Use weak pointers to simplify MenuCreator

src/Menus.cpp

@@ -170,10 +170,6 @@ MenuCreator::MenuCreator(){
 
 MenuCreator::~MenuCreator()
 {
-   if (wxGetApp().GetRecentFiles())
-   {
-      wxGetApp().GetRecentFiles()->RemoveMenu(mRecentFilesMenu);
-   }
 }
 
 enum {
@@ -1833,15 +1829,6 @@ void MenuCreator::CreateMenusAndCommands(AudacityProject &project)
 
 
       project.SetMenuBar(menubar.release());
-      // Bug 143 workaround.
-      // The bug is in wxWidgets.  For a menu that has scrollers, the
-      // scrollers have an ID of 0 (not wxID_NONE which is -3).
-      // Therefore wxWidgets attempts to find a help string. See
-      // wxFrameBase::ShowMenuHelp(int menuId)
-      // It finds a bogus automatic help string of "Recent &Files"
-      // from that submenu.
-      // So we set the help string for command with Id 0 to empty.
-      mRecentFilesMenu->GetParent()->SetHelpString( 0, "" );
    }
 
 
@@ -2188,19 +2175,35 @@ void MenuCreator::CreateRecentFilesMenu(CommandManager *c)
 {
    // Recent Files and Recent Projects menus
 
+   wxWeakRef<wxMenu> recentFilesMenu = c->BeginSubMenu(
+
 #ifdef __WXMAC__
-   /* i18n-hint: This is the name of the menu item on Mac OS X only */
+      /* i18n-hint: This is the name of the menu item on Mac OS X only */
-   mRecentFilesMenu = c->BeginSubMenu(_("Open Recent"));
+      _("Open Recent")
 #else
-   /* i18n-hint: This is the name of the menu item on Windows and Linux */
+      /* i18n-hint: This is the name of the menu item on Windows and Linux */
-   mRecentFilesMenu = c->BeginSubMenu(_("Recent &Files"));
+      _("Recent &Files")
 #endif
 
-   wxGetApp().GetRecentFiles()->UseMenu(mRecentFilesMenu);
+   );
-   wxGetApp().GetRecentFiles()->AddFilesToMenu(mRecentFilesMenu);
+
+   wxGetApp().GetRecentFiles()->UseMenu(recentFilesMenu);
+   wxGetApp().GetRecentFiles()->AddFilesToMenu(recentFilesMenu);
 
    c->EndSubMenu();
 
+   wxTheApp->CallAfter( [=] {
+      // Bug 143 workaround.
+      // The bug is in wxWidgets.  For a menu that has scrollers, the
+      // scrollers have an ID of 0 (not wxID_NONE which is -3).
+      // Therefore wxWidgets attempts to find a help string. See
+      // wxFrameBase::ShowMenuHelp(int menuId)
+      // It finds a bogus automatic help string of "Recent &Files"
+      // from that submenu.
+      // So we set the help string for command with Id 0 to empty.
+      if ( recentFilesMenu )
+         recentFilesMenu->GetParent()->SetHelpString( 0, "" );
+   });
 }
 
 // TODO: This surely belongs in CommandManager?
@@ -2250,9 +2253,6 @@ void MenuCreator::RebuildMenuBar(AudacityProject &project)
    }
 #endif
 
-   // Allow FileHistory to remove its own menu
-   wxGetApp().GetRecentFiles()->RemoveMenu(mRecentFilesMenu);
-
    // Delete the menus, since we will soon recreate them.
    // Rather oddly, the menus don't vanish as a result of doing this.
    {

src/Menus.h

@@ -617,9 +617,6 @@ public:
    void CreateRecentFilesMenu(CommandManager *c);
 
 public:
-// Recent files
-   wxMenu *mRecentFilesMenu;
-
    CommandFlag mLastFlags;
    
    // Last effect applied to this project

src/widgets/FileHistory.cpp

@@ -101,6 +101,8 @@ size_t FileHistory::GetCount()
 
 void FileHistory::UseMenu(wxMenu *menu)
 {
+   Compress();
+
    auto end = mMenus.end();
    auto iter = std::find(mMenus.begin(), end, menu);
    auto found = (iter != end);
@@ -112,19 +114,6 @@ void FileHistory::UseMenu(wxMenu *menu)
    }
 }
 
-void FileHistory::RemoveMenu(wxMenu *menu)
-{
-   auto end = mMenus.end();
-   auto iter = std::find(mMenus.begin(), end, menu);
-   auto found = (iter != end);
-
-   if (found)
-      mMenus.erase(iter);
-   else {
-      wxASSERT(false);
-   }
-}
-
 void FileHistory::Load(wxConfigBase & config, const wxString & group)
 {
    mHistory.Clear();
@@ -161,8 +150,10 @@ void FileHistory::Save(wxConfigBase & config, const wxString & group)
 
 void FileHistory::AddFilesToMenu()
 {
+   Compress();
    for (auto pMenu : mMenus)
-      AddFilesToMenu(pMenu);
+      if (pMenu)
+         AddFilesToMenu(pMenu);
 }
 
 void FileHistory::AddFilesToMenu(wxMenu *menu)
@@ -183,3 +174,15 @@ void FileHistory::AddFilesToMenu(wxMenu *menu)
    menu->Append(mIDBase, _("&Clear"));
    menu->Enable(mIDBase, mHistory.GetCount() > 0);
 }
+
+void FileHistory::Compress()
+{
+   // Clear up expired weak pointers
+   auto end = mMenus.end();
+   mMenus.erase(
+     std::remove_if( mMenus.begin(), end,
+        [](wxWeakRef<wxMenu> &pMenu){ return !pMenu; } ),
+     end
+   );
+}
+

src/widgets/FileHistory.h

@@ -19,6 +19,7 @@
 #include <wx/grid.h>
 #include <wx/string.h>
 #include <wx/window.h>
+#include <wx/weakref.h>
 
 class AUDACITY_DLL_API FileHistory
 {
@@ -30,7 +31,6 @@ class AUDACITY_DLL_API FileHistory
    void RemoveFileFromHistory(size_t i, bool update = true);
    void Clear();
    void UseMenu(wxMenu *menu);
-   void RemoveMenu(wxMenu *menu);
    void Load(wxConfigBase& config, const wxString & group);
    void Save(wxConfigBase& config, const wxString & group);
 
@@ -41,10 +41,12 @@ class AUDACITY_DLL_API FileHistory
    const wxString &GetHistoryFile(size_t i) const;
 
  private:
+   void Compress();
+
    size_t mMaxFiles;
    wxWindowID mIDBase;
 
-   std::vector<wxMenu*> mMenus;
+   std::vector< wxWeakRef< wxMenu > > mMenus;
    wxArrayString mHistory;
 
 };