update-index: add fsmonitor support to update-index

Add support in update-index to manually add/remove the fsmonitor
extension via --[no-]fsmonitor flags.

Add support in update-index to manually set/clear the fsmonitor
valid bit via --[no-]fsmonitor-valid flags.

Signed-off-by: Ben Peart <benpeart@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/update-index.c

@@ -33,6 +33,7 @@ static int force_remove;
 static int verbose;
 static int mark_valid_only;
 static int mark_skip_worktree_only;
+static int mark_fsmonitor_only;
 #define MARK_FLAG 1
 #define UNMARK_FLAG 2
 static struct strbuf mtime_dir = STRBUF_INIT;
@@ -229,12 +230,12 @@ static int mark_ce_flags(const char *path, int flag, int mark)
 	int namelen = strlen(path);
 	int pos = cache_name_pos(path, namelen);
 	if (0 <= pos) {
+		mark_fsmonitor_invalid(&the_index, active_cache[pos]);
 		if (mark)
 			active_cache[pos]->ce_flags |= flag;
 		else
 			active_cache[pos]->ce_flags &= ~flag;
 		active_cache[pos]->ce_flags |= CE_UPDATE_IN_BASE;
-		mark_fsmonitor_invalid(&the_index, active_cache[pos]);
 		cache_tree_invalidate_path(&the_index, path);
 		active_cache_changed |= CE_ENTRY_CHANGED;
 		return 0;
@@ -460,6 +461,11 @@ static void update_one(const char *path)
 			die("Unable to mark file %s", path);
 		return;
 	}
+	if (mark_fsmonitor_only) {
+		if (mark_ce_flags(path, CE_FSMONITOR_VALID, mark_fsmonitor_only == MARK_FLAG))
+			die("Unable to mark file %s", path);
+		return;
+	}
 
 	if (force_remove) {
 		if (remove_file_from_cache(path))
@@ -918,6 +924,7 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 	int lock_error = 0;
 	int split_index = -1;
 	int force_write = 0;
+	int fsmonitor = -1;
 	struct lock_file *lock_file;
 	struct parse_opt_ctx_t ctx;
 	strbuf_getline_fn getline_fn;
@@ -1011,6 +1018,14 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 			    N_("enable untracked cache without testing the filesystem"), UC_FORCE),
 		OPT_SET_INT(0, "force-write-index", &force_write,
 			N_("write out the index even if is not flagged as changed"), 1),
+		OPT_BOOL(0, "fsmonitor", &fsmonitor,
+			N_("enable or disable file system monitor")),
+		{OPTION_SET_INT, 0, "fsmonitor-valid", &mark_fsmonitor_only, NULL,
+			N_("mark files as fsmonitor valid"),
+			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, MARK_FLAG},
+		{OPTION_SET_INT, 0, "no-fsmonitor-valid", &mark_fsmonitor_only, NULL,
+			N_("clear fsmonitor valid bit"),
+			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, UNMARK_FLAG},
 		OPT_END()
 	};
 
@@ -1152,6 +1167,22 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 		die("BUG: bad untracked_cache value: %d", untracked_cache);
 	}
 
+	if (fsmonitor > 0) {
+		if (git_config_get_fsmonitor() == 0)
+			warning(_("core.fsmonitor is unset; "
+				"set it if you really want to "
+				"enable fsmonitor"));
+		add_fsmonitor(&the_index);
+		report(_("fsmonitor enabled"));
+	} else if (!fsmonitor) {
+		if (git_config_get_fsmonitor() == 1)
+			warning(_("core.fsmonitor is set; "
+				"remove it if you really want to "
+				"disable fsmonitor"));
+		remove_fsmonitor(&the_index);
+		report(_("fsmonitor disabled"));
+	}
+
 	if (active_cache_changed || force_write) {
 		if (newfd < 0) {
 			if (refresh_args.flags & REFRESH_QUIET)