ui-refs.c: avoid segfault on unparsed ref objects

When a ref refers to something other then a commit or tag object, cgit
could segfault when trying to display the tag info.

Noticed-by: Eugene Sajine <euguess@gmail.com>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>

1 files changed, 14 insertions, 12 deletions

diff --git a/ui-refs.c b/ui-refs.c
index d3b4f6e..6571cc4 100644
--- a/ui-refs.c
+++ b/ui-refs.c
@@ -21,65 +21,67 @@ static int cmp_age(int age1, int age2)
 		return 0;
 
 	if (age1 == 0)
 		return +1;
 
 	return -1;
 }
 
 static int cmp_ref_name(const void *a, const void *b)
 {
 	struct refinfo *r1 = *(struct refinfo **)a;
 	struct refinfo *r2 = *(struct refinfo **)b;
 
 	return strcmp(r1->refname, r2->refname);
 }
 
 static int cmp_branch_age(const void *a, const void *b)
 {
 	struct refinfo *r1 = *(struct refinfo **)a;
 	struct refinfo *r2 = *(struct refinfo **)b;
 
 	return cmp_age(r1->commit->committer_date, r2->commit->committer_date);
 }
 
+static int get_ref_age(struct refinfo *ref)
+{
+	if (!ref->object)
+		return 0;
+	switch (ref->object->type) {
+	case OBJ_TAG:
+		return ref->tag ? ref->tag->tagger_date : 0;
+	case OBJ_COMMIT:
+		return ref->commit ? ref->commit->committer_date : 0;
+	}
+	return 0;
+}
+
 static int cmp_tag_age(const void *a, const void *b)
 {
 	struct refinfo *r1 = *(struct refinfo **)a;
 	struct refinfo *r2 = *(struct refinfo **)b;
-	int r1date, r2date;
-
-	if (r1->object->type != OBJ_COMMIT)
-		r1date = r1->tag->tagger_date;
-	else
-		r1date = r1->commit->committer_date;
-
-	if (r2->object->type != OBJ_COMMIT)
-		r2date = r2->tag->tagger_date;
-	else
-		r2date = r2->commit->committer_date;
 
-	return cmp_age(r1date, r2date);
+	return cmp_age(get_ref_age(r1), get_ref_age(r2));
 }
 
 static int print_branch(struct refinfo *ref)
 {
 	struct commitinfo *info = ref->commit;
 	char *name = (char *)ref->refname;
 
 	if (!info)
 		return 1;
 	html("<tr><td>");
 	cgit_log_link(name, NULL, NULL, name, NULL, NULL, 0, NULL, NULL,
 		      ctx.qry.showmsg);
 	html("</td><td>");
 
 	if (ref->object->type == OBJ_COMMIT) {
 		cgit_commit_link(info->subject, NULL, NULL, name, NULL);
 		html("</td><td>");
 		html_txt(info->author);
 		html("</td><td colspan='2'>");
 		cgit_print_age(info->commit->date, -1, NULL);
 	} else {
 		html("</td><td></td><td>");
 		cgit_object_link(ref->object);
 	}