update-index: use enum for untracked cache options

Helped-by: Duy Nguyen <pclouds@gmail.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/update-index.c

@@ -35,6 +35,14 @@ static int mark_skip_worktree_only;
 #define UNMARK_FLAG 2
 static struct strbuf mtime_dir = STRBUF_INIT;
 
+/* Untracked cache mode */
+enum uc_mode {
+	UC_UNSPECIFIED = -1,
+	UC_DISABLE = 0,
+	UC_ENABLE,
+	UC_FORCE
+};
+
 __attribute__((format (printf, 1, 2)))
 static void report(const char *fmt, ...)
 {
@@ -902,7 +910,7 @@ static int reupdate_callback(struct parse_opt_ctx_t *ctx,
 int cmd_update_index(int argc, const char **argv, const char *prefix)
 {
 	int newfd, entries, has_errors = 0, line_termination = '\n';
-	int untracked_cache = -1;
+	enum uc_mode untracked_cache = UC_UNSPECIFIED;
 	int read_from_stdin = 0;
 	int prefix_length = prefix ? strlen(prefix) : 0;
 	int preferred_index_format = 0;
@@ -997,7 +1005,7 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 		OPT_BOOL(0, "untracked-cache", &untracked_cache,
 			N_("enable/disable untracked cache")),
 		OPT_SET_INT(0, "force-untracked-cache", &untracked_cache,
-			    N_("enable untracked cache without testing the filesystem"), 2),
+			    N_("enable untracked cache without testing the filesystem"), UC_FORCE),
 		OPT_END()
 	};
 
@@ -1104,10 +1112,10 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 		the_index.split_index = NULL;
 		the_index.cache_changed |= SOMETHING_CHANGED;
 	}
-	if (untracked_cache > 0) {
+	if (untracked_cache > UC_DISABLE) {
 		struct untracked_cache *uc;
 
-		if (untracked_cache < 2) {
+		if (untracked_cache < UC_FORCE) {
 			setup_work_tree();
 			if (!test_if_untracked_cache_is_supported())
 				return 1;
@@ -1122,7 +1130,7 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 		}
 		add_untracked_ident(the_index.untracked);
 		the_index.cache_changed |= UNTRACKED_CHANGED;
-	} else if (!untracked_cache && the_index.untracked) {
+	} else if (untracked_cache == UC_DISABLE && the_index.untracked) {
 		free_untracked_cache(the_index.untracked);
 		the_index.untracked = NULL;
 		the_index.cache_changed |= UNTRACKED_CHANGED;