OverlayPanel uses weak_ptr to Overlay, which simplifies other dtors

src/AdornedRulerPanel.cpp

@@ -110,7 +110,6 @@ class AdornedRulerPanel::QuickPlayRulerOverlay final : public Overlay
 {
 public:
    QuickPlayRulerOverlay(QuickPlayIndicatorOverlay &partner);
-   virtual ~QuickPlayRulerOverlay();
 
    // Available to this and to partner
 
@@ -149,20 +148,19 @@ private:
 class AdornedRulerPanel::QuickPlayIndicatorOverlay final : public Overlay
 {
    friend QuickPlayRulerOverlay;
+   friend AdornedRulerPanel;
 
 public:
    QuickPlayIndicatorOverlay(AudacityProject *project);
 
-   virtual ~QuickPlayIndicatorOverlay();
-
 private:
    std::pair<wxRect, bool> DoGetRectangle(wxSize size) override;
    void Draw(OverlayPanel &panel, wxDC &dc) override;
 
    AudacityProject *mProject;
 
-   std::unique_ptr<QuickPlayRulerOverlay> mPartner
-      { std::make_unique<QuickPlayRulerOverlay>(*this) };
+   std::shared_ptr<QuickPlayRulerOverlay> mPartner
+      { std::make_shared<QuickPlayRulerOverlay>(*this) };
 
    int mOldQPIndicatorPos { -1 };
    bool mOldQPIndicatorSnapped {};
@@ -179,14 +177,6 @@ AdornedRulerPanel::QuickPlayRulerOverlay::QuickPlayRulerOverlay(
    QuickPlayIndicatorOverlay &partner)
 : mPartner(partner)
 {
-   GetRuler()->AddOverlay(this);
-}
-
-AdornedRulerPanel::QuickPlayRulerOverlay::~QuickPlayRulerOverlay()
-{
-   auto ruler = GetRuler();
-   if (ruler)
-      ruler->RemoveOverlay(this);
 }
 
 AdornedRulerPanel *AdornedRulerPanel::QuickPlayRulerOverlay::GetRuler() const
@@ -286,15 +276,6 @@ AdornedRulerPanel::QuickPlayIndicatorOverlay::QuickPlayIndicatorOverlay(
    AudacityProject *project)
    : mProject(project)
 {
-   auto tp = mProject->GetTrackPanel();
-   tp->AddOverlay(this);
-}
-
-AdornedRulerPanel::QuickPlayIndicatorOverlay::~QuickPlayIndicatorOverlay()
-{
-   auto tp = mProject->GetTrackPanel();
-   if (tp)
-      tp->RemoveOverlay(this);
 }
 
 std::pair<wxRect, bool>
@@ -2175,7 +2156,10 @@ bool AdornedRulerPanel::TakesFocus() const
 
 void AdornedRulerPanel::CreateOverlays()
 {
-   if (!mOverlay)
+   if (!mOverlay) {
       mOverlay =
-         std::make_unique<QuickPlayIndicatorOverlay>( mProject );
+         std::make_shared<QuickPlayIndicatorOverlay>( mProject );
+      mProject->GetTrackPanel()->AddOverlay( mOverlay );
+      this->AddOverlay( mOverlay->mPartner );
+   }
 }

src/AdornedRulerPanel.h

@@ -193,7 +193,7 @@ private:
 
    // Cooperating objects
    class QuickPlayIndicatorOverlay;
-   std::unique_ptr<QuickPlayIndicatorOverlay> mOverlay;
+   std::shared_ptr<QuickPlayIndicatorOverlay> mOverlay;
 
    class QuickPlayRulerOverlay;
    

src/Project.cpp

@@ -1178,28 +1178,28 @@ AudacityProject::AudacityProject(wxWindow * parent, wxWindowID id,
                                              mRuler);
    mTrackPanel->UpdatePrefs();
 
-   mCursorOverlay = std::make_unique<EditCursorOverlay>(this);
+   mCursorOverlay = std::make_shared<EditCursorOverlay>(this);
 
    mBackgroundCell = std::make_shared<BackgroundCell>(this);
 
 #ifdef EXPERIMENTAL_SCRUBBING_BASIC
-   mScrubOverlay = std::make_unique<ScrubbingOverlay>(this);
+   mScrubOverlay = std::make_shared<ScrubbingOverlay>(this);
    mScrubber = std::make_unique<Scrubber>(this);
 #endif
 
    mPlaybackScroller = std::make_unique<PlaybackScroller>(this);
 
-   mIndicatorOverlay = std::make_unique<PlayIndicatorOverlay>(this);
+   mIndicatorOverlay = std::make_shared<PlayIndicatorOverlay>(this);
    
    this->Bind(EVT_TRACK_PANEL_TIMER,
       &ViewInfo::OnTimer,
       &mViewInfo);
 
    // Add the overlays, in the sequence in which they will be painted
-   mTrackPanel->AddOverlay(mIndicatorOverlay.get());
-   mTrackPanel->AddOverlay(mCursorOverlay.get());
+   mTrackPanel->AddOverlay( mIndicatorOverlay );
+   mTrackPanel->AddOverlay( mCursorOverlay );
 #ifdef EXPERIMENTAL_SCRUBBING_BASIC
-   mTrackPanel->AddOverlay(mScrubOverlay.get());
+   mTrackPanel->AddOverlay( mScrubOverlay );
 #endif
 
    mMenuManager->CreateMenusAndCommands(*this);
@@ -1337,14 +1337,6 @@ AudacityProject::~AudacityProject()
    // Tool manager gives us capture sometimes
    if(HasCapture())
       ReleaseMouse();
-
-   if(mTrackPanel) {
-#ifdef EXPERIMENTAL_SCRUBBING_BASIC
-      mTrackPanel->RemoveOverlay(mScrubOverlay.get());
-#endif
-      mTrackPanel->RemoveOverlay(mCursorOverlay.get());
-      mTrackPanel->RemoveOverlay(mIndicatorOverlay.get());
-   }
 }
 
 void AudacityProject::ApplyUpdatedTheme()

src/Project.h

@@ -33,7 +33,7 @@
 #include "toolbars/SelectionBarListener.h"
 #include "toolbars/SpectralSelectionBarListener.h"
 
-#include "MemoryX.h"
+#include <memory>
 #include <wx/defs.h>
 #include <wx/event.h>
 #include <wx/log.h>
@@ -774,13 +774,13 @@ private:
    friend class CommandManager;
 
    // TrackPanelOverlay objects
-   std::unique_ptr<Overlay>
+   std::shared_ptr<Overlay>
       mIndicatorOverlay, mCursorOverlay;
 
    std::shared_ptr<BackgroundCell> mBackgroundCell;
 
 #ifdef EXPERIMENTAL_SCRUBBING_BASIC
-   std::unique_ptr<Overlay> mScrubOverlay;
+   std::shared_ptr<Overlay> mScrubOverlay;
    std::unique_ptr<Scrubber> mScrubber;
 public:
    Scrubber &GetScrubber() { return *mScrubber; }

src/tracks/ui/EditCursorOverlay.cpp

@@ -37,15 +37,6 @@ EditCursorOverlay::EditCursorOverlay(AudacityProject *project, bool isMaster)
 {
 }
 
-EditCursorOverlay::~EditCursorOverlay()
-{
-   if (mIsMaster && mPartner) {
-      auto ruler = mProject->GetRulerPanel();
-      if (ruler)
-         ruler->RemoveOverlay(mPartner.get());
-   }
-}
-
 std::pair<wxRect, bool> EditCursorOverlay::DoGetRectangle(wxSize size)
 {
    const SelectedRegion &selection = mProject->GetSelection();
@@ -74,8 +65,8 @@ void EditCursorOverlay::Draw(OverlayPanel &panel, wxDC &dc)
    if (mIsMaster && !mPartner) {
       auto ruler = mProject->GetRulerPanel();
       if (ruler) {
-         mPartner = std::make_unique<EditCursorOverlay>(mProject, false);
-         ruler->AddOverlay(mPartner.get());
+         mPartner = std::make_shared<EditCursorOverlay>(mProject, false);
+         ruler->AddOverlay( mPartner );
       }
    }
 

src/tracks/ui/EditCursorOverlay.h

@@ -11,7 +11,7 @@ Paul Licameli split from TrackPanel.cpp
 #ifndef __AUDACITY_EDIT_CURSOR_OVERLAY__
 #define __AUDACITY_EDIT_CURSOR_OVERLAY__
 
-#include "../../MemoryX.h"
+#include <memory>
 #include "../../widgets/Overlay.h"
 
 class AudacityProject;
@@ -20,7 +20,6 @@ class EditCursorOverlay final : public Overlay
 {
 public:
    EditCursorOverlay(AudacityProject *project, bool isMaster = true);
-   virtual ~EditCursorOverlay();
 
 private:
    std::pair<wxRect, bool> DoGetRectangle(wxSize size) override;
@@ -28,7 +27,7 @@ private:
 
    AudacityProject *mProject;
    bool mIsMaster;
-   std::unique_ptr<EditCursorOverlay> mPartner;
+   std::shared_ptr<EditCursorOverlay> mPartner;
 
    int mLastCursorX;
    double mCursorTime;

src/tracks/ui/PlayIndicatorOverlay.cpp

@@ -115,15 +115,6 @@ PlayIndicatorOverlay::PlayIndicatorOverlay(AudacityProject *project)
       this);
 }
 
-PlayIndicatorOverlay::~PlayIndicatorOverlay()
-{
-   if (mPartner) {
-      auto ruler = mProject->GetRulerPanel();
-      if(ruler)
-         ruler->RemoveOverlay(mPartner.get());
-   }
-}
-
 void PlayIndicatorOverlay::OnTimer(wxCommandEvent &event)
 {
    // Let other listeners get the notification
@@ -133,8 +124,8 @@ void PlayIndicatorOverlay::OnTimer(wxCommandEvent &event)
    if (!mPartner) {
       auto ruler = mProject->GetRulerPanel();
       if (ruler) {
-         mPartner = std::make_unique<PlayIndicatorOverlayBase>(mProject, false);
-         ruler->AddOverlay(mPartner.get());
+         mPartner = std::make_shared<PlayIndicatorOverlayBase>(mProject, false);
+         ruler->AddOverlay( mPartner );
       }
    }
 

src/tracks/ui/PlayIndicatorOverlay.h

@@ -46,12 +46,11 @@ class PlayIndicatorOverlay final : public PlayIndicatorOverlayBase
 {
 public:
    PlayIndicatorOverlay(AudacityProject *project);
-   virtual ~PlayIndicatorOverlay();
 
 private:
    void OnTimer(wxCommandEvent &event);
 
-   std::unique_ptr<PlayIndicatorOverlayBase> mPartner;
+   std::shared_ptr<PlayIndicatorOverlayBase> mPartner;
 };
 
 #endif

src/widgets/OverlayPanel.cpp

@@ -20,18 +20,11 @@ OverlayPanel::OverlayPanel(wxWindow * parent, wxWindowID id,
 : BackedPanel(parent, id, pos, size, style)
 {}
 
-void OverlayPanel::AddOverlay(Overlay *pOverlay)
+void OverlayPanel::AddOverlay( const std::weak_ptr<Overlay> &pOverlay)
 {
    mOverlays.push_back(pOverlay);
 }
 
-bool OverlayPanel::RemoveOverlay(Overlay *pOverlay)
-{
-   const size_t oldSize = mOverlays.size();
-   mOverlays.erase(std::remove(mOverlays.begin(), mOverlays.end(), pOverlay), mOverlays.end());
-   return oldSize != mOverlays.size();
-}
-
 void OverlayPanel::ClearOverlays()
 {
    mOverlays.clear();
@@ -45,10 +38,14 @@ void OverlayPanel::DrawOverlays(bool repaint_all, wxDC *pDC)
    std::vector< Pair > pairs;
    pairs.reserve(n_pairs);
 
+   // First...
+   Compress();
+   // ... then assume pointers are not expired
+
    // Find out the rectangles and outdatedness for each overlay
    wxSize size(GetBackingDC().GetSize());
    for (const auto pOverlay : mOverlays)
-      pairs.push_back(pOverlay->GetRectangle(size));
+      pairs.push_back( pOverlay.lock()->GetRectangle(size) );
 
    // See what requires redrawing.  If repainting, all.
    // If not, then whatever is outdated, and whatever will be damaged by
@@ -96,7 +93,7 @@ void OverlayPanel::DrawOverlays(bool repaint_all, wxDC *pDC)
    auto it2 = pairs.begin();
    for (auto pOverlay : mOverlays) {
       if (repaint_all || it2->second)
-         pOverlay->Erase(dc, GetBackingDC());
+         pOverlay.lock()->Erase(dc, GetBackingDC());
       ++it2;
    }
 
@@ -107,11 +104,23 @@ void OverlayPanel::DrawOverlays(bool repaint_all, wxDC *pDC)
          // Guarantee a clean state of the dc each pass:
          ADCChanger changer{ &dc };
 
-         pOverlay->Draw(*this, dc);
+         pOverlay.lock()->Draw(*this, dc);
       }
       ++it2;
    }
 }
 
+void OverlayPanel::Compress()
+{
+   // remove any expired pointers
+   auto begin = mOverlays.begin();
+   auto end = mOverlays.end();
+   auto newEnd = std::remove_if( begin, end,
+      []( const std::weak_ptr<Overlay> &pOverlay ){
+         return pOverlay.expired(); } );
+   if ( end != newEnd )
+      mOverlays.resize( newEnd - begin );
+}
+
 BEGIN_EVENT_TABLE(OverlayPanel, BackedPanel)
 END_EVENT_TABLE()

src/widgets/OverlayPanel.h

@@ -9,6 +9,7 @@
 #ifndef __AUDACITY_OVERLAY_PANEL__
 #define __AUDACITY_OVERLAY_PANEL__
 
+#include <memory>
 #include <vector>
 #include "BackedPanel.h"
 
@@ -22,13 +23,11 @@ public:
                 // default as for wxPanel:
                 long style = wxTAB_TRAVERSAL | wxNO_BORDER);
 
-   // Registers and unregisters overlay objects.
+   // Registers overlay objects.
    // The sequence in which they were registered is the sequence in
    // which they are painted.
    // OverlayPanel is not responsible for their memory management.
-   void AddOverlay(Overlay *pOverlay);
-   // Returns true if the overlay was found
-   bool RemoveOverlay(Overlay *pOverlay);
+   void AddOverlay( const std::weak_ptr<Overlay> &pOverlay );
    void ClearOverlays();
 
    // Erases and redraws to the client area the overlays that have
@@ -41,7 +40,8 @@ public:
    void DrawOverlays(bool repaint_all, wxDC *pDC = nullptr);
    
 private:
-   std::vector<Overlay*> mOverlays;
+   void Compress();
+   std::vector< std::weak_ptr<Overlay> > mOverlays;
    
    
    DECLARE_EVENT_TABLE()