eventcontrollerscroll: Conditionally propagate ::scrollscroll-event-propagation

Currently, gtk_event_controller_scroll_handle_event() always returns
TRUE if it is handled, which stops the propagation of the event. If
there’s a single GtkEventControllerScroll in the widget hierarchy, that
means that no others will run, depending on the propagation phase. In
Nautilus, this can be observed when adding a scroll controller to the
GtkScrolledWindow (ctrl-scrolling controls the zoom level) - either the
scrolling or the zooming breaks.

Fixes https://gitlab.gnome.org/GNOME/gtk/issues/45

11 files changed, 51 insertions, 29 deletions

diff --git a/gtk/gtkcalendar.c b/gtk/gtkcalendar.c
index 643b86e5b9..c45df9200d 100644
--- a/gtk/gtkcalendar.c
+++ b/gtk/gtkcalendar.c
@@ -340,10 +340,10 @@ static gint calendar_get_xsep          (GtkCalendar *calendar);
 static gint calendar_get_ysep          (GtkCalendar *calendar);
 static gint calendar_get_inner_border  (GtkCalendar *calendar);
 
-static void gtk_calendar_scroll_controller_scroll (GtkEventControllerScroll *scroll,
-                                                   gdouble                   dx,
-                                                   gdouble                   dy,
-                                                   GtkWidget                *widget);
+static gboolean gtk_calendar_scroll_controller_scroll (GtkEventControllerScroll *scroll,
+                                                       gdouble                   dx,
+                                                       gdouble                   dy,
+                                                       GtkWidget                *widget);
 
 static char    *default_abbreviated_dayname[7];
 static char    *default_monthname[12];
@@ -2686,7 +2686,7 @@ gtk_calendar_drag_update (GtkGestureDrag *gesture,
   gtk_drag_set_icon_default (drag);
 }
 
-static void
+static gboolean
 gtk_calendar_scroll_controller_scroll (GtkEventControllerScroll *scroll,
                                        gdouble                   dx,
                                        gdouble                   dy,
@@ -2701,6 +2701,8 @@ gtk_calendar_scroll_controller_scroll (GtkEventControllerScroll *scroll,
     calendar_set_month_prev (calendar);
   else if (dy > 0)
     calendar_set_month_next (calendar);
+
+  return TRUE;
 }
 
 
diff --git a/gtk/gtkcombobox.c b/gtk/gtkcombobox.c
index f5844ad572..6893b8edcc 100644
--- a/gtk/gtkcombobox.c
+++ b/gtk/gtkcombobox.c
@@ -248,7 +248,7 @@ static void     gtk_combo_box_real_move_active     (GtkComboBox      *combo_box,
 static void     gtk_combo_box_real_popup           (GtkComboBox      *combo_box);
 static gboolean gtk_combo_box_real_popdown         (GtkComboBox      *combo_box);
 
-static void     gtk_combo_box_scroll_controller_scroll (GtkEventControllerScroll *scroll,
+static gboolean gtk_combo_box_scroll_controller_scroll (GtkEventControllerScroll *scroll,
                                                         gdouble                   dx,
                                                         gdouble                   dy,
                                                         GtkComboBox              *combo_box);
@@ -1798,7 +1798,7 @@ tree_first (GtkComboBox  *combo,
   return search_data.set;
 }
 
-static void
+static gboolean
 gtk_combo_box_scroll_controller_scroll (GtkEventControllerScroll *scroll,
                                         gdouble                   dx,
                                         gdouble                   dy,
@@ -1810,7 +1810,7 @@ gtk_combo_box_scroll_controller_scroll (GtkEventControllerScroll *scroll,
   GtkTreeIter new_iter;
 
   if (!gtk_combo_box_get_active_iter (combo_box, &iter))
-    return;
+    return FALSE;
 
   if (dy < 0)
     found = tree_prev (combo_box, priv->model, &iter, &new_iter);
@@ -1820,6 +1820,8 @@ gtk_combo_box_scroll_controller_scroll (GtkEventControllerScroll *scroll,
   if (found)
     gtk_combo_box_set_active_iter (combo_box, &new_iter);
 
+  return found;
+
 }
 
 /* callbacks */
diff --git a/gtk/gtkeventcontrollerscroll.c b/gtk/gtkeventcontrollerscroll.c
index db5db881d1..cef8257ec0 100644
--- a/gtk/gtkeventcontrollerscroll.c
+++ b/gtk/gtkeventcontrollerscroll.c
@@ -243,6 +243,7 @@ gtk_event_controller_scroll_handle_event (GtkEventController *controller,
   GtkEventControllerScroll *scroll = GTK_EVENT_CONTROLLER_SCROLL (controller);
   GdkScrollDirection direction = GDK_SCROLL_SMOOTH;
   gdouble dx = 0, dy = 0;
+  gboolean handled = TRUE;
 
   if (gdk_event_get_event_type (event) != GDK_SCROLL)
     return FALSE;
@@ -324,7 +325,7 @@ gtk_event_controller_scroll_handle_event (GtkEventController *controller,
 
   if (dx != 0 || dy != 0)
     {
-      g_signal_emit (controller, signals[SCROLL], 0, dx, dy);
+      g_signal_emit (controller, signals[SCROLL], 0, dx, dy, &handled);
 
       if (scroll->flags & GTK_EVENT_CONTROLLER_SCROLL_KINETIC)
         scroll_history_push (scroll, dx, dy, gdk_event_get_time (event));
@@ -344,7 +345,7 @@ gtk_event_controller_scroll_handle_event (GtkEventController *controller,
         }
     }
 
-  return TRUE;
+  return handled;
 }
 
 static void
@@ -394,14 +395,16 @@ gtk_event_controller_scroll_class_init (GtkEventControllerScrollClass *klass)
    *
    * Signals that the widget should scroll by the
    * amount specified by @dx and @dy.
+   *
+   * Returns: %TRUE if the scroll event was handled, %FALSE otherwise.
    **/
   signals[SCROLL] =
     g_signal_new (I_("scroll"),
                   GTK_TYPE_EVENT_CONTROLLER_SCROLL,
-                  G_SIGNAL_RUN_FIRST,
+                  G_SIGNAL_RUN_LAST,
                   0, NULL, NULL,
-		  _gtk_marshal_VOID__DOUBLE_DOUBLE,
-                  G_TYPE_NONE, 2, G_TYPE_DOUBLE, G_TYPE_DOUBLE);
+		  _gtk_marshal_BOOLEAN__DOUBLE_DOUBLE,
+                  G_TYPE_BOOLEAN, 2, G_TYPE_DOUBLE, G_TYPE_DOUBLE);
   /**
    * GtkEventControllerScroll::scroll-end:
    * @controller: The object that received the signal
diff --git a/gtk/gtkmarshalers.list b/gtk/gtkmarshalers.list
index 322feb18b6..322428e76d 100644
--- a/gtk/gtkmarshalers.list
+++ b/gtk/gtkmarshalers.list
@@ -23,6 +23,7 @@
 
 BOOLEAN:BOXED
 BOOLEAN:BOXED,BOXED
+BOOLEAN:DOUBLE,DOUBLE
 BOOLEAN:ENUM
 BOOLEAN:ENUM,BOOLEAN
 BOOLEAN:ENUM,DOUBLE
diff --git a/gtk/gtkmenu.c b/gtk/gtkmenu.c
index 1efbb2ed4d..d73f2df91d 100644
--- a/gtk/gtkmenu.c
+++ b/gtk/gtkmenu.c
@@ -247,7 +247,7 @@ static void     gtk_menu_grab_notify       (GtkWidget        *widget,
 static gboolean gtk_menu_captured_event    (GtkWidget        *widget,
                                             GdkEvent         *event);
 
-static void     gtk_menu_scroll_controller_scroll (GtkEventControllerScroll *scroll,
+static gboolean gtk_menu_scroll_controller_scroll (GtkEventControllerScroll *scroll,
                                                    gdouble                   dx,
                                                    gdouble                   dy,
                                                    GtkMenu                  *menu);
@@ -3211,13 +3211,15 @@ gtk_menu_scroll_timeout (gpointer data)
   return TRUE;
 }
 
-static void
+static gboolean
 gtk_menu_scroll_controller_scroll (GtkEventControllerScroll *scroll,
                                    gdouble                   dx,
                                    gdouble                   dy,
                                    GtkMenu                  *menu)
 {
   gtk_menu_scroll_by (menu, dy * MENU_SCROLL_STEP2);
+
+  return TRUE;
 }
 
 static void
diff --git a/gtk/gtkpathbar.c b/gtk/gtkpathbar.c
index eeaf6e4326..33313979fd 100644
--- a/gtk/gtkpathbar.c
+++ b/gtk/gtkpathbar.c
@@ -157,10 +157,10 @@ static void gtk_path_bar_update_button_appearance (GtkPathBar       *path_bar,
 						   ButtonData       *button_data,
 						   gboolean          current_dir);
 
-static void gtk_path_bar_scroll_controller_scroll (GtkEventControllerScroll *scroll,
-                                                   gdouble                   dx,
-                                                   gdouble                   dy,
-                                                   GtkPathBar               *path_bar);
+static gboolean gtk_path_bar_scroll_controller_scroll (GtkEventControllerScroll *scroll,
+                                                       gdouble                   dx,
+                                                       gdouble                   dy,
+                                                       GtkPathBar               *path_bar);
 
 static void
 add_cancellable (GtkPathBar   *path_bar,
@@ -728,7 +728,7 @@ gtk_path_bar_display_changed (GtkWidget  *widget,
   gtk_path_bar_check_icon_theme (GTK_PATH_BAR (widget));
 }
 
-static void
+static gboolean
 gtk_path_bar_scroll_controller_scroll (GtkEventControllerScroll *scroll,
                                        gdouble                   dx,
                                        gdouble                   dy,
@@ -738,6 +738,8 @@ gtk_path_bar_scroll_controller_scroll (GtkEventControllerScroll *scroll,
     gtk_path_bar_scroll_down (path_bar);
   else if (dy < 0)
     gtk_path_bar_scroll_up (path_bar);
+
+  return TRUE;
 }
 
 static void
diff --git a/gtk/gtkrange.c b/gtk/gtkrange.c
index 009293dd74..b848e623a2 100644
--- a/gtk/gtkrange.c
+++ b/gtk/gtkrange.c
@@ -236,7 +236,7 @@ static void          gtk_range_allocate_trough          (GtkGizmo            *gi
 static gboolean      gtk_range_render_trough            (GtkGizmo     *gizmo,
                                                          GtkSnapshot  *snapshot);
 
-static void          gtk_range_scroll_controller_scroll (GtkEventControllerScroll *scroll,
+static gboolean      gtk_range_scroll_controller_scroll (GtkEventControllerScroll *scroll,
                                                          gdouble                   dx,
                                                          gdouble                   dy,
                                                          GtkRange                 *range);
@@ -2228,7 +2228,7 @@ stop_scrolling (GtkRange *range)
   remove_autoscroll (range);
 }
 
-static void
+static gboolean
 gtk_range_scroll_controller_scroll (GtkEventControllerScroll *scroll,
                                     gdouble                   dx,
                                     gdouble                   dy,
@@ -2262,6 +2262,8 @@ gtk_range_scroll_controller_scroll (GtkEventControllerScroll *scroll,
   g_signal_emit (range, signals[CHANGE_VALUE], 0,
                  GTK_SCROLL_JUMP, gtk_adjustment_get_value (priv->adjustment) + delta,
                  &handled);
+
+  return TRUE;
 }
 
 static void
diff --git a/gtk/gtkscalebutton.c b/gtk/gtkscalebutton.c
index 04d90a783a..9c0dd43c2e 100644
--- a/gtk/gtkscalebutton.c
+++ b/gtk/gtkscalebutton.c
@@ -150,7 +150,7 @@ static void     cb_scale_value_changed          (GtkRange            *range,
 static void     cb_popup_mapped                 (GtkWidget           *popup,
                                                  gpointer             user_data);
 
-static void     gtk_scale_button_scroll_controller_scroll (GtkEventControllerScroll *scroll,
+static gboolean gtk_scale_button_scroll_controller_scroll (GtkEventControllerScroll *scroll,
                                                            gdouble                   dx,
                                                            gdouble                   dy,
                                                            GtkScaleButton           *button);
@@ -766,7 +766,7 @@ gtk_scale_button_set_orientation_private (GtkScaleButton *button,
     }
 }
 
-static void
+static gboolean
 gtk_scale_button_scroll_controller_scroll (GtkEventControllerScroll *scroll,
                                            gdouble                   dx,
                                            gdouble                   dy,
@@ -784,6 +784,8 @@ gtk_scale_button_scroll_controller_scroll (GtkEventControllerScroll *scroll,
              gtk_adjustment_get_upper (adjustment));
 
   gtk_scale_button_set_value (button, d);
+
+  return TRUE;
 }
 
 /*
diff --git a/gtk/gtkscrolledwindow.c b/gtk/gtkscrolledwindow.c
index 4c502846ae..7bee752377 100644
--- a/gtk/gtkscrolledwindow.c
+++ b/gtk/gtkscrolledwindow.c
@@ -1279,7 +1279,7 @@ scroll_controller_scroll_begin (GtkEventControllerScroll *scroll,
   priv->smooth_scroll = TRUE;
 }
 
-static void
+static gboolean
 scroll_controller_scroll (GtkEventControllerScroll *scroll,
                           gdouble                   delta_x,
                           gdouble                   delta_y,
@@ -1290,7 +1290,7 @@ scroll_controller_scroll (GtkEventControllerScroll *scroll,
   GdkModifierType state;
 
   if (!gtk_get_current_event_state (&state))
-    return;
+    return FALSE;
 
   shifted = (state & GDK_SHIFT_MASK) != 0;
 
@@ -1349,6 +1349,8 @@ scroll_controller_scroll (GtkEventControllerScroll *scroll,
       g_source_set_name_by_id (priv->scroll_events_overshoot_id,
                                "[gtk+] start_scroll_deceleration_cb");
     }
+
+  return TRUE;
 }
 
 static void
diff --git a/gtk/gtkspinbutton.c b/gtk/gtkspinbutton.c
index 9a112ebf7d..b9ac55d3de 100644
--- a/gtk/gtkspinbutton.c
+++ b/gtk/gtkspinbutton.c
@@ -689,7 +689,7 @@ swipe_gesture_update (GtkGesture       *gesture,
   gtk_spin_button_real_spin (spin_button, -vel_y / 20);
 }
 
-static void
+static gboolean
 scroll_controller_scroll (GtkEventControllerScroll *Scroll,
 			  gdouble                   dx,
 			  gdouble                   dy,
@@ -701,6 +701,8 @@ scroll_controller_scroll (GtkEventControllerScroll *Scroll,
   if (!gtk_widget_has_focus (widget))
     gtk_widget_grab_focus (widget);
   gtk_spin_button_real_spin (spin, -dy * gtk_adjustment_get_step_increment (priv->adjustment));
+
+  return TRUE;
 }
 
 static gboolean
diff --git a/gtk/gtktreeview.c b/gtk/gtktreeview.c
index f9ccd551c4..5205af8108 100644
--- a/gtk/gtktreeview.c
+++ b/gtk/gtktreeview.c
@@ -800,7 +800,7 @@ static void     gtk_tree_view_search_pressed_cb         (GtkGesture       *gestu
                                                          double            x,
                                                          double            y,
 							 GtkTreeView      *tree_view);
-static void     gtk_tree_view_search_scroll_event       (GtkWidget        *entry,
+static gboolean gtk_tree_view_search_scroll_event       (GtkWidget        *entry,
 							 gdouble           dx,
                                                          gdouble           dy,
 							 GtkTreeView      *tree_view);
@@ -14251,7 +14251,7 @@ gtk_tree_view_search_pressed_cb (GtkGesture  *gesture,
   gtk_tree_view_search_window_hide (widget, tree_view, keyb_device);
 }
 
-static void
+static gboolean
 gtk_tree_view_search_scroll_event (GtkWidget   *widget,
                                    gdouble      dx,
                                    gdouble      dy,
@@ -14277,6 +14277,8 @@ gtk_tree_view_search_scroll_event (GtkWidget   *widget,
 		       tree_view);
       g_source_set_name_by_id (tree_view->priv->typeselect_flush_timeout, "[gtk+] gtk_tree_view_search_entry_flush_timeout");
     }
+
+  return TRUE;
 }
 
 static gboolean