clutter: Pass events to pointer a11y before going through filters

We want all pointer events to be passed through the pointer a11y
processing before going through event filters: Once we go through event
filters, events might be dispatched to Wayland and get filtered out.

With the changes to immediately dispatch events to wayland, this changed
and the pointer a11y is now no longer seeing any events going to wayland
clients. Fix it by shuffling things around a bit and letting pointer
a11y take a peek at events earlier.

Fixes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/5192
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2332>

clutter/clutter/clutter-input-pointer-a11y-private.h

@@ -42,6 +42,9 @@ void _clutter_input_pointer_a11y_on_button_event (ClutterInputDevice   *device,
 CLUTTER_EXPORT
 gboolean _clutter_is_input_pointer_a11y_enabled  (ClutterInputDevice     *device);
 
+CLUTTER_EXPORT
+void _clutter_input_pointer_a11y_maybe_handle_event (ClutterEvent *event);
+
 G_END_DECLS
 
 #endif /* __CLUTTER_INPUT_POINTER_A11Y_H__ */

clutter/clutter/clutter-input-pointer-a11y.c

@@ -25,11 +25,13 @@
 
 #include "clutter-build-config.h"
 
+#include "clutter-backend-private.h"
 #include "clutter-enum-types.h"
 #include "clutter-input-device.h"
 #include "clutter-input-device-private.h"
 #include "clutter-input-pointer-a11y-private.h"
 #include "clutter-main.h"
+#include "clutter-private.h"
 #include "clutter-virtual-input-device.h"
 
 static gboolean
@@ -726,3 +728,39 @@ _clutter_is_input_pointer_a11y_enabled (ClutterInputDevice *device)
 
   return (is_secondary_click_enabled (device) || is_dwell_click_enabled (device));
 }
+
+void
+_clutter_input_pointer_a11y_maybe_handle_event (ClutterEvent *event)
+{
+
+  ClutterInputDevice *device = clutter_event_get_device (event);
+  ClutterMainContext *clutter_context;
+  ClutterBackend *backend;
+
+  if (!_clutter_is_input_pointer_a11y_enabled (device))
+    return;
+
+  if ((event->any.flags & CLUTTER_EVENT_FLAG_SYNTHETIC) != 0)
+    return;
+
+  clutter_context = _clutter_context_get_default ();
+  backend = clutter_context->backend;
+
+  if (!clutter_backend_is_display_server (backend))
+    return;
+
+  if (event->type == CLUTTER_MOTION)
+    {
+      float x, y;
+
+      clutter_event_get_coords (event, &x, &y);
+      _clutter_input_pointer_a11y_on_motion_event (device, x, y);
+    }
+  else if (event->type == CLUTTER_BUTTON_PRESS ||
+           event->type == CLUTTER_BUTTON_RELEASE)
+    {
+      _clutter_input_pointer_a11y_on_button_event (device,
+                                                   event->button.button,
+                                                   event->type == CLUTTER_BUTTON_PRESS);
+    }
+}

clutter/clutter/clutter-main.c

@@ -778,6 +778,7 @@ clutter_do_event (ClutterEvent *event)
 
   context->current_event = g_slist_prepend (context->current_event, event);
 
+  _clutter_input_pointer_a11y_maybe_handle_event (event);
   if (_clutter_event_process_filters (event, event_actor))
     {
       context->current_event =
@@ -830,13 +831,8 @@ _clutter_process_event_details (ClutterActor        *stage,
 {
   ClutterInputDevice *device = clutter_event_get_device (event);
   ClutterEventSequence *sequence = clutter_event_get_event_sequence (event);
-  ClutterMainContext *clutter_context;
-  ClutterBackend *backend;
   ClutterActor *target;
 
-  clutter_context = _clutter_context_get_default ();
-  backend = clutter_context->backend;
-
   switch (event->type)
     {
       case CLUTTER_NOTHING:
@@ -878,31 +874,8 @@ _clutter_process_event_details (ClutterActor        *stage,
         break;
 
       case CLUTTER_MOTION:
-        if (clutter_backend_is_display_server (backend) &&
-            !(event->any.flags & CLUTTER_EVENT_FLAG_SYNTHETIC))
-          {
-            if (_clutter_is_input_pointer_a11y_enabled (device))
-              {
-                gfloat x, y;
-
-                clutter_event_get_coords (event, &x, &y);
-                _clutter_input_pointer_a11y_on_motion_event (device, x, y);
-              }
-          }
-        G_GNUC_FALLTHROUGH;
       case CLUTTER_BUTTON_PRESS:
       case CLUTTER_BUTTON_RELEASE:
-        if (clutter_backend_is_display_server (backend))
-          {
-            if (_clutter_is_input_pointer_a11y_enabled (device) && (event->type != CLUTTER_MOTION))
-              {
-                _clutter_input_pointer_a11y_on_button_event (device,
-                                                             event->button.button,
-                                                             event->type == CLUTTER_BUTTON_PRESS);
-              }
-          }
-
-        G_GNUC_FALLTHROUGH;
       case CLUTTER_SCROLL:
       case CLUTTER_TOUCHPAD_PINCH:
       case CLUTTER_TOUCHPAD_SWIPE: