use std::time::Duration; use db::kvp::KEY_VALUE_STORE;use gpui::{AnyWindowHandle, ModelContext, Subscription, Task, WindowId};use util::ResultExt;use uuid::Uuid; pub struct Session {    session_id: String,    old_session_id: Option<String>,    old_window_ids: Option<Vec<WindowId>>,} const SESSION_ID_KEY: &str = "session_id";const SESSION_WINDOW_STACK_KEY: &str = "session_window_stack"; impl Session {    pub async fn new() -> Self {        let old_session_id = KEY_VALUE_STORE.read_kvp(SESSION_ID_KEY).ok().flatten();         let session_id = Uuid::new_v4().to_string();         KEY_VALUE_STORE            .write_kvp(SESSION_ID_KEY.to_string(), session_id.clone())            .await            .log_err();         let old_window_ids = KEY_VALUE_STORE            .read_kvp(SESSION_WINDOW_STACK_KEY)            .ok()            .flatten()            .and_then(|json| serde_json::from_str::<Vec<u64>>(&json).ok())            .map(|vec| {                vec.into_iter()                    .map(WindowId::from)                    .collect::<Vec<WindowId>>()            });         Self {            session_id,            old_session_id,            old_window_ids,        }    }     #[cfg(any(test, feature = "test-support"))]    pub fn test() -> Self {        Self {            session_id: Uuid::new_v4().to_string(),            old_session_id: None,            old_window_ids: None,        }    }     pub fn id(&self) -> &str {        &self.session_id    }} pub struct AppSession {    session: Session,    _serialization_task: Option<Task<()>>,    _subscriptions: Vec<Subscription>,} impl AppSession {    pub fn new(session: Session, cx: &mut ModelContext<Self>) -> Self {        let _subscriptions = vec![cx.on_app_quit(Self::app_will_quit)];         let _serialization_task = Some(cx.spawn(|_, cx| async move {            loop {                if let Some(windows) = cx.update(|cx| cx.window_stack()).ok().flatten() {                    store_window_stack(windows).await;                }                 cx.background_executor()                    .timer(Duration::from_millis(100))                    .await;            }        }));         Self {            session,            _subscriptions,            _serialization_task,        }    }     fn app_will_quit(&mut self, cx: &mut ModelContext<Self>) -> Task<()> {        if let Some(windows) = cx.window_stack() {            cx.background_executor().spawn(store_window_stack(windows))        } else {            Task::ready(())        }    }     pub fn id(&self) -> &str {        self.session.id()    }     pub fn last_session_id(&self) -> Option<&str> {        self.session.old_session_id.as_deref()    }     pub fn last_session_window_stack(&self) -> Option<Vec<WindowId>> {        self.session.old_window_ids.clone()    }} async fn store_window_stack(windows: Vec<AnyWindowHandle>) {    let window_ids = windows        .into_iter()        .map(|window| window.window_id().as_u64())        .collect::<Vec<_>>();     if let Ok(window_ids_json) = serde_json::to_string(&window_ids) {        KEY_VALUE_STORE            .write_kvp(SESSION_WINDOW_STACK_KEY.to_string(), window_ids_json)            .await            .log_err();    }}