More stl idiom for TrackList and its iterators

src/Menus.cpp

@@ -2912,7 +2912,7 @@ void AudacityProject::SortTracks(int flags)
    // This one place outside of TrackList where we must use undisguised
    // std::list iterators!  Avoid this elsewhere!
    std::vector<ListOfTracks::iterator> arr;
-   arr.reserve(mTracks->GetCount());
+   arr.reserve(mTracks->size());
    bool lastTrackLinked = false;
    //sort by linked tracks. Assumes linked track follows owner in list.
 
@@ -4332,7 +4332,7 @@ bool AudacityProject::DoEffect(const PluginID & ID, int flags)
 
    wxGetApp().SetMissingAliasedFileWarningShouldShow(true);
 
-   int nTracksOriginally = GetTrackCount();
+   auto nTracksOriginally = GetTrackCount();
    TrackListIterator iter(GetTracks());
    Track *t = iter.First();
    WaveTrack *newTrack{};

src/Project.cpp

@@ -1484,7 +1484,7 @@ void AudacityProject::SetProjectTitle( int number)
 
 bool AudacityProject::GetIsEmpty()
 {
-   return mTracks->IsEmpty();
+   return mTracks->empty();
 }
 
 bool AudacityProject::SnapSelection()
@@ -2896,7 +2896,7 @@ void AudacityProject::OpenFiles(AudacityProject *proj)
       // there are no tracks, but there's an Undo history, etc, then
       // bad things can happen, including data files moving to the NEW
       // project directory, etc.
-      if ( proj && ( proj->mDirty || !proj->mTracks->IsEmpty() ) )
+      if ( proj && ( proj->mDirty || !proj->mTracks->empty() ) )
          proj = nullptr;
 
       // This project is clean; it's never been touched.  Therefore
@@ -4145,7 +4145,7 @@ AudacityProject::AddImportedTracks(const wxString &fileName,
    const auto numTracks = newTracks.size();
    SelectNone();
 
-   bool initiallyEmpty = mTracks->IsEmpty();
+   bool initiallyEmpty = mTracks->empty();
    double newRate = 0;
    wxString trackNameBase = fileName.AfterLast(wxFILE_SEP_PATH).BeforeLast('.');
    bool isLinked = false;

src/Project.h

@@ -176,7 +176,7 @@ class AUDACITY_DLL_API AudacityProject final : public wxFrame,
 
    TrackList *GetTracks() { return mTracks.get(); }
    const TrackList *GetTracks() const { return mTracks.get(); }
-   const int GetTrackCount(){ return GetTracks()->GetCount(); }
+   size_t GetTrackCount() const { return GetTracks()->size(); }
    UndoManager *GetUndoManager() { return mUndoManager.get(); }
 
    sampleFormat GetDefaultFormat() { return mDefaultFormat; }

src/Track.cpp

@@ -1142,18 +1142,17 @@ bool TrackList::Contains(const Track * t) const
    return make_iterator_range( *this ).contains( t );
 }
 
-bool TrackList::IsEmpty() const
+bool TrackList::empty() const
 {
-   return empty();
+   return begin() == end();
 }
 
-int TrackList::GetCount() const
+size_t TrackList::size() const
 {
    int cnt = 0;
 
-   if (!empty()) {
+   if (!empty())
       cnt = back()->GetIndex() + 1;
-   }
 
    return cnt;
 }
@@ -1303,7 +1302,7 @@ namespace {
    double doubleMin(double a, double b) { return std::min(a, b); }
    double doubleMax(double a, double b) { return std::max(a, b); }
    inline double Accumulate
-      (const ListOfTracks &list,
+      (const TrackList &list,
        double (Track::*memfn)() const,
        double (*combine)(double, double))
    {
@@ -1316,8 +1315,8 @@ namespace {
       auto iter = list.begin();
       double acc = (**iter++.*memfn)();
       return std::accumulate(iter, list.end(), acc,
-         [=](double acc, const ListOfTracks::value_type &pTrack) {
+         [=](double acc, const Track *pTrack) {
-         return combine(acc, (*pTrack.*memfn)());
+            return combine(acc, (*pTrack.*memfn)());
       });
    }
 }

src/Track.h

@@ -365,6 +365,8 @@ class AUDACITY_DLL_API TrackListIterator /* not final */
    Track *operator * () const;
 
    TrackListIterator &operator++ () { (void) Next(); return *this; }
+   TrackListIterator operator++ (int)
+   { auto copy = *this; operator++(); return copy; }
 
    bool operator == (const TrackListIterator &other) const;
    bool operator != (const TrackListIterator &other) const
@@ -415,6 +417,8 @@ public:
    const Track *operator * () const { return *mIter; }
 
    TrackListConstIterator &operator++ () { (void) Next(); return *this; }
+   TrackListConstIterator operator++ (int)
+   { auto copy = *this; operator++(); return copy; }
 
    bool operator == (const TrackListConstIterator &other) const
    { return mIter == other.mIter; }
@@ -666,8 +670,8 @@ class TrackList final : public wxEvtHandler, public ListOfTracks
       return {};
    }
 
-   bool IsEmpty() const;
+   bool empty() const;
-   int GetCount() const;
+   size_t size() const;
 
    double GetStartTime() const;
    double GetEndTime() const;

src/TrackPanel.cpp

@@ -1088,7 +1088,7 @@ bool TrackPanel::IsMouseCaptured()
 
 void TrackPanel::UpdateViewIfNoTracks()
 {
-   if (mTracks->IsEmpty())
+   if (mTracks->empty())
    {
       // BG: There are no more tracks on screen
       //BG: Set zoom to normal

src/commands/SelectCommand.cpp

@@ -108,7 +108,7 @@ bool SelectCommand::Apply(CommandExecutionContext context)
          Error(wxT("Trying to select a negatively numbered track!"));
          return false;
       }
-      if (lastTrack >= tracks->GetCount())
+      if (lastTrack >= (long)tracks->size())
       {
          Error(wxT("Trying to select higher number track than exists!"));
          return false;

src/tracks/ui/CommonTrackPanelCell.cpp

@@ -29,7 +29,7 @@ unsigned CommonTrackPanelCell::HandleWheelRotation
 {
    using namespace RefreshCode;
 
-   if (pProject->GetTracks()->IsEmpty())
+   if (pProject->GetTracks()->empty())
       // Scrolling and Zoom in and out commands are disabled when there are no tracks.
       // This should be disabled too for consistency.  Otherwise
       // you do see changes in the time ruler.