Review uses of safenew...

... add comments and assertions, and use make_unique instead where possible

src/MixerBoard.cpp

@@ -934,6 +934,7 @@ MixerBoard::MixerBoard(AudacityProject* pProject,
    this->LoadMusicalInstruments(); // Set up mMusicalInstruments.
    mProject = pProject;
 
+   wxASSERT(pProject); // to justify safenew
    mScrolledWindow =
       safenew MixerBoardScrolledWindow(
          pProject, // AudacityProject* project,

src/Project.cpp

@@ -169,7 +169,8 @@ scroll information.  It also has some status flags.
 
 #include "../images/AudacityLogoAlpha.xpm"
 
-std::unique_ptr<TrackList> AudacityProject::msClipboard{ safenew TrackList() };
+std::unique_ptr<TrackList> AudacityProject::msClipboard
+   { std::make_unique<TrackList>() };
 double AudacityProject::msClipT0 = 0.0;
 double AudacityProject::msClipT1 = 0.0;
 AudacityProject *AudacityProject::msClipProject = NULL;
@@ -829,7 +830,7 @@ AudacityProject::AudacityProject(wxWindow * parent, wxWindowID id,
      mSelectionFormat(gPrefs->Read(wxT("/SelectionFormat"), wxT(""))),
      mFrequencySelectionFormatName(gPrefs->Read(wxT("/FrequencySelectionFormatName"), wxT(""))),
      mBandwidthSelectionFormatName(gPrefs->Read(wxT("/BandwidthSelectionFormatName"), wxT(""))),
-     mUndoManager(safenew UndoManager),
+     mUndoManager(std::make_unique<UndoManager>()),
      mViewInfo(0.0, 1.0, ZoomInfo::GetDefaultZoom())
 {
    // Note that the first field of the status bar is a dummy, and it's width is set

src/SplashDialog.cpp

@@ -143,6 +143,7 @@ void SplashDialog::Show2( wxWindow * pParent )
    if( pSelf == NULL )
    {
       // pParent owns it
+      wxASSERT(pParent);
       pSelf = safenew SplashDialog( pParent );
    }
    pSelf->mpHtml->SetPage(HelpText( wxT("welcome") ));

src/TimerRecordDialog.cpp

@@ -778,6 +778,7 @@ TimerRecordPathCtrl * TimerRecordDialog::NewPathControl(wxWindow *wParent, const
                                                         const wxString &sCaption, const wxString &sValue)
 {
    TimerRecordPathCtrl * pTextCtrl;
+   wxASSERT(wParent); // to justify safenew
    pTextCtrl = safenew TimerRecordPathCtrl(wParent, iID, sValue);
    pTextCtrl->SetName(sCaption);
    return pTextCtrl;

src/toolbars/MeterToolBar.cpp

@@ -113,6 +113,7 @@ void MeterToolBar::ReCreateButtons()
 
 void MeterToolBar::Populate()
 {
+   wxASSERT(mProject); // to justify safenew
    Add((mSizer = safenew wxGridBagSizer()), 1, wxEXPAND);
 
    if( mWhichMeters & kWithRecordMeter ){

src/toolbars/ToolBar.cpp

@@ -758,6 +758,7 @@ AButton * ToolBar::MakeButton(wxWindow *parent,
    wxImagePtr down2      (OverlayImage(eDown,   eStandardDown, xoff + 1, yoff + 1));
    wxImagePtr disable2   (OverlayImage(eUp,     eDisabled, xoff, yoff));
 
+   wxASSERT(parent); // to justify safenew
    AButton * button =
       safenew AButton(parent, id, placement, size, *up2, *hilite2, *down2,
             *disable2, processdownevents);

src/toolbars/ToolBar.h

@@ -181,6 +181,7 @@ class ToolBar /* not final */ : public wxPanelWrapper
             int border = 0,
             wxObject *userData = NULL);
 
+   // Takes ownership of sizer
    void Add(wxSizer *sizer,
              int proportion = 0,
              int flag = 0,

src/toolbars/ToolManager.cpp

@@ -363,6 +363,7 @@ ToolManager::ToolManager( AudacityProject *parent, wxWindow *topDockParent )
    mLeft = std::make_unique<wxRegion>( 3, &pt[0] );
 
    // Create the indicator frame
+   // parent is null but FramePtr ensures destruction
    mIndicator = FramePtr{ safenew wxFrame( NULL,
                              wxID_ANY,
                              wxEmptyString,
@@ -410,6 +411,8 @@ ToolManager::ToolManager( AudacityProject *parent, wxWindow *topDockParent )
    mBotDock = safenew ToolDock( this, mParent, BotDockID );
 
    // Create all of the toolbars
+   // All have the project as parent window
+   wxASSERT(parent);
    mBars[ ToolsBarID ]         =  ToolBar::Holder{ safenew ToolsToolBar() };
    mBars[ TransportBarID ]     =  ToolBar::Holder{ safenew ControlToolBar() };
    mBars[ RecordMeterBarID ]   =  ToolBar::Holder{ safenew MeterToolBar( parent, RecordMeterBarID ) };
@@ -583,6 +586,7 @@ void ToolManager::Reset()
          // Maybe construct a NEW floater
          // this happens if we have just been bounced out of a dock.
          if( floater == NULL ) {
+            wxASSERT(mParent);
             floater = safenew ToolFrame( mParent, this, bar, wxPoint(-1,-1) );
             bar->Reparent( floater );
          }
@@ -761,6 +765,7 @@ void ToolManager::ReadConfig()
          bar->Create( mTopDock );
 
          // Construct a NEW floater
+         wxASSERT(mParent);
          ToolFrame *f = safenew ToolFrame( mParent, this, bar, wxPoint( x, y ) );
 
          // Set the width and height
@@ -1327,6 +1332,7 @@ void ToolManager::OnGrabber( GrabberEvent & event )
       mDragBar->SetPositioned();
 
       // Construct a NEW floater
+      wxASSERT(mParent);
       mDragWindow = safenew ToolFrame( mParent, this, mDragBar, mp );
 
       // Make sure the ferry is visible

src/widgets/BackedPanel.cpp

@@ -14,7 +14,7 @@ BackedPanel::BackedPanel(wxWindow * parent, wxWindowID id,
             const wxSize & size,
             long style)
 : wxPanelWrapper(parent, id, pos, size, style)
-, mBacking{ safenew wxBitmap(1, 1) }
+, mBacking{ std::make_unique<wxBitmap>(1, 1) }
 {
    // Preinit the backing DC and bitmap so routines that require it will
    // not cause a crash if they run before the panel is fully initialized.
@@ -52,7 +52,7 @@ void BackedPanel::ResizeBacking()
       mBackingDC.SelectObject(wxNullBitmap);
 
    wxSize sz = GetClientSize();
-   mBacking.reset(safenew wxBitmap);
+   mBacking = std::make_unique<wxBitmap>();
    mBacking->Create(sz.x, sz.y); //, *dc);
    mBackingDC.SelectObject(*mBacking);
 }

src/widgets/ErrorDialog.cpp

@@ -184,6 +184,7 @@ void ShowModelessErrorDialog(wxWindow *parent,
                              const wxString &helpURL,
                              const bool Close)
 {
+   wxASSERT(parent);
    ErrorDialog *dlog = safenew ErrorDialog(parent, dlogTitle, message, helpURL, Close, false);
    dlog->CentreOnParent();
    dlog->Show();
@@ -199,6 +200,7 @@ void ShowAliasMissingDialog(AudacityProject *parent,
                             const wxString &helpURL,
                             const bool Close)
 {
+   wxASSERT(parent); // to justify safenew
    ErrorDialog *dlog = safenew AliasedFileMissingDialog(parent, dlogTitle, message, helpURL, Close, false);
    // Don't center because in many cases (effect, export, etc) there will be a progress bar in the center that blocks this.
    // instead put it just above or on the top of the project.

src/widgets/HelpSystem.cpp

@@ -100,6 +100,7 @@ void HelpSystem::ShowHtmlText(wxWindow *pParent,
 {
    LinkingHtmlWindow *html;
 
+   wxASSERT(pParent); // to justify safenew
    auto pFrame = safenew wxFrame {
       pParent, wxID_ANY, Title, wxDefaultPosition, wxDefaultSize,
 #if defined(__WXMAC__)
@@ -195,6 +196,7 @@ void HelpSystem::ShowHelpDialog(wxWindow *parent,
                     const wxString &remoteURL,
                     bool bModal)
 {
+   wxASSERT(parent); // to justify safenew
    AudacityProject * pProj = GetActiveProject();
    wxString HelpMode = wxT("Local");
 
@@ -341,6 +343,7 @@ void HelpSystem::ShowHelpDialog(wxWindow *parent,
    wxLogMessage(wxT("webHelpPage %s, localHelpPage %s"),
               webHelpPage.c_str(), localHelpPage.c_str());
 
+   wxASSERT(parent); // to justify safenew
    HelpSystem::ShowHelpDialog(
       parent, 
       localHelpPage,

src/widgets/LinkingHtmlWindow.cpp

@@ -124,7 +124,7 @@ void LinkingHtmlWindow::OnLinkClicked(const wxHtmlLinkInfo& link)
          wxFileName( FileNames::HtmlHelpDir(), href.Mid( 10 ) + wxT(".htm") ).GetFullPath();
       if( wxFileExists( FileName ) )
       {
-         HelpSystem::ShowHelpDialog(NULL, FileName, wxT(""));
+         HelpSystem::ShowHelpDialog(this, FileName, wxT(""));
          return;
       }
       else