wayland: add inhibit shortcut mechanism

Add a mechanism to MetaWaylandSurface that inhibits compositor's own
shortcuts when the surface has input focus, so that clients can receive
all key events regardless of the compositor own shortcuts.

This will help with implementing "fake" active grabs in Wayland and
XWayland clients.

https://bugzilla.gnome.org/show_bug.cgi?id=783342

data/org.gnome.mutter.wayland.gschema.xml.in

@@ -49,5 +49,9 @@
       <default><![CDATA[['<Primary><Alt>F12']]]></default>
       <summary>Switch to VT 12</summary>
     </key>
+    <key name="restore-shortcuts" type="as">
+      <default><![CDATA[['<Shift><Control>Escape']]]></default>
+      <summary>Re-enable shortcuts</summary>
+    </key>
   </schema>
 </schemalist>

src/core/keybindings.c

@@ -1716,6 +1716,16 @@ process_event (MetaDisplay          *display,
       (!window && binding->flags & META_KEY_BINDING_PER_WINDOW))
     goto not_found;
 
+  if (display->focus_window &&
+      !(binding->handler->flags & META_KEY_BINDING_NON_MASKABLE))
+    {
+      ClutterInputDevice *source;
+
+      source = clutter_event_get_source_device ((ClutterEvent *) event);
+      if (meta_window_shortcuts_inhibited (display->focus_window, source))
+        goto not_found;
+    }
+
   /* If the compositor filtered out the keybindings, that
    * means they don't want the binding to trigger, so we do
    * the same thing as if the binding didn't exist. */
@@ -3364,6 +3374,23 @@ handle_rotate_monitor (MetaDisplay    *display,
   meta_monitor_manager_rotate_monitor (monitor_manager);
 }
 
+static void
+handle_restore_shortcuts (MetaDisplay     *display,
+                          MetaScreen      *screen,
+                          MetaWindow      *window,
+                          ClutterKeyEvent *event,
+                          MetaKeyBinding  *binding,
+                          gpointer         dummy)
+{
+  ClutterInputDevice *source;
+
+  source = clutter_event_get_source_device ((ClutterEvent *) event);
+
+  meta_topic (META_DEBUG_KEYBINDINGS, "Restoring normal keyboard shortcuts\n");
+
+  meta_window_force_restore_shortcuts (display->focus_window, source);
+}
+
 /**
  * meta_keybindings_set_custom_handler:
  * @name: The name of the keybinding to set
@@ -3674,89 +3701,96 @@ init_builtin_key_bindings (MetaDisplay *display)
       add_builtin_keybinding (display,
                               "switch-to-session-1",
                               mutter_wayland_keybindings,
-                              META_KEY_BINDING_NONE,
+                              META_KEY_BINDING_NON_MASKABLE,
                               META_KEYBINDING_ACTION_NONE,
                               handle_switch_vt, 1);
 
       add_builtin_keybinding (display,
                               "switch-to-session-2",
                               mutter_wayland_keybindings,
-                              META_KEY_BINDING_NONE,
+                              META_KEY_BINDING_NON_MASKABLE,
                               META_KEYBINDING_ACTION_NONE,
                               handle_switch_vt, 2);
 
       add_builtin_keybinding (display,
                               "switch-to-session-3",
                               mutter_wayland_keybindings,
-                              META_KEY_BINDING_NONE,
+                              META_KEY_BINDING_NON_MASKABLE,
                               META_KEYBINDING_ACTION_NONE,
                               handle_switch_vt, 3);
 
       add_builtin_keybinding (display,
                               "switch-to-session-4",
                               mutter_wayland_keybindings,
-                              META_KEY_BINDING_NONE,
+                              META_KEY_BINDING_NON_MASKABLE,
                               META_KEYBINDING_ACTION_NONE,
                               handle_switch_vt, 4);
 
       add_builtin_keybinding (display,
                               "switch-to-session-5",
                               mutter_wayland_keybindings,
-                              META_KEY_BINDING_NONE,
+                              META_KEY_BINDING_NON_MASKABLE,
                               META_KEYBINDING_ACTION_NONE,
                               handle_switch_vt, 5);
 
       add_builtin_keybinding (display,
                               "switch-to-session-6",
                               mutter_wayland_keybindings,
-                              META_KEY_BINDING_NONE,
+                              META_KEY_BINDING_NON_MASKABLE,
                               META_KEYBINDING_ACTION_NONE,
                               handle_switch_vt, 6);
 
       add_builtin_keybinding (display,
                               "switch-to-session-7",
                               mutter_wayland_keybindings,
-                              META_KEY_BINDING_NONE,
+                              META_KEY_BINDING_NON_MASKABLE,
                               META_KEYBINDING_ACTION_NONE,
                               handle_switch_vt, 7);
 
       add_builtin_keybinding (display,
                               "switch-to-session-8",
                               mutter_wayland_keybindings,
-                              META_KEY_BINDING_NONE,
+                              META_KEY_BINDING_NON_MASKABLE,
                               META_KEYBINDING_ACTION_NONE,
                               handle_switch_vt, 8);
 
       add_builtin_keybinding (display,
                               "switch-to-session-9",
                               mutter_wayland_keybindings,
-                              META_KEY_BINDING_NONE,
+                              META_KEY_BINDING_NON_MASKABLE,
                               META_KEYBINDING_ACTION_NONE,
                               handle_switch_vt, 9);
 
       add_builtin_keybinding (display,
                               "switch-to-session-10",
                               mutter_wayland_keybindings,
-                              META_KEY_BINDING_NONE,
+                              META_KEY_BINDING_NON_MASKABLE,
                               META_KEYBINDING_ACTION_NONE,
                               handle_switch_vt, 10);
 
       add_builtin_keybinding (display,
                               "switch-to-session-11",
                               mutter_wayland_keybindings,
-                              META_KEY_BINDING_NONE,
+                              META_KEY_BINDING_NON_MASKABLE,
                               META_KEYBINDING_ACTION_NONE,
                               handle_switch_vt, 11);
 
       add_builtin_keybinding (display,
                               "switch-to-session-12",
                               mutter_wayland_keybindings,
-                              META_KEY_BINDING_NONE,
+                              META_KEY_BINDING_NON_MASKABLE,
                               META_KEYBINDING_ACTION_NONE,
                               handle_switch_vt, 12);
     }
 #endif /* HAVE_NATIVE_BACKEND */
 
+  add_builtin_keybinding (display,
+                          "restore-shortcuts",
+                          mutter_wayland_keybindings,
+                          META_KEY_BINDING_NON_MASKABLE,
+                          META_KEYBINDING_ACTION_NONE,
+                          handle_restore_shortcuts, 0);
+
   /************************ PER WINDOW BINDINGS ************************/
 
   /* These take a window as an extra parameter; they have no effect

src/core/window-private.h

@@ -535,6 +535,10 @@ struct _MetaWindowClass
                                   gboolean    user_op);
   void (*main_monitor_changed)   (MetaWindow *window,
                                   const MetaLogicalMonitor *old);
+  void (*force_restore_shortcuts) (MetaWindow         *window,
+                                   ClutterInputDevice *source);
+  gboolean (*shortcuts_inhibited) (MetaWindow         *window,
+                                   ClutterInputDevice *source);
 };
 
 /* These differ from window->has_foo_func in that they consider
@@ -763,4 +767,9 @@ MetaPlacementRule *meta_window_get_placement_rule (MetaWindow *window);
 
 void meta_window_force_placement (MetaWindow *window);
 
+void meta_window_force_restore_shortcuts (MetaWindow         *window,
+                                          ClutterInputDevice *source);
+
+gboolean meta_window_shortcuts_inhibited (MetaWindow         *window,
+                                          ClutterInputDevice *source);
 #endif

src/core/window.c

@@ -8066,3 +8066,17 @@ meta_window_get_placement_rule (MetaWindow *window)
 {
   return window->placement_rule;
 }
+
+void
+meta_window_force_restore_shortcuts (MetaWindow         *window,
+                                     ClutterInputDevice *source)
+{
+  META_WINDOW_GET_CLASS (window)->force_restore_shortcuts (window, source);
+}
+
+gboolean
+meta_window_shortcuts_inhibited (MetaWindow         *window,
+                                 ClutterInputDevice *source)
+{
+  return META_WINDOW_GET_CLASS (window)->shortcuts_inhibited (window, source);
+}

src/meta/prefs.h

@@ -370,6 +370,7 @@ typedef enum _MetaKeyBindingAction
  * @META_KEY_BINDING_PER_WINDOW: per-window
  * @META_KEY_BINDING_BUILTIN: built-in
  * @META_KEY_BINDING_IS_REVERSED: is reversed
+ * @META_KEY_BINDING_NON_MASKABLE: always active
  */
 typedef enum
 {
@@ -377,6 +378,7 @@ typedef enum
   META_KEY_BINDING_PER_WINDOW   = 1 << 0,
   META_KEY_BINDING_BUILTIN      = 1 << 1,
   META_KEY_BINDING_IS_REVERSED  = 1 << 2,
+  META_KEY_BINDING_NON_MASKABLE = 1 << 3,
 } MetaKeyBindingFlags;
 
 /**

src/wayland/meta-wayland-surface.c

@@ -130,6 +130,8 @@ enum {
   SURFACE_DESTROY,
   SURFACE_UNMAPPED,
   SURFACE_CONFIGURE,
+  SURFACE_SHORTCUTS_INHIBITED,
+  SURFACE_SHORTCUTS_RESTORED,
   N_SURFACE_SIGNALS
 };
 
@@ -1334,6 +1336,8 @@ wl_surface_destructor (struct wl_resource *resource)
   if (surface->wl_subsurface)
     wl_resource_destroy (surface->wl_subsurface);
 
+  g_hash_table_destroy (surface->shortcut_inhibited_seats);
+
   g_object_unref (surface);
 
   meta_wayland_compositor_repick (compositor);
@@ -1385,6 +1389,7 @@ meta_wayland_surface_create (MetaWaylandCompositor *compositor,
   sync_drag_dest_funcs (surface);
 
   surface->outputs_to_destroy_notify_id = g_hash_table_new (NULL, NULL);
+  surface->shortcut_inhibited_seats = g_hash_table_new (NULL, NULL);
 
   return surface;
 }
@@ -1881,6 +1886,22 @@ meta_wayland_surface_class_init (MetaWaylandSurfaceClass *klass)
                   0, NULL, NULL,
                   g_cclosure_marshal_VOID__VOID,
                   G_TYPE_NONE, 0);
+
+  surface_signals[SURFACE_SHORTCUTS_INHIBITED] =
+    g_signal_new ("shortcuts-inhibited",
+                  G_TYPE_FROM_CLASS (object_class),
+                  G_SIGNAL_RUN_LAST,
+                  0, NULL, NULL,
+                  g_cclosure_marshal_VOID__VOID,
+                  G_TYPE_NONE, 0);
+
+  surface_signals[SURFACE_SHORTCUTS_RESTORED] =
+    g_signal_new ("shortcuts-restored",
+                  G_TYPE_FROM_CLASS (object_class),
+                  G_SIGNAL_RUN_LAST,
+                  0, NULL, NULL,
+                  g_cclosure_marshal_VOID__VOID,
+                  G_TYPE_NONE, 0);
 }
 
 static void
@@ -2219,3 +2240,29 @@ meta_wayland_surface_calculate_input_region (MetaWaylandSurface *surface)
 
   return region;
 }
+
+void
+meta_wayland_surface_inhibit_shortcuts (MetaWaylandSurface *surface,
+                                        MetaWaylandSeat    *seat)
+{
+  g_hash_table_add (surface->shortcut_inhibited_seats, seat);
+  g_signal_emit (surface, surface_signals[SURFACE_SHORTCUTS_INHIBITED], 0);
+}
+
+void
+meta_wayland_surface_restore_shortcuts (MetaWaylandSurface *surface,
+                                        MetaWaylandSeat    *seat)
+{
+  g_signal_emit (surface, surface_signals[SURFACE_SHORTCUTS_RESTORED], 0);
+  g_hash_table_remove (surface->shortcut_inhibited_seats, seat);
+}
+
+gboolean
+meta_wayland_surface_is_shortcuts_inhibited (MetaWaylandSurface *surface,
+                                             MetaWaylandSeat    *seat)
+{
+  if (surface->shortcut_inhibited_seats == NULL)
+    return FALSE;
+
+  return g_hash_table_contains (surface->shortcut_inhibited_seats, seat);
+}

src/wayland/meta-wayland-surface.h

@@ -240,6 +240,9 @@ struct _MetaWaylandSurface
     gboolean pending_pos;
     GSList *pending_placement_ops;
   } sub;
+
+  /* table of seats for which shortcuts are inhibited */
+  GHashTable *shortcut_inhibited_seats;
 };
 
 void                meta_wayland_shell_init     (MetaWaylandCompositor *compositor);
@@ -326,4 +329,13 @@ gboolean            meta_wayland_surface_begin_grab_op (MetaWaylandSurface *surf
 void                meta_wayland_surface_window_managed (MetaWaylandSurface *surface,
                                                          MetaWindow         *window);
 
+void                meta_wayland_surface_inhibit_shortcuts (MetaWaylandSurface *surface,
+                                                            MetaWaylandSeat    *seat);
+
+void                meta_wayland_surface_restore_shortcuts (MetaWaylandSurface *surface,
+                                                            MetaWaylandSeat    *seat);
+
+gboolean            meta_wayland_surface_is_shortcuts_inhibited (MetaWaylandSurface *surface,
+                                                                 MetaWaylandSeat    *seat);
+
 #endif

src/wayland/meta-wayland.c

@@ -404,3 +404,40 @@ meta_wayland_finalize (void)
 
   meta_xwayland_stop (&compositor->xwayland_manager);
 }
+
+void
+meta_wayland_compositor_restore_shortcuts (MetaWaylandCompositor *compositor,
+                                           ClutterInputDevice    *source)
+{
+  MetaWaylandKeyboard *keyboard;
+
+  /* Clutter is not multi-seat aware yet, use the default seat instead */
+  keyboard = compositor->seat->keyboard;
+  if (!keyboard || !keyboard->focus_surface)
+    return;
+
+  if (!meta_wayland_surface_is_shortcuts_inhibited (keyboard->focus_surface,
+                                                    compositor->seat))
+    return;
+
+  meta_wayland_surface_restore_shortcuts (keyboard->focus_surface,
+                                          compositor->seat);
+}
+
+gboolean
+meta_wayland_compositor_is_shortcuts_inhibited (MetaWaylandCompositor *compositor,
+                                                ClutterInputDevice    *source)
+{
+  MetaWaylandKeyboard *keyboard;
+
+  if (clutter_input_device_get_device_type (source) != CLUTTER_KEYBOARD_DEVICE)
+    return FALSE;
+
+  /* Clutter is not multi-seat aware yet, use the default seat instead */
+  keyboard = compositor->seat->keyboard;
+  if (keyboard && keyboard->focus_surface != NULL)
+    return meta_wayland_surface_is_shortcuts_inhibited (keyboard->focus_surface,
+                                                        compositor->seat);
+
+  return FALSE;
+}

src/wayland/meta-wayland.h

@@ -58,5 +58,10 @@ void                    meta_wayland_compositor_destroy_frame_callbacks (MetaWay
 const char             *meta_wayland_get_wayland_display_name   (MetaWaylandCompositor *compositor);
 const char             *meta_wayland_get_xwayland_display_name  (MetaWaylandCompositor *compositor);
 
+void                    meta_wayland_compositor_restore_shortcuts      (MetaWaylandCompositor *compositor,
+                                                                        ClutterInputDevice    *source);
+gboolean                meta_wayland_compositor_is_shortcuts_inhibited (MetaWaylandCompositor *compositor,
+                                                                        ClutterInputDevice    *source);
+
 #endif
 

src/wayland/meta-window-wayland.c

@@ -520,6 +520,24 @@ meta_window_wayland_init (MetaWindowWayland *wl_window)
                     G_CALLBACK (appears_focused_changed), NULL);
 }
 
+static void
+meta_window_wayland_force_restore_shortcuts (MetaWindow         *window,
+                                             ClutterInputDevice *source)
+{
+  MetaWaylandCompositor *compositor = meta_wayland_compositor_get_default ();
+
+  meta_wayland_compositor_restore_shortcuts (compositor, source);
+}
+
+static gboolean
+meta_window_wayland_shortcuts_inhibited (MetaWindow         *window,
+                                         ClutterInputDevice *source)
+{
+  MetaWaylandCompositor *compositor = meta_wayland_compositor_get_default ();
+
+  return meta_wayland_compositor_is_shortcuts_inhibited (compositor, source);
+}
+
 static void
 meta_window_wayland_class_init (MetaWindowWaylandClass *klass)
 {
@@ -537,6 +555,8 @@ meta_window_wayland_class_init (MetaWindowWaylandClass *klass)
   window_class->update_main_monitor = meta_window_wayland_update_main_monitor;
   window_class->main_monitor_changed = meta_window_wayland_main_monitor_changed;
   window_class->get_client_pid = meta_window_wayland_get_client_pid;
+  window_class->force_restore_shortcuts = meta_window_wayland_force_restore_shortcuts;
+  window_class->shortcuts_inhibited = meta_window_wayland_shortcuts_inhibited;
 }
 
 MetaWindow *

src/x11/window-x11.c

@@ -1504,6 +1504,27 @@ meta_window_x11_get_client_pid (MetaWindow *window)
   return pid;
 }
 
+static void
+meta_window_x11_force_restore_shortcuts (MetaWindow         *window,
+                                         ClutterInputDevice *source)
+{
+  /*
+   * Not needed on X11 because clients can use a keyboard grab
+   * to bypass the compositor shortcuts.
+   */
+}
+
+static gboolean
+meta_window_x11_shortcuts_inhibited (MetaWindow         *window,
+                                     ClutterInputDevice *source)
+{
+  /*
+   * On X11, we don't use a shortcuts inhibitor, clients just grab
+   * the keyboard.
+   */
+  return FALSE;
+}
+
 static void
 meta_window_x11_class_init (MetaWindowX11Class *klass)
 {
@@ -1525,6 +1546,8 @@ meta_window_x11_class_init (MetaWindowX11Class *klass)
   window_class->update_main_monitor = meta_window_x11_update_main_monitor;
   window_class->main_monitor_changed = meta_window_x11_main_monitor_changed;
   window_class->get_client_pid = meta_window_x11_get_client_pid;
+  window_class->force_restore_shortcuts = meta_window_x11_force_restore_shortcuts;
+  window_class->shortcuts_inhibited = meta_window_x11_shortcuts_inhibited;
 }
 
 void