Crate grafos_fence 

Typed epoch/fencing helpers for stale-write rejection and leader fencing.

This crate provides lightweight primitives for tracking monotonic epochs and rejecting operations that carry a stale generation number. No I/O, no_std compatible.

Core types

Type	Purpose
FenceEpoch	Monotonic epoch counter
Fenced<T>	A value tagged with the epoch it was produced in
FenceGuard	Stateful checker that rejects stale epochs
StaleEpochError	Error returned when an epoch is behind the current one

Quick start

use grafos_fence::{FenceEpoch, Fenced, FenceGuard};

let mut guard = FenceGuard::new(FenceEpoch::zero());

// First write at epoch 0 — accepted
let msg = Fenced::at_zero("hello");
assert!(guard.check(msg.epoch()).is_ok());

// Leader failover bumps the epoch
let new_epoch = guard.advance();

// Old-epoch write is now rejected
assert!(guard.check(msg.epoch()).is_err());

// New-epoch write succeeds
let msg2 = Fenced::new(new_epoch, "world");
assert!(guard.check(msg2.epoch()).is_ok());

Structs

FenceEpoch

A monotonic epoch counter used for fencing stale operations.

FenceGuard

A stateful epoch checker that rejects operations with stale epochs.

Fenced

A value tagged with the epoch in which it was produced.

StaleEpochError

Error returned when an incoming epoch is behind the expected epoch.

Functions

bump_epoch

Free function: returns an epoch one greater than old.