Enum SessionState 

#[non_exhaustive]
pub enum SessionState {
    Greeting,
    Ehlo,
    Authentication,
    StartTls,
    MailFrom,
    RcptTo,
    Data,
    Quit,
    Closed,
}

The phases of an SMTP exchange tracked by the client.

This enum is non_exhaustive so that future SMTP extensions can add new phases without forcing a major version bump.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Greeting

Connection has been established but the server greeting has not yet been read.

Ehlo

The greeting has been received but EHLO has not yet been sent (or has not yet succeeded).

Authentication

EHLO has succeeded. Authentication may be performed, or skipped.

StartTls

STARTTLS has been issued and accepted (220 from server). The transport is being upgraded; on success the state moves to Ehlo to re-issue the greeting per RFC 3207 §4.2.

MailFrom

Ready to issue MAIL FROM for a new transaction.

RcptTo

MAIL FROM has been accepted; ready to issue RCPT TO.

Data

At least one RCPT TO has been accepted; ready to issue DATA.

Quit

QUIT has been sent; the next operation is to close the transport.

Closed

The session is finished, either cleanly or due to a fatal error. No further SMTP operations are permitted.

Implementations

impl SessionState

pub const fn is_terminal(self) -> bool

Return true if the session is over and no further SMTP operations are permitted.

pub const fn can_transition_to(self, next: Self) -> bool

Return true if next is a valid follow-on state from self.

This encodes the protocol’s ordering rules. The crate::client::SmtpClient consults this before performing any operation and returns an crate::error::InvalidInputError if the transition is not allowed.

Trait Implementations

impl Clone for SessionState

fn clone(&self) -> SessionState

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SessionState

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for SessionState

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for SessionState

fn eq(&self, other: &SessionState) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for SessionState

impl Eq for SessionState

impl StructuralPartialEq for SessionState