Bug2567: Macros using cut and paste should work on multiple files

src/BatchProcessDialog.cpp

@@ -37,6 +37,7 @@
 #include <wx/imaglist.h>
 #include <wx/settings.h>
 
+#include "Clipboard.h"
 #include "ShuttleGui.h"
 #include "Menus.h"
 #include "Prefs.h"
@@ -433,6 +434,14 @@ void ApplyMacroDialog::OnApplyToFiles(wxCommandEvent & WXUNUSED(event))
 
    mMacroCommands.ReadMacro(name); 
    {
+      // Move global clipboard contents aside temporarily
+      Clipboard tempClipboard;
+      auto &globalClipboard = Clipboard::Get();
+      globalClipboard.Swap(tempClipboard);
+      auto cleanup = finally([&]{
+         globalClipboard.Swap(tempClipboard);
+      });
+
       wxWindowDisabler wd(&activityWin);
       for (i = 0; i < (int)files.size(); i++) {
          if (i > 0) {
@@ -457,6 +466,10 @@ void ApplyMacroDialog::OnApplyToFiles(wxCommandEvent & WXUNUSED(event))
 
          // Ensure project is completely reset
          ProjectManager::Get(*project).ResetProjectToEmpty();
+         // Bug2567:
+         // Must also destroy the clipboard, to be sure sample blocks are
+         // all freed and their ids can be reused safely in the next pass
+         globalClipboard.Clear();
 
          if (!success)
             break;

src/Clipboard.cpp

@@ -18,6 +18,14 @@ Clipboard::Clipboard()
 
 Clipboard::~Clipboard() = default;
 
+void Clipboard::Swap( Clipboard &other )
+{
+   std::swap( mTracks, other.mTracks );
+   std::swap( mProject, other.mProject );
+   std::swap( mT0, other.mT0 );
+   std::swap( mT1, other.mT1 );
+}
+
 Clipboard &Clipboard::Get()
 {
    static Clipboard instance;

src/Clipboard.h

@@ -43,10 +43,13 @@ public:
      TrackList && newContents, double t0, double t1,
      const std::weak_ptr<AudacityProject> &pProject );
 
-private:
    Clipboard();
    ~Clipboard();
 
+   void Swap( Clipboard &other );
+
+private:
+
    std::shared_ptr<TrackList> mTracks;
    std::weak_ptr<AudacityProject> mProject{};
    double mT0{ 0 };