Struct KeyedSnapshotHook 

pub struct KeyedSnapshotHook<K, V> { /* private fields */ }

A hook handle controlling a snapshot (or batch) operator over a keyed singleton with keys K and values V.

A decision for a keyed snapshot hook picks which buffered version of each key’s state the next tick execution observes. See hydro_lang::sim::hooks for the decisions offered.

Implementations

impl<K, V> KeyedSnapshotHook<K, V>

pub fn reveal( &self, entries: impl IntoIterator<Item = (K, V)>, ) -> DecisionFuture

where K: Serialize + DeserializeOwned + Hash + Eq, V: Serialize + DeserializeOwned,

Available on crate feature sim only.

Scripts the next tick execution to observe, for each named key, the buffered version equal to the named value: scans forward from that key’s currently-revealed version through the buffered ones and releases the first equal version, skipping over earlier versions. Keys that are not named observe their previously revealed version again (or stay absent if they have never been revealed).

This is a combined assertion and release, and the recommended way to script keyed snapshots: naming the state each key means makes any mis-synchronization fail loudly at the reveal.

Panics

Panics immediately if entries names the same key more than once: a key observes exactly one version per tick execution.

pub fn reveal_latest(&self) -> DecisionFuture

where K: Serialize + DeserializeOwned, V: Serialize + DeserializeOwned,

Available on crate feature sim only.

Scripts the next tick execution to observe, for every key, the newest version that has arrived by the time the tick fires (keys with nothing newer observe their previously revealed version again). Under fuzzing, which versions are newest co-varies with the schedule being explored; use Self::reveal to name them exactly.

pub fn keep(&self) -> DecisionFuture

where K: Serialize + DeserializeOwned, V: Serialize + DeserializeOwned,

Available on crate feature sim only.

Scripts the next tick execution to observe every key’s previously revealed version again.

pub fn pause(&self)

Available on crate feature sim only.

Declares that buffering at this operator is intended: while paused, the hook is exempt from the missing-decision error, never causes its tick to run, and — if its tick runs anyway because other hooks feed it — contributes its “nothing new” behavior each time. Scripting any decision implicitly resumes the hook.

A pause takes its place in the script like everything else: requested while a decision is still pending, the hold begins once that decision has been consumed.

pub fn resume(&self)

Available on crate feature sim only.

Ends a Self::pause (and clears Self::auto_pause mode).

pub fn auto_pause(&self)

Available on crate feature sim only.

Sets a standing mode where this hook only ever acts when scripted: it holds immediately, and every scripted decision leaves a fresh hold in place behind it.

This deliberately opts out of the forgotten-hook protection: if the test forgets a step, the operator silently holds its data instead of failing. The one auto_pause() line at the top of a test is the reviewer-visible marker that this hook’s timing is entirely script-driven, missed steps and all.

pub async fn pause_while<Fut: Future>(&self, body: Fut) -> Fut::Output

Available on crate feature sim only.

Pauses the hook exactly for the duration of body (resuming even on panic), so a bracketed buffering phase cannot leak a paused hook.

pub fn pause_until( &self, predicate: impl Fn(&KeyedSnapshotStatus) -> bool + Unpin, ) -> PauseUntilFuture<KeyedSnapshotStatus, impl Fn(&KeyedSnapshotStatus) -> bool + Unpin>

Available on crate feature sim only.

Pauses the hook and returns a future that resolves once the hook’s pending-input status satisfies predicate — a synchronization point for scripts where the right decision is not knowable upfront. The status is read on demand at every scheduling point. After the future resolves, the hook is unpaused; the ordinary missing-decision error applies from there on.

pub fn pause_until_versions( &self, n: usize, ) -> PauseUntilFuture<KeyedSnapshotStatus, impl Fn(&KeyedSnapshotStatus) -> bool + Unpin>

Available on crate feature sim only.

Pauses the hook and returns a future that resolves once at least n newer versions are buffered (in total, across all keys); see Self::pause_until.

Trait Implementations

impl<K, V> Clone for KeyedSnapshotHook<K, V>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<K, V> Copy for KeyedSnapshotHook<K, V>

impl<K, V> Debug for KeyedSnapshotHook<K, V>

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

Formats the value using the given formatter.

impl<K, V> SimHook for KeyedSnapshotHook<K, V>

where K: Hash + Eq + Clone + Serialize + DeserializeOwned, V: Clone + PartialEq + Serialize + DeserializeOwned,

fn create(next_id: &mut dyn FnMut() -> usize) -> Self

Creates every handle in this value, allocating fresh IDs via next_id.