wayland: Provide information about scroll devices

The Wayland protocol does not share XI2's wealth of information
about individual devices, but it does provide discriminating
information about the source for scroll events. Pass this on to
the application by creating separate slave devices for these,
and setting them as source device on the scroll events.

These devices can be discriminated by their input-source property:
wheel      - GDK_SOURCE_MOUSE
finger     - GDK_SOURCE_TOUCHPAD
continuous - GDK_SOURCE_TRACKPOINT

https://bugzilla.gnome.org/show_bug.cgi?id=767093

fix up

1 files changed, 139 insertions, 15 deletions

diff --git a/gdk/wayland/gdkdevice-wayland.c b/gdk/wayland/gdkdevice-wayland.c
index 887b7ee721..b19fd64b96 100644
--- a/gdk/wayland/gdkdevice-wayland.c
+++ b/gdk/wayland/gdkdevice-wayland.c
@@ -69,6 +69,7 @@ struct _GdkWaylandPointerFrameData
   gdouble delta_x, delta_y;
   int32_t discrete_x, discrete_y;
   gint8 is_scroll_stop;
+  enum wl_pointer_axis_source source;
 };
 
 struct _GdkWaylandPointerData {
@@ -151,6 +152,9 @@ struct _GdkWaylandSeat
   GdkDevice *master_pointer;
   GdkDevice *master_keyboard;
   GdkDevice *pointer;
+  GdkDevice *wheel_scrolling;
+  GdkDevice *finger_scrolling;
+  GdkDevice *continuous_scrolling;
   GdkDevice *keyboard;
   GdkDevice *touch_master;
   GdkDevice *touch;
@@ -1068,6 +1072,9 @@ static const struct gtk_primary_selection_device_listener primary_selection_devi
   primary_selection_selection,
 };
 
+static GdkDevice * get_scroll_device (GdkWaylandSeat              *seat,
+                                      enum wl_pointer_axis_source  source);
+
 static GdkEvent *
 create_scroll_event (GdkWaylandSeat *seat,
                      gboolean        emulated)
@@ -1078,7 +1085,7 @@ create_scroll_event (GdkWaylandSeat *seat,
   event = gdk_event_new (GDK_SCROLL);
   event->scroll.window = g_object_ref (seat->pointer_info.focus);
   gdk_event_set_device (event, seat->master_pointer);
-  gdk_event_set_source_device (event, seat->pointer);
+  gdk_event_set_source_device (event, get_scroll_device (seat, seat->pointer_info.frame.source));
   event->scroll.time = seat->pointer_info.time;
   event->scroll.state = device_get_modifiers (seat->master_pointer);
   gdk_event_set_screen (event, display->screen);
@@ -1180,7 +1187,10 @@ gdk_wayland_seat_flush_frame_event (GdkWaylandSeat *seat)
       seat->pointer_info.frame.event = NULL;
     }
   else
-    flush_scroll_event (seat, &seat->pointer_info.frame);
+    {
+      flush_scroll_event (seat, &seat->pointer_info.frame);
+      seat->pointer_info.frame.source = 0;
+    }
 }
 
 static GdkEvent *
@@ -1523,15 +1533,12 @@ pointer_handle_axis_source (void                        *data,
                             enum wl_pointer_axis_source  source)
 {
   GdkWaylandSeat *seat = data;
+  GdkWaylandPointerFrameData *pointer_frame = &seat->pointer_info.frame;
 
   if (!seat->pointer_info.focus)
     return;
 
-  /* We don't need to handle the scroll source right now. It only has real
-   * meaning for 'finger' (to trigger kinetic scrolling). The axis_stop
-   * event will generate the zero delta required to trigger kinetic
-   * scrolling, so explicitly handling the source is not required.
-   */
+  pointer_frame->source = source;
 
   GDK_NOTE (EVENTS,
             g_message ("axis source %s, seat %p", get_axis_source_name (source), seat));
@@ -2769,8 +2776,40 @@ seat_handle_capabilities (void                    *data,
         g_list_remove (device_manager->devices, seat->pointer);
 
       g_signal_emit_by_name (device_manager, "device-removed", seat->pointer);
-      g_object_unref (seat->pointer);
-      seat->pointer = NULL;
+      g_clear_object (&seat->pointer);
+
+      if (seat->wheel_scrolling)
+        {
+          _gdk_device_set_associated_device (seat->wheel_scrolling, NULL);
+
+          device_manager->devices =
+            g_list_remove (device_manager->devices, seat->wheel_scrolling);
+
+          g_signal_emit_by_name (device_manager, "device-removed", seat->wheel_scrolling);
+          g_clear_object (&seat->wheel_scrolling);
+        }
+
+      if (seat->finger_scrolling)
+        {
+          _gdk_device_set_associated_device (seat->finger_scrolling, NULL);
+
+          device_manager->devices =
+            g_list_remove (device_manager->devices, seat->finger_scrolling);
+
+          g_signal_emit_by_name (device_manager, "device-removed", seat->finger_scrolling);
+          g_clear_object (&seat->finger_scrolling);
+        }
+
+      if (seat->continuous_scrolling)
+        {
+          _gdk_device_set_associated_device (seat->continuous_scrolling, NULL);
+
+          device_manager->devices =
+            g_list_remove (device_manager->devices, seat->continuous_scrolling);
+
+          g_signal_emit_by_name (device_manager, "device-removed", seat->continuous_scrolling);
+          g_clear_object (&seat->continuous_scrolling);
+        }
     }
 
   if ((caps & WL_SEAT_CAPABILITY_KEYBOARD) && !seat->wl_keyboard)
@@ -2807,8 +2846,7 @@ seat_handle_capabilities (void                    *data,
         g_list_remove (device_manager->devices, seat->keyboard);
 
       g_signal_emit_by_name (device_manager, "device-removed", seat->keyboard);
-      g_object_unref (seat->keyboard);
-      seat->keyboard = NULL;
+      g_clear_object (&seat->keyboard);
     }
 
   if ((caps & WL_SEAT_CAPABILITY_TOUCH) && !seat->wl_touch)
@@ -2865,10 +2903,8 @@ seat_handle_capabilities (void                    *data,
 
       g_signal_emit_by_name (device_manager, "device-removed", seat->touch_master);
       g_signal_emit_by_name (device_manager, "device-removed", seat->touch);
-      g_object_unref (seat->touch_master);
-      g_object_unref (seat->touch);
-      seat->touch_master = NULL;
-      seat->touch = NULL;
+      g_clear_object (&seat->touch_master);
+      g_clear_object (&seat->touch);
     }
 
   if (seat->master_pointer)
@@ -2877,6 +2913,88 @@ seat_handle_capabilities (void                    *data,
     gdk_drag_context_set_device (seat->drop_context, seat->touch_master);
 }
 
+static GdkDevice *
+get_scroll_device (GdkWaylandSeat              *seat,
+                   enum wl_pointer_axis_source  source)
+{
+  GdkWaylandDeviceManager *device_manager = GDK_WAYLAND_DEVICE_MANAGER (seat->device_manager);
+
+  if (!seat->pointer)
+    return NULL;
+
+  switch (source)
+    {
+    case WL_POINTER_AXIS_SOURCE_WHEEL:
+      if (seat->wheel_scrolling == NULL)
+        {
+          seat->wheel_scrolling = g_object_new (GDK_TYPE_WAYLAND_DEVICE,
+                                                "name", "Wayland Wheel Scrolling",
+                                                "type", GDK_DEVICE_TYPE_SLAVE,
+                                                "input-source", GDK_SOURCE_MOUSE,
+                                                "input-mode", GDK_MODE_SCREEN,
+                                                "has-cursor", TRUE,
+                                                "display", seat->display,
+                                                "device-manager", seat->device_manager,
+                                                "seat", seat,
+                                                NULL);
+          _gdk_device_set_associated_device (seat->wheel_scrolling, seat->master_pointer);
+
+          device_manager->devices =
+            g_list_append (device_manager->devices, seat->wheel_scrolling);
+
+          g_signal_emit_by_name (device_manager, "device-added", seat->wheel_scrolling);
+        }
+      return seat->wheel_scrolling;
+
+    case WL_POINTER_AXIS_SOURCE_FINGER:
+      if (seat->finger_scrolling == NULL)
+        {
+          seat->finger_scrolling = g_object_new (GDK_TYPE_WAYLAND_DEVICE,
+                                                 "name", "Wayland Finger Scrolling",
+                                                 "type", GDK_DEVICE_TYPE_SLAVE,
+                                                 "input-source", GDK_SOURCE_TOUCHPAD,
+                                                 "input-mode", GDK_MODE_SCREEN,
+                                                 "has-cursor", TRUE,
+                                                 "display", seat->display,
+                                                 "device-manager", seat->device_manager,
+                                                 "seat", seat,
+                                                 NULL);
+          _gdk_device_set_associated_device (seat->finger_scrolling, seat->master_pointer);
+
+          device_manager->devices =
+            g_list_append (device_manager->devices, seat->finger_scrolling);
+
+          g_signal_emit_by_name (device_manager, "device-added", seat->finger_scrolling);
+        }
+      return seat->finger_scrolling;
+
+    case WL_POINTER_AXIS_SOURCE_CONTINUOUS:
+      if (seat->continuous_scrolling == NULL)
+        {
+          seat->continuous_scrolling = g_object_new (GDK_TYPE_WAYLAND_DEVICE,
+                                                     "name", "Wayland Continuous Scrolling",
+                                                     "type", GDK_DEVICE_TYPE_SLAVE,
+                                                     "input-source", GDK_SOURCE_TRACKPOINT,
+                                                     "input-mode", GDK_MODE_SCREEN,
+                                                     "has-cursor", TRUE,
+                                                     "display", seat->display,
+                                                     "device-manager", seat->device_manager,
+                                                     "seat", seat,
+                                                     NULL);
+          _gdk_device_set_associated_device (seat->continuous_scrolling, seat->master_pointer);
+
+          device_manager->devices =
+            g_list_append (device_manager->devices, seat->continuous_scrolling);
+
+          g_signal_emit_by_name (device_manager, "device-added", seat->continuous_scrolling);
+        }
+      return seat->continuous_scrolling;
+
+    default:
+      return seat->pointer;
+    }
+}
+
 static void
 seat_handle_name (void           *data,
                   struct wl_seat *seat,
@@ -3973,6 +4091,12 @@ gdk_wayland_seat_get_slaves (GdkSeat             *seat,
   GdkWaylandSeat *wayland_seat = GDK_WAYLAND_SEAT (seat);
   GList *slaves = NULL;
 
+  if (wayland_seat->finger_scrolling && (capabilities & GDK_SEAT_CAPABILITY_POINTER))
+    slaves = g_list_prepend (slaves, wayland_seat->finger_scrolling);
+  if (wayland_seat->continuous_scrolling && (capabilities & GDK_SEAT_CAPABILITY_POINTER))
+    slaves = g_list_prepend (slaves, wayland_seat->continuous_scrolling);
+  if (wayland_seat->wheel_scrolling && (capabilities & GDK_SEAT_CAPABILITY_POINTER))
+    slaves = g_list_prepend (slaves, wayland_seat->wheel_scrolling);
   if (wayland_seat->pointer && (capabilities & GDK_SEAT_CAPABILITY_POINTER))
     slaves = g_list_prepend (slaves, wayland_seat->pointer);
   if (wayland_seat->keyboard && (capabilities & GDK_SEAT_CAPABILITY_KEYBOARD))