[gtk/wip/carlosg/fixes: 1/8] gtkgesture: Do not coalesce hold events with other touchpad gestures

[Carlos Garnacho <carlosg src gnome org>]

commit 023924bca90248d1006bdc0d67d54827c387412e
Author: Carlos Garnacho <carlosg gnome org>
Date:   Fri Aug 5 11:24:58 2022 +0200

    gtkgesture: Do not coalesce hold events with other touchpad gestures
    
    This delaying of the cancel event was made to avoid intermediate cancellation
    for >=2fg hold gestures followed by pinch/swipe gestures, and it worked as
    long as everything was considered to have the same sequence.
    
    Since each pinch/swipe pointer gesture now gets its own sequence, this no
    longer applies, nor works. This results in zoom/rotate/swipe gestures being
    stuck since the sequence for the touchpad events changes mid-gesture.
    
    Sticking to this pattern of giving touchpad gestures their own sequence,
    these hold events cannot be assumed to coalesce with other touchpad gestures,
    it is better to let it propagate altogether so that both the hold gesture
    and the incoming gesture trigger coherent begin and end/cancel phases.
    
    In the worst case, this results in "::begin, ::cancel, ::begin , ..." before
    triggering a touchpad gesture, but the extra begin/cancel ought to be a safe
    no-op in widgets.
    
    Closes: https://gitlab.gnome.org/GNOME/gtk/-/issues/5003

 gtk/gtkgesture.c | 41 ++---------------------------------------
 1 file changed, 2 insertions(+), 39 deletions(-)
---
diff --git a/gtk/gtkgesture.c b/gtk/gtkgesture.c
index 32756afccc..705a4ba593 100644
--- a/gtk/gtkgesture.c
+++ b/gtk/gtkgesture.c
@@ -162,7 +162,6 @@ struct _GtkGesturePrivate
   GdkDevice *device;
   GList *group_link;
   guint n_points;
-  guint hold_timeout_id;
   guint recognized : 1;
   guint touchpad : 1;
 };
@@ -175,8 +174,6 @@ static guint signals[N_SIGNALS] = { 0 };
                                       gdk_event_get_event_type (e) == GDK_TOUCHPAD_PINCH || \
                                       gdk_event_get_event_type (e) == GDK_TOUCHPAD_HOLD)
 
-#define HOLD_TIMEOUT_MS 50
-
 GList * _gtk_gesture_get_group_link (GtkGesture *gesture);
 
 G_DEFINE_ABSTRACT_TYPE_WITH_PRIVATE (GtkGesture, gtk_gesture, GTK_TYPE_EVENT_CONTROLLER)
@@ -225,7 +222,6 @@ gtk_gesture_finalize (GObject *object)
 
   gtk_gesture_ungroup (gesture);
   g_list_free (priv->group_link);
-  g_clear_handle_id (&priv->hold_timeout_id, g_source_remove);
 
   g_hash_table_destroy (priv->points);
 
@@ -583,22 +579,6 @@ _gtk_gesture_cancel_all (GtkGesture *gesture)
   _gtk_gesture_check_empty (gesture);
 }
 
-static gboolean
-gtk_gesture_hold_timeout (gpointer user_data)
-{
-  GtkGesture *gesture;
-  GtkGesturePrivate *priv;
-
-  gesture = user_data;
-  priv = gtk_gesture_get_instance_private (gesture);
-
-  if (priv->touchpad)
-    _gtk_gesture_cancel_sequence (gesture, priv->last_sequence);
-
-  priv->hold_timeout_id = 0;
-  return G_SOURCE_REMOVE;
-}
-
 static gboolean
 gesture_within_surface (GtkGesture *gesture,
                         GdkSurface  *surface)
@@ -664,10 +644,6 @@ gtk_gesture_handle_event (GtkEventController *controller,
       (event_type == GDK_TOUCHPAD_PINCH && phase == GDK_TOUCHPAD_GESTURE_PHASE_BEGIN) ||
       (event_type == GDK_TOUCHPAD_HOLD && phase == GDK_TOUCHPAD_GESTURE_PHASE_BEGIN))
     {
-      if ((event_type == GDK_TOUCHPAD_PINCH || event_type == GDK_TOUCHPAD_SWIPE) &&
-          _gtk_gesture_has_matching_touchpoints (gesture))
-        g_clear_handle_id (&priv->hold_timeout_id, g_source_remove);
-
       if (_gtk_gesture_update_point (gesture, event, target, x, y, TRUE))
         {
           gboolean triggered_recognition;
@@ -738,20 +714,12 @@ gtk_gesture_handle_event (GtkEventController *controller,
         _gtk_gesture_cancel_sequence (gesture, sequence);
     }
   else if ((event_type == GDK_TOUCHPAD_SWIPE && phase == GDK_TOUCHPAD_GESTURE_PHASE_CANCEL) ||
-           (event_type == GDK_TOUCHPAD_PINCH && phase == GDK_TOUCHPAD_GESTURE_PHASE_CANCEL))
+           (event_type == GDK_TOUCHPAD_PINCH && phase == GDK_TOUCHPAD_GESTURE_PHASE_CANCEL) ||
+           (event_type == GDK_TOUCHPAD_HOLD && phase == GDK_TOUCHPAD_GESTURE_PHASE_CANCEL))
     {
       if (priv->touchpad)
         _gtk_gesture_cancel_sequence (gesture, sequence);
     }
-  else if (event_type == GDK_TOUCHPAD_HOLD && phase == GDK_TOUCHPAD_GESTURE_PHASE_CANCEL)
-    {
-      if (priv->hold_timeout_id == 0)
-        {
-          priv->hold_timeout_id = g_timeout_add (HOLD_TIMEOUT_MS,
-                                                 gtk_gesture_hold_timeout,
-                                                 gesture);
-        }
-    }
   else if (event_type == GDK_GRAB_BROKEN)
     {
       GdkSurface *surface;
@@ -777,10 +745,6 @@ gtk_gesture_handle_event (GtkEventController *controller,
 static void
 gtk_gesture_reset (GtkEventController *controller)
 {
-  GtkGesture *gesture = GTK_GESTURE (controller);
-  GtkGesturePrivate *priv = gtk_gesture_get_instance_private (gesture);
-
-  g_clear_handle_id (&priv->hold_timeout_id, g_source_remove);
   _gtk_gesture_cancel_all (GTK_GESTURE (controller));
 }
 
@@ -949,7 +913,6 @@ gtk_gesture_init (GtkGesture *gesture)
   priv->points = g_hash_table_new_full (NULL, NULL, NULL,
                                         (GDestroyNotify) free_point_data);
   priv->group_link = g_list_prepend (NULL, gesture);
-  priv->hold_timeout_id = 0;
 }
 
 /**