Break cycle of ScriptCommandRelay and CommandBuilder

src/commands/CommandBuilder.cpp

@@ -26,7 +26,6 @@ system by constructing BatchCommandEval objects.
 
 #include "CommandDirectory.h"
 #include "Command.h"
-#include "ScriptCommandRelay.h"
 #include "CommandContext.h"
 #include "CommandTargets.h"
 #include "../Shuttle.h"
@@ -83,7 +82,7 @@ void CommandBuilder::BuildCommand(const wxString &cmdName,
 {
    // Stage 1: create a Command object of the right type
 
-   auto scriptOutput = ScriptCommandRelay::GetResponseTarget();
+   auto scriptOutput = std::make_shared< ResponseQueueTarget >();
    auto output
       = std::make_unique<CommandOutputTargets>(std::make_unique<NullProgressTarget>(),
                                 scriptOutput,
@@ -192,7 +191,8 @@ void CommandBuilder::BuildCommand(const wxString &cmdStringArg)
    int splitAt = cmdString.Find(wxT(':'));
    if (splitAt < 0 && cmdString.Find(wxT(' ')) >= 0) {
       mError = wxT("Command is missing ':'");
-      ScriptCommandRelay::SendResponse(wxT("\n"));
+      ResponseQueueTarget::sResponseQueue().AddResponse(
+         Response{wxT("\n")});
       mValid = false;
       return;
    }

src/commands/CommandTargets.cpp

@@ -458,3 +458,9 @@ void StatusBarTarget::Update(const wxString &message)
 {
    mStatus.SetStatusText(message, 0);
 }
+
+ResponseQueue &ResponseQueueTarget::sResponseQueue()
+{
+   static ResponseQueue queue;
+   return queue;
+}

src/commands/CommandTargets.h

@@ -221,23 +221,23 @@ public:
    void Update(const wxString &message) override;
 };
 
-/// Adds messages to a response queue (to be sent back to a script)
+/// Adds messages to the global response queue (to be sent back to a script)
 class ResponseQueueTarget final : public CommandMessageTarget
 {
 private:
-   ResponseQueue &mResponseQueue;
    wxString mBuffer;
 public:
-   ResponseQueueTarget(ResponseQueue &responseQueue)
-      : mResponseQueue(responseQueue),
-       mBuffer( wxEmptyString )
+   static ResponseQueue &sResponseQueue();
+
+   ResponseQueueTarget()
+      : mBuffer( wxEmptyString )
    { }
    virtual ~ResponseQueueTarget()
    {
       if( mBuffer.StartsWith("\n" ) )
          mBuffer = mBuffer.Mid( 1 );
-      mResponseQueue.AddResponse( mBuffer  );
-      mResponseQueue.AddResponse(wxString(wxT("\n")));
+      sResponseQueue().AddResponse( mBuffer  );
+      sResponseQueue().AddResponse(wxString(wxT("\n")));
    }
    void Update(const wxString &message) override
    {

src/commands/ScriptCommandRelay.cpp

@@ -31,7 +31,6 @@ code out of ModuleManager.
 // Declare static class members
 CommandHandler *ScriptCommandRelay::sCmdHandler;
 tpRegScriptServerFunc ScriptCommandRelay::sScriptFn;
-ResponseQueue ScriptCommandRelay::sResponseQueue;
 
 void ScriptCommandRelay::SetRegScriptServerFunc(tpRegScriptServerFunc scriptFn)
 {
@@ -162,22 +161,8 @@ void * ExecForLisp( char * pIn ){
 };
 
 
-/// Adds a response to the queue to be sent back to the script
-void ScriptCommandRelay::SendResponse(const wxString &response)
-{
-   sResponseQueue.AddResponse(response);
-}
-
 /// Gets a response from the queue (may block)
 Response ScriptCommandRelay::ReceiveResponse()
 {
-   return ScriptCommandRelay::sResponseQueue.WaitAndGetResponse();
-}
-
-/// Get a pointer to a message target which allows commands to send responses
-/// back to a script.
-std::shared_ptr<ResponseQueueTarget> ScriptCommandRelay::GetResponseTarget()
-{
-   // This should be deleted by a Command destructor
-   return std::make_shared<ResponseQueueTarget>(sResponseQueue);
+   return ResponseQueueTarget::sResponseQueue().WaitAndGetResponse();
 }

src/commands/ScriptCommandRelay.h

@@ -22,9 +22,7 @@
 
 class wxWindow;
 class CommandHandler;
-class ResponseQueue;
 class Response;
-class ResponseQueueTarget;
 class OldStyleCommand;
 using OldStyleCommandPointer = std::shared_ptr<OldStyleCommand>;
 class wxString;
@@ -42,7 +40,6 @@ class ScriptCommandRelay
       // N.B. Static class members also have to be declared in the .cpp file
       static CommandHandler *sCmdHandler;
       static tpRegScriptServerFunc sScriptFn;
-      static ResponseQueue sResponseQueue;
 
    public:
 
@@ -52,9 +49,7 @@ class ScriptCommandRelay
       static void Run();
       static void PostCommand(
          wxWindow *pWindow, const OldStyleCommandPointer &cmd);
-      static void SendResponse(const wxString &response);
       static Response ReceiveResponse();
-      static std::shared_ptr<ResponseQueueTarget> GetResponseTarget();
 };
 
 #endif /* End of include guard: __SCRIPT_COMMAND_RELAY__ */