[gnome-desktop] idle-monitor: Clarify code and comments about alarm rescheduling workaround

[Bastien Nocera <hadess src gnome org>]

commit 626de2acb020e62a4276ef8acbe72cf940157d5a
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Thu Jan 17 23:52:57 2013 -0500

    idle-monitor: Clarify code and comments about alarm rescheduling workaround
    
    Segment the code out in its own function, point out that this is an Xorg
    bug, and don't actually set any attributes -- just call XSyncChangeAlarm.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=688227

 libgnome-desktop/gnome-idle-monitor.c |   18 ++++++++++++++----
 1 files changed, 14 insertions(+), 4 deletions(-)
---
diff --git a/libgnome-desktop/gnome-idle-monitor.c b/libgnome-desktop/gnome-idle-monitor.c
index 844861f..053d290 100644
--- a/libgnome-desktop/gnome-idle-monitor.c
+++ b/libgnome-desktop/gnome-idle-monitor.c
@@ -120,6 +120,18 @@ _xsync_alarm_set (GnomeIdleMonitor *monitor,
        return XSyncCreateAlarm (monitor->priv->display, flags, &attr);
 }
 
+static void
+ensure_alarm_rescheduled (Display    *dpy,
+                         XSyncAlarm  alarm)
+{
+       XSyncAlarmAttributes attr;
+
+       /* Some versions of Xorg have an issue where alarms aren't
+        * always rescheduled. Calling XSyncChangeAlarm, even
+        * without any attributes, will reschedule the alarm. */
+       XSyncChangeAlarm (dpy, alarm, 0, &attr);
+}
+
 static GnomeIdleMonitorWatch *
 find_watch_for_alarm (GnomeIdleMonitor *monitor,
                      XSyncAlarm        alarm)
@@ -144,7 +156,6 @@ handle_alarm_notify_event (GnomeIdleMonitor     *monitor,
                g_signal_emit (monitor, signals[BECAME_ACTIVE], 0);
        } else {
                GnomeIdleMonitorWatch *watch;
-               XSyncAlarmAttributes attr;
 
                watch = find_watch_for_alarm (monitor, alarm_event->alarm);
                if (watch == NULL)
@@ -158,9 +169,8 @@ handle_alarm_notify_event (GnomeIdleMonitor     *monitor,
                                         watch->user_data);
                }
 
-               /* Reset the alarm so it can be triggered again */
-               attr.events = TRUE;
-               XSyncChangeAlarm (watch->display, watch->xalarm, XSyncCAEvents, &attr);
+               ensure_alarm_rescheduled (monitor->priv->display,
+                                         watch->xalarm);
        }
 }