clutter: Notify ClutterActions about sequences that were cancelled

We're almost there, everything is in place to notify ClutterActions
about a sequence getting pulled away under its feet.

The only thing that's missing is the actual notification to actions now,
so let's do that.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2342>

clutter/clutter/clutter-action-private.h

@@ -39,6 +39,10 @@ void clutter_action_set_phase (ClutterAction     *action,
 gboolean clutter_action_handle_event (ClutterAction      *action,
                                       const ClutterEvent *event);
 
+void clutter_action_sequence_cancelled (ClutterAction        *action,
+                                        ClutterInputDevice   *device,
+                                        ClutterEventSequence *sequence);
+
 G_END_DECLS
 
 #endif /* CLUTTER_ACTION_PRIVATE_H */

clutter/clutter/clutter-action.c

@@ -101,3 +101,14 @@ clutter_action_handle_event (ClutterAction      *action,
 {
   return CLUTTER_ACTION_GET_CLASS (action)->handle_event (action, event);
 }
+
+void
+clutter_action_sequence_cancelled (ClutterAction        *action,
+                                   ClutterInputDevice   *device,
+                                   ClutterEventSequence *sequence)
+{
+  ClutterActionClass *action_class = CLUTTER_ACTION_GET_CLASS (action);
+
+  if (action_class->sequence_cancelled)
+    action_class->sequence_cancelled (action, device, sequence);
+}

clutter/clutter/clutter-action.h

@@ -52,6 +52,10 @@ struct _ClutterActionClass
   gboolean (* handle_event) (ClutterAction      *action,
                              const ClutterEvent *event);
 
+  void (* sequence_cancelled) (ClutterAction        *action,
+                               ClutterInputDevice   *device,
+                               ClutterEventSequence *sequence);
+
   void (* _clutter_action1) (void);
   void (* _clutter_action2) (void);
   void (* _clutter_action3) (void);

clutter/clutter/clutter-stage.c

@@ -4289,7 +4289,12 @@ remove_all_actions_from_chain (PointerDeviceEntry *entry)
         &g_array_index (entry->event_emission_chain, EventReceiver, i);
 
       if (receiver->action)
-        g_clear_object (&receiver->action);
+        {
+          clutter_action_sequence_cancelled (receiver->action,
+                                             entry->device,
+                                             entry->sequence);
+          g_clear_object (&receiver->action);
+        }
     }
 }
 
@@ -4339,6 +4344,7 @@ clutter_stage_maybe_lost_implicit_grab (ClutterStage         *self,
 {
   ClutterStagePrivate *priv = self->priv;
   PointerDeviceEntry *entry = NULL;
+  unsigned int i;
 
   if (sequence != NULL)
     entry = g_hash_table_lookup (priv->touch_sequences, sequence);
@@ -4350,6 +4356,15 @@ clutter_stage_maybe_lost_implicit_grab (ClutterStage         *self,
   if (!entry->press_count)
     return;
 
+  for (i = 0; i < entry->event_emission_chain->len; i++)
+    {
+      EventReceiver *receiver =
+        &g_array_index (entry->event_emission_chain, EventReceiver, i);
+
+      if (receiver->action)
+        clutter_action_sequence_cancelled (receiver->action, device, sequence);
+    }
+
   sync_crossings_on_implicit_grab_end (self, entry);
 
   clutter_actor_set_implicitly_grabbed (entry->implicit_grab_actor, FALSE);
@@ -4505,7 +4520,12 @@ cancel_implicit_grab_on_actor (PointerDeviceEntry *entry,
             clutter_actor_meta_get_actor (CLUTTER_ACTOR_META (receiver->action));
 
           if (!action_actor || action_actor == actor)
-            g_clear_object (&receiver->action);
+            {
+              clutter_action_sequence_cancelled (receiver->action,
+                                                 entry->device,
+                                                 entry->sequence);
+              g_clear_object (&receiver->action);
+            }
         }
     }