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use std::error::Error as StdError;
use std::fmt;
use std::sync::Arc;
use tokio::sync::Notify;
use imap_codec::imap_types::core::Tag;
use crate::imap::mailbox_view::MailboxView;
use crate::mail::user::User;
#[derive(Debug)]
pub enum Error {
ForbiddenTransition,
}
impl fmt::Display for Error {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "Forbidden Transition")
}
}
impl StdError for Error {}
pub enum State {
NotAuthenticated,
Authenticated(Arc<User>),
Selected(Arc<User>, MailboxView, MailboxPerm),
Idle(Arc<User>, MailboxView, MailboxPerm, Tag<'static>, Arc<Notify>),
Logout,
}
impl fmt::Display for State {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
use State::*;
match self {
NotAuthenticated => write!(f, "NotAuthenticated"),
Authenticated(..) => write!(f, "Authenticated"),
Selected(..) => write!(f, "Selected"),
Idle(..) => write!(f, "Idle"),
Logout => write!(f, "Logout"),
}
}
}
#[derive(Clone)]
pub enum MailboxPerm {
ReadOnly,
ReadWrite,
}
pub enum Transition {
None,
Authenticate(Arc<User>),
Select(MailboxView, MailboxPerm),
Idle(Tag<'static>, Notify),
UnIdle,
Unselect,
Logout,
}
impl fmt::Display for Transition {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
use Transition::*;
match self {
None => write!(f, "None"),
Authenticate(..) => write!(f, "Authenticated"),
Select(..) => write!(f, "Selected"),
Idle(..) => write!(f, "Idle"),
UnIdle => write!(f, "UnIdle"),
Unselect => write!(f, "Unselect"),
Logout => write!(f, "Logout"),
}
}
}
// See RFC3501 section 3.
// https://datatracker.ietf.org/doc/html/rfc3501#page-13
impl State {
pub fn apply(&mut self, tr: Transition) -> Result<(), Error> {
tracing::debug!(state=%self, transition=%tr, "try change state");
let new_state = match (std::mem::replace(self, State::Logout), tr) {
(s, Transition::None) => s,
(State::NotAuthenticated, Transition::Authenticate(u)) => State::Authenticated(u),
(
State::Authenticated(u) | State::Selected(u, _, _),
Transition::Select(m, p),
) => State::Selected(u, m, p),
(State::Selected(u, _, _) , Transition::Unselect) => {
State::Authenticated(u.clone())
}
(State::Selected(u, m, p), Transition::Idle(t, s)) => {
State::Idle(u, m, p, t, Arc::new(s))
},
(State::Idle(u, m, p, _, _), Transition::UnIdle) => {
State::Selected(u, m, p)
},
(_, Transition::Logout) => State::Logout,
(s, t) => {
tracing::error!(state=%s, transition=%t, "forbidden transition");
return Err(Error::ForbiddenTransition)
}
};
*self = new_state;
tracing::debug!(state=%self, "transition succeeded");
Ok(())
}
}
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