[PATCH xserver] wayland: Emulate crossing for native window

[Olivier Fourdan]

Emitting a LeaveNotify event every time the pointer leaves an X11 window
may confuse focus follow mouse mode in window managers such as
mutter/gnome-shell.

Keep the previously found X window and compare against the new one, and
if they match then it means the pointer has left an Xwayland window for
a native Wayland surface, only in this case fake the crossing to the
root window.

Signed-off-by: Olivier Fourdan <ofourdan at redhat.com>
---
 hw/xwayland/xwayland-input.c | 15 ++++++++++++++-
 hw/xwayland/xwayland.c       |  3 ++-
 hw/xwayland/xwayland.h       |  1 +
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/hw/xwayland/xwayland-input.c b/hw/xwayland/xwayland-input.c
index e295c71..043379e 100644
--- a/hw/xwayland/xwayland-input.c
+++ b/hw/xwayland/xwayland-input.c
@@ -959,7 +959,7 @@ xwl_xy_to_window(ScreenPtr screen, SpritePtr sprite, int x, int y)
         }
     }
 
-    if (xwl_seat == NULL || !xwl_seat->focus_window) {
+    if (xwl_seat == NULL) {
         sprite->spriteTraceGood = 1;
         return sprite->spriteTrace[0];
     }
@@ -969,6 +969,19 @@ xwl_xy_to_window(ScreenPtr screen, SpritePtr sprite, int x, int y)
     xwl_seat->xwl_screen->XYToWindow = screen->XYToWindow;
     screen->XYToWindow = xwl_xy_to_window;
 
+    /* If the pointer has left the Wayland surface but the DIX still
+     * finds the pointer within the previous X11 window, it means that
+     * the pointer has crossed to another native Wayland window, in this
+     * case, pretend we entered the root window so that a LeaveNotify
+     * event is emitted.
+     */
+    if (xwl_seat->focus_window == NULL && xwl_seat->last_xwindow == ret) {
+        sprite->spriteTraceGood = 1;
+        return sprite->spriteTrace[0];
+    }
+
+    xwl_seat->last_xwindow = ret;
+
     return ret;
 }
 
diff --git a/hw/xwayland/xwayland.c b/hw/xwayland/xwayland.c
index 8c49b0b..1b29491 100644
--- a/hw/xwayland/xwayland.c
+++ b/hw/xwayland/xwayland.c
@@ -323,7 +323,8 @@ xwl_unrealize_window(WindowPtr window)
     xorg_list_for_each_entry(xwl_seat, &xwl_screen->seat_list, link) {
         if (xwl_seat->focus_window && xwl_seat->focus_window->window == window)
             xwl_seat->focus_window = NULL;
-
+        if (xwl_seat->last_xwindow == window)
+            xwl_seat->last_xwindow = NullWindow;
         xwl_seat_clear_touch(xwl_seat, window);
     }
 
diff --git a/hw/xwayland/xwayland.h b/hw/xwayland/xwayland.h
index b8a58e7..aa78b44 100644
--- a/hw/xwayland/xwayland.h
+++ b/hw/xwayland/xwayland.h
@@ -132,6 +132,7 @@ struct xwl_seat {
     struct wl_surface *cursor;
     struct wl_callback *cursor_frame_cb;
     Bool cursor_needs_update;
+    WindowPtr last_xwindow;
 
     struct xorg_list touches;
 
-- 
2.7.4