Struct GenerationFence 

pub struct GenerationFence { /* private fields */ }

Binds requests to a host generation. The epoch advances every time the host the lifecycle is bound to changes (first bind, replacement, exit). A Ticket issued under an older epoch can never complete: its reply is Stale, so a late reply from a previous host cannot answer a request made to the next one.

Transports that multiplex requests over one connection use it directly: issue when a request is written, admit_reply (or admit_reply_from when the reply carries the epoch it was read under) when its reply arrives.

Implementations

impl GenerationFence

pub fn new() -> Self

pub fn epoch(&self) -> u64

The current epoch (0 before any host was bound).

pub fn advance(&self) -> u64

A different host generation was bound (or the host left): every outstanding Ticket is now stale. Returns the new epoch.

pub fn issue(&self, bound_epoch: u64) -> Result<Ticket, Stale>

Issue a request under bound_epoch, the epoch the caller’s connection was bound to. Refused when that is no longer the current epoch.

pub fn admit_reply(&self, ticket: &Ticket) -> Result<(), Stale>

A reply arrived for ticket. Admitted only while the epoch it was issued under is still the current one.

pub fn admit_reply_from( &self, ticket: &Ticket, reply_epoch: u64, ) -> Result<(), Stale>

admit_reply for a reply that itself names the epoch of the connection it was read from: it must equal the ticket’s epoch as well.

Trait Implementations

impl Debug for GenerationFence

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

Formats the value using the given formatter.

impl Default for GenerationFence

fn default() -> Self

Returns the “default value” for a type.