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Simplified handling of clock changes

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Per Malmberg 2018-05-22 21:45:00 +02:00
parent efeb1e4769
commit 0436cda4ef
1 changed files with 23 additions and 10 deletions
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33
libcron/Cron.h
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@ -128,24 +128,37 @@ namespace libcron
}
if (first_tick)
{
first_tick = false;
}
else if (now > last_tick && now - last_tick <= std::chrono::hours{3})
else
{
// Reschedule all tasks.
for (auto& t : tasks.get_tasks())
// https://linux.die.net/man/8/cron
constexpr auto three_hours = std::chrono::hours{3};
auto diff = now - last_tick;
auto absolute_diff = diff > diff.zero() ? diff : -diff;
if(absolute_diff >= three_hours)
{
t.calculate_next(now);
// Time changes of more than 3 hours are considered to be corrections to the
// clock or timezone, and the new time is used immediately.
for (auto& t : tasks.get_tasks())
{
t.calculate_next(now);
}
}
}
else if (now < last_tick && now - last_tick <= -std::chrono::hours{3})
{
// Reschedule all tasks.
for (auto& t : tasks.get_tasks())
else
{
t.calculate_next(now);
// Change of less than three hours
// If time has moved backwards: Since tasks are not rescheduled, they won't run before
// we're back at least the original point in time which prevents running tasks twice.
// If time has moved forward, tasks that would have run since last tick will be run.
}
}