Rewrite many iterations over tracks and channels in src/commands

src/commands/CompareAudioCommand.cpp

@@ -76,20 +76,20 @@ bool CompareAudioCommand::GetSelection(const CommandContext &context, AudacityPr
 
    // Get the selected tracks and check that there are at least two to
    // compare
-   SelectedTrackListOfKindIterator iter(Track::Wave, proj.GetTracks());
+   auto trackRange = proj.GetTracks()->Selected< const WaveTrack >();
-   mTrack0 = (WaveTrack*)(iter.First());
+   mTrack0 = *trackRange.first;
    if (mTrack0 == NULL)
    {
       context.Error(wxT("No tracks selected! Select two tracks to compare."));
       return false;
    }
-   mTrack1 = (WaveTrack*)(iter.Next());
+   mTrack1 = * ++ trackRange.first;
    if (mTrack1 == NULL)
    {
       context.Error(wxT("Only one track selected! Select two tracks to compare."));
       return false;
    }
-   if (iter.Next() != NULL)
+   if ( * ++ trackRange.first )
    {
       context.Status(wxT("More than two tracks selected - only the first two will be compared."));
    }

src/commands/GetInfoCommand.cpp

@@ -267,7 +267,7 @@ bool GetInfoCommand::SendTracks(const CommandContext & context)
          context.AddItem( t->GetEndTime(), "end" );
          context.AddItem( t->GetPan() , "pan");
          context.AddItem( t->GetGain() , "gain");
-         context.AddItem( t->GetLinked() ? 2:1, "channels");
+         context.AddItem( TrackList::Channels(t).size(), "channels");
          context.AddBool( t->GetSolo(), "solo" );
          context.AddBool( t->GetMute(), "mute");
       } );
@@ -280,28 +280,18 @@ bool GetInfoCommand::SendTracks(const CommandContext & context)
 bool GetInfoCommand::SendClips(const CommandContext &context)
 {
    TrackList *tracks = context.GetProject()->GetTracks();
-   TrackListIterator iter(tracks);
-   Track *t = iter.First();
    int i=0;
    context.StartArray();
-   while (t) {
+   for (auto waveTrack : tracks->Leaders<WaveTrack>()) {
-      if (t->GetKind() == Track::Wave) {
+      WaveClipPointers ptrs( waveTrack->SortedClipArray());
-         WaveTrack *waveTrack = static_cast<WaveTrack*>(t);
+      for(WaveClip * pClip : ptrs ) {
-         WaveClipPointers ptrs( waveTrack->SortedClipArray());
+         context.StartStruct();
-         for(WaveClip * pClip : ptrs ) {
+         context.AddItem( (double)i, "track" );
-            context.StartStruct();
+         context.AddItem( pClip->GetStartTime(), "start" );
-            context.AddItem( (double)i, "track" );
+         context.AddItem( pClip->GetEndTime(), "end" );
-            context.AddItem( pClip->GetStartTime(), "start" );
+         context.AddItem( pClip->GetColourIndex(), "color" );
-            context.AddItem( pClip->GetEndTime(), "end" );
+         context.EndStruct();
-            context.AddItem( pClip->GetColourIndex(), "color" );
-            context.EndStruct();
-         }
       }
-      // Skip second tracks of stereo...
-      if( t->GetLinked() )
-         t= iter.Next();
-      if( t )
-         t=iter.Next();
       i++;
    }
    context.EndArray();
@@ -312,43 +302,33 @@ bool GetInfoCommand::SendClips(const CommandContext &context)
 bool GetInfoCommand::SendEnvelopes(const CommandContext &context)
 {
    TrackList *tracks = context.GetProject()->GetTracks();
-   TrackListIterator iter(tracks);
-   Track *t = iter.First();
    int i=0;
    int j=0;
    context.StartArray();
-   while (t) {
+   for (auto waveTrack : tracks->Leaders<WaveTrack>()) {
-      if (t->GetKind() == Track::Wave) {
+      WaveClipPointers ptrs( waveTrack->SortedClipArray());
-         WaveTrack *waveTrack = static_cast<WaveTrack*>(t);
+      for(WaveClip * pClip : ptrs ) {
-         WaveClipPointers ptrs( waveTrack->SortedClipArray());
+         context.StartStruct();
-         for(WaveClip * pClip : ptrs ) {
+         context.AddItem( (double)i, "track" );
-            context.StartStruct();
+         context.AddItem( (double)j, "clip" );
-            context.AddItem( (double)i, "track" );
+         context.AddItem( pClip->GetStartTime(), "start" );
-            context.AddItem( (double)j, "clip" );
+         Envelope * pEnv = pClip->GetEnvelope();
-            context.AddItem( pClip->GetStartTime(), "start" );
+         context.StartField( "points" );
-            Envelope * pEnv = pClip->GetEnvelope();
+         context.StartArray();
-            context.StartField( "points" );
+         double offset = pEnv->mOffset;
-            context.StartArray();
+         for( size_t k=0;k<pEnv->mEnv.size(); k++)
-            double offset = pEnv->mOffset;
+         {
-            for( size_t k=0;k<pEnv->mEnv.size(); k++)
+            context.StartStruct( );
-            {
+            context.AddItem( pEnv->mEnv[k].GetT()+offset, "t" );
-               context.StartStruct( );
+            context.AddItem( pEnv->mEnv[k].GetVal(), "y" );
-               context.AddItem( pEnv->mEnv[k].GetT()+offset, "t" );
-               context.AddItem( pEnv->mEnv[k].GetVal(), "y" );
-               context.EndStruct();
-            }
-            context.EndArray();
-            context.EndField();
-            context.AddItem( pClip->GetEndTime(), "end" );
             context.EndStruct();
-            j++;
          }
+         context.EndArray();
+         context.EndField();
+         context.AddItem( pClip->GetEndTime(), "end" );
+         context.EndStruct();
+         j++;
       }
-      // Skip second tracks of stereo...
-      if( t->GetLinked() )
-         t= iter.Next();
-      if( t )
-         t=iter.Next();
    }
    context.EndArray();
 

src/commands/ScreenshotCommand.cpp

@@ -777,20 +777,14 @@ wxRect ScreenshotCommand::GetTrackRect( AudacityProject * pProj, TrackPanel * pa
       return rect;
    };
 
-   TrackListIterator iter(pProj->GetTracks());
    int count = 0;
-   for (auto t = iter.First(); t; t = iter.Next()) {
+   for (auto t : pProj->GetTracks()->Leaders()) {
       count +=  1;
       if( count > n )
       {
          wxRect r =  FindRectangle( *panel, *t );
          return r;
       }
-      if( t->GetLinked() ){
-         t = iter.Next();
-         if( !t )
-            break;
-      }
    }
    return wxRect( 0,0,0,0);
 }

src/commands/SelectCommand.cpp

@@ -220,31 +220,30 @@ bool SelectTracksCommand::Apply(const CommandContext &context)
    if( !bHasFirstTrack ) 
       mFirstTrack = 0.0;
 
-   // Stereo second tracks count as 0.5 of a track.
+   // Multiple channels count as fractions of a track.
    double last = mFirstTrack+mNumTracks;
    double first = mFirstTrack;
-   bool bIsSecondChannel = false;
+
-   TrackListIterator iter(tracks);
+   for (auto t : tracks->Leaders()) {
-   Track *t = iter.First();
+      auto channels = TrackList::Channels(t);
-   while (t) {
+      double term = 0.0;
       // Add 0.01 so we are free of rounding errors in comparisons.
-      // Optionally add 0.5 for second track which counts as is half a track
+      constexpr double fudge = 0.01;
-      double track = index + 0.01 + (bIsSecondChannel ? 0.5 : 0.0);
+      for (auto channel : channels) {
-      bool sel = first <= track && track <= last;
+         double track = index + fudge + term;
-      if( mMode == 0 ){ // Set
+         bool sel = first <= track && track <= last;
-         t->SetSelected(sel);
+         if( mMode == 0 ){ // Set
+            t->SetSelected(sel);
+         }
+         else if( mMode == 1 && sel ){ // Add
+            t->SetSelected(sel);
+         }
+         else if( mMode == 2 && sel ){ // Remove
+            t->SetSelected(!sel);
+         }
+         term += (1.0 - fudge) / channels.size();
       }
-      else if( mMode == 1 && sel ){ // Add
+      ++index;
-         t->SetSelected(sel);
-      }
-      else if( mMode == 2 && sel ){ // Remove
-         t->SetSelected(!sel);
-      }
-      // Do second channel in stereo track too.
-      bIsSecondChannel = t->GetLinked();
-      if( !bIsSecondChannel )
-         ++index;
-      t = iter.Next();
    }
    return true;
 }

src/commands/SetLabelCommand.cpp

@@ -67,27 +67,21 @@ bool SetLabelCommand::Apply(const CommandContext & context)
    //wxString mode = GetString(wxT("Type"));
    AudacityProject * p = context.GetProject();
    TrackList *tracks = context.GetProject()->GetTracks();
-   TrackListIterator iter(tracks);
-   Track *t = iter.First();
    LabelStruct * pLabel = NULL;
    int i=0;
    int nn=0;
 
-   LabelTrack *labelTrack = nullptr;
+   LabelTrack *labelTrack {};
-   while (t && i<=mLabelIndex) {
+   for (auto lt : tracks->Any<LabelTrack>()) {
-      if (t->GetKind() == Track::Label) {
+      if( i > mLabelIndex )
-         labelTrack = static_cast<LabelTrack*>(t);
+         break;
-         if( labelTrack )
+      labelTrack = lt;
-         {
+      for (nn = 0;
-            for (nn = 0; 
+         (nn< (int)labelTrack->mLabels.size()) && i<=mLabelIndex; 
-               (nn< (int)labelTrack->mLabels.size()) && i<=mLabelIndex; 
+         nn++) {
-               nn++) {
+         i++;
-               i++;
+         pLabel = &labelTrack->mLabels[nn];
-               pLabel = &labelTrack->mLabels[nn];
-            }
-         }
       }
-      t = iter.Next();
    }
 
    if ( (i< mLabelIndex) || (pLabel == NULL))

src/commands/SetTrackInfoCommand.cpp

@@ -92,28 +92,26 @@ bool SetTrackBase::Apply(const CommandContext & context  )
 {
    long i = 0;// track counter
    long j = 0;// channel counter
-   TrackListIterator iter(context.GetProject()->GetTracks());
+   auto tracks = context.GetProject()->GetTracks();
-   Track *t = iter.First();
+   for ( auto t : tracks->Leaders() )
-   bIsSecondChannel = false;
-   while (t )
    {
-      bool bThisTrack =
+      auto channels = TrackList::Channels(t);
+      for ( auto channel : channels ) {
+         bool bThisTrack =
 #ifdef USE_OWN_TRACK_SELECTION
          (bHasTrackIndex && (i==mTrackIndex)) ||
          (bHasChannelIndex && (j==mChannelIndex ) ) ||
          (!bHasTrackIndex && !bHasChannelIndex) ;
 #else
-         t->GetSelected();
+         channel->GetSelected();
 #endif
 
-      if( bThisTrack ){
+         if( bThisTrack ){
-         ApplyInner( context, t );
+            ApplyInner( context, t );
+         }
+         ++j; // count all channels
       }
-      bIsSecondChannel = t->GetLinked();
+      ++i; // count groups of channels
-      if( !bIsSecondChannel )
-         ++i;
-      j++;
-      t = iter.Next();
    }
    return true;
 }