QTimer/QObject::startTimer: improve the detection of overflow

Converting from int milliseconds to int64_t nanoseconds can't overflow
(it won't even for picoseconds, so we'll be fine for a couple more
decades), so we only need to address the cases where the millisecond
value was passed in int64_t: that is, in the std::chrono::milliseconds
overloads. For the other cases, I added a comment.

Amends bfc7535a10f7a6e3723f354b41f08a0fe1d18719 to not allow the
detected overflow to happen at all, which could cause the timer to
become very small. Instead, we saturate to the maximum, which is about
292 years (just under 106752 days). That's longer than computers have
existed, so the chance that some Qt application is still running on a
computer without any reboots from today to 24th century is remote at
best.

This parallels QDeadlineTimer, which already has code to saturate when
using milliseconds.

Change-Id: I6818d78a57394e37857bfffd17b9b1465b6a5d19
Reviewed-by: Ahmad Samir <a.samirh78@gmail.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/src/dbus/qdbusintegrator.cpp b/src/dbus/qdbusintegrator.cpp
index 89b9b2d17e..836562f496 100644
--- a/src/dbus/qdbusintegrator.cpp
+++ b/src/dbus/qdbusintegrator.cpp
@@ -151,7 +151,8 @@ static dbus_bool_t qDBusAddTimeout(DBusTimeout *timeout, void *data)
 
     Q_ASSERT(d->timeouts.key(timeout, 0) == 0);
 
-    int timerId = d->startTimer(std::chrono::milliseconds{q_dbus_timeout_get_interval(timeout)});
+    using namespace std::chrono_literals;
+    int timerId = d->startTimer(q_dbus_timeout_get_interval(timeout) * 1ms); // no overflow possible
     if (!timerId)
         return false;