Struct Ring 

pub struct Ring<T> { /* private fields */ }

Fixed-capacity append-only ring for process-local mirrors. capacity == 0 means “disabled” (stores nothing, hands each item straight back), the correct default when a durable store is authoritative.

Clone produces a snapshot with its OWN independent SizeGauge, seeded to the current length. push is public, so a clone can be appended to; giving the clone a fresh gauge guarantees that writing through a snapshot (for example the public append on a receipt_log() snapshot) can never corrupt the owning structure’s telemetry gauge.

Implementations

impl<T> Ring<T>

pub fn with_capacity(capacity: usize, gauge: SizeGauge) -> Self

pub fn push(&mut self, item: T) -> Option<T>

Push, evicting the oldest entry when at capacity. Returns the evicted item (if any) so callers may act before it drops. Never grows past capacity.

pub fn iter(&self) -> impl Iterator<Item = &T>

pub fn len(&self) -> usize

pub fn is_empty(&self) -> bool

pub fn capacity(&self) -> usize

Trait Implementations

impl<T: Clone> Clone for Ring<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for Ring<T>

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

Formats the value using the given formatter.