Remove AudacityApp::GetLogger() & HelpActions::DoShowLog()

src/AudacityApp.cpp

@@ -831,13 +831,6 @@ locations of the missing files."), missingFileName);
    }
 }
 
-AudacityLogger *AudacityApp::GetLogger()
-{
-   // Use dynamic_cast so that we get a NULL ptr if we haven't yet
-   // setup our logger.
-   return dynamic_cast<AudacityLogger *>(wxLog::GetActiveTarget());
-}
-
 #if defined(__WXMSW__)
 #define WL(lang, sublang) (lang), (sublang),
 #else
@@ -944,7 +937,7 @@ void AudacityApp::GenerateCrashReport(wxDebugReport::Context ctx)
 #endif
    }
 
-   AudacityLogger *logger = GetLogger();
+   auto logger = AudacityLogger::Get();
    if (logger)
    {
       rpt.AddText(wxT("log.txt"), logger->GetLog(), _TS("Audacity Log"));
@@ -1051,11 +1044,8 @@ bool AudacityApp::OnInit()
    // Ensure we have an event loop during initialization
    wxEventLoopGuarantor eventLoop;
 
-   // wxWidgets will clean up the logger for the main thread, so we can say
+   // cause initialization of wxWidgets' global logger target
-   // safenew.  See:
+   (void) AudacityLogger::Get();
-   // http://docs.wxwidgets.org/3.0/classwx_log.html#a2525bf54fa3f31dc50e6e3cd8651e71d
-   std::unique_ptr < wxLog >
-      { wxLog::SetActiveTarget(safenew AudacityLogger) }; // DELETE old
 
 #if defined(__WXMAC__)
    // Disable window animation

src/AudacityApp.h

@@ -36,7 +36,6 @@ class IPCServ;
 class Importer;
 class CommandHandler;
 class AppCommandEvent;
-class AudacityLogger;
 class AudacityProject;
 
 class AliasBlockFile;
@@ -93,8 +92,6 @@ class AudacityApp final : public wxApp {
     void AssociateFileTypes();
    #endif
 
-   AudacityLogger *GetLogger();
-
 #if defined(EXPERIMENTAL_CRASH_REPORT)
    void GenerateCrashReport(wxDebugReport::Context ctx);
 #endif

src/AudacityLogger.cpp

@@ -22,6 +22,7 @@ Provides thread-safe logging based on the wxWidgets log facility.
 #include "FileNames.h"
 #include "ShuttleGui.h"
 
+#include <mutex>
 #include <wx/filedlg.h>
 #include <wx/log.h>
 #include <wx/frame.h>
@@ -50,6 +51,22 @@ enum
    LoggerID_Close
 };
 
+AudacityLogger *AudacityLogger::Get()
+{
+   static std::once_flag flag;
+   std::call_once( flag, []{
+      // wxWidgets will clean up the logger for the main thread, so we can say
+      // safenew.  See:
+      // http://docs.wxwidgets.org/3.0/classwx_log.html#a2525bf54fa3f31dc50e6e3cd8651e71d
+      std::unique_ptr < wxLog > // DELETE any previous logger
+         { wxLog::SetActiveTarget(safenew AudacityLogger) };
+   } );
+
+   // Use dynamic_cast so that we get a NULL ptr in case our logger
+   // is no longer the target.
+   return dynamic_cast<AudacityLogger *>(wxLog::GetActiveTarget());
+}
+
 AudacityLogger::AudacityLogger()
 :  wxEvtHandler(),
    wxLog()

src/AudacityLogger.h

@@ -27,7 +27,9 @@ class wxTextCtrl;
 
 class AudacityLogger final : public wxEvtHandler, public wxLog {
  public:
-   AudacityLogger();
+ 
+   // Get the singleton instance or null
+   static AudacityLogger *Get();
 
    void Show(bool show = true);
 
@@ -40,6 +42,8 @@ class AudacityLogger final : public wxEvtHandler, public wxLog {
    void DoLogText(const wxString & msg) override;
 
  private:
+   AudacityLogger();
+
    void OnCloseWindow(wxCloseEvent & e);
    void OnClose(wxCommandEvent & e);
    void OnClear(wxCommandEvent & e);

src/Menus.h

@@ -180,7 +180,6 @@ bool DoAudacityCommand(
 /// Namespace for functions for Help menu
 namespace HelpActions {
 void DoHelpWelcome( AudacityProject & );
-void DoShowLog( AudacityProject& );
 }
 
 #endif

src/menus/HelpMenus.cpp

@@ -75,14 +75,6 @@ namespace HelpActions {
 
 // exported helper functions
 
-void DoShowLog( AudacityProject & )
-{
-   AudacityLogger *logger = wxGetApp().GetLogger();
-   if (logger) {
-      logger->Show();
-   }
-}
-
 void DoHelpWelcome( AudacityProject &project )
 {
    SplashDialog::Show2( &project );
@@ -135,7 +127,10 @@ void OnMidiDeviceInfo(const CommandContext &context)
 
 void OnShowLog( const CommandContext &context )
 {
-   DoShowLog( context.project );
+   auto logger = AudacityLogger::Get();
+   if (logger) {
+      logger->Show();
+   }
 }
 
 #if defined(EXPERIMENTAL_CRASH_REPORT)

src/widgets/MultiDialog.cpp

@@ -21,8 +21,6 @@ for each problem encountered, since there can be many orphans.
 #include "../Audacity.h"
 #include "MultiDialog.h"
 
-#include "../Project.h"
-
 #include <wx/app.h>
 #include <wx/button.h>
 #include <wx/dialog.h>
@@ -34,7 +32,7 @@ for each problem encountered, since there can be many orphans.
 #include <wx/artprov.h>
 #include <wx/radiobox.h>
 
-#include "../Menus.h"
+#include "../AudacityLogger.h"
 #include "wxPanelWrapper.h"
 
 class MultiDialog final : public wxDialogWrapper
@@ -153,8 +151,10 @@ void MultiDialog::OnOK(wxCommandEvent & WXUNUSED(event))
 
 void MultiDialog::OnShowLog(wxCommandEvent & WXUNUSED(event))
 {
-   auto project = GetActiveProject();
+   auto logger = AudacityLogger::Get();
-   HelpActions::DoShowLog(*project);
+   if (logger) {
+      logger->Show();
+   }
 }