scalar unregister: stop FSMonitor daemon

Especially on Windows, we will need to stop that daemon, just in case
that the directory needs to be removed (the daemon would otherwise hold
a handle to that directory, preventing it from being deleted).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

contrib/scalar/scalar.c

@@ -269,6 +269,31 @@ static int start_fsmonitor_daemon(void)
 	return 0;
 }
 
+static int stop_fsmonitor_daemon(void)
+{
+#ifdef HAVE_FSMONITOR_DAEMON_BACKEND
+	struct strbuf err = STRBUF_INIT;
+	struct child_process cp = CHILD_PROCESS_INIT;
+
+	cp.git_cmd = 1;
+	strvec_pushl(&cp.args, "fsmonitor--daemon", "stop", NULL);
+	if (!pipe_command(&cp, NULL, 0, NULL, 0, &err, 0)) {
+		strbuf_release(&err);
+		return 0;
+	}
+
+	if (fsmonitor_ipc__get_state() == IPC_STATE__LISTENING) {
+		write_in_full(2, err.buf, err.len);
+		strbuf_release(&err);
+		return error(_("could not stop the FSMonitor daemon"));
+	}
+
+	strbuf_release(&err);
+#endif
+
+	return 0;
+}
+
 static int register_dir(void)
 {
 	int res = add_or_remove_enlistment(1);
@@ -295,6 +320,9 @@ static int unregister_dir(void)
 	if (add_or_remove_enlistment(0) < 0)
 		res = -1;
 
+	if (stop_fsmonitor_daemon() < 0)
+		res = -1;
+
 	return res;
 }