refs: break out check for reflog autocreation

This is just for clarity.

Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

refs.c

@@ -3053,6 +3053,16 @@ static int copy_msg(char *buf, const char *msg)
 	return cp - buf;
 }
 
+static int should_autocreate_reflog(const char *refname)
+{
+	if (!log_all_ref_updates)
+		return 0;
+	return starts_with(refname, "refs/heads/") ||
+		starts_with(refname, "refs/remotes/") ||
+		starts_with(refname, "refs/notes/") ||
+		!strcmp(refname, "HEAD");
+}
+
 /* This function will fill in *err and return -1 on failure */
 int log_ref_setup(const char *refname, struct strbuf *sb_logfile, struct strbuf *err)
 {
@@ -3063,11 +3073,7 @@ int log_ref_setup(const char *refname, struct strbuf *sb_logfile, struct strbuf
 	logfile = sb_logfile->buf;
 	/* make sure the rest of the function can't change "logfile" */
 	sb_logfile = NULL;
-	if (log_all_ref_updates &&
-	    (starts_with(refname, "refs/heads/") ||
-	     starts_with(refname, "refs/remotes/") ||
-	     starts_with(refname, "refs/notes/") ||
-	     !strcmp(refname, "HEAD"))) {
+	if (should_autocreate_reflog(refname)) {
 		if (safe_create_leading_directories(logfile) < 0) {
 			strbuf_addf(err, "unable to create directory for %s: "
 				    "%s", logfile, strerror(errno));