Fl_Sys_Menu_Bar: make it strict equivalent of Fl_Menu_Bar outside macOS

4 files changed, 65 insertions, 37 deletions

diff --git a/FL/Fl_Sys_Menu_Bar.H b/FL/Fl_Sys_Menu_Bar.H
index afb4f6d6e..c586625ac 100644
--- a/FL/Fl_Sys_Menu_Bar.H
+++ b/FL/Fl_Sys_Menu_Bar.H
@@ -29,15 +29,20 @@
 class Fl_Sys_Menu_Bar_Driver;
 
 /**
- A class to create and modify menus that appear on Mac OS X in the menu bar at the top of the screen.
- To use this class, just replace Fl_Menu_Bar with Fl_Sys_Menu_Bar, and on the Mac platform
+ A class to create and modify menus that appear on macOS in the menu bar at the top of the screen.
+ 
+ On other than macOS platforms, Fl_Sys_Menu_Bar is a synonym of class Fl_Menu_Bar.
+ 
+ On the macOS  platform, replace Fl_Menu_Bar with Fl_Sys_Menu_Bar, and
  a system menu at the top of the screen will be available. This menu will match an array
  of Fl_Menu_Item's exactly as in all other FLTK menus (except for the submenu with the
- application's own name; see below).
- 
-  On other than Mac OS X platforms, Fl_Sys_Menu_Bar is a synonym of class Fl_Menu_Bar.
+ application's own name and the 'Window' menu; see below). There is, though, an important difference between
+ an Fl_Sys_Menu_Bar object under macOS and under other platforms: only a single object
+ from this class can be created, because macOS uses a single system menu bar. Therefore,
+ porting to macOS an app that creates, on other platforms,  several Fl_Menu_Bar objects, one for each of several windows,
+ is more complex that just replacing Fl_Menu_Bar by Fl_Sys_Menu_Bar.
  
-  On the MacOS platform, the system menu bar of any FLTK app begins with the Application
+  On the macOS platform, the system menu bar of any FLTK app begins with the Application
   menu which the FLTK library automatically constructs. Functions
   Fl_Mac_App_Menu::custom_application_menu_items() and Fl_Sys_Menu_Bar::about() can be used to further customize
   the Application menu. The FLTK library also automatically constructs and handles a Window menu which can be
@@ -50,7 +55,7 @@ class Fl_Sys_Menu_Bar_Driver;
  Changes to the menu state are immediately visible in the menubar when they are made
  using member functions of the Fl_Sys_Menu_Bar class. Other changes (e.g., by a call to
  Fl_Menu_Item::set()) should be followed by a call to update() to be
- visible in the menubar across all platforms. Global variable \ref fl_sys_menu_bar points to
+ visible in the menubar across all platforms. macOS global variable \ref fl_sys_menu_bar points to
  the unique, current system menu bar.
  
  A few FLTK menu features are not supported by the Mac System menu:
@@ -90,6 +95,7 @@ class Fl_Sys_Menu_Bar_Driver;
 
   */
 class FL_EXPORT Fl_Sys_Menu_Bar : public Fl_Menu_Bar {
+  static Fl_Sys_Menu_Bar_Driver *driver();
 protected:
   virtual void draw();
 public:
@@ -102,7 +108,6 @@ public:
   } window_menu_style_enum;
   Fl_Sys_Menu_Bar(int x,int y,int w,int h,const char *l=0);
   virtual ~Fl_Sys_Menu_Bar();
-  static Fl_Sys_Menu_Bar_Driver *driver();
   /** Return the system menu's array of Fl_Menu_Item's
    */
   const Fl_Menu_Item *menu() const {return Fl_Menu_::menu();}
diff --git a/src/Fl_MacOS_Sys_Menu_Bar.mm b/src/Fl_MacOS_Sys_Menu_Bar.mm
index 2a4fdd304..10d82b09a 100644
--- a/src/Fl_MacOS_Sys_Menu_Bar.mm
+++ b/src/Fl_MacOS_Sys_Menu_Bar.mm
@@ -43,6 +43,10 @@ static void move_tab_cb(Fl_Widget *, void *data);
 static void merge_all_windows_cb(Fl_Widget *, void *data);
 #endif
 
+Fl_Sys_Menu_Bar_Driver *Fl_Sys_Menu_Bar::driver() {
+  return Fl_MacOS_Sys_Menu_Bar_Driver::driver();
+}
+
 
 void Fl_MacOS_Sys_Menu_Bar_Driver::draw() {
   bar->deactivate(); // prevent Fl_Sys_Menu_Bar object from receiving events
diff --git a/src/Fl_Sys_Menu_Bar.cxx b/src/Fl_Sys_Menu_Bar.cxx
index f207b8f38..50487efac 100644
--- a/src/Fl_Sys_Menu_Bar.cxx
+++ b/src/Fl_Sys_Menu_Bar.cxx
@@ -17,6 +17,7 @@
 //
 
 
+#include "config_lib.h"
 #include "Fl_Sys_Menu_Bar_Driver.H"
 #include <FL/platform.H>
 
@@ -30,20 +31,24 @@ Fl_Sys_Menu_Bar *fl_sys_menu_bar = 0;
 Fl_Sys_Menu_Bar::Fl_Sys_Menu_Bar(int x,int y,int w,int h,const char *l)
 : Fl_Menu_Bar(x,y,w,h,l)
 {
-  if (fl_sys_menu_bar) delete fl_sys_menu_bar;
-  fl_sys_menu_bar = this;
-  driver()->bar = this;
+  if (driver()) {
+    if (fl_sys_menu_bar) delete fl_sys_menu_bar;
+    fl_sys_menu_bar = this;
+    driver()->bar = this;
+  }
 }
 
 /** The destructor */
 Fl_Sys_Menu_Bar::~Fl_Sys_Menu_Bar()
 {
-  fl_sys_menu_bar = 0;
-  clear();
+  if (driver()) {
+    fl_sys_menu_bar = 0;
+    clear();
+  }
 }
 
 void Fl_Sys_Menu_Bar::update() {
-  driver()->update();
+  if (driver()) driver()->update();
 }
 
 /**
@@ -55,24 +60,29 @@ void Fl_Sys_Menu_Bar::update() {
  */
 void Fl_Sys_Menu_Bar::menu(const Fl_Menu_Item *m)
 {
-  driver()->menu(m);
+  if (driver()) driver()->menu(m);
+  else Fl_Menu_Bar::menu(m);
 }
 
 /** Changes the shortcut of item i to n.
  */
 void Fl_Sys_Menu_Bar::shortcut (int i, int s) {
-  driver()->shortcut(i, s);
+  if (driver()) driver()->shortcut(i, s);
+  else Fl_Menu_Bar::shortcut(i, s);
 }
 
 /** Turns the radio item "on" for the menu item and turns "off" adjacent radio items of the same group.*/
 void Fl_Sys_Menu_Bar::setonly (Fl_Menu_Item *item) {
-  driver()->setonly(item);
+  if (driver()) driver()->setonly(item);
+  else Fl_Menu_Bar::setonly(item);
+
 }
 
 /** Sets the flags of item i
  \see Fl_Menu_::mode(int i, int fl) */
 void   Fl_Sys_Menu_Bar::mode (int i, int fl) {
-  driver()->mode(i, fl);
+  if (driver()) driver()->mode(i, fl);
+  else Fl_Menu_Bar::mode(i, fl);
 }
 
 /**
@@ -93,7 +103,8 @@ void   Fl_Sys_Menu_Bar::mode (int i, int fl) {
  */
 int Fl_Sys_Menu_Bar::add(const char* label, int shortcut, Fl_Callback *cb, void *user_data, int flags)
 {
-  return driver()->add(label, shortcut, cb, user_data, flags);
+  if (driver()) return driver()->add(label, shortcut, cb, user_data, flags);
+  else return Fl_Menu_Bar::add(label, shortcut, cb, user_data, flags);
 }
 
 /**
@@ -104,7 +115,7 @@ int Fl_Sys_Menu_Bar::add(const char* label, int shortcut, Fl_Callback *cb, void
  */
 int Fl_Sys_Menu_Bar::add(const char* str)
 {
-  return driver()->add(str);
+  return driver() ? driver()->add(str) : Fl_Menu_Bar::add(str);
 }
 
 /**
@@ -118,7 +129,8 @@ int Fl_Sys_Menu_Bar::add(const char* str)
  */
 int Fl_Sys_Menu_Bar::insert(int index, const char* label, int shortcut, Fl_Callback *cb, void *user_data, int flags)
 {
-  return driver()->insert(index, label, shortcut, cb, user_data, flags);
+  return driver() ? driver()->insert(index, label, shortcut, cb, user_data, flags) :
+  Fl_Menu_Bar::insert(index, label, shortcut, cb, user_data, flags);
 }
 
 /** Set the Fl_Menu_Item array pointer to null, indicating a zero-length menu.
@@ -126,7 +138,8 @@ int Fl_Sys_Menu_Bar::insert(int index, const char* label, int shortcut, Fl_Callb
  */
 void Fl_Sys_Menu_Bar::clear()
 {
-  driver()->clear();
+  if (driver()) driver()->clear();
+  else Fl_Menu_Bar::clear();
 }
 
 /** Clears the specified submenu pointed to by index of all menu items.
@@ -134,7 +147,7 @@ void Fl_Sys_Menu_Bar::clear()
  */
 int Fl_Sys_Menu_Bar::clear_submenu(int index)
 {
-  return driver()->clear_submenu(index);
+  return driver() ? driver()->clear_submenu(index) : Fl_Menu_Bar::clear_submenu(index);
 }
 
 /**
@@ -144,7 +157,8 @@ int Fl_Sys_Menu_Bar::clear_submenu(int index)
  */
 void Fl_Sys_Menu_Bar::remove(int index)
 {
-  driver()->remove(index);
+  if (driver()) driver()->remove(index);
+  else Fl_Menu_Bar::remove(index);
 }
 
 /**
@@ -155,7 +169,8 @@ void Fl_Sys_Menu_Bar::remove(int index)
  */
 void Fl_Sys_Menu_Bar::replace(int index, const char *name)
 {
-  driver()->replace(index, name);
+  if (driver()) driver()->replace(index, name);
+  else Fl_Menu_Bar::replace(index, name);
 }
 
 /**
@@ -166,19 +181,22 @@ void Fl_Sys_Menu_Bar::replace(int index, const char *name)
  \param data   a pointer transmitted as 2nd argument to the callback.
  */
 void Fl_Sys_Menu_Bar::about(Fl_Callback *cb, void *data) {
-  fl_open_display(); // create the system menu, if needed
-  driver()->about(cb, data);
+  if (driver()) {
+    fl_open_display(); // create the system menu, if needed
+    driver()->about(cb, data);
+  }
 }
 
 void Fl_Sys_Menu_Bar::draw() {
-  driver()->draw();
+  if (driver()) driver()->draw();
+  else Fl_Menu_Bar::draw();
 }
 
 
 
 /** Get the style of the Window menu in the system menu bar */
 Fl_Sys_Menu_Bar::window_menu_style_enum Fl_Sys_Menu_Bar::window_menu_style() {
-  return Fl_Sys_Menu_Bar_Driver::window_menu_style();
+  return driver() ? Fl_Sys_Menu_Bar_Driver::window_menu_style() : no_window_menu;
 }
 
 /** Set the desired style of the Window menu in the system menu bar.
@@ -199,7 +217,7 @@ Fl_Sys_Menu_Bar::window_menu_style_enum Fl_Sys_Menu_Bar::window_menu_style() {
  \version 1.4
  */
 void Fl_Sys_Menu_Bar::window_menu_style(Fl_Sys_Menu_Bar::window_menu_style_enum style) {
-  Fl_Sys_Menu_Bar_Driver::window_menu_style(style);
+  if (driver()) Fl_Sys_Menu_Bar_Driver::window_menu_style(style);
 }
 
 /** Adds a Window menu, to the end of the system menu bar.
@@ -215,17 +233,18 @@ void Fl_Sys_Menu_Bar::window_menu_style(Fl_Sys_Menu_Bar::window_menu_style_enum
  \version 1.4
  */
 void Fl_Sys_Menu_Bar::create_window_menu() {
-  fl_open_display();
-  driver()->create_window_menu();
+  if (driver()) {
+    fl_open_display();
+    fl_sys_menu_bar->driver()->create_window_menu();
+  }
 }
 
 #if !defined(FL_DOXYGEN)
+#if ! defined(FL_CFG_WIN_COCOA)
 Fl_Sys_Menu_Bar_Driver *Fl_Sys_Menu_Bar::driver() {
-  if (!Fl_Sys_Menu_Bar_Driver::driver_) { // initialize this static variable if it was not initialized previously
-    Fl_Sys_Menu_Bar_Driver::driver_ = new Fl_Sys_Menu_Bar_Driver();
-  }
-  return Fl_Sys_Menu_Bar_Driver::driver_;
+  return NULL;
 }
+#endif // !FL_CFG_WIN_COCOA
 
 Fl_Sys_Menu_Bar_Driver *Fl_Sys_Menu_Bar_Driver::driver_ = 0;
 
diff --git a/src/Fl_cocoa.mm b/src/Fl_cocoa.mm
index 5d789f032..258209091 100644
--- a/src/Fl_cocoa.mm
+++ b/src/Fl_cocoa.mm
@@ -2930,7 +2930,7 @@ Fl_X* Fl_Cocoa_Window_Driver::makeWindow()
   fl_open_display();
   NSInteger winlevel = NSNormalWindowLevel;
   NSUInteger winstyle;
-  Fl_Sys_Menu_Bar::driver()->create_window_menu(); // effective once at most
+  Fl_Sys_Menu_Bar::create_window_menu(); // effective once at most
   Fl_Window* w = pWindow;
   if (w->parent()) {
     w->border(0);