keybindings: Send trigger when a key accelerator is deactivated

This is neccessary to support the GlobalShortcuts portal which demands Deactivate events.

https://gitlab.gnome.org/GNOME/xdg-desktop-portal-gnome/-/issues/47

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3680>

src/core/display-private.h

@@ -254,6 +254,9 @@ void meta_display_overlay_key_activate (MetaDisplay *display);
 void meta_display_accelerator_activate (MetaDisplay           *display,
                                         guint                  action,
                                         const ClutterKeyEvent *event);
+void meta_display_accelerator_deactivate (MetaDisplay           *display,
+                                          guint                  action,
+                                          const ClutterKeyEvent *event);
 gboolean meta_display_modifiers_accelerator_activate (MetaDisplay *display);
 
 void meta_display_update_focus_window (MetaDisplay *display,

src/core/display.c

@@ -156,6 +156,7 @@ enum
   X11_DISPLAY_CLOSING,
   OVERLAY_KEY,
   ACCELERATOR_ACTIVATED,
+  ACCELERATOR_DEACTIVATED,
   MODIFIERS_ACCELERATOR_ACTIVATED,
   FOCUS_WINDOW,
   WINDOW_CREATED,
@@ -330,6 +331,14 @@ meta_display_class_init (MetaDisplayClass *klass)
                   NULL, NULL, NULL,
                   G_TYPE_NONE, 3, G_TYPE_UINT, CLUTTER_TYPE_INPUT_DEVICE, G_TYPE_UINT);
 
+  display_signals[ACCELERATOR_DEACTIVATED] =
+    g_signal_new ("accelerator-deactivated",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL, NULL,
+                  G_TYPE_NONE, 3, G_TYPE_UINT, CLUTTER_TYPE_INPUT_DEVICE, G_TYPE_UINT);
+
   /**
    * MetaDisplay::modifiers-accelerator-activated:
    * @display: the #MetaDisplay instance
@@ -2528,6 +2537,17 @@ meta_display_accelerator_activate (MetaDisplay           *display,
                  clutter_event_get_time ((const ClutterEvent *) event));
 }
 
+void
+meta_display_accelerator_deactivate (MetaDisplay           *display,
+                                     guint                  action,
+                                     const ClutterKeyEvent *event)
+{
+  g_signal_emit (display, display_signals[ACCELERATOR_DEACTIVATED], 0,
+                 action,
+                 clutter_event_get_source_device ((const ClutterEvent *) event),
+                 clutter_event_get_time ((const ClutterEvent *) event));
+}
+
 gboolean
 meta_display_modifiers_accelerator_activate (MetaDisplay *display)
 {

src/core/keybindings-private.h

@@ -71,6 +71,8 @@ struct _MetaKeyBinding
   MetaKeyCombo combo;
   MetaResolvedKeyCombo resolved_combo;
   gint flags;
+  /* The binding should respond to release, and was just pressed */
+  gboolean release_pending;
   MetaKeyHandler *handler;
 };
 

src/core/keybindings.c

@@ -1698,7 +1698,10 @@ handle_external_grab (MetaDisplay           *display,
 {
   MetaKeyBindingManager *keys = &display->key_binding_manager;
   guint action = get_keybinding_action (keys, &binding->resolved_combo);
-  meta_display_accelerator_activate (display, action, event);
+  if (clutter_event_type ((ClutterEvent *) event) == CLUTTER_KEY_RELEASE)
+    meta_display_accelerator_deactivate (display, action, event);
+  else
+    meta_display_accelerator_activate (display, action, event);
 }
 
 
@@ -1855,10 +1858,6 @@ process_event (MetaDisplay          *display,
   MetaKeyBinding *binding;
   ClutterModifierType modifiers;
 
-  /* we used to have release-based bindings but no longer. */
-  if (clutter_event_type ((ClutterEvent *) event) == CLUTTER_KEY_RELEASE)
-    return FALSE;
-
   modifiers = get_modifiers ((ClutterEvent *) event);
   resolved_combo.mask = mask_from_event_params (keys, modifiers);
 
@@ -1904,11 +1903,40 @@ process_event (MetaDisplay          *display,
       return TRUE;
     }
 
-  meta_topic (META_DEBUG_KEYBINDINGS,
+  if (clutter_event_type ((ClutterEvent *) event) == CLUTTER_KEY_RELEASE)
-              "Running handler for %s",
+    {
-              binding->name);
+      if (binding->release_pending)
+        {
+          meta_topic (META_DEBUG_KEYBINDINGS,
+                      "Running release handler for %s",
+                      binding->name);
 
-  invoke_handler (display, binding->handler, window, event, binding);
+          invoke_handler (display, binding->handler, window, event, binding);
+          binding->release_pending = FALSE;
+        }
+      else
+        {
+          meta_topic (META_DEBUG_KEYBINDINGS,
+                      "Ignore release for handler %s",
+                      binding->name);
+        }
+    }
+  else
+    {
+      meta_topic (META_DEBUG_KEYBINDINGS,
+                  "Running handler for %s",
+                  binding->name);
+
+      invoke_handler (display, binding->handler, window, event, binding);
+      if (!binding->release_pending &&
+          ((binding->flags & META_KEY_BINDING_TRIGGER_RELEASE) != 0))
+        {
+          meta_topic (META_DEBUG_KEYBINDINGS,
+                      "Preparing release for handler %s",
+                      binding->name);
+          binding->release_pending = TRUE;
+        }
+    }
 
   return TRUE;
 
@@ -3260,6 +3288,7 @@ meta_display_init_keys (MetaDisplay *display)
 
   handler = g_new0 (MetaKeyHandler, 1);
   handler->name = g_strdup ("external-grab");
+  handler->flags = META_KEY_BINDING_TRIGGER_RELEASE;
   handler->func = handle_external_grab;
   handler->default_func = handle_external_grab;
   g_ref_count_init (&handler->ref_count);

src/meta/prefs.h

@@ -430,6 +430,7 @@ typedef enum _MetaKeyBindingAction
  * @META_KEY_BINDING_IGNORE_AUTOREPEAT: ignore autorepeat
  * @META_KEY_BINDING_NO_AUTO_GRAB: not grabbed automatically
  * @META_KEY_BINDING_CUSTOM_TRIGGER: uses a custom keybinding action
+ * @META_KEY_BINDING_TRIGGER_RELEASE: notifies on release in addition to press
  */
 typedef enum
 {
@@ -441,6 +442,7 @@ typedef enum
   META_KEY_BINDING_IGNORE_AUTOREPEAT = 1 << 4,
   META_KEY_BINDING_NO_AUTO_GRAB = 1 << 5,
   META_KEY_BINDING_CUSTOM_TRIGGER = 1 << 6,
+  META_KEY_BINDING_TRIGGER_RELEASE = 1 << 7,
 } MetaKeyBindingFlags;
 
 /**