introduce global variable

src/global/global.rs

@@ -0,0 +1,11 @@
+use std::sync::Mutex;
+use lazy_static::lazy_static;
+
+lazy_static! {
+    pub static ref DIR_PATH: Mutex<Option<String>> = Mutex::new(None);
+}
+
+pub fn set_dir_path(path: String) {
+    let mut directory_path = DIR_PATH.lock().unwrap();
+    *directory_path = Some(path);
+}