[gtk+] wayland: Avoid spurious crossing events from master touch device

[Carlos Garnacho <carlosg src gnome org>]

commit 783c30219891e873c9ea07fb83b603b647ef3d47
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu May 12 13:34:42 2016 +0200

    wayland: Avoid spurious crossing events from master touch device
    
    Only generate crossing events on wl_touch.down for the virtual master
    device used for touch events, and only whenever this virtual device
    actually moves across surfaces. This behavior resembles better what is
    expected in X11, where the pointer is warped to the touch position
    on XITouchBegin.
    
    This avoids the double emission of leave events when the pointer
    emulating touch is lifted, that crossing event will be instead
    generated when/if the focus surface changes.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=766314

 gdk/wayland/gdkdevice-wayland.c |   46 ++++++++++++++++++++++++--------------
 1 files changed, 29 insertions(+), 17 deletions(-)
---
diff --git a/gdk/wayland/gdkdevice-wayland.c b/gdk/wayland/gdkdevice-wayland.c
index 2da74de..1e3bc83 100644
--- a/gdk/wayland/gdkdevice-wayland.c
+++ b/gdk/wayland/gdkdevice-wayland.c
@@ -2072,6 +2072,33 @@ mimic_pointer_emulating_touch_info (GdkDevice           *device,
 }
 
 static void
+touch_handle_master_pointer_crossing (GdkWaylandSeat      *seat,
+                                      GdkWaylandTouchData *touch,
+                                      uint32_t             time)
+{
+  GdkWaylandPointerData *pointer;
+
+  pointer = GDK_WAYLAND_DEVICE (seat->touch_master)->pointer;
+
+  if (pointer->focus == touch->window)
+    return;
+
+  if (pointer->focus)
+    {
+      emulate_touch_crossing (pointer->focus, NULL,
+                              seat->touch_master, seat->touch, touch,
+                              GDK_LEAVE_NOTIFY, GDK_CROSSING_NORMAL, time);
+    }
+
+  if (touch->window)
+    {
+      emulate_touch_crossing (touch->window, NULL,
+                              seat->touch_master, seat->touch, touch,
+                              GDK_ENTER_NOTIFY, GDK_CROSSING_NORMAL, time);
+    }
+}
+
+static void
 touch_handle_down (void              *data,
                    struct wl_touch   *wl_touch,
                    uint32_t           serial,
@@ -2097,9 +2124,7 @@ touch_handle_down (void              *data,
 
   if (touch->initial_touch)
     {
-      emulate_touch_crossing (touch->window, NULL,
-                              seat->touch_master, seat->touch, touch,
-                              GDK_ENTER_NOTIFY, GDK_CROSSING_NORMAL, time);
+      touch_handle_master_pointer_crossing (seat, touch, time);
       GDK_WAYLAND_DEVICE(seat->touch_master)->emulating_touch = touch;
       mimic_pointer_emulating_touch_info (seat->touch_master, touch);
     }
@@ -2133,16 +2158,7 @@ touch_handle_up (void            *data,
   _gdk_wayland_display_deliver_event (seat->display, event);
 
   if (touch->initial_touch)
-    {
-      GdkWaylandPointerData *pointer_info;
-
-      emulate_touch_crossing (touch->window, NULL,
-                              seat->touch_master, seat->touch, touch,
-                              GDK_LEAVE_NOTIFY, GDK_CROSSING_NORMAL, time);
-      GDK_WAYLAND_DEVICE(seat->touch_master)->emulating_touch = NULL;
-      pointer_info = GDK_WAYLAND_DEVICE (seat->touch_master)->pointer;
-      g_clear_object (&pointer_info->focus);
-    }
+    GDK_WAYLAND_DEVICE(seat->touch_master)->emulating_touch = NULL;
 
   gdk_wayland_seat_remove_touch (seat, id);
 }
@@ -2193,10 +2209,6 @@ touch_handle_cancel (void            *data,
     {
       touch = GDK_WAYLAND_DEVICE (wayland_seat->touch_master)->emulating_touch;
       GDK_WAYLAND_DEVICE (wayland_seat->touch_master)->emulating_touch = NULL;
-      emulate_touch_crossing (touch->window, NULL,
-                              wayland_seat->touch_master, wayland_seat->touch,
-                              touch, GDK_LEAVE_NOTIFY, GDK_CROSSING_NORMAL,
-                              GDK_CURRENT_TIME);
     }
 
   g_hash_table_iter_init (&iter, wayland_seat->touches);