From 6c17aa66c6d76d496d3a7614d84eeefe25647a16 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20Dre=C3=9Fler?= <verdre@v0yd.nl>
Date: Tue, 29 Mar 2022 13:19:24 +0200
Subject: [PATCH] clutter: Remove device/sequence entry when TOUCH_END get
 filtered out

Mutters event filter can prevent events from getting processed by
Clutter, this can also happen for TOUCH_END/CANCEL events. Processing
these events in Clutter is crucial for proper tracking of touch
sequences though, that's because Clutter adds a PointerDeviceEntry to
the stage on a TOUCH_BEGIN *before* going through the event filter, but
removes that entry on a TOUCH_END *after* going through the filter. So
Clutter really needs to see those TOUCH_END events, or else there will
be a stale PointerDeviceEntry on the ClutterStage.

Make sure those TOUCH_END/CANCEL events always get seen by Clutter by
removing the device entry immediately when those get filtered out.

Because there might still be events belonging to this sequence in the
event queue of the stage, we need to flush the queue before removing the
entry, too.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2350>
---
 clutter/clutter/clutter-main.c | 56 +++++++++++++++++++---------------
 1 file changed, 31 insertions(+), 25 deletions(-)

diff --git a/clutter/clutter/clutter-main.c b/clutter/clutter/clutter-main.c
index 239d36838..a2ee338b6 100644
--- a/clutter/clutter/clutter-main.c
+++ b/clutter/clutter/clutter-main.c
@@ -724,6 +724,30 @@ update_device_for_event (ClutterStage *stage,
                                                time_ms);
 }
 
+static void
+remove_device_for_event (ClutterStage *stage,
+                         ClutterEvent *event,
+                         gboolean      emit_crossing)
+{
+  ClutterInputDevice *device = clutter_event_get_device (event);
+  ClutterEventSequence *sequence = clutter_event_get_event_sequence (event);
+  graphene_point_t point;
+  uint32_t time;
+
+  clutter_event_get_coords (event, &point.x, &point.y);
+  time = clutter_event_get_time (event);
+
+  clutter_stage_update_device (stage,
+                               device, sequence,
+                               point,
+                               time,
+                               NULL,
+                               NULL,
+                               TRUE);
+
+  clutter_stage_remove_device_entry (stage, device, sequence);
+}
+
 /**
  * clutter_do_event:
  * @event: a #ClutterEvent.
@@ -784,6 +808,13 @@ clutter_do_event (ClutterEvent *event)
       context->current_event =
         g_slist_delete_link (context->current_event, context->current_event);
 
+      if (event->type == CLUTTER_TOUCH_END ||
+          event->type == CLUTTER_TOUCH_CANCEL)
+        {
+          _clutter_stage_process_queued_events (event->any.stage);
+          remove_device_for_event (event->any.stage, event, TRUE);
+        }
+
       return;
     }
 
@@ -799,31 +830,6 @@ clutter_do_event (ClutterEvent *event)
   _clutter_stage_queue_event (event->any.stage, event, TRUE);
 }
 
-static void
-remove_device_for_event (ClutterStage *stage,
-                         ClutterEvent *event,
-                         gboolean      emit_crossing)
-{
-  ClutterInputDevice *device = clutter_event_get_device (event);
-  ClutterEventSequence *sequence = clutter_event_get_event_sequence (event);
-  graphene_point_t point;
-  uint32_t time;
-
-  clutter_event_get_coords (event, &point.x, &point.y);
-  time = clutter_event_get_time (event);
-
-  clutter_stage_update_device (stage,
-                               device, sequence,
-                               point,
-                               time,
-                               NULL,
-                               NULL,
-                               TRUE);
-
-  clutter_stage_remove_device_entry (stage, device, sequence);
-}
-
-
 static void
 _clutter_process_event_details (ClutterActor        *stage,
                                 ClutterMainContext  *context,