Track::SetSelected is not virtual...

... which will simplify later rewrites that associate selection state with
the track group, not the track.

Since LabelTrack isn't notified immediately of selection changes, instead it
always tests whether it is selected, before using the stored selected label
index.

src/LabelTrack.cpp

@@ -751,7 +751,7 @@ void LabelStruct::getXPos( wxDC & dc, int * xPos1, int cursorPos) const
 
 bool LabelTrack::CalcCursorX(int * x) const
 {
-   if (mSelIndex >= 0) {
+   if ( HasSelection() ) {
       wxMemoryDC dc;
 
       if (msFont.Ok()) {
@@ -883,7 +883,7 @@ void LabelTrack::Draw
 #ifdef EXPERIMENTAL_TRACK_PANEL_HIGHLIGHTING
          highlight = highlightTrack && target->GetLabelNum() == i;
 #endif
-         bool selected = mSelIndex == i;
+         bool selected = GetSelectedIndex() == i;
 
          if( selected )
             dc.SetBrush( AColor::labelTextEditBrush );
@@ -897,7 +897,7 @@ void LabelTrack::Draw
    }
 
    // Draw highlights
-   if ((mInitialCursorPos != mCurrentCursorPos) && (mSelIndex >= 0 ))
+   if ( (mInitialCursorPos != mCurrentCursorPos) && HasSelection() )
    {
       int xpos1, xpos2;
       CalcHighlightXs(&xpos1, &xpos2);
@@ -906,15 +906,15 @@ void LabelTrack::Draw
 
    // Draw the text and the label boxes.
    { int i = -1; for (auto &labelStruct : mLabels) { ++i;
-      if( mSelIndex==i)
+      if( GetSelectedIndex() == i )
          dc.SetBrush(AColor::labelTextEditBrush);
       labelStruct.DrawText( dc, r );
-      if( mSelIndex==i)
+      if( GetSelectedIndex() == i )
          dc.SetBrush(AColor::labelTextNormalBrush);
    }}
 
    // Draw the cursor, if there is one.
-   if( mDrawCursor && mSelIndex >=0 )
+   if( mDrawCursor && HasSelection() )
    {
       const auto &labelStruct = mLabels[mSelIndex];
       int xPos = labelStruct.xText;
@@ -1011,7 +1011,7 @@ void LabelTrack::calculateFontHeight(wxDC & dc) const
 
 bool LabelTrack::IsTextSelected() const
 {
-   if (mSelIndex == -1)
+   if ( !HasSelection() )
       return false;
    if (mCurrentCursorPos == mInitialCursorPos)
       return false;
@@ -1064,7 +1064,7 @@ bool LabelTrack::CutSelectedText()
 ///  @return true if text is selected in text box, false otherwise
 bool LabelTrack::CopySelectedText()
 {
-   if (mSelIndex == -1)
+   if ( !HasSelection() )
       return false;
 
    const auto &labelStruct = mLabels[mSelIndex];
@@ -1095,7 +1095,7 @@ bool LabelTrack::CopySelectedText()
 ///  @return true if mouse is clicked in text box, false otherwise
 bool LabelTrack::PasteSelectedText(double sel0, double sel1)
 {
-   if (mSelIndex == -1)
+   if ( !HasSelection() )
       AddLabel(SelectedRegion(sel0, sel1), wxT(""));
 
    wxString text, left, right;
@@ -1139,6 +1139,16 @@ bool LabelTrack::IsTextClipSupported()
 }
 
 
+int LabelTrack::GetSelectedIndex() const
+{
+   // may make delayed update of mutable mSelIndex after track selection change
+   if ( GetSelected() )
+      return mSelIndex = std::max( -1,
+         std::min<int>( mLabels.size() - 1, mSelIndex ) );
+   else
+      return mSelIndex = -1;
+}
+
 double LabelTrack::GetOffset() const
 {
    return mOffset;
@@ -1173,13 +1183,6 @@ Track::Holder LabelTrack::Clone() const
    return std::make_shared<LabelTrack>( *this );
 }
 
-void LabelTrack::SetSelected(bool s)
-{
-   Track::SetSelected(s);
-   if (!s)
-      Unselect();
-}
-
 /// TODO: Investigate what happens with large
 /// numbers of labels, might need a binary search
 /// rather than a linear one.
@@ -1555,7 +1558,7 @@ bool LabelTrack::HandleGlyphDragRelease
          MayAdjustLabel( hit, hit.mMouseOverLabelRight, +1, bAllowSwapping, fNewX );
       }
 
-      if( mSelIndex >=0 )
+      if( HasSelection() )
       {
          //Set the selection region to be equal to
          //the NEW size of the label.
@@ -1600,7 +1603,7 @@ void LabelTrack::HandleTextDragRelease(const wxMouseEvent & evt)
    }
 
    if (evt.RightUp()) {
-      if ((mSelIndex != -1) && OverTextBox(GetLabel(mSelIndex), evt.m_x, evt.m_y)) {
+      if (HasSelection() && OverTextBox(GetLabel(mSelIndex), evt.m_x, evt.m_y)) {
          // popup menu for editing
          ShowContextMenu();
       }
@@ -1753,7 +1756,7 @@ bool LabelTrackView::DoCaptureKey(wxKeyEvent & event)
        !mLabels.empty())
       return true;
 
-   if ( pTrack->mSelIndex >= 0 ) {
+   if ( pTrack->HasSelection() ) {
       if (IsGoodLabelEditKey(event)) {
          return true;
       }
@@ -1888,7 +1891,7 @@ bool LabelTrackView::DoKeyDown(SelectedRegion &newSel, wxKeyEvent & event)
    auto &mInitialCursorPos = pTrack->mInitialCursorPos;
    auto &mCurrentCursorPos = pTrack->mCurrentCursorPos;
    auto &mRestoreFocus = pTrack->mRestoreFocus;
-   if ( pTrack->mSelIndex >= 0 ) {
+   if ( pTrack->HasSelection() ) {
       auto &labelStruct = mLabels[mSelIndex];
       auto &title = labelStruct.title;
       switch (keyCode) {
@@ -2123,7 +2126,7 @@ bool LabelTrackView::DoChar(SelectedRegion &WXUNUSED(newSel), wxKeyEvent & event
    
    // If we've reached this point and aren't currently editing, add NEW label
    const auto pTrack = FindLabelTrack();
-   if ( pTrack->mSelIndex < 0 ) {
+   if ( !pTrack->HasSelection() ) {
       // Don't create a NEW label for a space
       if (wxIsspace(charCode)) {
          event.Skip();
@@ -2216,7 +2219,11 @@ void LabelTrack::ShowContextMenu()
       menu.Enable(OnDeleteSelectedLabelID, true);
       menu.Enable(OnEditSelectedLabelID, true);
 
-      wxASSERT(mSelIndex >= 0);
+      if( !HasSelection() ) {
+         wxASSERT( false );
+         return;
+      }
+
       const LabelStruct *ls = GetLabel(mSelIndex);
 
       wxClientDC dc(parent);
@@ -2318,7 +2325,8 @@ void LabelTrack::Unselect()
 
 bool LabelTrack::HasSelection() const
 {
-   return (mSelIndex >= 0 && mSelIndex < (int)mLabels.size());
+   auto selIndex = GetSelectedIndex();
+   return (selIndex >= 0 && selIndex < (int)mLabels.size());
 }
 
 /// Export labels including label start and end-times.