Struct mz_persist_client::internal::watch::StateWatch

pub struct StateWatch<K, V, T, D> {
    metrics: Arc<Metrics>,
    state: Arc<LockingTypedState<K, V, T, D>>,
    seqno_high_water: SeqNo,
    rx: Receiver<SeqNo>,
}

A reactive subscription to changes in LockingTypedState.

Invariants:

• The state.seqno only advances (never regresses). This is guaranteed by LockingTypedState.
• seqno_high_water is always <= state.seqno.
• If seqno_high_water is < state.seqno, then we’ll get a notification on rx. This is maintained by notifying new seqnos under the same lock which adds them.
• seqno_high_water always holds the highest value received in the channel This is maintained by wait_for_seqno_gt taking an exclusive reference to self.

Fields

metrics: Arc<Metrics>

state: Arc<LockingTypedState<K, V, T, D>>

seqno_high_water: SeqNo

rx: Receiver<SeqNo>

Implementations

impl<K, V, T, D> StateWatch<K, V, T, D>

pub(crate) fn new( state: Arc<LockingTypedState<K, V, T, D>>, metrics: Arc<Metrics>, ) -> Self

pub async fn wait_for_seqno_ge(&mut self, requested: SeqNo) -> &mut Self

Blocks until the State has a SeqNo >= the requested one.

This method is cancel-safe.

Trait Implementations

impl<K: Debug, V: Debug, T: Debug, D: Debug> Debug for StateWatch<K, V, T, D>

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

Formats the value using the given formatter.