libobs/util: Fix tv_nsec becoming 1000000000 in os_event_timedwait

[norihiro]

Description

Fix the carry condition of tv_nsec in the static function add_ms_to_ts, which add specified time in millisecond to an absolute time in struct timespec.

Motivation and Context

The static function add_ms_to_ts calculate the absolute time that will passed to pthread_cond_timedwait in the function os_event_timedwait.

When tv_nsec is 1000000000, some implementation of pthread_cond_timedwait, such as glibc on Linux, immediately return with an error code EINVAL.

How Has This Been Tested?

OS: Fedora 39

Tested with a modification as below to accelerate the failure condition.

 static inline void add_ms_to_ts(struct timespec *ts, unsigned long milliseconds)
 {
         ts->tv_sec += milliseconds / 1000;
         ts->tv_nsec += (milliseconds % 1000) * 1000000;
+
+        if (ts->tv_nsec > 999000000) {
+                blog(LOG_INFO, "setting tv_nsec = 1000000000");
+                ts->tv_nsec = 1000000000;
+        }
+
         if (ts->tv_nsec > 1000000000) {
                 ts->tv_sec += 1;
                 ts->tv_nsec -= 1000000000;
         }
 }

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.