From 02ae9a86077c629eb6f998c4f824bb9b9c4e60ce Mon Sep 17 00:00:00 2001
From: Patrick Oppenlander <patrick.oppenlander@gmail.com>
Date: Thu, 8 Feb 2024 14:36:26 +1100
Subject: [PATCH] leapdb: make twice per day check logic common

We want to do the twice per day check regardless of the data source.
Move the check up one level from get_tz_leap() into LDB_GetLeap().
---
 leapdb.c | 41 ++++++++++++++++++++---------------------
 1 file changed, 20 insertions(+), 21 deletions(-)

diff --git a/leapdb.c b/leapdb.c
index 676a0d5..32f753a 100644
--- a/leapdb.c
+++ b/leapdb.c
@@ -41,24 +41,10 @@ static char *leap_tzname;
 static NTP_Leap
 get_tz_leap(time_t when, int *tai_offset)
 {
-  static time_t last_tz_leap_check;
-  static NTP_Leap tz_leap;
-  static int tz_tai_offset;
-
   struct tm stm, *tm;
   time_t t;
   char *tz_env, tz_orig[128];
-
-  *tai_offset = tz_tai_offset;
-
-  /* Do this check at most twice a day */
-  when = when / (12 * 3600) * (12 * 3600);
-  if (last_tz_leap_check == when)
-      return tz_leap;
-
-  last_tz_leap_check = when;
-  tz_leap = LEAP_Normal;
-  tz_tai_offset = 0;
+  NTP_Leap tz_leap = LEAP_Normal;
 
   tm = gmtime(&when);
   if (!tm)
@@ -79,7 +65,7 @@ get_tz_leap(time_t when, int *tai_offset)
   /* Get the TAI-UTC offset, which started at the epoch at 10 seconds */
   t = mktime(&stm);
   if (t != -1)
-    tz_tai_offset = t - when + 10;
+    *tai_offset = t - when + 10;
 
   /* Set the time to 23:59:60 and see how it overflows in mktime() */
   stm.tm_sec = 60;
@@ -102,8 +88,6 @@ get_tz_leap(time_t when, int *tai_offset)
   else if (stm.tm_sec == 1)
     tz_leap = LEAP_DeleteSecond;
 
-  *tai_offset = tz_tai_offset;
-
   return tz_leap;
 }
 
@@ -132,10 +116,25 @@ LDB_Initialise(void)
 NTP_Leap
 LDB_GetLeap(time_t when, int *tai_offset)
 {
-  *tai_offset = 0;
+  static time_t last_ldb_leap_check;
+  static NTP_Leap ldb_leap;
+  static int ldb_tai_offset;
+
+  /* Do this check at most twice a day */
+  when = when / (12 * 3600) * (12 * 3600);
+  if (last_ldb_leap_check == when)
+    goto out;
+
+  last_ldb_leap_check = when;
+  ldb_leap = LEAP_Normal;
+  ldb_tai_offset = 0;
+
   if (leap_tzname)
-    return get_tz_leap(when, tai_offset);
-  return LEAP_Normal;
+    ldb_leap = get_tz_leap(when, &ldb_tai_offset);
+
+out:
+  *tai_offset = ldb_tai_offset;
+  return ldb_leap;
 }
 
 /* ================================================== */