To divine the timezone and daylight savings time, effective as of the

  given date, we need to change our strategy altogether from the old
  FileTimeToLocalFileTime to the SystemTimeToTzSpecificLocalTime API.

  We also need to leave the responsibility of mapping tm_gmtoff and
  tm_isdst to the caller, because this isn't the function that can best
  guess at the gyrations.

  This code tests out fine after introducing %R to the win32 extra
  translations.  However, there is still the time zone disparity since
  the existing tests only succeed on PST machines.


git-svn-id: http://svn.apache.org/repos/asf/apr/apr/trunk@64286 13f79535-47bb-0310-9956-ffa450edef68

2 files changed, 69 insertions, 45 deletions

diff --git a/time/win32/time.c b/time/win32/time.c
index 8917297a4..157a583de 100644
--- a/time/win32/time.c
+++ b/time/win32/time.c
@@ -72,14 +72,25 @@
  */
 #define IsLeapYear(y) ((!(y % 4)) ? (((!(y % 400)) && (y % 100)) ? 1 : 0) : 0)
 
-static void SystemTimeToAprExpTime(apr_time_exp_t *xt, SYSTEMTIME *tm, BOOL lt)
+static LPTIME_ZONE_INFORMATION GetLocalTimeZone()
+{
+    static int init = 0;
+    static TIME_ZONE_INFORMATION tz;
+
+    if (!init) {
+        GetTimeZoneInformation(&tz);
+        init = 1;
+    }
+    return &tz;
+}
+
+static void SystemTimeToAprExpTime(apr_time_exp_t *xt, SYSTEMTIME *tm)
 {
-    TIME_ZONE_INFORMATION tz;
-    DWORD rc;
     static const int dayoffset[12] =
     {0, 31, 59, 90, 120, 151, 182, 212, 243, 273, 304, 334};
 
-    /* XXX: this is a looser - can't forefit precision like this
+    /* Note; the caller is responsible for filling in detailed tm_usec,
+     * tm_gmtoff and tm_isdst data when applicable.
      */
     xt->tm_usec = tm->wMilliseconds * 1000;
     xt->tm_sec  = tm->wSecond;
@@ -90,41 +101,14 @@ static void SystemTimeToAprExpTime(apr_time_exp_t *xt, SYSTEMTIME *tm, BOOL lt)
     xt->tm_year = tm->wYear - 1900;
     xt->tm_wday = tm->wDayOfWeek;
     xt->tm_yday = dayoffset[xt->tm_mon] + (tm->wDay - 1);
+    xt->tm_isdst = 0;
+    xt->tm_gmtoff = 0;
 
     /* If this is a leap year, and we're past the 28th of Feb. (the
      * 58th day after Jan. 1), we'll increment our tm_yday by one.
      */
     if (IsLeapYear(tm->wYear) && (xt->tm_yday > 58))
         xt->tm_yday++;
-
-    if (!lt) {
-        xt->tm_isdst = 0;
-        xt->tm_gmtoff = 0;
-        return;
-    }
-
-    rc = GetTimeZoneInformation(&tz);
-    switch (rc) {
-    case TIME_ZONE_ID_UNKNOWN:
-        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 + tz.DaylightBias) * -60;
-        break;
-    default:
-        xt->tm_isdst = 0;
-        xt->tm_gmtoff = 0;
-    }
-    return;
 }
 
 APR_DECLARE(apr_status_t) apr_time_ansi_put(apr_time_t *result, 
@@ -157,35 +141,69 @@ APR_DECLARE(apr_status_t) apr_time_exp_gmt(apr_time_exp_t *result,
     SYSTEMTIME st;
     AprTimeToFileTime(&ft, input);
     FileTimeToSystemTime(&ft, &st);
-    SystemTimeToAprExpTime(result, &st, 0);
+    /* The Platform SDK documents that SYSTEMTIME/FILETIME are
+     * generally UTC, so no timezone info needed
+     */
+    SystemTimeToAprExpTime(result, &st);
     result->tm_usec = (apr_int32_t) (input % APR_USEC_PER_SEC);
     return APR_SUCCESS;
 }
 
 APR_DECLARE(apr_status_t) apr_time_exp_tz(apr_time_exp_t *result, 
-                                          apr_time_t input, apr_int32_t offs)
+                                          apr_time_t input, 
+                                          apr_int32_t offs)
 {
     FILETIME ft;
     SYSTEMTIME st;
     AprTimeToFileTime(&ft, input + (offs *  APR_USEC_PER_SEC));
     FileTimeToSystemTime(&ft, &st);
-    SystemTimeToAprExpTime(result, &st, 0);
+    /* The Platform SDK documents that SYSTEMTIME/FILETIME are
+     * generally UTC, so we will simply note the offs used.
+     */
+    SystemTimeToAprExpTime(result, &st);
     result->tm_usec = (apr_int32_t) (input % APR_USEC_PER_SEC);
     result->tm_gmtoff = offs;
     return APR_SUCCESS;
 }
 
 APR_DECLARE(apr_status_t) apr_time_exp_lt(apr_time_exp_t *result,
-                                                apr_time_t input)
+                                          apr_time_t input)
 {
-    SYSTEMTIME st;
+    SYSTEMTIME st, localst;
     FILETIME ft, localft;
+    TIME_ZONE_INFORMATION *tz;
+    apr_time_t localtime;
 
+    tz = GetLocalTimeZone();
     AprTimeToFileTime(&ft, input);
-    FileTimeToLocalFileTime(&ft, &localft);
-    FileTimeToSystemTime(&localft, &st);
-    SystemTimeToAprExpTime(result, &st, 1);
+    FileTimeToSystemTime(&ft, &st);
+
+    /* The Platform SDK documents that SYSTEMTIME/FILETIME are
+     * generally UTC.  We use SystemTimeToTzSpecificLocalTime
+     * because FileTimeToLocalFileFime is documented that the
+     * resulting time local file time would have DST relative
+     * to the *present* date, not the date converted.
+     */
+    SystemTimeToTzSpecificLocalTime(tz, &st, &localst);
+    SystemTimeToAprExpTime(result, &localst);
     result->tm_usec = (apr_int32_t) (input % APR_USEC_PER_SEC);
+
+    /* Recover the resulting time as an apr time and use the
+     * delta for gmtoff in seconds (and ignore msec rounding) 
+     */
+    SystemTimeToFileTime(&localst, &localft);
+    FileTimeToAprTime(&localtime, &localft);
+    result->tm_gmtoff = (int)apr_time_sec(localtime) 
+                      - (int)apr_time_sec(input);
+
+    /* To compute the dst flag, we compare the expected 
+     * local (standard) timezone bias to the delta.
+     * [Note, in war time or double daylight time the
+     * resulting tm_isdst is, desireably, 2 hours]
+     */
+    result->tm_isdst = (result->tm_gmtoff / 3600)
+                     - (-(tz->Bias + tz->StandardBias) / 60);
+
     return APR_SUCCESS;
 }
 
@@ -268,10 +286,10 @@ APR_DECLARE(apr_status_t) apr_os_exp_time_put(apr_time_exp_t *aprtime,
                                               apr_os_exp_time_t **ostime,
                                               apr_pool_t *cont)
 {
-    /* XXX: sanity failure, what is system time, gmt or local ?
-     *      Assume local for this moment.
+    /* The Platform SDK documents that SYSTEMTIME/FILETIME are
+     * generally UTC, so no timezone info needed
      */
-    SystemTimeToAprExpTime(aprtime, *ostime, 1);
+    SystemTimeToAprExpTime(aprtime, *ostime);
     return APR_SUCCESS;
 }
 
diff --git a/time/win32/timestr.c b/time/win32/timestr.c
index 513418357..6c93c6290 100644
--- a/time/win32/timestr.c
+++ b/time/win32/timestr.c
@@ -159,7 +159,8 @@ APR_DECLARE(apr_status_t) apr_ctime(char *date_str, apr_time_t t)
 #ifndef _WIN32_WCE
 
 int win32_strftime_extra(char *s, size_t max, const char *format,
-                         const struct tm *tm) {
+                         const struct tm *tm) 
+{
    /* If the new format string is bigger than max, the result string won't fit
     * anyway. If format strings are added, made sure the padding below is
     * enough */
@@ -192,6 +193,11 @@ int win32_strftime_extra(char *s, size_t max, const char *format,
                 i += 2;
                 j += 11;
                 break;
+            case 'R':
+                memcpy(new_format + j, "%H:%M", 5);
+                i += 2;
+                j += 5;
+                break;
             case 'T':
                 memcpy(new_format + j, "%H:%M:%S", 8);
                 i += 2;