Big patch to cover about 6 different issues in order to correct rare

2005-02-20  Elijah Newren  <newren@gmail.com>

	Big patch to cover about 6 different issues in order to correct
	rare problems with timestamps (make sure window selected in
	tasklist actually gets focus, sanity check timestamps to avoid
	rogue apps hosing the system, correct the updating of
	net_wm_user_time, correctly handle timestamps of 0 when comparing
	xserver timestamps for those who have had their systems up for
	over 25 days or so, add some debugging information to verbose
	logs, some code cleanups).  Fixes all issues listed in #167358.

	* src/display.h: (struct _MetaDisplay): clarify comment on
	last_focus_time, introduce a new variable--last_user_time,
	(XSERVER_TIME_IS_BEFORE macro): put this functionality into a
	separate macro and then introduce a new macro with this name that
	uses the old one but adds additional special-case checks for
	timestamps that are 0, (comment to
	meta_display_set_input_focus_window): add information about how
	last_user_time should be used in this function

	* src/display.c (santiy_check_timestamps): new function,
	(meta_display_open): intialize display->last_user_time,
	(meta_display_get_current_time_roundtrip): use the timestamp,
	which is known to be good, in order to sanity_check_timestamps,
	(event_callback): use the new meta_window_ste_user_time() function
	in order to correct problems, use the timestamp of KeyPress and
	ButtonPress events, which are known to be good, in order to
	sanity_check_timestamps, (timestamp_too_old): new function for
	common behavior of meta_display_focus_the_no_focus_window and
	meta_display_set_input_focus_window, with added checking for
	display->last_user_time in addition to display->last_focus_time,
	(meta_display_set_input_focus_window): replace some of the code
	with a call to timestamp_too_old(),
	(meta_display_focus_the_no_focus_window): replace some of th ecode
	with a call to timestamp_too_old()

	* src/window.h: (meta_window_set_user_time): new function to
	abstract the many things that need to be done when updating the
	net_wm_user_time of any window

	* src/window.c: (meta_window_activate): add debugging spew, make
	sure the comparison is made with last_user_time NOT
	last_focus_time, use meta_window_set_user_time() function in order
	to correct problems, (meta_window_client_message): add a newline
	to a debugging message to make them easier to read,
	(meta_window_set_user_time): new function

	* src/window-props.c (reload_net_wm_user_time): use the new
	meta_window_ste_user_time() function in order to correct problems

6 files changed, 229 insertions, 44 deletions

diff --git a/ChangeLog b/ChangeLog
index f129c579..e152a4f0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,53 @@
+2005-02-20  Elijah Newren  <newren@gmail.com>
+
+	Big patch to cover about 6 different issues in order to correct
+	rare problems with timestamps (make sure window selected in
+	tasklist actually gets focus, sanity check timestamps to avoid
+	rogue apps hosing the system, correct the updating of
+	net_wm_user_time, correctly handle timestamps of 0 when comparing
+	xserver timestamps for those who have had their systems up for
+	over 25 days or so, add some debugging information to verbose
+	logs, some code cleanups).  Fixes all issues listed in #167358.
+
+	* src/display.h: (struct _MetaDisplay): clarify comment on
+	last_focus_time, introduce a new variable--last_user_time,
+	(XSERVER_TIME_IS_BEFORE macro): put this functionality into a
+	separate macro and then introduce a new macro with this name that
+	uses the old one but adds additional special-case checks for
+	timestamps that are 0, (comment to
+	meta_display_set_input_focus_window): add information about how
+	last_user_time should be used in this function
+	
+	* src/display.c (santiy_check_timestamps): new function,
+	(meta_display_open): intialize display->last_user_time,
+	(meta_display_get_current_time_roundtrip): use the timestamp,
+	which is known to be good, in order to sanity_check_timestamps,
+	(event_callback): use the new meta_window_ste_user_time() function
+	in order to correct problems, use the timestamp of KeyPress and
+	ButtonPress events, which are known to be good, in order to
+	sanity_check_timestamps, (timestamp_too_old): new function for
+	common behavior of meta_display_focus_the_no_focus_window and
+	meta_display_set_input_focus_window, with added checking for
+	display->last_user_time in addition to display->last_focus_time,
+	(meta_display_set_input_focus_window): replace some of the code
+	with a call to timestamp_too_old(),
+	(meta_display_focus_the_no_focus_window): replace some of th ecode
+	with a call to timestamp_too_old()
+
+	* src/window.h: (meta_window_set_user_time): new function to
+	abstract the many things that need to be done when updating the
+	net_wm_user_time of any window
+
+	* src/window.c: (meta_window_activate): add debugging spew, make
+	sure the comparison is made with last_user_time NOT
+	last_focus_time, use meta_window_set_user_time() function in order
+	to correct problems, (meta_window_client_message): add a newline
+	to a debugging message to make them easier to read,
+	(meta_window_set_user_time): new function
+
+	* src/window-props.c (reload_net_wm_user_time): use the new
+	meta_window_ste_user_time() function in order to correct problems
+
 2005-02-16  Elijah Newren  <newren@gmail.com>
 
 	* src/display.c: (event_callback): trivial fix to a log message:
diff --git a/src/display.c b/src/display.c
index 8b0c8c98..33c0d8f1 100644
--- a/src/display.c
+++ b/src/display.c
@@ -115,6 +115,9 @@ static void    update_window_grab_modifiers (MetaDisplay *display);
 static void    prefs_changed_callback    (MetaPreference pref,
                                           void          *data);
 
+static void    sanity_check_timestamps   (MetaDisplay *display,
+                                          Time         known_good_timestamp);
+
 static void
 set_utf8_string_hint (MetaDisplay *display,
                       Window xwindow,
@@ -645,6 +648,7 @@ meta_display_open (const char *name)
   }
 
   display->last_focus_time = timestamp;
+  display->last_user_time = timestamp;
   display->compositor = meta_compositor_new (display);
   
   screens = NULL;
@@ -1146,6 +1150,8 @@ meta_display_get_current_time_roundtrip (MetaDisplay *display)
       timestamp = property_event.xproperty.time;
     }
 
+  sanity_check_timestamps (display, timestamp);
+
   return timestamp;
 }
 
@@ -1563,11 +1569,8 @@ event_callback (XEvent   *event,
   if (window && ((event->type == KeyPress) || (event->type == ButtonPress)))
     {
       g_assert (CurrentTime != display->current_time);
-      meta_topic (META_DEBUG_WINDOW_STATE,
-                  "Metacity set %s's net_wm_user_time to %lu.\n",
-                  window->desc, display->current_time);
-      window->net_wm_user_time_set = TRUE;
-      window->net_wm_user_time = display->current_time;
+      meta_window_set_user_time (window, display->current_time);
+      sanity_check_timestamps (display, display->current_time);
     }
   
   switch (event->type)
@@ -4648,21 +4651,114 @@ meta_display_focus_sentinel_clear (MetaDisplay *display)
   return (display->sentinel_counter == 0);
 }
 
+static void
+sanity_check_timestamps (MetaDisplay *display,
+                         Time         timestamp)
+{
+  if (XSERVER_TIME_IS_BEFORE (timestamp, display->last_focus_time))
+    {
+      meta_warning ("last_focus_time (%lu) is greater than comparison "
+                    "timestamp (%lu).  This most likely represents a buggy "
+                    "client sending inaccurate timestamps in messages such as "
+                    "_NET_ACTIVE_WINDOW.  Trying to work around...\n",
+                    display->last_focus_time, (unsigned long)timestamp);
+      display->last_focus_time = timestamp;
+    }
+  if (XSERVER_TIME_IS_BEFORE (timestamp, display->last_user_time))
+    {
+      GSList *windows;
+      GSList *tmp;
+
+      meta_warning ("last_user_time (%lu) is greater than comparison "
+                    "timestamp (%lu).  This most likely represents a buggy "
+                    "client sending inaccurate timestamps in messages such as "
+                    "_NET_ACTIVE_WINDOW.  Trying to work around...\n",
+                    display->last_user_time, (unsigned long)timestamp);
+      display->last_user_time = timestamp;
+
+      windows = meta_display_list_windows (display);
+      tmp = windows;
+      while (tmp != NULL)
+        {
+          MetaWindow *window = tmp->data;
+          
+          if (XSERVER_TIME_IS_BEFORE (timestamp, window->net_wm_user_time))
+            {
+              meta_warning ("%s appears to be one of the offending windows "
+                            "with a timestamp of %lu.  Working around...\n",
+                            window->desc, window->net_wm_user_time);
+              window->net_wm_user_time = timestamp;
+            }
+          
+          tmp = tmp->next;
+        }
+
+      g_slist_free (windows);
+    }
+}
+
+static gboolean
+timestamp_too_old (MetaDisplay *display,
+                   MetaWindow  *window,
+                   Time        *timestamp)
+{
+  /* FIXME: If Soeren's suggestion in bug 151984 is implemented, it will allow
+   * us to sanity check the timestamp here and ensure it doesn't correspond to
+   * a future time (though we would want to rename to 
+   * timestamp_too_old_or_in_future).
+   */
+
+  MetaWindow *focus_window;
+  focus_window = display->focus_window;
+
+  if (*timestamp == CurrentTime)
+    {
+      meta_warning ("Got a request to focus %s with a timestamp of 0.  This "
+                    "shouldn't happen!\n",
+                    window ? window->desc : "the no_focus_window");
+      meta_print_backtrace ();
+      *timestamp = meta_display_get_current_time_roundtrip (display);
+      return FALSE;
+    }
+  else if (XSERVER_TIME_IS_BEFORE (*timestamp, display->last_focus_time))
+    {
+      if (XSERVER_TIME_IS_BEFORE (*timestamp, display->last_user_time))
+        {
+          meta_topic (META_DEBUG_FOCUS,
+                      "Ignoring focus request for %s since %lu "
+                      "is less than %lu and %lu.\n",
+                      window ? window->desc : "the no_focus_window",
+                      *timestamp,
+                      (unsigned long) display->last_user_time,
+                      (unsigned long) display->last_focus_time);
+          return TRUE;
+        }
+      else
+        {
+          meta_topic (META_DEBUG_FOCUS,
+                      "Received focus request for %s which is newer than most "
+                      "recent user_time, but less recent than "
+                      "last_focus_time (%lu < %lu < %lu); adjusting "
+                      "accordingly.  (See bug 167358)\n",
+                      window ? window->desc : "the no_focus_window",
+                      display->last_user_time,
+                      *timestamp,
+                      display->last_focus_time);
+          *timestamp = display->last_focus_time;
+          return FALSE;
+        }
+    }
+
+  return FALSE;
+}
+
 void
 meta_display_set_input_focus_window (MetaDisplay *display, 
                                      MetaWindow  *window,
                                      gboolean     focus_frame,
                                      Time         timestamp)
 {
-  if (timestamp == CurrentTime)
-    {
-      meta_warning ("meta_display_set_input_focus_window called with a "
-                    "timestamp of 0 for window %s.  This shouldn't happen!\n",
-                    window->desc);
-      meta_print_backtrace ();
-      timestamp = meta_display_get_current_time_roundtrip (display);
-    }
-  else if (XSERVER_TIME_IS_BEFORE (timestamp, display->last_focus_time))
+  if (timestamp_too_old (display, window, &timestamp))
     return;
 
   XSetInputFocus (display->xdisplay,
@@ -4680,18 +4776,8 @@ void
 meta_display_focus_the_no_focus_window (MetaDisplay *display, 
                                         Time         timestamp)
 {
-  if (timestamp == CurrentTime)
-    {
-      meta_warning ("meta_display_focus_the_no_focus_window called with a "
-                    "timestamp of 0.  This shouldn't happen!\n");
-      meta_print_backtrace ();
-      timestamp = meta_display_get_current_time_roundtrip (display);
-    }
-  else if (XSERVER_TIME_IS_BEFORE (timestamp, display->last_focus_time))
-    {
-      meta_warning ("Ignoring focus request for no_focus_window since %lu is less than %lu.\n", timestamp, display->last_focus_time);
+  if (timestamp_too_old (display, NULL, &timestamp))
     return;
-    }
 
   XSetInputFocus (display->xdisplay,
                   display->no_focus_window,
diff --git a/src/display.h b/src/display.h
index 07070342..df309efb 100644
--- a/src/display.h
+++ b/src/display.h
@@ -198,9 +198,12 @@ struct _MetaDisplay
    */
   MetaWindow *expected_focus_window;
 
-  /* last timestamp that a window was focused */
+  /* last timestamp passed to XSetInputFocus */
   Time last_focus_time;
 
+  /* last user interaction time in any app */
+  Time last_user_time;
+
   guint static_gravity_works : 1;
   
   /*< private-ish >*/
@@ -361,11 +364,21 @@ struct _MetaDisplay
  * has occurred, this is equivalent to
  *   time1 < time2
  * Of course, the rest of the ugliness of this macro comes from accounting
- * for the fact that wraparound can occur.
+ * for the fact that wraparound can occur and the fact that a timestamp of
+ * 0 must be special-cased since it means older than anything else. 
+ *
+ * Note that this is NOT an equivalent for time1 <= time2; if that's what
+ * you need then you'll need to swap the order of the arguments and negate
+ * the result.
  */
-#define XSERVER_TIME_IS_BEFORE(time1, time2)                       \
-  ( (( time1 < time2 ) && ( time2 - time1 < ((guint32)-1)/2 )) ||  \
-    (( time1 > time2 ) && ( time1 - time2 > ((guint32)-1)/2 ))     \
+#define XSERVER_TIME_IS_BEFORE_ASSUMING_REAL_TIMESTAMPS(time1, time2) \
+  ( (( time1 < time2 ) && ( time2 - time1 < ((guint32)-1)/2 )) ||     \
+    (( time1 > time2 ) && ( time1 - time2 > ((guint32)-1)/2 ))        \
+  )
+#define XSERVER_TIME_IS_BEFORE(time1, time2)                          \
+  ( time1 == 0 ||                                                     \
+    (XSERVER_TIME_IS_BEFORE_ASSUMING_REAL_TIMESTAMPS(time1, time2) && \
+     time2 != 0)                                                      \
   )
 
 gboolean      meta_display_open                (const char  *name);
@@ -507,9 +520,11 @@ gboolean meta_display_focus_sentinel_clear (MetaDisplay *display);
 /* meta_display_set_input_focus_window is like XSetInputFocus, except
  * that (a) it can't detect timestamps later than the current time,
  * since Metacity isn't part of the XServer, and thus gives erroneous
- * behavior in this circumstance (so don't do it), and (b) it uses
- * display->last_focus_time and display->expected_focus_window since
- * we don't have access to the true Xserver ones.
+ * behavior in this circumstance (so don't do it), (b) it uses
+ * display->last_focus_time since we don't have access to the true
+ * Xserver one, (c) it makes use of display->user_time since checking
+ * whether a window should be allowed to be focused should depend
+ * on user_time events (see bug 167358, comment 15 in particular)
  */
 void meta_display_set_input_focus_window   (MetaDisplay *display, 
                                             MetaWindow  *window,
diff --git a/src/window-props.c b/src/window-props.c
index 2bde03b5..34881ff1 100644
--- a/src/window-props.c
+++ b/src/window-props.c
@@ -186,12 +186,7 @@ reload_net_wm_user_time (MetaWindow    *window,
   if (value->type != META_PROP_VALUE_INVALID)
     {
       gulong cardinal = value->v.cardinal;
-
-      window->net_wm_user_time_set = TRUE;
-      window->net_wm_user_time = cardinal;
-      meta_topic (META_DEBUG_STARTUP,
-                  "Window %s has _NET_WM_USER_TIME of %lu\n",
-                  window->desc, window->net_wm_user_time);
+      meta_window_set_user_time (window, cardinal);
     }
 }
 
diff --git a/src/window.c b/src/window.c
index 8470e259..c281b87f 100644
--- a/src/window.c
+++ b/src/window.c
@@ -2206,15 +2206,20 @@ void
 meta_window_activate (MetaWindow *window,
                       guint32     timestamp)
 {
+  meta_topic (META_DEBUG_FOCUS,
+              "_NET_ACTIVE_WINDOW message sent for %s at time %lu.\n",
+              window->desc, (unsigned long)timestamp);
+
   /* Older EWMH spec didn't specify a timestamp, so it can be 0 and we
    * have to treat that as a new request.
    */
-  if (XSERVER_TIME_IS_BEFORE (timestamp, window->display->last_focus_time) &&
+  if (XSERVER_TIME_IS_BEFORE (timestamp, window->display->last_user_time) &&
       timestamp != 0)
     {
       meta_topic (META_DEBUG_FOCUS,
-                  "_NET_ACTIVE_WINDOW message sent but with a timestamp that"
-                  "requests the window not be active, so we're ignoring it.\n");
+                  "last_user_time (%lu) is more recent; ignoring "
+                  " _NET_ACTIVE_WINDOW message.\n",
+                  window->display->last_user_time);
       window->wm_state_demands_attention = TRUE;
       set_net_wm_state (window);
       return;
@@ -2223,7 +2228,7 @@ meta_window_activate (MetaWindow *window,
   if (timestamp == 0)
     timestamp = meta_display_get_current_time_roundtrip (window->display);
 
-  window->net_wm_user_time = timestamp;
+  meta_window_set_user_time (window, timestamp);
 
   /* disable show desktop mode unless we're a desktop component */
   maybe_leave_show_desktop_mode (window);
@@ -4305,7 +4310,7 @@ meta_window_client_message (MetaWindow *window,
   else if (event->xclient.message_type ==
            display->atom_net_active_window)
     {
-      meta_verbose ("_NET_ACTIVE_WINDOW request for window '%s', activating",
+      meta_verbose ("_NET_ACTIVE_WINDOW request for window '%s', activating\n",
                     window->desc);
 
       if (event->xclient.data.l[0] != 0)
@@ -7378,3 +7383,34 @@ meta_window_stack_just_below (MetaWindow *window,
                   window->desc, below_this_one->desc);
     }
 }
+
+void
+meta_window_set_user_time (MetaWindow *window,
+                           Time        timestamp)
+{
+  /* FIXME: If Soeren's suggestion in bug 151984 is implemented, it will allow
+   * us to sanity check the timestamp here and ensure it doesn't correspond to
+   * a future time.
+   */
+
+  /* Only update the time if this timestamp is newer... */
+  if (window->net_wm_user_time_set &&
+      XSERVER_TIME_IS_BEFORE (timestamp, window->net_wm_user_time))
+    {
+      meta_topic (META_DEBUG_STARTUP,
+                  "Window %s _NET_WM_USER_TIME not updated to %lu, because it "
+                  "is less than %lu\n",
+                  window->desc, timestamp, window->net_wm_user_time);
+
+    }
+  else
+    {
+      meta_topic (META_DEBUG_STARTUP,
+                  "Window %s has _NET_WM_USER_TIME of %lu\n",
+                  window->desc, timestamp);
+      window->net_wm_user_time_set = TRUE;
+      window->net_wm_user_time = timestamp;
+      if (XSERVER_TIME_IS_BEFORE (window->display->last_user_time, timestamp))
+        window->display->last_user_time = timestamp;
+    }
+}
diff --git a/src/window.h b/src/window.h
index 960f364f..e9efa0c4 100644
--- a/src/window.h
+++ b/src/window.h
@@ -532,4 +532,7 @@ void meta_window_queue_update_icon (MetaWindow *window);
 void meta_window_stack_just_below (MetaWindow *window,
                                    MetaWindow *below_this_one);
 
+void meta_window_set_user_time (MetaWindow *window,
+                                Time        timestamp);
+
 #endif