More careful use of weak pointers to tracks in UIHandles

src/SelectionState.cpp

@@ -130,7 +130,7 @@ void SelectionState::ChangeSelectionOnShiftClick
    Track* pFirst = nullptr;
    Track* pLast = nullptr;
    // We will either extend from the first or from the last.
-   auto pExtendFrom = mLastPickedTrack.lock();
+   auto pExtendFrom = tracks.Lock(mLastPickedTrack);
 
    if( !pExtendFrom ) {
       TrackListIterator iter( &tracks );

src/Track.h

@@ -606,6 +606,17 @@ class TrackList final : public wxEvtHandler, public ListOfTracks
    /// Mainly a test function. Uses a linear search, so could be slow.
    bool Contains(const Track * t) const;
 
+   // Return non-null only if the weak pointer is not, and the track is
+   // owned by this list; constant time.
+   template <typename Subclass>
+   std::shared_ptr<Subclass> Lock(const std::weak_ptr<Subclass> &wTrack)
+   {
+      auto pTrack = wTrack.lock();
+      if (pTrack && this == pTrack->mList)
+         return pTrack;
+      return {};
+   }
+
    bool IsEmpty() const;
    int GetCount() const;
 

src/TrackPanelResizeHandle.cpp

@@ -153,7 +153,7 @@ UIHandle::Result TrackPanelResizeHandle::Click
 UIHandle::Result TrackPanelResizeHandle::Drag
 (const TrackPanelMouseEvent &evt, AudacityProject *pProject)
 {
-   auto pTrack = mpTrack.lock();
+   auto pTrack = pProject->GetTracks()->Lock(mpTrack);
    if ( !pTrack )
       return RefreshCode::Cancelled;
 
@@ -338,7 +338,7 @@ UIHandle::Result TrackPanelResizeHandle::Release
 
 UIHandle::Result TrackPanelResizeHandle::Cancel(AudacityProject *pProject)
 {
-   auto pTrack = mpTrack.lock();
+   auto pTrack = pProject->GetTracks()->Lock(mpTrack);
    if ( !pTrack )
       return RefreshCode::Cancelled;
 
@@ -357,7 +357,7 @@ UIHandle::Result TrackPanelResizeHandle::Cancel(AudacityProject *pProject)
       pTrack->SetHeight(mInitialUpperActualHeight);
       pTrack->SetMinimized(mInitialMinimized);
 #ifdef EXPERIMENTAL_OUTPUT_DISPLAY
-      if( !MONO_WAVE_PAN(mpTrack) )
+      if( !MONO_WAVE_PAN(pTrack) )
 #endif
       {
          next->SetHeight(mInitialActualHeight);
@@ -371,7 +371,7 @@ UIHandle::Result TrackPanelResizeHandle::Cancel(AudacityProject *pProject)
       pTrack->SetHeight(mInitialActualHeight);
       pTrack->SetMinimized(mInitialMinimized);
 #ifdef EXPERIMENTAL_OUTPUT_DISPLAY
-      if( !MONO_WAVE_PAN(mpTrack) )
+      if( !MONO_WAVE_PAN(pTrack) )
 #endif
       {
          prev->SetHeight(mInitialUpperActualHeight);

src/tracks/labeltrack/ui/LabelDefaultClickHandle.cpp

@@ -53,7 +53,7 @@ void LabelDefaultClickHandle::RestoreState( AudacityProject *pProject )
 {
    if ( mLabelState ) {
       for ( const auto &pair : mLabelState->mPairs )
-         if (auto pLt = pair.first.lock())
+         if (auto pLt = pProject->GetTracks()->Lock(pair.first))
             pLt->RestoreFlags( pair.second );
       mLabelState.reset();
    }

src/tracks/labeltrack/ui/LabelTextHandle.cpp

@@ -122,7 +122,7 @@ UIHandle::Result LabelTextHandle::Drag
    auto result = LabelDefaultClickHandle::Drag( evt, pProject );
 
    const wxMouseEvent &event = evt.event;
-   auto pLT = mpLT.lock();
+   auto pLT = pProject->GetTracks()->Lock(mpLT);
    if(pLT)
       pLT->HandleTextDragRelease(event);
 
@@ -170,7 +170,7 @@ UIHandle::Result LabelTextHandle::Release
    }
 
    const wxMouseEvent &event = evt.event;
-   auto pLT = mpLT.lock();
+   auto pLT = pProject->GetTracks()->Lock(mpLT);
    if (pLT)
       pLT->HandleTextDragRelease(event);
 

src/tracks/playabletrack/notetrack/ui/NoteTrackControls.cpp

@@ -121,7 +121,7 @@ UIHandle::Result NoteTrackClickHandle::Release
 {
    using namespace RefreshCode;
 
-   auto pTrack = mpTrack.lock();
+   auto pTrack = pProject->GetTracks()->Lock(mpTrack);
    if (!pTrack)
       return Cancelled;
 

src/tracks/playabletrack/notetrack/ui/NoteTrackVRulerControls.cpp

@@ -127,14 +127,15 @@ UIHandle::Result NoteTrackVZoomHandle::Drag
 (const TrackPanelMouseEvent &evt, AudacityProject *pProject)
 {
    using namespace RefreshCode;
-   if (!mpTrack.lock())
+   auto pTrack = pProject->GetTracks()->Lock(mpTrack);
+   if (!pTrack)
       return Cancelled;
 
    const wxMouseEvent &event = evt.event;
    mZoomEnd = event.m_y;
    if (IsDragZooming(mZoomStart, mZoomEnd)) {
       // changed Note track to work like audio track
-      //         mpTrack->VScroll(mZoomStart, mZoomEnd);
+      //         pTrack->VScroll(mZoomStart, mZoomEnd);
       return RefreshAll;
    }
    return RefreshNone;
@@ -151,7 +152,7 @@ UIHandle::Result NoteTrackVZoomHandle::Release
  wxWindow *pParent)
 {
    using namespace RefreshCode;
-   auto pTrack = mpTrack.lock();
+   auto pTrack = pProject->GetTracks()->Lock(mpTrack);
    if (!pTrack)
       return RefreshNone;
 
@@ -184,7 +185,7 @@ UIHandle::Result NoteTrackVZoomHandle::Cancel(AudacityProject *pProject)
 void NoteTrackVZoomHandle::DrawExtras
 (DrawingPass pass, wxDC * dc, const wxRegion &, const wxRect &panelRect)
 {
-   if (!mpTrack.lock())
+   if (!mpTrack.lock()) //? TrackList::Lock()
       return;
 
    if ( pass == UIHandle::Cells &&

src/tracks/playabletrack/wavetrack/ui/WaveTrackVRulerControls.cpp

@@ -571,10 +571,11 @@ UIHandle::Result WaveTrackVZoomHandle::Click
 }
 
 UIHandle::Result WaveTrackVZoomHandle::Drag
-(const TrackPanelMouseEvent &evt, AudacityProject *)
+(const TrackPanelMouseEvent &evt, AudacityProject *pProject)
 {
    using namespace RefreshCode;
-   if (!mpTrack.lock())
+   auto pTrack = pProject->GetTracks()->Lock(mpTrack);
+   if (!pTrack)
       return Cancelled;
 
    const wxMouseEvent &event = evt.event;
@@ -595,7 +596,7 @@ UIHandle::Result WaveTrackVZoomHandle::Release
  wxWindow *pParent)
 {
    using namespace RefreshCode;
-   auto pTrack = mpTrack.lock();
+   auto pTrack = pProject->GetTracks()->Lock(mpTrack);
    if (!pTrack)
       return RefreshNone;
 
@@ -640,7 +641,7 @@ UIHandle::Result WaveTrackVZoomHandle::Cancel(AudacityProject*)
 void WaveTrackVZoomHandle::DrawExtras
 (DrawingPass pass, wxDC * dc, const wxRegion &, const wxRect &panelRect)
 {
-   if (!mpTrack.lock())
+   if (!mpTrack.lock()) // TrackList::Lock()?
       return;
 
    if ( pass == UIHandle::Cells &&

src/tracks/ui/ButtonHandle.cpp

@@ -59,11 +59,12 @@ UIHandle::Result ButtonHandle::Click
 }
 
 UIHandle::Result ButtonHandle::Drag
-(const TrackPanelMouseEvent &evt, AudacityProject *)
+(const TrackPanelMouseEvent &evt, AudacityProject *pProject)
 {
    const wxMouseEvent &event = evt.event;
    using namespace RefreshCode;
-   if (!mpTrack.lock())
+   auto pTrack = pProject->GetTracks()->Lock(mpTrack);
+   if (!pTrack)
       return Cancelled;
 
    const int newState =
@@ -88,7 +89,7 @@ UIHandle::Result ButtonHandle::Release
  wxWindow *pParent)
 {
    using namespace RefreshCode;
-   auto pTrack = mpTrack.lock();
+   auto pTrack = pProject->GetTracks()->Lock(mpTrack);
    if (!pTrack)
       return Cancelled;
 

src/tracks/ui/SelectHandle.cpp

@@ -617,7 +617,7 @@ UIHandle::Result SelectHandle::Click
 #endif
             mSelStartValid = true;
             mSelStart = value;
-            AdjustSelection(viewInfo, event.m_x, mRect.x, pTrack);
+            AdjustSelection(pProject, viewInfo, event.m_x, mRect.x, pTrack);
             break;
          }
 #ifdef EXPERIMENTAL_SPECTRAL_EDITING
@@ -796,7 +796,7 @@ UIHandle::Result SelectHandle::Drag
    }
 
    // Also fuhggeddaboudit if not in a track.
-   auto pTrack = mpTrack.lock();
+   auto pTrack = pProject->GetTracks()->Lock(mpTrack);
    if (!pTrack)
       return RefreshNone;
 
@@ -836,13 +836,13 @@ UIHandle::Result SelectHandle::Drag
          (pProject, viewInfo, y, mRect.y, mRect.height, pTrack.get());
       else
 #endif
-         if (mFreqSelTrack.lock() == pTrack)
+         if (pProject->GetTracks()->Lock(mFreqSelTrack) == pTrack)
             AdjustFreqSelection(
                                 static_cast<WaveTrack*>(pTrack.get()),
                                 viewInfo, y, mRect.y, mRect.height);
 #endif
       
-      AdjustSelection(viewInfo, x, mRect.x, clickedTrack.get());
+      AdjustSelection(pProject, viewInfo, x, mRect.x, clickedTrack.get());
    }
 
    return RefreshNone
@@ -997,7 +997,7 @@ void SelectHandle::OnTimer(wxCommandEvent &event)
       }
    }
 
-   auto pTrack = mpTrack.lock();
+   auto pTrack = mpTrack.lock(); // TrackList::Lock() ?
    if (mAutoScrolling && pTrack) {
       // AS: To keep the selection working properly as we scroll,
       //  we fake a mouse event (remember, this method is called
@@ -1026,7 +1026,7 @@ void SelectHandle::StartSelection
       mSnapLeft = -1;
       mSnapRight = -1;
       bool snappedPoint, snappedTime;
-      auto pTrack = mpTrack.lock();
+      auto pTrack = pProject->GetTracks()->Lock(mpTrack);
       if (mSnapManager->Snap(pTrack.get(), mSelStart, false,
          &s, &snappedPoint, &snappedTime)) {
          if (snappedPoint)
@@ -1045,7 +1045,8 @@ void SelectHandle::StartSelection
 
 /// Extend or contract the existing selection
 void SelectHandle::AdjustSelection
-(ViewInfo &viewInfo, int mouseXCoordinate, int trackLeftEdge,
+(AudacityProject *pProject,
+ ViewInfo &viewInfo, int mouseXCoordinate, int trackLeftEdge,
  Track *track)
 {
    if (!mSelStartValid)
@@ -1059,7 +1060,7 @@ void SelectHandle::AdjustSelection
 
    auto pTrack = Track::Pointer( track );
    if (!pTrack)
-      pTrack = mpTrack.lock();
+      pTrack = pProject->GetTracks()->Lock(mpTrack);
 
    if (mSelStart < selend) {
       sel0 = mSelStart;

src/tracks/ui/SelectHandle.h

@@ -74,7 +74,8 @@ private:
    void StartSelection
       (AudacityProject *pProject, int mouseXCoordinate, int trackLeftEdge);
    void AdjustSelection
-      (ViewInfo &viewInfo, int mouseXCoordinate, int trackLeftEdge,
+      (AudacityProject *pProject,
+       ViewInfo &viewInfo, int mouseXCoordinate, int trackLeftEdge,
        Track *pTrack);
 
    void StartFreqSelection

src/tracks/ui/SliderHandle.cpp

@@ -12,6 +12,7 @@ Paul Licameli
 #include "SliderHandle.h"
 #include "../../widgets/ASlider.h"
 #include "../../HitTestResult.h"
+#include "../../Project.h"
 #include "../../RefreshCode.h"
 #include "../../TrackPanelMouseEvent.h"
 
@@ -98,3 +99,9 @@ UIHandle::Result SliderHandle::Cancel(AudacityProject *pProject)
    mpTrack.reset();
    return RefreshCode::RefreshCell | result;
 }
+
+LWSlider *SliderHandle::GetSlider( AudacityProject *pProject )
+{
+   auto pTrack = pProject->GetTracks()->Lock(mpTrack);
+   return mSliderFn( pProject, mRect, pTrack.get() );
+}

src/tracks/ui/SliderHandle.h

@@ -61,8 +61,7 @@ protected:
    wxRect mRect{};
    using SliderFn = LWSlider *(*)( AudacityProject*, const wxRect&, Track* );
    SliderFn mSliderFn;
-   LWSlider *GetSlider( AudacityProject *pProject )
-   { return mSliderFn( pProject, mRect, mpTrack.lock().get() ); }
+   LWSlider *GetSlider( AudacityProject *pProject );
 
    float mStartingValue {};
 };