From 339d76704400a6ea514817d91a2e935a13ecc928 Mon Sep 17 00:00:00 2001
From: Dana Jansens <danakj@orodu.net>
Date: Wed, 28 Mar 2007 01:52:06 +0000
Subject: [PATCH] handle time wrapping around.

---
 openbox/client.c |  6 ++++--
 openbox/event.c  | 12 ++++++++++++
 openbox/event.h  |  4 ++++
 openbox/grab.c   | 23 +++++++++++------------
 4 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/openbox/client.c b/openbox/client.c
index a51ecfd7..203c6dbc 100644
--- a/openbox/client.c
+++ b/openbox/client.c
@@ -3031,9 +3031,11 @@ void client_activate(ObClient *self, gboolean here, gboolean user)
              "source=%s\n",
              self->window, event_curtime, client_last_user_time,
              (user ? "user" : "application"));
-    if (!user && event_curtime && event_curtime < client_last_user_time)
+    if (!user && event_curtime &&
+        !event_time_after(event_curtime, client_last_user_time))
+    {
         client_hilite(self, TRUE);
-    else {
+    } else {
         if (client_normal(self) && screen_showing_desktop)
             screen_show_desktop(FALSE);
         if (self->iconic)
diff --git a/openbox/event.c b/openbox/event.c
index 75cf5d2e..15724968 100644
--- a/openbox/event.c
+++ b/openbox/event.c
@@ -1376,3 +1376,15 @@ void event_ignore_queued_enters()
     }
     g_slist_free(saved);
 }
+
+gboolean event_time_after(Time t1, Time t2)
+{
+    /*
+      Timestamp values wrap around (after about 49.7 days). The server, given
+      its current time is represented by timestamp T, always interprets
+      timestamps from clients by treating half of the timestamp space as being
+      later in time than T.
+      - http://tronche.com/gui/x/xlib/input/pointer-grabbing.html
+    */
+    return t1 >= t2 && t1 <= t2 + (1 << (sizeof(Time)*8-1));
+}
diff --git a/openbox/event.h b/openbox/event.h
index 44bf54a0..4221e54d 100644
--- a/openbox/event.h
+++ b/openbox/event.h
@@ -47,4 +47,8 @@ void event_ignore_queued_enters();
    window for focus */
 void event_halt_focus_delay();
 
+/*! Compare t1 and t2, taking into account wraparound. True if t1
+  comes at the same time or later than t2. */
+gboolean event_time_after(Time t1, Time t2);
+
 #endif
diff --git a/openbox/grab.c b/openbox/grab.c
index f63da5e9..991956da 100644
--- a/openbox/grab.c
+++ b/openbox/grab.c
@@ -38,6 +38,14 @@ static guint pgrabs = 0;
 /*! The time at which the last grab was made */
 static Time  grab_time = CurrentTime;
 
+static Time ungrab_time()
+{
+    Time t = event_curtime;
+    if (!(t == 0 || event_time_after(t, grab_time)))
+        t = grab_time;
+    return t;
+}
+
 gboolean grab_on_keyboard()
 {
     return kgrabs > 0;
@@ -65,10 +73,7 @@ gboolean grab_keyboard(gboolean grab)
             ret = TRUE;
     } else if (kgrabs > 0) {
         if (--kgrabs == 0) {
-            Time t = event_curtime;
-            if (t != 0 && t < grab_time)
-                t = grab_time;
-            XUngrabKeyboard(ob_display, t);
+            XUngrabKeyboard(ob_display, ungrab_time());
         }
         ret = TRUE;
     }
@@ -94,10 +99,7 @@ gboolean grab_pointer(gboolean grab, ObCursor cur)
             ret = TRUE;
     } else if (pgrabs > 0) {
         if (--pgrabs == 0) {
-            Time t = event_curtime;
-            if (t != 0 && t < grab_time)
-                t = grab_time;
-            XUngrabPointer(ob_display, event_curtime);
+            XUngrabPointer(ob_display, ungrab_time());
         }
         ret = TRUE;
     }
@@ -122,10 +124,7 @@ gboolean grab_pointer_window(gboolean grab, ObCursor cur, Window win)
             ret = TRUE;
     } else if (pgrabs > 0) {
         if (--pgrabs == 0) {
-            Time t = event_curtime;
-            if (t != 0 && t < grab_time)
-                t = grab_time;
-            XUngrabPointer(ob_display, event_curtime);
+            XUngrabPointer(ob_display, ungrab_time());
         }
         ret = TRUE;
     }
-- 
2.45.2