Subversion got bitten by the APR time functions on Windows again. The culprit, as usual, was incorrect semantics of the tm_gmtoff field in apr_time_exp_t in the presence of DST. I decided that enough was enough, and it was time to do something about it.

It turned out that none of the tests in testtime.c tickled that particular problem, so I added a test case (see patch below). The test passed on Unix with and withoug DST, and failed on Windows with DST enabled; again, as expected.

I tracked down the provblem to the way tm_gmtoff was computed from the system's timezone info. Reading the docs for GetTimezoneInformation suggested that we should be using the StandardBias and DaylightBias fields compute tm_gmtoff, so that's what I did. The test now passes on Win2k (and presumably NT and XP) both with and without DST, and the relevant Subversion test passes, too.

Now, before I commit this patch, I'd like to ask people to test it on Win95/98/Me (and possibly WinCE). I don't have access to any of these platforms, and the docs suggest there may be some difference on the Win9x series at least.

Thanks,
   Brane


Index: time/win32/time.c =================================================================== RCS file: /home/cvspublic/apr/time/win32/time.c,v retrieving revision 1.33 diff -u -r1.33 time.c --- time/win32/time.c 22 May 2002 00:57:24 -0000 1.33 +++ time/win32/time.c 6 Jun 2002 12:45:28 -0000 @@ -105,16 +105,19 @@ rc = GetTimeZoneInformation(&tz); switch (rc) { case TIME_ZONE_ID_UNKNOWN: - case TIME_ZONE_ID_STANDARD: xt->tm_isdst = 0; /* Bias = UTC - local time in minutes * tm_gmtoff is seconds east of UTC */ xt->tm_gmtoff = tz.Bias * -60; break; + case TIME_ZONE_ID_STANDARD: + xt->tm_isdst = 0; + xt->tm_gmtoff = (tz.Bias + tz.StandardBias) * -60; + break; case TIME_ZONE_ID_DAYLIGHT: xt->tm_isdst = 1; - xt->tm_gmtoff = tz.Bias * -60; + xt->tm_gmtoff = (tz.Bias + tz.DaylightBias) * -60; break; default: xt->tm_isdst = 0; @@ -224,8 +227,7 @@ { apr_status_t status = apr_time_exp_get(t, xt); if (status == APR_SUCCESS) - *t -= (apr_time_t) (xt->tm_isdst * 3600 - + xt->tm_gmtoff) * APR_USEC_PER_SEC; + *t -= (apr_time_t) xt->tm_gmtoff * APR_USEC_PER_SEC; return status; }

Index: test/testtime.c
===================================================================
RCS file: /home/cvspublic/apr/test/testtime.c,v
retrieving revision 1.32
diff -u -r1.32 testtime.c
--- test/testtime.c     15 Apr 2002 00:01:09 -0000      1.32
+++ test/testtime.c     6 Jun 2002 12:45:27 -0000
@@ -62,6 +62,23 @@

#define STR_SIZE 45

+static const char* print_time (apr_pool_t *pool, const apr_time_exp_t *xt)
+{
+    return apr_psprintf (pool,
+                         "%04d-%02d-%02d %02d:%02d:%02d.%06d %+05d [%d %s]%s",
+                         xt->tm_year + 1900,
+                         xt->tm_mon,
+                         xt->tm_mday,
+                         xt->tm_hour,
+                         xt->tm_min,
+                         xt->tm_sec,
+                         xt->tm_usec,
+                         xt->tm_gmtoff,
+                         xt->tm_yday + 1,
+                         apr_day_snames[xt->tm_wday],
+                         (xt->tm_isdst ? " DST" : ""));
+}
+
int main(void)
{
    apr_time_t now;
@@ -84,19 +101,38 @@
    printf("OK\n");

    STD_TEST_NEQ("    apr_time_exp_gmt", apr_time_exp_gmt(&xt, now))
+    printf("        (%s)\n", print_time(p, &xt));

    STD_TEST_NEQ("    apr_time_exp_lt", apr_time_exp_lt(&xt2, now))
+    printf("        (%s)\n", print_time(p, &xt2));

    STD_TEST_NEQ("    apr_time_exp_get (GMT)", apr_time_exp_get(&imp, &xt))

    printf("%-60s", "    checking GMT explode == implode");
-    if (imp != now) {
+    hr_off_64 = (apr_int64_t) xt.tm_gmtoff * APR_USEC_PER_SEC;
+    if (imp != now + hr_off_64) {
       printf("mismatch\n"
                "\t\tapr_now()                %" APR_INT64_T_FMT "\n"
                "\t\tapr_implode() returned   %" APR_INT64_T_FMT "\n"
                "\t\terror delta was          %" APR_TIME_T_FMT "\n"
-                "\t\tshould have been         0\n",
-                now, imp, imp-now);
+                "\t\tshould have been         %" APR_INT64_T_FMT "\n",
+                now, imp, imp-now, hr_off_64);
+       exit(-1);
+    }
+    printf("OK\n");
+
+    STD_TEST_NEQ("    apr_time_exp_get (localtime)",
+                 apr_time_exp_get(&imp, &xt2))
+
+    printf("%-60s", "    checking localtime explode == implode");
+    hr_off_64 = (apr_int64_t) xt2.tm_gmtoff * APR_USEC_PER_SEC;
+    if (imp != now + hr_off_64) {
+       printf("mismatch\n"
+                "\t\tapr_now()                %" APR_INT64_T_FMT "\n"
+                "\t\tapr_implode() returned   %" APR_INT64_T_FMT "\n"
+                "\t\terror delta was          %" APR_TIME_T_FMT "\n"
+                "\t\tshould have been         %" APR_INT64_T_FMT "\n",
+                now, imp, imp-now, hr_off_64);
       exit(-1);
    }
    printf("OK\n");
@@ -178,7 +214,8 @@
        exit(-1);
    }
    printf("OK\n");
-    printf("        ( %lld - %lld = %lld )\n", imp, now, imp - now);
+    printf("        ( %" APR_TIME_T_FMT " - %" APR_TIME_T_FMT
+           " = %" APR_INT64_T_FMT " )\n", imp, now, imp - now);

    printf("\nTest Complete.\n");
    return 0;





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