parse_date_format(): convert a format name to an enum date_mode

Factor out the code to parse --date=<format> parameter to revision
walkers into a separate function, parse_date_format().  This function
is passed a string and converts it to an enum date_format:

 - "relative"         => DATE_RELATIVE
 - "iso8601" or "iso" => DATE_ISO8601
 - "rfc2822"          => DATE_RFC2822
 - "short"            => DATE_SHORT
 - "local"            => DATE_LOCAL
 - "default"          => DATE_NORMAL

In the event that none of these strings is found, the function die()s.

Signed-off-by: Andy Parkins <andyparkins@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/date.c b/date.c
index 93bef6efbe..8f70500270 100644
--- a/date.c
+++ b/date.c
@@ -584,6 +584,26 @@ int parse_date(const char *date, char *result, int maxlen)
 	return date_string(then, offset, result, maxlen);
 }
 
+enum date_mode parse_date_format(const char *format)
+{
+	if (!strcmp(format, "relative"))
+		return DATE_RELATIVE;
+	else if (!strcmp(format, "iso8601") ||
+		 !strcmp(format, "iso"))
+		return DATE_ISO8601;
+	else if (!strcmp(format, "rfc2822") ||
+		 !strcmp(format, "rfc"))
+		return DATE_RFC2822;
+	else if (!strcmp(format, "short"))
+		return DATE_SHORT;
+	else if (!strcmp(format, "local"))
+		return DATE_LOCAL;
+	else if (!strcmp(format, "default"))
+		return DATE_NORMAL;
+	else
+		die("unknown date format %s", format);
+}
+
 void datestamp(char *buf, int bufsize)
 {
 	time_t now;