52 lines
1.5 KiB
Rust
52 lines
1.5 KiB
Rust
use std::error::Error as StdError;
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use std::fmt;
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use crate::imap::mailbox_view::MailboxView;
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use crate::mail::user::User;
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#[derive(Debug)]
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pub enum Error {
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ForbiddenTransition,
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}
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impl fmt::Display for Error {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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write!(f, "Forbidden Transition")
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}
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}
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impl StdError for Error {}
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pub enum State {
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NotAuthenticated,
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Authenticated(User),
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Selected(User, MailboxView),
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// Examined is like Selected, but indicates that the mailbox is read-only
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Examined(User, MailboxView),
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Logout,
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}
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pub enum Transition {
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None,
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Authenticate(User),
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Examine(MailboxView),
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Select(MailboxView),
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Unselect,
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Logout,
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}
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// See RFC3501 section 3.
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// https://datatracker.ietf.org/doc/html/rfc3501#page-13
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impl State {
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pub fn apply(self, tr: Transition) -> Result<Self, Error> {
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match (self, tr) {
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(s, Transition::None) => Ok(s),
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(State::NotAuthenticated, Transition::Authenticate(u)) => Ok(State::Authenticated(u)),
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(State::Authenticated(u), Transition::Select(m)) => Ok(State::Selected(u, m)),
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(State::Authenticated(u), Transition::Examine(m)) => Ok(State::Examined(u, m)),
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(State::Selected(u, _), Transition::Unselect) => Ok(State::Authenticated(u)),
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(State::Examined(u, _), Transition::Unselect) => Ok(State::Authenticated(u)),
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(_, Transition::Logout) => Ok(State::Logout),
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_ => Err(Error::ForbiddenTransition),
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}
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}
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}
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