelTrack>(GetDirManager());
+   auto tmp = std::make_shared<LabelTrack>(GetDirManager());
    const auto lt = static_cast<LabelTrack*>(tmp.get());
 
    for (auto &labelStruct: mLabels) {
@@ -2534,8 +2534,7 @@ Track::Holder LabelTrack::Copy(double t0, double t1, bool) const
    }
    lt->mClipLen = (t1 - t0);
 
-   // This std::move is needed to "upcast" the pointer type
-   return std::move(tmp);
+   return tmp;
 }
 
 

src/LabelTrack.h

@@ -161,7 +161,7 @@ class AUDACITY_DLL_API LabelTrack final : public Track
    double GetStartTime() const override;
    double GetEndTime() const override;
 
-   using Holder = std::unique_ptr<LabelTrack>;
+   using Holder = std::shared_ptr<LabelTrack>;
    Track::Holder Duplicate() const override;
 
    void SetSelected(bool s) override;

src/Mix.h

@@ -49,7 +49,8 @@ class WaveTrackCache;
 void MixAndRender(TrackList * tracks, TrackFactory *factory,
                   double rate, sampleFormat format,
                   double startTime, double endTime,
-                  std::unique_ptr<WaveTrack> &uLeft, std::unique_ptr<WaveTrack> &uRight);
+                  std::shared_ptr<WaveTrack> &uLeft,
+                  std::shared_ptr<WaveTrack> &uRight);
 
 void MixBuffers(unsigned numChannels, int *channelFlags, float *gains,
                 samplePtr src,

src/NoteTrack.cpp

@@ -104,7 +104,7 @@ SONFNS(AutoSave)
 
 NoteTrack::Holder TrackFactory::NewNoteTrack()
 {
-   return std::make_unique<NoteTrack>(mDirManager);
+   return std::make_shared<NoteTrack>(mDirManager);
 }
 
 NoteTrack::NoteTrack(const std::shared_ptr<DirManager> &projDirManager)
@@ -155,7 +155,7 @@ Alg_seq &NoteTrack::GetSeq() const
 
 Track::Holder NoteTrack::Duplicate() const
 {
-   auto duplicate = std::make_unique<NoteTrack>(mDirManager);
+   auto duplicate = std::make_shared<NoteTrack>(mDirManager);
    duplicate->Init(*this);
    // The duplicate begins life in serialized state.  Often the duplicate is
    // pushed on the Undo stack.  Then we want to un-serialize it (or a further
@@ -190,8 +190,7 @@ Track::Holder NoteTrack::Duplicate() const
 #ifdef EXPERIMENTAL_MIDI_OUT
    duplicate->SetVelocity(GetVelocity());
 #endif
-   // This std::move is needed to "upcast" the pointer type
-   return std::move(duplicate);
+   return duplicate;
 }
 
 
@@ -463,7 +462,7 @@ Track::Holder NoteTrack::Cut(double t0, double t1)
       //( std::min( t1, GetEndTime() ) ) - ( std::max( t0, GetStartTime() ) )
    //);
 
-   auto newTrack = std::make_unique<NoteTrack>(mDirManager);
+   auto newTrack = std::make_shared<NoteTrack>(mDirManager);
 
    newTrack->Init(*this);
 
@@ -480,8 +479,7 @@ Track::Holder NoteTrack::Cut(double t0, double t1)
    //(mBottomNote, mDirManager,
    // mSerializationBuffer, mSerializationLength, mVisibleChannels)
 
-   // This std::move is needed to "upcast" the pointer type
-   return std::move(newTrack);
+   return newTrack;
 }
 
 Track::Holder NoteTrack::Copy(double t0, double t1, bool) const
@@ -491,7 +489,7 @@ Track::Holder NoteTrack::Copy(double t0, double t1, bool) const
 
    double len = t1-t0;
 
-   auto newTrack = std::make_unique<NoteTrack>(mDirManager);
+   auto newTrack = std::make_shared<NoteTrack>(mDirManager);
 
    newTrack->Init(*this);
 
@@ -504,8 +502,7 @@ Track::Holder NoteTrack::Copy(double t0, double t1, bool) const
    // (mBottomNote, mDirManager, mSerializationBuffer,
    // mSerializationLength, mVisibleChannels)
 
-   // This std::move is needed to "upcast" the pointer type
-   return std::move(newTrack);
+   return newTrack;
 }
 
 bool NoteTrack::Trim(double t0, double t1)

src/NoteTrack.h

@@ -75,7 +75,7 @@ class AUDACITY_DLL_API NoteTrack final
        const AudacityProject *pProject, int currentTool, bool bMultiTool)
       override;
 
-   using Holder = std::unique_ptr<NoteTrack>;
+   using Holder = std::shared_ptr<NoteTrack>;
    Track::Holder Duplicate() const override;
 
    double GetOffset() const override;

src/TimeTrack.cpp

@@ -33,9 +33,9 @@
 #define TIMETRACK_MIN 0.01
 #define TIMETRACK_MAX 10.0
 
-std::unique_ptr<TimeTrack> TrackFactory::NewTimeTrack()
+std::shared_ptr<TimeTrack> TrackFactory::NewTimeTrack()
 {
-   return std::make_unique<TimeTrack>(mDirManager, mZoomInfo);
+   return std::make_shared<TimeTrack>(mDirManager, mZoomInfo);
 }
 
 TimeTrack::TimeTrack(const std::shared_ptr<DirManager> &projDirManager, const ZoomInfo *zoomInfo):
@@ -108,8 +108,7 @@ Track::Holder TimeTrack::Cut( double t0, double t1 )
 
 Track::Holder TimeTrack::Copy( double t0, double t1, bool ) const
 {
-   auto result = std::make_unique<TimeTrack>( *this, &t0, &t1 );
-   return Track::Holder{ std::move( result ) };
+   return std::make_shared<TimeTrack>( *this, &t0, &t1 );
 }
 
 void TimeTrack::Clear(double t0, double t1)
@@ -143,7 +142,7 @@ void TimeTrack::InsertSilence(double t, double len)
 
 Track::Holder TimeTrack::Duplicate() const
 {
-   return std::make_unique<TimeTrack>(*this);
+   return std::make_shared<TimeTrack>(*this);
 }
 
 bool TimeTrack::GetInterpolateLog() const

src/Track.cpp

@@ -728,35 +728,10 @@ Track *TrackList::FindById( TrackId id )
    return it->get();
 }
 
-template<typename TrackKind>
-Track *TrackList::Add(std::unique_ptr<TrackKind> &&t)
+Track *TrackList::DoAddToHead(const std::shared_ptr<Track> &t)
 {
-   Track *pTrack;
-   push_back(ListOfTracks::value_type(pTrack = t.release()));
-
-   auto n = getPrev( getEnd() );
-
-   pTrack->SetOwner(mSelf, n);
-   pTrack->SetId( TrackId{ ++sCounter } );
-   RecalcPositions(n);
-   AdditionEvent(n);
-   return back().get();
-}
-
-// Make instantiations for the linker to find
-template Track *TrackList::Add<TimeTrack>(std::unique_ptr<TimeTrack> &&);
-#if defined(USE_MIDI)
-template Track *TrackList::Add<NoteTrack>(std::unique_ptr<NoteTrack> &&);
-#endif
-template Track *TrackList::Add<WaveTrack>(std::unique_ptr<WaveTrack> &&);
-template Track *TrackList::Add<LabelTrack>(std::unique_ptr<LabelTrack> &&);
-template Track *TrackList::Add<Track>(std::unique_ptr<Track> &&);
-
-template<typename TrackKind>
-Track *TrackList::AddToHead(std::unique_ptr<TrackKind> &&t)
-{
-   Track *pTrack;
-   push_front(ListOfTracks::value_type(pTrack = t.release()));
+   Track *pTrack = t.get();
+   push_front(ListOfTracks::value_type(t));
    auto n = getBegin();
    pTrack->SetOwner(mSelf, n);
    pTrack->SetId( TrackId{ ++sCounter } );
@@ -765,11 +740,7 @@ Track *TrackList::AddToHead(std::unique_ptr<TrackKind> &&t)
    return front().get();
 }
 
-// Make instantiations for the linker to find
-template Track *TrackList::AddToHead<TimeTrack>(std::unique_ptr<TimeTrack> &&);
-
-template<typename TrackKind>
-Track *TrackList::Add(std::shared_ptr<TrackKind> &&t)
+Track *TrackList::DoAdd(const std::shared_ptr<Track> &t)
 {
    push_back(t);
 
@@ -782,10 +753,6 @@ Track *TrackList::Add(std::shared_ptr<TrackKind> &&t)
    return back().get();
 }
 
-// Make instantiations for the linker to find
-template Track *TrackList::Add<Track>(std::shared_ptr<Track> &&);
-template Track *TrackList::Add<WaveTrack>(std::shared_ptr<WaveTrack> &&);
-
 void TrackList::GroupChannels(
    Track &track, size_t groupSize, bool resetChannels )
 {
@@ -1234,8 +1201,7 @@ TrackList::RegisterPendingChangedTrack( Updater updater, Track *src )
 {
    std::shared_ptr<Track> pTrack;
    if (src)
-      // convert from unique_ptr to shared_ptr
-      pTrack.reset( src->Duplicate().release() );
+      pTrack = src->Duplicate();
 
    if (pTrack) {
       mUpdaters.push_back( updater );

src/Track.h

@@ -367,7 +367,7 @@ private:
 
    void Init(const Track &orig);
 
-   using Holder = std::unique_ptr<Track>;
+   using Holder = std::shared_ptr<Track>;
    virtual Holder Duplicate() const = 0;
 
    // Called when this track is merged to stereo with another, and should
@@ -1330,6 +1330,9 @@ class TrackList final : public wxEvtHandler, public ListOfTracks
    }
 
 private:
+   Track *DoAddToHead(const std::shared_ptr<Track> &t);
+   Track *DoAdd(const std::shared_ptr<Track> &t);
+
    template< typename TrackType, typename InTrackType >
       static TrackIterRange< TrackType >
          Channels_( TrackIter< InTrackType > iter1 )
@@ -1369,15 +1372,12 @@ public:
 
    /// Add a Track, giving it a fresh id
    template<typename TrackKind>
-   Track *Add(std::unique_ptr<TrackKind> &&t);
+      TrackKind *AddToHead( const std::shared_ptr< TrackKind > &t )
+         { return static_cast< TrackKind* >( DoAddToHead( t ) ); }
 
-   /// Add a Track, giving it a fresh id
    template<typename TrackKind>
-   Track *AddToHead(std::unique_ptr<TrackKind> &&t);
-
-   /// Add a Track, giving it a fresh id
-   template<typename TrackKind>
-   Track *Add(std::shared_ptr<TrackKind> &&t);
+      TrackKind *Add( const std::shared_ptr< TrackKind > &t )
+         { return static_cast< TrackKind* >( DoAdd( t ) ); }
 
    /** \brief Define a group of channels starting at the given track
    *
@@ -1632,13 +1632,13 @@ class AUDACITY_DLL_API TrackFactory
  public:
    // These methods are defined in WaveTrack.cpp, NoteTrack.cpp,
    // LabelTrack.cpp, and TimeTrack.cpp respectively
-   std::unique_ptr<WaveTrack> DuplicateWaveTrack(const WaveTrack &orig);
-   std::unique_ptr<WaveTrack> NewWaveTrack(sampleFormat format = (sampleFormat)0,
+   std::shared_ptr<WaveTrack> DuplicateWaveTrack(const WaveTrack &orig);
+   std::shared_ptr<WaveTrack> NewWaveTrack(sampleFormat format = (sampleFormat)0,
                            double rate = 0);
-   std::unique_ptr<LabelTrack> NewLabelTrack();
-   std::unique_ptr<TimeTrack> NewTimeTrack();
+   std::shared_ptr<LabelTrack> NewLabelTrack();
+   std::shared_ptr<TimeTrack> NewTimeTrack();
 #if defined(USE_MIDI)
-   std::unique_ptr<NoteTrack> NewNoteTrack();
+   std::shared_ptr<NoteTrack> NewNoteTrack();
 #endif
 };
 

src/WaveTrack.cpp

@@ -70,15 +70,13 @@ using std::max;
 
 WaveTrack::Holder TrackFactory::DuplicateWaveTrack(const WaveTrack &orig)
 {
-   return std::unique_ptr<WaveTrack>
-   { static_cast<WaveTrack*>(orig.Duplicate().release()) };
+   return std::static_pointer_cast<WaveTrack>( orig.Duplicate() );
 }
 
 
 WaveTrack::Holder TrackFactory::NewWaveTrack(sampleFormat format, double rate)
 {
-   return std::unique_ptr<WaveTrack>
-   { safenew WaveTrack(mDirManager, format, rate) };
+   return std::make_shared<WaveTrack> ( mDirManager, format, rate );
 }
 
 WaveTrack::WaveTrack(const std::shared_ptr<DirManager> &projDirManager, sampleFormat format, double rate) :
@@ -395,7 +393,7 @@ int WaveTrack::ZeroLevelYCoordinate(wxRect rect) const
 
 Track::Holder WaveTrack::Duplicate() const
 {
-   return Track::Holder{ safenew WaveTrack{ *this } };
+   return std::make_shared<WaveTrack>( *this );
 }
 
 double WaveTrack::GetRate() const
@@ -629,9 +627,8 @@ Track::Holder WaveTrack::Copy(double t0, double t1, bool forClipboard) const
    if (t1 < t0)
       THROW_INCONSISTENCY_EXCEPTION;
 
-   WaveTrack *newTrack;
-   Track::Holder result
-   { newTrack = safenew WaveTrack{ mDirManager } };
+   auto result = std::make_shared<WaveTrack>( mDirManager );
+   WaveTrack *newTrack = result.get();
 
    newTrack->Init(*this);
 

src/WaveTrack.h

@@ -58,28 +58,24 @@ using Regions = std::vector < Region >;
 class Envelope;
 
 class AUDACITY_DLL_API WaveTrack final : public PlayableTrack {
-
- private:
+public:
 
    //
    // Constructor / Destructor / Duplicator
    //
-   // Private since only factories are allowed to construct WaveTracks
-   //
 
    WaveTrack(const std::shared_ptr<DirManager> &projDirManager,
              sampleFormat format = (sampleFormat)0,
              double rate = 0);
    WaveTrack(const WaveTrack &orig);
 
-   void Init(const WaveTrack &orig);
-
-public:
    // overwrite data excluding the sample sequence but including display
    // settings
    void Reinit(const WaveTrack &orig);
 
 private:
+   void Init(const WaveTrack &orig);
+
    Track::Holder Duplicate() const override;
 
    friend class TrackFactory;
@@ -87,7 +83,7 @@ private:
  public:
 
    typedef WaveTrackLocation Location;
-   using Holder = std::unique_ptr<WaveTrack>;
+   using Holder = std::shared_ptr<WaveTrack>;
 
    virtual ~WaveTrack();
 

src/effects/Effect.cpp

@@ -1207,7 +1207,7 @@ bool Effect::DoEffect(wxWindow *parent,
    // We don't yet know the effect type for code in the Nyquist Prompt, so
    // assume it requires a track and handle errors when the effect runs.
    if ((GetType() == EffectTypeGenerate || GetPath() == NYQUIST_PROMPT_ID) && (mNumTracks == 0)) {
-      newTrack = static_cast<WaveTrack*>(mTracks->Add(mFactory->NewWaveTrack()));
+      newTrack = mTracks->Add(mFactory->NewWaveTrack());
       newTrack->SetSelected(true);
    }
 
@@ -1553,7 +1553,7 @@ bool Effect::ProcessTrack(int count,
 
    auto chans = std::min<unsigned>(mNumAudioOut, mNumChannels);
 
-   std::unique_ptr<WaveTrack> genLeft, genRight;
+   std::shared_ptr<WaveTrack> genLeft, genRight;
 
    decltype(len) genLength = 0;
    bool isGenerator = GetType() == EffectTypeGenerate;
@@ -2073,11 +2073,11 @@ void Effect::CopyInputTracks(bool allSyncLockSelected)
    }
 }
 
-Track *Effect::AddToOutputTracks(std::unique_ptr<Track> &&t)
+Track *Effect::AddToOutputTracks(const std::shared_ptr<Track> &t)
 {
    mIMap.push_back(NULL);
    mOMap.push_back(t.get());
-   return mOutputTracks->Add(std::move(t));
+   return mOutputTracks->Add(t);
 }
 
 Effect::AddedAnalysisTrack::AddedAnalysisTrack(Effect *pEffect, const wxString &name)

src/effects/Effect.h

@@ -443,7 +443,7 @@ protected:
    void ReplaceProcessedTracks(const bool bGoodResult);
 
    // Use this to append a NEW output track.
-   Track *AddToOutputTracks(std::unique_ptr<Track> &&t);
+   Track *AddToOutputTracks(const std::shared_ptr<Track> &t);
 
 //
 // protected data

src/effects/SBSMSEffect.cpp

@@ -59,8 +59,8 @@ public:
    // Not required by callbacks, but makes for easier cleanup
    std::unique_ptr<Resampler> resampler;
    std::unique_ptr<SBSMSQuality> quality;
-   std::unique_ptr<WaveTrack> outputLeftTrack;
-   std::unique_ptr<WaveTrack> outputRightTrack;
+   std::shared_ptr<WaveTrack> outputLeftTrack;
+   std::shared_ptr<WaveTrack> outputRightTrack;
 
    std::exception_ptr mpException {};
 };

src/effects/nyquist/Nyquist.cpp

@@ -1419,7 +1419,7 @@ bool NyquistEffect::ProcessOne()
       return false;
    }
 
-   std::unique_ptr<WaveTrack> outputTrack[2];
+   std::shared_ptr<WaveTrack> outputTrack[2];
 
    double rate = mCurTrack[0]->GetRate();
    for (int i = 0; i < outChannels; i++) {

src/import/ImportRaw.h

@@ -23,7 +23,7 @@ class wxWindow;
 
 // Newly constructed WaveTracks that are not yet owned by a TrackList
 // are held in unique_ptr not shared_ptr
-using NewChannelGroup = std::vector< std::unique_ptr<WaveTrack> >;
+using NewChannelGroup = std::vector< std::shared_ptr<WaveTrack> >;
 using TrackHolders = std::vector< NewChannelGroup >;
 
 

src/menus/LabelMenus.cpp

@@ -41,10 +41,8 @@ int DoAddLabel(
    auto lt = * iter.Filter< LabelTrack >();
 
    // If none found, start a NEW label track and use it
-   if (!lt) {
-      lt = static_cast<LabelTrack*>
-         (tracks->Add(trackFactory->NewLabelTrack()));
-   }
+   if (!lt)
+      lt = tracks->Add(trackFactory->NewLabelTrack());
 
 // LLL: Commented as it seemed a little forceful to remove users
 //      selection when adding the label.  This does not happen if
@@ -158,7 +156,7 @@ void EditByLabel(
    }
 }
 
-using EditDestFunction = std::unique_ptr<Track> (WaveTrack::*)(double, double);
+using EditDestFunction = std::shared_ptr<Track> (WaveTrack::*)(double, double);
 
 //Executes the edit function on all selected wave tracks with
 //regions specified by selected labels

src/toolbars/ControlToolBar.cpp

@@ -1168,9 +1168,7 @@ bool ControlToolBar::DoRecord(AudacityProject &project,
 
          Track *first {};
          for (int c = 0; c < recordingChannels; c++) {
-            std::shared_ptr<WaveTrack> newTrack{
-               p->GetTrackFactory()->NewWaveTrack().release()
-            };
+            auto newTrack = p->GetTrackFactory()->NewWaveTrack();
             if (!first)
                first = newTrack.get();
 

src/toolbars/TranscriptionToolBar.h

@@ -156,7 +156,7 @@ class TranscriptionToolBar final : public ToolBar {
    int mBackgroundWidth;
    int mBackgroundHeight;
 
-   std::unique_ptr<TimeTrack> mTimeTrack;
+   std::shared_ptr<TimeTrack> mTimeTrack;
 
  public: