Struct SubscribeAnnouncesStateMachine 

pub struct SubscribeAnnouncesStateMachine {
    state: SubscribeAnnouncesState,
}

State machine for the SUBSCRIBE_ANNOUNCES flow (draft-08). Idle → Pending → Active → Done.

Fields

state: SubscribeAnnouncesState

Implementations

impl SubscribeAnnouncesStateMachine

pub fn new() -> Self

Creates a new machine in SubscribeAnnouncesState::Idle.

pub fn state(&self) -> SubscribeAnnouncesState

Returns the current state.

pub fn on_subscribe_announces_sent(&mut self) -> Result<(), NamespaceError>

Idle → Pending.

pub fn on_subscribe_announces_ok(&mut self) -> Result<(), NamespaceError>

Pending → Active.

pub fn on_subscribe_announces_error(&mut self) -> Result<(), NamespaceError>

Pending → Done.

pub fn on_unsubscribe_announces(&mut self) -> Result<(), NamespaceError>

Active → Done (UNSUBSCRIBE_ANNOUNCES sent).

pub fn on_subscribe_announces_received(&mut self) -> Result<(), NamespaceError>

Idle → Pending (a SUBSCRIBE_ANNOUNCES arrived from the peer).

The mirror of on_subscribe_announces_sent, named for the direction it runs in rather than shared with it: the two state edges coincide, so a message dispatched to the wrong one of them would move the record silently instead of naming the event it was not.

pub fn on_subscribe_announces_ok_sent(&mut self) -> Result<(), NamespaceError>

Pending → Active (this endpoint accepted the peer’s request with a SUBSCRIBE_ANNOUNCES_OK).

Section 4.1: “A publisher MUST send exactly one SUBSCRIBE_ANNOUNCES_OK or SUBSCRIBE_ANNOUNCES_ERROR in response to a SUBSCRIBE_ANNOUNCES.”

One answer and no second one: the record leaves Pending on the first, and a second call finds it somewhere else.

pub fn on_subscribe_announces_error_sent( &mut self, ) -> Result<(), NamespaceError>

Pending → Done (this endpoint refused the peer’s request with a SUBSCRIBE_ANNOUNCES_ERROR).

The other half of the same sentence: one message back, and this is the other one it can be.

pub fn on_unsubscribe_announces_received( &mut self, ) -> Result<(), NamespaceError>

Active → Done (the peer withdrew the namespace subscription with an UNSUBSCRIBE_ANNOUNCES).

Section 7.14: “A subscriber issues a UNSUBSCRIBE_ANNOUNCES message to a publisher indicating it is no longer interested in ANNOUNCE and UNANNOUNCE messages for the specified track namespace prefix.”

Active is the acceptance, which is the state a namespace subscription reaches by being answered SUBSCRIBE_ANNOUNCES_OK and no other way, so a withdrawal of one never answered is refused here.

Trait Implementations

impl Default for SubscribeAnnouncesStateMachine

fn default() -> Self

Returns the “default value” for a type.