[mutter/gnome-3-36] clutter-seat: Handle device events and emit signals

[Marco Trevisan <marcotrevi src gnome org>]

commit 0444769a89663cddb4f1e378c40f590aa5f3d7ff
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Fri Jul 17 17:40:12 2020 +0200

    clutter-seat: Handle device events and emit signals
    
    Clutter device events are special events coming from the backend when an
    input device is added or removed.
    
    When such events are processed, we should make the seat to handle them by
    calling vfunc that can be implemented by each backend and eventually
    emitting the appropriate signal.
    
    If a device is removed, we can also safely dispose it, as it can be
    considered stale at this point.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1371
    
    (cherry picked from commit cf67c54f87e7ae035a6bf0f19fd37e1751af41d1)

 clutter/clutter/clutter-main.c |  7 +++++++
 clutter/clutter/clutter-seat.c | 40 ++++++++++++++++++++++++++++++++++++++++
 clutter/clutter/clutter-seat.h |  6 ++++++
 3 files changed, 53 insertions(+)
---
diff --git a/clutter/clutter/clutter-main.c b/clutter/clutter/clutter-main.c
index 445941c191..d6149e13f0 100644
--- a/clutter/clutter/clutter-main.c
+++ b/clutter/clutter/clutter-main.c
@@ -2121,6 +2121,13 @@ _clutter_process_event_details (ClutterActor        *stage,
 
       case CLUTTER_DEVICE_ADDED:
       case CLUTTER_DEVICE_REMOVED:
+        if (!_clutter_event_process_filters (event))
+          {
+            ClutterSeat *seat;
+
+            seat = clutter_backend_get_default_seat (context->backend);
+            clutter_seat_handle_device_event (seat, event);
+          }
         break;
 
       case CLUTTER_EVENT_LAST:
diff --git a/clutter/clutter/clutter-seat.c b/clutter/clutter/clutter-seat.c
index d0852fa44b..fca0722a7d 100644
--- a/clutter/clutter/clutter-seat.c
+++ b/clutter/clutter/clutter-seat.c
@@ -663,6 +663,46 @@ clutter_seat_compress_motion (ClutterSeat        *seat,
     seat_class->compress_motion (seat, event, to_discard);
 }
 
+gboolean
+clutter_seat_handle_device_event (ClutterSeat  *seat,
+                                  ClutterEvent *event)
+{
+  ClutterSeatClass *seat_class;
+  ClutterInputDevice *device;
+
+  g_return_val_if_fail (CLUTTER_IS_SEAT (seat), FALSE);
+  g_return_val_if_fail (event, FALSE);
+
+  g_assert (event->type == CLUTTER_DEVICE_ADDED ||
+            event->type == CLUTTER_DEVICE_REMOVED);
+
+  seat_class = CLUTTER_SEAT_GET_CLASS (seat);
+
+  if (seat_class->handle_device_event)
+    {
+      if (!seat_class->handle_device_event (seat, event))
+        return FALSE;
+    }
+
+  device = clutter_event_get_source_device (event);
+  g_assert_true (CLUTTER_IS_INPUT_DEVICE (device));
+
+  switch (event->type)
+    {
+      case CLUTTER_DEVICE_ADDED:
+        g_signal_emit (seat, signals[DEVICE_ADDED], 0, device);
+        break;
+      case CLUTTER_DEVICE_REMOVED:
+        g_signal_emit (seat, signals[DEVICE_REMOVED], 0, device);
+        g_object_run_dispose (G_OBJECT (device));
+        break;
+      default:
+        break;
+    }
+
+  return TRUE;
+}
+
 void
 clutter_seat_warp_pointer (ClutterSeat *seat,
                            int          x,
diff --git a/clutter/clutter/clutter-seat.h b/clutter/clutter/clutter-seat.h
index e12965e00f..eb1dd82bf2 100644
--- a/clutter/clutter/clutter-seat.h
+++ b/clutter/clutter/clutter-seat.h
@@ -106,6 +106,9 @@ struct _ClutterSeatClass
                             ClutterEvent       *event,
                             const ClutterEvent *to_discard);
 
+  gboolean (* handle_device_event) (ClutterSeat  *seat,
+                                    ClutterEvent *event);
+
   void (* warp_pointer) (ClutterSeat *seat,
                          int          x,
                          int          y);
@@ -180,6 +183,9 @@ void clutter_seat_compress_motion (ClutterSeat        *seat,
                                    ClutterEvent       *event,
                                    const ClutterEvent *to_discard);
 
+gboolean clutter_seat_handle_device_event (ClutterSeat  *seat,
+                                           ClutterEvent *event);
+
 CLUTTER_EXPORT
 void clutter_seat_warp_pointer (ClutterSeat *seat,
                                 int          x,