From ab68a26e84fcc01f084c5337e71db391e07c7954 Mon Sep 17 00:00:00 2001
From: Sergei Fedosov <s.fedosov@corp.mail.ru>
Date: Mon, 19 Jul 2021 14:42:30 +0300
Subject: [PATCH] Sync AnyEvent timer (brutal way) if timeskew more than 60
 seconds.

AnyEvent does not sync its timers with system time, so cron jobs that
scheduled for particular time, shoots with time skew after wakeup from
hibernate or suspend. And AnyEvent have no mechanism to sync its timers
with local system time. The only way to "sync" timers is to remove and
re-add watchers, so timers begin count time from beginning.

To workaround timekeeping issue for AnyEvent::Timer::Cron let's add
another time-based call back that will send SIGHUP to script if local
system time differs from time counter more than 60 seconds. SIGHUP
should trigger signal handler that remove all event watchers, re-read
config and re-add event watchers effectively reloads config and re-launch
timers for AnyEvent.
---
 i3status-anyevent | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/i3status-anyevent b/i3status-anyevent
index 66e7d67..8d17f86 100644
--- a/i3status-anyevent
+++ b/i3status-anyevent
@@ -40,6 +40,9 @@ my $i3 = i3 ();
 my $done = AnyEvent->condvar;
 $i3->connect->recv or die 'Unable to connect to i3';
 
+# Local Time Counter
+my $TC = time();
+
 # event pool
 my @EP;
 
@@ -758,6 +761,20 @@ sub add_events () {
 				}
 			)
 		}
+
+		# also we need workaround for timers after sleep or hibernate
+		push @EP, AnyEvent->timer (
+			after    => 60,   # first invoke after 1 minute
+			interval => 60,   # then invoke every 1 second
+			cb       => sub { # the callback to invoke
+				$TC = $TC + 60;
+				my $timeskew = $TC - time ();
+
+				if (($timeskew > 60) || ($timeskew < -60)) {
+					kill 'HUP', $$;
+				}
+			}
+		);
 	}
 
 	return;