Amended the dynamic menu handling

for the case where we have many windows and
you want to change the menu on change of focus

Which is a classic example of writing code before
it is needed.

src/display_wallet.cpp

@@ -3,8 +3,7 @@ using ro::base58;
 static constexpr char SrcFilename[]{ "src/display_wallet.cpp" };
 display_wallet::display_wallet(wxWindow* parent, wxFileName& walletfile) :
 	wxPanel(parent, myID_WALLET_UI, wxDefaultPosition, wxDefaultSize, wxTAB_TRAVERSAL, wxT("Wallet")),
-	m_db(nullptr),
-	m_menuitem_add_name(this, &display_wallet::add_name_event_handler)
+	m_db(nullptr), m_DisplayWalletEditMenu(1)
 {
 	wxLogMessage(wxT("Loading %s"), walletfile.GetFullPath());
 	try {
@@ -73,10 +72,16 @@ display_wallet::display_wallet(wxWindow* parent, wxFileName& walletfile) :
 		this->SetSize(this->GetParent()->GetClientSize());
 		singletonFrame->m_LastUsedWallet.Assign(walletfile);
 
-		wxMenu* menuFile{ singletonFrame->GetMenuBar()->GetMenu(0) };
-		singletonFrame->GetMenuBar()->EnableTop(1, true); //enable edit menu.
-		wxMenu* menuEdit{ singletonFrame->GetMenuBar()->GetMenu(1) };
-		m_menuitem_add_name.Insert(menuEdit, 0, "add name", "create new Zooko identity");
+		m_DisplayWalletEditMenu.Menu->Append(
+			myID_DISPLAY_WALLET_ADD_NAME, 
+			"add name", "create new Zooko identity"
+		);
+		m_DisplayWalletEditMenu.Menu->Bind(
+			wxEVT_MENU,
+			&display_wallet::add_name_event_handler,
+			this, myID_DISPLAY_WALLET_ADD_NAME
+		);
+		m_DisplayWalletEditMenu.Replace();
 	}
 	catch (const MyException&) {
 		throw;
@@ -91,10 +96,8 @@ display_wallet::display_wallet(wxWindow* parent, wxFileName& walletfile) :
 
 
 }
-display_wallet::~display_wallet() {
-	assert(true);
-	singletonFrame->GetMenuBar()->EnableTop(1, false); //disable edit menu.
 
+display_wallet::~display_wallet() {
 }
 
 void display_wallet::close_menu_event_handler(wxCommandEvent& event) {

src/display_wallet.h

@@ -14,6 +14,6 @@ private:
 	wxBoxSizer* m_rSizer;
 	void close_menu_event_handler(wxCommandEvent&);
 	void add_name_event_handler(wxCommandEvent&);
-	MenuLink m_menuitem_add_name;
 	void OnClose(wxCloseEvent& event);
+	wxMenuTracker m_DisplayWalletEditMenu;
 };

src/frame.cpp

@@ -1,6 +1,36 @@
 #include "stdafx.h"
 static constexpr char SrcFilename[]{ "src/frame.cpp" };
 
+// ----------------------------------------------------------------------------
+//wxMenuTracker
+// ----------------------------------------------------------------------------
+
+wxMenuTracker::wxMenuTracker(const int i) : Menu(new wxMenu), MenuPosition(i) {};
+
+wxMenu* wxMenuTracker::InitialAndFinal[]{ nullptr, new wxMenu, nullptr };
+
+void wxMenuTracker::Replace() {
+	singletonFrame->GetMenuBar()->Replace(
+		MenuPosition,
+		Menu,
+		menu_strings[MenuPosition].head
+	);
+	singletonFrame->GetMenuBar()->EnableTop(MenuPosition, true); //enable edit menu.
+};
+wxMenuTracker::~wxMenuTracker() {
+	auto menu_bar = singletonFrame->GetMenuBar();
+	if (menu_bar->GetMenu(MenuPosition) == Menu) {
+		assert(InitialAndFinal[MenuPosition]);
+		menu_bar->Replace(
+			MenuPosition,
+			InitialAndFinal[MenuPosition],
+			menu_strings[MenuPosition].head
+		);
+		menu_bar->EnableTop(MenuPosition, false);
+		delete Menu;
+	}
+};
+
 // ----------------------------------------------------------------------------
 // frame
 // ----------------------------------------------------------------------------
@@ -158,16 +188,34 @@ Frame::Frame(const wxString& wxs)
 		menuFile->Append(wxID_EXIT);
 		menuFile->Bind(wxEVT_MENU, &Frame::OnExit, this, wxID_EXIT);
 		
+		wxMenu* menuEdit = wxMenuTracker::InitialAndFinal[1];
 		wxMenu* menuHelp = new wxMenu;
 		menuHelp->Append(wxID_ABOUT);
 		menuHelp->Bind(wxEVT_MENU, &Frame::OnAbout, this, wxID_ABOUT);
 		wxMenuBar* menuBar = new wxMenuBar;
 		menuBar->Append(menuFile, menu_strings[0].head);
-		menuBar->Append(new wxMenu, menu_strings[1].head); //Edit menu, initially empty and disabled
+		menuBar->Append(menuEdit, menu_strings[1].head); //Edit menu, initially empty and disabled
 		menuBar->Append(menuHelp, menu_strings[2].head);
 		SetMenuBar(menuBar);
-		CreateStatusBar();
 		menuBar->EnableTop(1, false); //disable edit menu.
+		if constexpr (debug_mode) {
+			//	Check that the initial values of all replaceable menus
+			//	are at their default values as if the window handling them
+			//	had just been destroyed and not yet replaced.
+			for (int i = 0; i < std::size(wxMenuTracker::InitialAndFinal); i++) {
+				assert(
+					!wxMenuTracker::InitialAndFinal[i]
+					||
+					(
+						wxMenuTracker::InitialAndFinal[i] == menuBar->GetMenu(i)
+						&&
+						!menuBar->IsEnabledTop(i)
+					)
+				);
+
+			}
+		}
+		CreateStatusBar();
 			// child controls
 		wxPanel* panel{ nullptr };
 		m_panel = panel;
@@ -518,4 +566,22 @@ Frame::~Frame() {
 	Config.Write(wxT("LastUsed"), m_LastUsedWallet.GetFullPath());
 	Config.SetPath(wxT("/"));
 	Config.Flush();
+	if constexpr (debug_mode) {
+		//	Check that the final values of all replaceable menus
+		// are at what they should be because the window handling
+		// them should have been destroyed.
+		auto menuBar = this->GetMenuBar();
+		for (int i = 0; i < std::size(wxMenuTracker::InitialAndFinal); i++) {
+			assert(
+				!wxMenuTracker::InitialAndFinal[i]
+				||
+				(
+					wxMenuTracker::InitialAndFinal[i] == menuBar->GetMenu(i)
+					&&
+					!menuBar->IsEnabledTop(i)
+				)
+			);
+
+		}
+	}
 }

src/frame.h

@@ -1,4 +1,39 @@
 #pragma once
+	//	wxWidgets has drop down menus, wxMenu, owned by the wxMenuBar,
+	// which is owned by the Frame window, but menus subject to replacement need
+	// to be destroyed by the child window. 
+	//	wxMenuOwner tracks a drop down menu that might be at a location in
+	// the menubar, places it in that location in the menubar on demand,
+	// and on destruction destroys it
+	//	If, on destruction wxMenuBar is still pointing to this wxMenu, it
+	// replaces it with the default (empty) menu for that location.
+	// and disables it.
+	//	We maintain an array of default empty wxMenu menus that are nullptr for
+	// locations not subject to replacement, and are the disabled initial and final 
+	// wxMenuBar values for locations in the Menubar where the real drop down
+	// in the menubar will be installed by wxMenuTracker.
+struct wxMenuTracker {
+	wxMenuTracker(int);
+	void Replace();
+	~wxMenuTracker() noexcept;
+	//	Non nullptr members of InitialAndFinal have to be explicitly initially placed
+	// in the menubar in the frame constructor and explicitly disabled in
+	// the frame initializer.  In the debug build, congruence between the menu bar
+	// and InitialAndFinal should be checked with assert.
+	static wxMenu* InitialAndFinal[3];
+	wxMenuTracker(wxMenuTracker&&) = delete;	// Move constructor
+	wxMenuTracker(const wxMenuTracker&) = delete;	// Copy constructor
+	wxMenuTracker& operator=(wxMenuTracker&&) = delete;	// Move assignment.
+	wxMenuTracker& operator=(const wxMenuTracker&) = delete;	// Copy assignment.
+	bool operator==(const wxMenuTracker&) const = delete;
+	auto operator<=>(const wxMenuTracker&) const = delete;
+	wxMenu* Menu;
+	const int MenuPosition;
+	//	The menu title is defined elsewhere as an array
+	// of const strings
+	// menu_strings[MenuPosition].head
+};
+
 template  <typename T>
 //	This class exists to record the needed to unbind a drop down menu action and delete
 //	the corresponding item from the drop down menu when the handler is destroyed.

src/stdafx.h

@@ -106,7 +106,7 @@ enum MyIDs {
 	myID_DELETECONFIG = wxID_HIGHEST + 1, myID_ERRORMESSAGE, myID_Hello,
 	myID_MAINFRAME,
 	myID_MAINFRAME_PANEL, myID_TESTWINDOW, myID_WELCOME_TO_ROCOIN, myID_WALLET_UI,
-	mID_CLOSE_WALLET, myID_MYEXIT
+	mID_CLOSE_WALLET, myID_MYEXIT, myID_DISPLAY_WALLET_ADD_NAME
 };
 
 #include "localization.h"