From 9c1b972ca15dafc8899e96c1425805248f0a4b40 Mon Sep 17 00:00:00 2001
From: "Owen W. Taylor" <otaylor@fishsoup.net>
Date: Mon, 16 Dec 2013 16:01:04 -0500
Subject: [PATCH] Fix problems with focus tracking

When a client spontaneously focuses their window, perhaps in response
to WM_TAKE_FOCUS we'll get a FocusOut/FocusIn pair with same serial.
Updating display->focus_serial in response to FocusOut then was causing
us to ignore FocusIn and think that the focus was not on any window.

We need to distinguish this spontaneous case from the case where we
set the focus ourselves - when we set the focus ourselves, we're careful
to combine the SetFocus with a property change so that we know definitively
what focus events we have already accounted for.

https://bugzilla.gnome.org/show_bug.cgi?id=720558
---
 src/core/display-private.h |  8 ++++++++
 src/core/display.c         | 25 +++++++++++++++++++------
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/src/core/display-private.h b/src/core/display-private.h
index 169682ee8..a8fa75363 100644
--- a/src/core/display-private.h
+++ b/src/core/display-private.h
@@ -145,6 +145,14 @@ struct _MetaDisplay
    */
   guint allow_terminal_deactivation : 1;
 
+  /* If true, server->focus_serial refers to us changing the focus; in
+   * this case, we can ignore focus events that have exactly focus_serial,
+   * since we take care to make another request immediately afterwards.
+   * But if focus is being changed by another client, we have to accept
+   * multiple events with the same serial.
+   */
+  guint focused_by_us : 1;
+
   guint static_gravity_works : 1;
   
   /*< private-ish >*/
diff --git a/src/core/display.c b/src/core/display.c
index 0f20d143b..455db3120 100644
--- a/src/core/display.c
+++ b/src/core/display.c
@@ -1670,11 +1670,13 @@ update_focus_window (MetaDisplay   *display,
                      MetaFocusType  type,
                      MetaWindow    *window,
                      Window         xwindow,
-                     gulong         serial)
+                     gulong         serial,
+                     gboolean       focused_by_us)
 {
   MetaWaylandCompositor *compositor;
 
   display->focus_serial = serial;
+  display->focused_by_us = focused_by_us;
 
   if (display->focus_xwindow == xwindow &&
       display->focus_type == type &&
@@ -1811,7 +1813,8 @@ request_xserver_input_focus_change (MetaDisplay   *display,
                        type,
                        meta_window,
                        xwindow,
-                       serial);
+                       serial,
+                       TRUE);
 
   meta_error_trap_pop (display);
 
@@ -1940,13 +1943,21 @@ handle_window_focus_event (MetaDisplay  *display,
   else
     g_return_if_reached ();
 
-  if (display->server_focus_serial > display->focus_serial)
+  /* If display->focused_by_us, then the focus_serial will be used only
+   * for a focus change we made and have already accounted for.
+   * (See request_xserver_input_focus_change().) Otherwise, we can get
+   * multiple focus events with the same serial.
+   */
+  if (display->server_focus_serial > display->focus_serial ||
+      (!display->focused_by_us &&
+       display->server_focus_serial == display->focus_serial))
     {
       update_focus_window (display,
                            type,
                            focus_window,
                            focus_window ? focus_window->xwindow : None,
-                           display->server_focus_serial);
+                           display->server_focus_serial,
+                           FALSE);
     }
 }
 
@@ -3185,7 +3196,8 @@ meta_display_handle_xevent (MetaDisplay *display,
   display->current_time = event_get_time (display, event);
   display->monitor_cache_invalidated = TRUE;
 
-  if (event->xany.serial > display->focus_serial &&
+  if (display->focused_by_us &&
+      event->xany.serial > display->focus_serial &&
       display->focus_window &&
       !window_has_xwindow (display->focus_window, display->server_focus_window))
     {
@@ -3195,7 +3207,8 @@ meta_display_handle_xevent (MetaDisplay *display,
                            META_FOCUS_NONE,
                            meta_display_lookup_x_window (display, display->server_focus_window),
                            display->server_focus_window,
-                           display->server_focus_serial);
+                           display->server_focus_serial,
+                           FALSE);
     }
 
   screen = meta_display_screen_for_root (display, event->xany.window);