Use event taps for keyboard grab on macOS

vncviewer/CConn.cxx

@@ -95,6 +95,7 @@ CConn::CConn(const char* vncServerName, network::Socket* socket=nullptr)
 
   if(sock == nullptr) {
     try {
+      // FIXME: This shouldn't block
 #ifndef WIN32
       if (strchr(vncServerName, '/') != nullptr) {
         sock = new network::UnixSocket(vncServerName);

vncviewer/DesktopWindow.cxx

@@ -195,15 +195,15 @@ DesktopWindow::DesktopWindow(int w, int h, const char *name,
 #else
     delayedFullscreen = true;
 #endif
+
+    // Full screen events are not sent out for a hidden window,
+    // so send a fake one here to set up things properly.
+    if (fullscreen_active())
+      handle(FL_FULLSCREEN);
   }
 
   show();
 
-  // Full screen events are not sent out for a hidden window,
-  // so send a fake one here to set up things properly.
-  if (fullscreen_active())
-    handle(FL_FULLSCREEN);
-
   // Unfortunately, current FLTK does not allow us to set the
   // maximized property on Windows and X11 before showing the window.
   // See STR #2083 and STR #2178
@@ -260,6 +260,8 @@ DesktopWindow::~DesktopWindow()
   Fl::remove_timeout(menuOverlay, this);
   Fl::remove_timeout(updateOverlay, this);
 
+  ungrabKeyboard();
+
   OptionsDialog::removeCallback(handleOptions);
 
   delete overlay;
@@ -677,10 +679,6 @@ void DesktopWindow::resize(int x, int y, int w, int h)
 
     repositionWidgets();
   }
-
-  // Some systems require a grab after the window size has been changed.
-  // Otherwise they might hold on to displays, resulting in them being unusable.
-  maybeGrabKeyboard();
 }
 
 
@@ -823,6 +821,7 @@ int DesktopWindow::handle(int event)
 {
   switch (event) {
   case FL_FULLSCREEN:
+    vlog.error("FL_FULLSCREEN");
     fullScreen.setParam(fullscreen_active());
 
     // Update scroll bars
@@ -908,9 +907,11 @@ int DesktopWindow::fltkDispatch(int event, Fl_Window *win)
     // all monitors and the user clicked on another application.
     // Make sure we update our grabs with the focus changes.
     case FL_FOCUS:
+      vlog.error("FL_FOCUS");
       dw->maybeGrabKeyboard();
       break;
     case FL_UNFOCUS:
+      vlog.error("FL_UNFOCUS");
       if (fullscreenSystemKeys) {
         dw->ungrabKeyboard();
       }
@@ -941,14 +942,6 @@ int DesktopWindow::fltkHandle(int event)
     // not be resized to cover the new screen. A timer makes sense
     // also on other systems, to make sure that whatever desktop
     // environment has a chance to deal with things before we do.
-    // Please note that when using FullscreenSystemKeys on macOS, the
-    // display configuration cannot be changed: macOS will not detect
-    // added or removed screens and there will be no
-    // FL_SCREEN_CONFIGURATION_CHANGED event. This is by design:
-    // "When you capture a display, you have exclusive use of the
-    // display. Other applications and system services are not allowed
-    // to use the display or change its configuration. In addition,
-    // they are not notified of display changes"
     Fl::remove_timeout(reconfigureFullscreen);
     Fl::add_timeout(0.5, reconfigureFullscreen);
   }
@@ -1026,14 +1019,15 @@ void DesktopWindow::fullscreen_on()
   }
 #ifdef __APPLE__
   // This is a workaround for a bug in FLTK, see: https://github.com/fltk/fltk/pull/277
-  int savedLevel;
-  savedLevel = cocoa_get_level(this);
+  // FIXME: Does this still happen? Maybe side effect of releasing displays
+  //int savedLevel;
+  //savedLevel = cocoa_get_level(this);
 #endif
   fullscreen_screens(top, bottom, left, right);
 #ifdef __APPLE__
   // This is a workaround for a bug in FLTK, see: https://github.com/fltk/fltk/pull/277
-  if (cocoa_get_level(this) != savedLevel)
-    cocoa_set_level(this, savedLevel);
+  //if (cocoa_get_level(this) != savedLevel)
+  //  cocoa_set_level(this, savedLevel);
 #endif
 
   if (!fullscreen_active())
@@ -1095,10 +1089,10 @@ void DesktopWindow::grabKeyboard()
     return;
   }
 #elif defined(__APPLE__)
-  int ret;
-  
-  ret = cocoa_capture_displays(this);
-  if (ret != 0) {
+  bool ret;
+
+  ret = cocoa_tap_keyboard(this);
+  if (!ret) {
     vlog.error(_("Failure grabbing keyboard"));
     return;
   }
@@ -1153,7 +1147,7 @@ void DesktopWindow::ungrabKeyboard()
 #if defined(WIN32)
   win32_disable_lowlevel_keyboard(fl_xid(this));
 #elif defined(__APPLE__)
-  cocoa_release_displays(this);
+  cocoa_untap_keyboard();
 #else
   // FLTK has a grab so lets not mess with it
   if (Fl::grab())

vncviewer/OptionsDialog.cxx

@@ -44,6 +44,10 @@
 #include "fltk/Fl_Monitor_Arrangement.h"
 #include "fltk/Fl_Navigation.h"
 
+#ifdef __APPLE__
+#include "cocoa.h"
+#endif
+
 #include <FL/Fl.H>
 #include <FL/Fl_Tabs.H>
 #include <FL/Fl_Button.H>
@@ -872,6 +876,7 @@ void OptionsDialog::createInputPage(int tx, int ty, int tw, int th)
                                                       CHECK_MIN_WIDTH,
                                                       CHECK_HEIGHT,
                                                       _("Pass system keys directly to server (full screen)")));
+    systemKeysCheckbox->callback(handleSystemKeys, this);
     ty += CHECK_HEIGHT + TIGHT_MARGIN;
 
     menuKeyChoice = new Fl_Choice(LBLLEFT(tx, ty, 150, CHOICE_HEIGHT, _("Menu key")));
@@ -1117,6 +1122,20 @@ void OptionsDialog::handleRSAAES(Fl_Widget* /*widget*/, void *data)
 }
 
 
+void OptionsDialog::handleSystemKeys(Fl_Widget* /*widget*/, void* data)
+{
+#ifdef __APPLE__
+  OptionsDialog* dialog = (OptionsDialog*)data;
+
+  // Pop up the access dialog if needed
+  if (dialog->systemKeysCheckbox->value())
+    cocoa_is_trusted(true);
+#else
+  (void)data;
+#endif
+}
+
+
 void OptionsDialog::handleClipboard(Fl_Widget* /*widget*/, void *data)
 {
   (void)data;

vncviewer/OptionsDialog.h

@@ -64,6 +64,8 @@ class OptionsDialog : public Fl_Window {
   static void handleX509(Fl_Widget *widget, void *data);
   static void handleRSAAES(Fl_Widget *widget, void *data);
 
+  static void handleSystemKeys(Fl_Widget *widget, void *data);
+
   static void handleClipboard(Fl_Widget *widget, void *data);
 
   static void handleFullScreenMode(Fl_Widget *widget, void *data);

vncviewer/cocoa.h

@@ -21,11 +21,10 @@
 
 class Fl_Window;
 
-int cocoa_get_level(Fl_Window *win);
-void cocoa_set_level(Fl_Window *win, int level);
+bool cocoa_is_trusted(bool prompt=false);
 
-int cocoa_capture_displays(Fl_Window *win);
-void cocoa_release_displays(Fl_Window *win);
+bool cocoa_tap_keyboard(Fl_Window* win);
+void cocoa_untap_keyboard();
 
 typedef struct CGColorSpace *CGColorSpaceRef;