More const qualifiers, for copying of tracks, and replacing in lists of tracks

... (the tracks may be const, not the list, when replacing)

src/LabelTrack.cpp

@@ -1270,7 +1270,7 @@ void LabelStruct::MoveLabel( int iEdge, double fNewTime)
 }
 
 LabelStruct::TimeRelations LabelStruct::RegionRelation(
-      double reg_t0, double reg_t1, LabelTrack * WXUNUSED(parent))
+      double reg_t0, double reg_t1, const LabelTrack * WXUNUSED(parent))
 {
    bool retainLabels = false;
 
@@ -2422,7 +2422,7 @@ bool LabelTrack::SplitCut(double t0, double t1, Track ** dest)
 }
 #endif
 
-bool LabelTrack::Copy(double t0, double t1, Track ** dest)
+bool LabelTrack::Copy(double t0, double t1, Track ** dest) const
 {
    *dest = new LabelTrack(GetDirManager());
    int len = mLabels.Count();

src/LabelTrack.h

@@ -81,7 +81,7 @@ public:
    /// and end of parent to be within a region that borders them (this makes
    /// it possible to DELETE capture all labels with a Select All).
    TimeRelations RegionRelation(double reg_t0, double reg_t1,
-                                LabelTrack *parent = NULL);
+                                const LabelTrack *parent = NULL);
 
 public:
    SelectedRegion selectedRegion;
@@ -157,7 +157,7 @@ class AUDACITY_DLL_API LabelTrack final : public Track
    // or Paste() because then it
    // is no longer recognised as a virtual function matching the
    // one in Track.
-   bool Copy (double t0, double t1, Track ** dest) override;// const;
+   bool Copy (double t0, double t1, Track ** dest) const override;
    bool Clear(double t0, double t1) override;
    bool Paste(double t, const Track * src) override;
    bool Repeat(double t0, double t1, int n);

src/Menus.cpp

@@ -4592,7 +4592,7 @@ void AudacityProject::OnCutLabels()
 
   // Because of grouping the copy may need to operate on different tracks than
   // the clear, so we do these actions separately.
-  EditClipboardByLabel( &WaveTrack::Copy );
+  EditClipboardByLabel( &WaveTrack::CopyNonconst );
 
   if( gPrefs->Read( wxT( "/GUI/EnableCutLines" ), ( long )0 ) )
      EditByLabel( &WaveTrack::ClearAndAddCutLine, true );
@@ -4635,7 +4635,7 @@ void AudacityProject::OnCopyLabels()
   if( mViewInfo.selectedRegion.isPoint() )
      return;
 
-  EditClipboardByLabel( &WaveTrack::Copy );
+  EditClipboardByLabel( &WaveTrack::CopyNonconst );
 
   msClipProject = this;
 

src/NoteTrack.cpp

@@ -469,7 +469,7 @@ bool NoteTrack::Cut(double t0, double t1, Track **dest){
    return true;
 }
 
-bool NoteTrack::Copy(double t0, double t1, Track **dest){
+bool NoteTrack::Copy(double t0, double t1, Track **dest) const {
 
    //dest goes onto clipboard
    *dest = NULL; // This is redundant and matches WaveTrack::Copy

src/NoteTrack.h

@@ -90,7 +90,7 @@ class AUDACITY_DLL_API NoteTrack final : public Track {
 
    // High-level editing
    bool Cut  (double t0, double t1, Track **dest) override;
-   bool Copy (double t0, double t1, Track **dest) override;
+   bool Copy (double t0, double t1, Track **dest) const override;
    bool Trim (double t0, double t1) /* not override */;
    bool Clear(double t0, double t1) override;
    bool Paste(double t, const Track *src) override;

src/Track.cpp

@@ -132,7 +132,7 @@ Track::~Track()
 }
 
 
-const TrackListNode *Track::GetNode()
+const TrackListNode *Track::GetNode() const
 {
    return mNode;
 }
@@ -837,18 +837,22 @@ void TrackList::AddToHead(Track * t)
    ResizedEvent(n);
 }
 
-void TrackList::Replace(Track * t, Track * with, bool deletetrack)
+void TrackList::Replace(const Track * t, const Track * with, bool deletetrack)
 {
-   if (t && with) {
-      TrackListNode *node = (TrackListNode *) t->GetNode();
+   Track *const mutableT = const_cast<Track*>(t);
+   Track *const mutableWith = const_cast<Track*>(with);
 
-      t->SetOwner(NULL, NULL);
+   if (mutableT && with) {
+      TrackListNode *node =
+         const_cast<TrackListNode *>(mutableT->GetNode());
+
+      mutableT->SetOwner(NULL, NULL);
       if (deletetrack) {
          delete t;
       }
 
-      node->t = with;
-      with->SetOwner(this, node);
+      node->t = mutableWith;
+      mutableWith->SetOwner(this, node);
       RecalcPositions(node);
       UpdatedEvent(node);
       ResizedEvent(node);

src/Track.h

@@ -102,7 +102,7 @@ class AUDACITY_DLL_API Track /* not final */ : public XMLTagHandler
 #endif
    Track *GetLink() const;
 
-   const TrackListNode *GetNode();
+   const TrackListNode *GetNode() const;
    void SetOwner(TrackList *list, TrackListNode *node);
 
  // Keep in Track
@@ -181,7 +181,7 @@ class AUDACITY_DLL_API Track /* not final */ : public XMLTagHandler
    DirManager* GetDirManager() const { return mDirManager; }
 
    virtual bool Cut  (double WXUNUSED(t0), double WXUNUSED(t1), Track ** WXUNUSED(dest)) {return false;}
-   virtual bool Copy (double WXUNUSED(t0), double WXUNUSED(t1), Track ** WXUNUSED(dest)) {return false;}
+   virtual bool Copy (double WXUNUSED(t0), double WXUNUSED(t1), Track ** WXUNUSED(dest)) const {return false;}
    virtual bool Clear(double WXUNUSED(t0), double WXUNUSED(t1)) {return false;}
    virtual bool Paste(double WXUNUSED(t), const Track * WXUNUSED(src)) {return false;}
 
@@ -385,7 +385,8 @@ class AUDACITY_DLL_API TrackList final : public wxEvtHandler
    void AddToHead(Track * t);
 
    /// Replace first track with second track
-   void Replace(Track * t, Track * with, bool deletetrack = false);
+   /// Non-const function of TrackList, but it can take pointers to const tracks
+   void Replace(const Track * t, const Track * with, bool deletetrack = false);
 
    /// Remove this Track or all children of this TrackList.
    void Remove(Track * t, bool deletetrack = false);

src/WaveClip.cpp

@@ -1407,7 +1407,7 @@ void WaveClip::WriteXML(XMLWriter &xmlFile)
    xmlFile.EndTag(wxT("waveclip"));
 }
 
-bool WaveClip::CreateFromCopy(double t0, double t1, WaveClip* other)
+bool WaveClip::CreateFromCopy(double t0, double t1, const WaveClip* other)
 {
    sampleCount s0, s1;
 

src/WaveClip.h

@@ -279,7 +279,7 @@ public:
    void MarkChanged() { mDirty++; }
 
    /// Create clip from copy, discarding previous information in the clip
-   bool CreateFromCopy(double t0, double t1, WaveClip* other);
+   bool CreateFromCopy(double t0, double t1, const WaveClip* other);
 
    /** Getting high-level data from the for screen display and clipping
     * calculations and Contrast */

src/WaveTrack.cpp

@@ -623,7 +623,7 @@ bool WaveTrack::Trim (double t0, double t1)
 
 
 
-bool WaveTrack::Copy(double t0, double t1, Track **dest)
+bool WaveTrack::Copy(double t0, double t1, Track **dest) const
 {
    *dest = NULL;
 
@@ -636,9 +636,9 @@ bool WaveTrack::Copy(double t0, double t1, Track **dest)
 
    WaveClipList::compatibility_iterator it;
 
-   for (it=GetClipIterator(); it; it=it->GetNext())
+   for (it = const_cast<WaveTrack*>(this)->GetClipIterator(); it; it = it->GetNext())
    {
-      WaveClip *clip = it->GetData();
+      const WaveClip *clip = it->GetData();
 
       if (t0 <= clip->GetStartTime() && t1 >= clip->GetEndTime())
       {
@@ -713,6 +713,11 @@ bool WaveTrack::Copy(double t0, double t1, Track **dest)
    return true;
 }
 
+bool WaveTrack::CopyNonconst(double t0, double t1, Track **dest)
+{
+   return Copy(t0, t1, dest);
+}
+
 bool WaveTrack::Clear(double t0, double t1)
 {
    return HandleClear(t0, t1, false, false);

src/WaveTrack.h

@@ -154,7 +154,8 @@ class AUDACITY_DLL_API WaveTrack final : public Track {
    //
 
    bool Cut(double t0, double t1, Track **dest) override;
-   bool Copy(double t0, double t1, Track **dest) override;
+   bool Copy(double t0, double t1, Track **dest) const override;
+   bool CopyNonconst(double t0, double t1, Track **dest) /* not override */;
    bool Clear(double t0, double t1) override;
    bool Paste(double t0, const Track *src) override;
    bool ClearAndPaste(double t0, double t1,