[gtk/wip/exalm/consumes-motion: 4/6] windowhandle: Don't drag on capture phase

[Alexander Mikhaylenko <alexm src gnome org>]

commit 14a019a8292da4e2228db1f183cb5b17461916fc
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Fri Dec 25 12:35:57 2020 +0500

    windowhandle: Don't drag on capture phase
    
    This was needed to work around widgets claiming event sequences on press,
    by ignoring them and starting the drag anyway unless they have certain
    event controllers on them.
    
    The most visible offender was GtkButton, but since the last commit it
    doesn't claim the sequence anymore and we can remove the hack.

 gtk/gtkwidget.c        | 33 --------------------------------
 gtk/gtkwidgetprivate.h |  4 ----
 gtk/gtkwindowhandle.c  | 51 ++++----------------------------------------------
 3 files changed, 4 insertions(+), 84 deletions(-)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index b26103e87b..214b728ee1 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -11324,39 +11324,6 @@ gtk_widget_remove_controller (GtkWidget          *widget,
     gtk_list_list_model_item_removed (priv->controller_observer, before);
 }
 
-gboolean
-gtk_widget_consumes_motion (GtkWidget        *widget,
-                            GtkWidget        *parent,
-                            GdkEventSequence *sequence)
-{
-  GtkWidgetPrivate *priv = gtk_widget_get_instance_private (widget);
-
-  while (widget != NULL && widget != parent)
-    {
-      GList *l;
-
-      for (l = priv->event_controllers; l; l = l->next)
-        {
-          GtkEventController *controller = l->data;
-
-          if (controller == NULL ||
-              !GTK_IS_GESTURE (controller))
-            continue;
-
-          if ((!GTK_IS_GESTURE_SINGLE (controller) ||
-               GTK_IS_GESTURE_DRAG (controller) ||
-               GTK_IS_GESTURE_SWIPE (controller)) &&
-              gtk_gesture_handles_sequence (GTK_GESTURE (controller), sequence))
-            return TRUE;
-        }
-
-      widget = priv->parent;
-      priv = gtk_widget_get_instance_private (widget);
-    }
-
-  return FALSE;
-}
-
 void
 gtk_widget_reset_controllers (GtkWidget *widget)
 {
diff --git a/gtk/gtkwidgetprivate.h b/gtk/gtkwidgetprivate.h
index eb6959fe7c..b7e2a67b84 100644
--- a/gtk/gtkwidgetprivate.h
+++ b/gtk/gtkwidgetprivate.h
@@ -278,10 +278,6 @@ void              _gtk_widget_update_parent_muxer          (GtkWidget    *widget
 GtkActionMuxer *  _gtk_widget_get_action_muxer             (GtkWidget    *widget,
                                                             gboolean      create);
 
-gboolean          gtk_widget_consumes_motion               (GtkWidget        *widget,
-                                                            GtkWidget        *parent,
-                                                            GdkEventSequence *sequence);
-
 gboolean          gtk_widget_has_tick_callback             (GtkWidget *widget);
 
 gboolean          gtk_widget_has_size_request              (GtkWidget *widget);
diff --git a/gtk/gtkwindowhandle.c b/gtk/gtkwindowhandle.c
index 5a6beeb273..f4f2fa6e49 100644
--- a/gtk/gtkwindowhandle.c
+++ b/gtk/gtkwindowhandle.c
@@ -60,7 +60,6 @@ struct _GtkWindowHandle {
 
   GtkGesture *click_gesture;
   GtkGesture *drag_gesture;
-  GtkGesture *bubble_drag_gesture;
 
   GtkWidget *child;
   GtkWidget *fallback_menu;
@@ -400,36 +399,12 @@ drag_gesture_update_cb (GtkGestureDrag  *gesture,
   if (ABS (offset_x) > double_click_distance ||
       ABS (offset_y) > double_click_distance)
     {
-      GdkEventSequence *sequence;
       double start_x, start_y;
       double native_x, native_y;
       double window_x, window_y;
       GtkNative *native;
       GdkSurface *surface;
 
-      sequence = gtk_gesture_single_get_current_sequence (GTK_GESTURE_SINGLE (gesture));
-
-      if (gtk_event_controller_get_propagation_phase (GTK_EVENT_CONTROLLER (gesture)) == GTK_PHASE_CAPTURE)
-        {
-          GtkWidget *event_widget = gtk_gesture_get_last_target (GTK_GESTURE (gesture), sequence);
-
-          /* Check whether the target widget should be left alone at handling
-           * the sequence, this is better done late to give room for gestures
-           * there to go denied.
-           *
-           * Besides claiming gestures, we must bail out too if there's gestures
-           * in the "none" state at this point, as those are still handling events
-           * and can potentially go claimed, and we don't want to stop the target
-           * widget from doing anything.
-           */
-          if (event_widget != GTK_WIDGET (self) &&
-              gtk_widget_consumes_motion (event_widget, GTK_WIDGET (self), sequence))
-            {
-              gtk_gesture_set_state (GTK_GESTURE (gesture), GTK_EVENT_SEQUENCE_DENIED);
-              return;
-            }
-        }
-
       gtk_gesture_set_state (GTK_GESTURE (gesture), GTK_EVENT_SEQUENCE_CLAIMED);
 
       gtk_gesture_drag_get_start_point (gesture, &start_x, &start_y);
@@ -458,19 +433,6 @@ drag_gesture_update_cb (GtkGestureDrag  *gesture,
     }
 }
 
-static GtkGesture *
-create_drag_gesture (GtkWindowHandle *self)
-{
-  GtkGesture *gesture;
-
-  gesture = gtk_gesture_drag_new ();
-  g_signal_connect (gesture, "drag-update",
-                    G_CALLBACK (drag_gesture_update_cb), self);
-  gtk_widget_add_controller (GTK_WIDGET (self), GTK_EVENT_CONTROLLER (gesture));
-
-  return gesture;
-}
-
 static void
 gtk_window_handle_unrealize (GtkWidget *widget)
 {
@@ -562,19 +524,14 @@ gtk_window_handle_init (GtkWindowHandle *self)
 {
   self->click_gesture = gtk_gesture_click_new ();
   gtk_gesture_single_set_button (GTK_GESTURE_SINGLE (self->click_gesture), 0);
-  gtk_event_controller_set_propagation_phase (GTK_EVENT_CONTROLLER (self->click_gesture),
-                                              GTK_PHASE_BUBBLE);
   g_signal_connect (self->click_gesture, "pressed",
                     G_CALLBACK (click_gesture_pressed_cb), self);
   gtk_widget_add_controller (GTK_WIDGET (self), GTK_EVENT_CONTROLLER (self->click_gesture));
 
-  self->drag_gesture = create_drag_gesture (self);
-  gtk_event_controller_set_propagation_phase (GTK_EVENT_CONTROLLER (self->drag_gesture),
-                                              GTK_PHASE_CAPTURE);
-
-  self->bubble_drag_gesture = create_drag_gesture (self);
-  gtk_event_controller_set_propagation_phase (GTK_EVENT_CONTROLLER (self->bubble_drag_gesture),
-                                              GTK_PHASE_BUBBLE);
+  self->drag_gesture = gtk_gesture_drag_new ();
+  g_signal_connect (self->drag_gesture, "drag-update",
+                    G_CALLBACK (drag_gesture_update_cb), self);
+  gtk_widget_add_controller (GTK_WIDGET (self), GTK_EVENT_CONTROLLER (self->drag_gesture));
 }
 
 static GtkBuildableIface *parent_buildable_iface;