tag: move layout into page function

This also allows us to return proper HTTP error codes when something
goes wrong.

Signed-off-by: John Keeping <john@keeping.me.uk>

cmd.c

@@ -171,7 +171,7 @@ struct cgit_cmd *cgit_get_cmd(void)
 		def_cmd(snapshot, 1, 0, 0, 0),
 		def_cmd(stats, 1, 0, 1, 0),
 		def_cmd(summary, 1, 0, 0, 0),
-		def_cmd(tag, 1, 1, 0, 0),
+		def_cmd(tag, 1, 0, 0, 0),
 		def_cmd(tree, 1, 1, 1, 0),
 	};
 	int i;

ui-tag.c

@@ -52,20 +52,24 @@ void cgit_print_tag(char *revname)
 
 	strbuf_addf(&fullref, "refs/tags/%s", revname);
 	if (get_sha1(fullref.buf, sha1)) {
-		cgit_print_error("Bad tag reference: %s", revname);
+		cgit_print_error_page(404, "Not found",
+			"Bad tag reference: %s", revname);
 		goto cleanup;
 	}
 	obj = parse_object(sha1);
 	if (!obj) {
-		cgit_print_error("Bad object id: %s", sha1_to_hex(sha1));
+		cgit_print_error_page(500, "Internal server error",
+			"Bad object id: %s", sha1_to_hex(sha1));
 		goto cleanup;
 	}
 	if (obj->type == OBJ_TAG) {
 		tag = lookup_tag(sha1);
 		if (!tag || parse_tag(tag) || !(info = cgit_parse_tag(tag))) {
-			cgit_print_error("Bad tag object: %s", revname);
+			cgit_print_error_page(500, "Internal server error",
+				"Bad tag object: %s", revname);
 			goto cleanup;
 		}
+		cgit_print_layout_start();
 		html("<table class='commit-info'>\n");
 		htmlf("<tr><td>tag name</td><td>");
 		html_txt(revname);
@@ -93,7 +97,9 @@ void cgit_print_tag(char *revname)
 			print_download_links(revname);
 		html("</table>\n");
 		print_tag_content(info->msg);
+		cgit_print_layout_end();
 	} else {
+		cgit_print_layout_start();
 		html("<table class='commit-info'>\n");
 		htmlf("<tr><td>tag name</td><td>");
 		html_txt(revname);
@@ -104,6 +110,7 @@ void cgit_print_tag(char *revname)
 		if (ctx.repo->snapshots)
 			print_download_links(revname);
 		html("</table>\n");
+		cgit_print_layout_end();
 	}
 
 cleanup: