[mutter/wip/carlosg/input-thread: 62/159] seat-native: Process device added/removed events as ClutterEvents

[Carlos Garnacho <carlosg src gnome org>]

commit 56091f78ede0014674c6458eaf5cb1d3331e49fb
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Fri Jul 17 17:50:17 2020 +0200

    seat-native: Process device added/removed events as ClutterEvents
    
    Delay the addition and removal of devices using ClutterDeviceEvent's so that
    they are processed following the libinput event order, and that we don't
    have to flush the events on removal.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1371

 src/backends/native/meta-seat-native.c | 105 +++++++++++++++++----------------
 1 file changed, 55 insertions(+), 50 deletions(-)
---
diff --git a/src/backends/native/meta-seat-native.c b/src/backends/native/meta-seat-native.c
index d561e322af..dbfc0c459f 100644
--- a/src/backends/native/meta-seat-native.c
+++ b/src/backends/native/meta-seat-native.c
@@ -1391,14 +1391,13 @@ update_touch_mode (MetaSeatNative *seat)
     }
 }
 
-static void
+static ClutterInputDevice *
 evdev_add_device (MetaSeatNative         *seat,
                   struct libinput_device *libinput_device)
 {
   ClutterInputDeviceType type;
   ClutterInputDevice *device, *master = NULL;
   ClutterActor *stage;
-  gboolean check_touch_mode = FALSE;
 
   device = meta_input_device_native_new (seat, libinput_device);
   stage = CLUTTER_ACTOR (meta_seat_native_get_stage (seat));
@@ -1421,25 +1420,7 @@ evdev_add_device (MetaSeatNative         *seat,
       _clutter_input_device_add_slave (master, device);
     }
 
-  g_signal_emit_by_name (seat, "device-added", device);
-
-  if (type == CLUTTER_TOUCHSCREEN_DEVICE)
-    {
-      seat->has_touchscreen = TRUE;
-      check_touch_mode = TRUE;
-    }
-
-  if (libinput_device_has_capability (libinput_device,
-                                      LIBINPUT_DEVICE_CAP_SWITCH) &&
-      libinput_device_switch_has_switch (libinput_device,
-                                         LIBINPUT_SWITCH_TABLET_MODE))
-    {
-      seat->has_tablet_switch = TRUE;
-      check_touch_mode = TRUE;
-    }
-
-  if (check_touch_mode)
-    update_touch_mode (seat);
+  return device;
 }
 
 static void
@@ -1447,38 +1428,56 @@ evdev_remove_device (MetaSeatNative        *seat,
                      MetaInputDeviceNative *device_evdev)
 {
   ClutterInputDevice *device;
-  ClutterInputDeviceType device_type;
 
   device = CLUTTER_INPUT_DEVICE (device_evdev);
   seat->devices = g_slist_remove (seat->devices, device);
 
-  g_signal_emit_by_name (seat, "device-removed", device);
+  g_object_unref (device);
+}
+
+static gboolean
+meta_seat_native_handle_device_event (ClutterSeat  *seat,
+                                      ClutterEvent *event)
+{
+  MetaSeatNative *seat_native = META_SEAT_NATIVE (seat);
+  ClutterInputDevice *device = event->device.device;
+  MetaInputDeviceNative *device_native = META_INPUT_DEVICE_NATIVE (device);
+  gboolean check_touch_mode;
 
-  device_type = clutter_input_device_get_device_type (device);
+  check_touch_mode =
+    clutter_input_device_get_device_type (device) == CLUTTER_TOUCHSCREEN_DEVICE;
 
-  if (device_type == CLUTTER_TOUCHSCREEN_DEVICE)
+  switch (event->type)
     {
-      seat->has_touchscreen = has_touchscreen (seat);
-      update_touch_mode (seat);
-    }
+      case CLUTTER_DEVICE_ADDED:
+        seat_native->has_touchscreen = check_touch_mode;
 
-  if (seat->repeat_timer && seat->repeat_device == device)
-    meta_seat_native_clear_repeat_timer (seat);
+        if (libinput_device_has_capability (device_native->libinput_device,
+                                            LIBINPUT_DEVICE_CAP_SWITCH) &&
+            libinput_device_switch_has_switch (device_native->libinput_device,
+                                               LIBINPUT_SWITCH_TABLET_MODE))
+          {
+            seat_native->has_tablet_switch = TRUE;
+            check_touch_mode = TRUE;
+          }
+        break;
 
-  g_object_run_dispose (G_OBJECT (device));
-  g_object_unref (device);
-}
+      case CLUTTER_DEVICE_REMOVED:
+        if (check_touch_mode)
+          seat_native->has_touchscreen = has_touchscreen (seat_native);
 
-static void
-flush_event_queue (void)
-{
-  ClutterEvent *event;
+        if (seat_native->repeat_timer && seat_native->repeat_device == device)
+          meta_seat_native_clear_repeat_timer (seat_native);
+        break;
 
-  while ((event = clutter_event_get ()) != NULL)
-    {
-      _clutter_process_event (event);
-      clutter_event_free (event);
+      default:
+        break;
     }
+
+  if (check_touch_mode)
+    update_touch_mode (seat_native);
+
+  return TRUE;
 }
 
 static gboolean
@@ -1486,35 +1485,40 @@ process_base_event (MetaSeatNative        *seat,
                     struct libinput_event *event)
 {
   ClutterInputDevice *device;
+  ClutterEvent *device_event;
   struct libinput_device *libinput_device;
-  gboolean handled = TRUE;
 
   switch (libinput_event_get_type (event))
     {
     case LIBINPUT_EVENT_DEVICE_ADDED:
       libinput_device = libinput_event_get_device (event);
 
-      evdev_add_device (seat, libinput_device);
+      device = evdev_add_device (seat, libinput_device);
+      device_event = clutter_event_new (CLUTTER_DEVICE_ADDED);
+      clutter_event_set_device (device_event, device);
       break;
 
     case LIBINPUT_EVENT_DEVICE_REMOVED:
-      /* Flush all queued events, there
-       * might be some from this device.
-       */
-      flush_event_queue ();
-
       libinput_device = libinput_event_get_device (event);
 
       device = libinput_device_get_user_data (libinput_device);
+      device_event = clutter_event_new (CLUTTER_DEVICE_REMOVED);
+      clutter_event_set_device (device_event, device);
       evdev_remove_device (seat,
                            META_INPUT_DEVICE_NATIVE (device));
       break;
 
     default:
-      handled = FALSE;
+      device_event = NULL;
     }
 
-  return handled;
+  if (device_event)
+    {
+      queue_event (device_event);
+      return TRUE;
+    }
+
+  return FALSE;
 }
 
 static ClutterScrollSource
@@ -2763,6 +2767,7 @@ meta_seat_native_class_init (MetaSeatNativeClass *klass)
   seat_class->get_supported_virtual_device_types = meta_seat_native_get_supported_virtual_device_types;
   seat_class->compress_motion = meta_seat_native_compress_motion;
   seat_class->warp_pointer = meta_seat_native_warp_pointer;
+  seat_class->handle_device_event = meta_seat_native_handle_device_event;
 
   props[PROP_SEAT_ID] =
     g_param_spec_string ("seat-id",