[PATCH] Fix AUTHOR_DATE timezone confusion

This switches git-commit-tree to using curl_getdate() for the
AUTHOR_DATE, and thus fixes the problem with "mktime()" parsing dates in
the local timezone.  It also ends up being more permissive about the
format of the date. 

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Makefile

@@ -91,6 +91,7 @@ git-diff-tree-helper: diff-tree-helper.c
 git-tar-tree: tar-tree.c
 
 git-http-pull: LIBS += -lcurl
+git-commit-tree: LIBS += -lcurl
 
 # Library objects..
 blob.o: $(LIB_H)

commit-tree.c

@@ -10,6 +10,7 @@
 #include <string.h>
 #include <ctype.h>
 #include <time.h>
+#include <curl/curl.h>
 
 #define BLOCKING (1ul << 14)
 
@@ -80,146 +81,22 @@ static void remove_special(char *p)
 	}
 }
 
-static const char *month_names[] = {
-        "Jan", "Feb", "Mar", "Apr", "May", "Jun",
-        "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
-};
-
-static const char *weekday_names[] = {
-        "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
-};
-
-
-static char *skipfws(char *str)
-{
-	while (isspace(*str))
-		str++;
-	return str;
-}
-
-	
 /* Gr. strptime is crap for this; it doesn't have a way to require RFC2822
    (i.e. English) day/month names, and it doesn't work correctly with %z. */
-static void parse_rfc2822_date(char *date, char *result, int maxlen)
+static void parse_date(char *date, time_t *now, char *result, int maxlen)
 {
-	struct tm tm;
 	char *p;
-	int i, offset;
 	time_t then;
 
-	memset(&tm, 0, sizeof(tm));
-
-	/* Skip day-name */
-	p = skipfws(date);
-	if (!isdigit(*p)) {
-		for (i=0; i<7; i++) {
-			if (!strncmp(p,weekday_names[i],3) && p[3] == ',') {
-				p = skipfws(p+4);
-				goto day;
-			}
-		}
-		return;
-	}					
-
-	/* day */
- day:
-	tm.tm_mday = strtoul(p, &p, 10);
-
-	if (tm.tm_mday < 1 || tm.tm_mday > 31)
-		return;
-
-	if (!isspace(*p))
-		return;
-
-	p = skipfws(p);
-
-	/* month */
-
-	for (i=0; i<12; i++) {
-		if (!strncmp(p, month_names[i], 3) && isspace(p[3])) {
-			tm.tm_mon = i;
-			p = skipfws(p+strlen(month_names[i]));
-			goto year;
-		}
-	}
-	return; /* Error -- bad month */
-
-	/* year */
- year:	
-	tm.tm_year = strtoul(p, &p, 10);
-
-	if (!tm.tm_year && !isspace(*p))
-		return;
-
-	if (tm.tm_year > 1900)
-		tm.tm_year -= 1900;
-		
-	p=skipfws(p);
-
-	/* hour */
-	if (!isdigit(*p))
-		return;
-	tm.tm_hour = strtoul(p, &p, 10);
-	
-	if (!tm.tm_hour > 23)
-		return;
-
-	if (*p != ':')
-		return; /* Error -- bad time */
-	p++;
-
-	/* minute */
-	if (!isdigit(*p))
-		return;
-	tm.tm_min = strtoul(p, &p, 10);
-	
-	if (!tm.tm_min > 59)
+	if ((then = curl_getdate(date, now)) == 0)
 		return;
 
-	if (isspace(*p))
-		goto zone;
-
-	if (*p != ':')
-		return; /* Error -- bad time */
-	p++;
-
-	/* second */
-	if (!isdigit(*p))
-		return;
-	tm.tm_sec = strtoul(p, &p, 10);
-	
-	if (!tm.tm_sec > 59)
-		return;
-
-	if (!isspace(*p))
-		return;
-
- zone:
-	p = skipfws(p);
-
-	if (*p == '-')
-		offset = -60;
-	else if (*p == '+')
-		offset = 60;
-	else
-	       return;
-
-	if (!isdigit(p[1]) || !isdigit(p[2]) || !isdigit(p[3]) || !isdigit(p[4]))
-		return;
-
-	i = strtoul(p+1, NULL, 10);
-	offset *= ((i % 100) + ((i / 100) * 60));
-
-	if (*(skipfws(p + 5)))
-		return;
-
-	then = mktime(&tm); /* mktime appears to ignore the GMT offset, stupidly */
-	if (then == -1)
-		return;
-
-	then -= offset;
-
-	snprintf(result, maxlen, "%lu %5.5s", then, p);
+	/* find the timezone at the end */
+	p = date + strlen(date);
+	while (p > date && isdigit(*--p))
+		;
+	if ((*p == '+' || *p == '-') && strlen(p) == 5)
+		snprintf(result, maxlen, "%lu %5.5s", then, p);
 }
 
 static void check_valid(unsigned char *sha1, const char *expect)
@@ -298,7 +175,7 @@ int main(int argc, char **argv)
 	email = getenv("AUTHOR_EMAIL") ? : realemail;
 	audate = getenv("AUTHOR_DATE");
 	if (audate)
-		parse_rfc2822_date(audate, date, sizeof(date));
+		parse_date(audate, &now, date, sizeof(date));
 
 	remove_special(gecos); remove_special(realgecos); remove_special(commitgecos);
 	remove_special(email); remove_special(realemail); remove_special(commitemail);