date parsing: be friendlier to our European friends.

This does three things, only applies to cases where the user
manually tries to override the author/commit time by environment
variables, with non-ISO, non-2822 format date-string:

 - Refuses to use the interpretation to put the date in the
   future; recent kernel history has a commit made with
   10/03/2006 which is recorded as October 3rd.

 - Adds '.' as the possible year-month-date separator.  We
   learned from our European friends on the #git channel that
   dd.mm.yyyy is the norm there.

 - When the separator is '.', we prefer dd.mm.yyyy over
   mm.dd.yyyy; otherwise mm/dd/yy[yy] takes precedence over
   dd/mm/yy[yy].

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/date.c b/date.c
index 376d25d..034d722 100644 (file)
--- a/date.c
+++ b/date.c
@@ -197,26 +197,43 @@ static int match_alpha(const char *date, struct tm *tm, int *offset)
        return skip_alpha(date);
 }
 
-static int is_date(int year, int month, int day, struct tm *tm)
+static int is_date(int year, int month, int day, struct tm *now_tm, time_t now, struct tm *tm)
 {
        if (month > 0 && month < 13 && day > 0 && day < 32) {
+               struct tm check = *tm;
+               struct tm *r = (now_tm ? &check : tm);
+               time_t specified;
+
+               r->tm_mon = month - 1;
+               r->tm_mday = day;
                if (year == -1) {
-                       tm->tm_mon = month-1;
-                       tm->tm_mday = day;
-                       return 1;
+                       if (!now_tm)
+                               return 1;
+                       r->tm_year = now_tm->tm_year;
                }
-               if (year >= 1970 && year < 2100) {
-                       year -= 1900;
-               } else if (year > 70 && year < 100) {
-                       /* ok */
-               } else if (year < 38) {
-                       year += 100;
-               } else
+               else if (year >= 1970 && year < 2100)
+                       r->tm_year = year - 1900;
+               else if (year > 70 && year < 100)
+                       r->tm_year = year;
+               else if (year < 38)
+                       r->tm_year = year + 100;
+               else
                        return 0;
+               if (!now_tm)
+                       return 1;
+
+               specified = my_mktime(r);
 
-               tm->tm_mon = month-1;
-               tm->tm_mday = day;
-               tm->tm_year = year;
+               /* Be it commit time or author time, it does not make
+                * sense to specify timestamp way into the future.  Make
+                * sure it is not later than ten days from now...
+                */
+               if (now + 10*24*3600 < specified)
+                       return 0;
+               tm->tm_mon = r->tm_mon;
+               tm->tm_mday = r->tm_mday;
+               if (year != -1)
+                       tm->tm_year = r->tm_year;
                return 1;
        }
        return 0;
@@ -224,6 +241,9 @@ static int is_date(int year, int month, int day, struct tm *tm)
 
 static int match_multi_number(unsigned long num, char c, const char *date, char *end, struct tm *tm)
 {
+       time_t now;
+       struct tm now_tm;
+       struct tm *refuse_future;
        long num2, num3;
 
        num2 = strtol(end+1, &end, 10);
@@ -246,19 +266,33 @@ static int match_multi_number(unsigned long num, char c, const char *date, char
 
        case '-':
        case '/':
+       case '.':
+               now = time(NULL);
+               refuse_future = NULL;
+               if (gmtime_r(&now, &now_tm))
+                       refuse_future = &now_tm;
+
                if (num > 70) {
                        /* yyyy-mm-dd? */
-                       if (is_date(num, num2, num3, tm))
+                       if (is_date(num, num2, num3, refuse_future, now, tm))
                                break;
                        /* yyyy-dd-mm? */
-                       if (is_date(num, num3, num2, tm))
+                       if (is_date(num, num3, num2, refuse_future, now, tm))
                                break;
                }
-               /* mm/dd/yy ? */
-               if (is_date(num3, num, num2, tm))
+               /* Our eastern European friends say dd.mm.yy[yy]
+                * is the norm there, so giving precedence to
+                * mm/dd/yy[yy] form only when separator is not '.'
+                */
+               if (c != '.' &&
+                   is_date(num3, num, num2, refuse_future, now, tm))
+                       break;
+               /* European dd.mm.yy[yy] or funny US dd/mm/yy[yy] */
+               if (is_date(num3, num2, num, refuse_future, now, tm))
                        break;
-               /* dd/mm/yy ? */
-               if (is_date(num3, num2, num, tm))
+               /* Funny European mm.dd.yy */
+               if (c == '.' &&
+                   is_date(num3, num, num2, refuse_future, now, tm))
                        break;
                return 0;
        }
@@ -288,10 +322,11 @@ static int match_digit(const char *date, struct tm *tm, int *offset, int *tm_gmt
        }
 
        /*
-        * Check for special formats: num[:-/]num[same]num
+        * Check for special formats: num[-.:/]num[same]num
         */
        switch (*end) {
        case ':':
+       case '.':
        case '/':
        case '-':
                if (isdigit(end[1])) {