Struct SnapshotManager 

pub struct SnapshotManager { /* private fields */ }

Write/read handle of the snapshot caches, obtained via Engine::snapshot.

Feed adapters (message channels) call upsert / remove when data arrives; the scheduler reads the same store at each task prepare. upsert auto-registers the target with default options when it does not exist yet, so a feed never drops data on an unregistered name — register explicitly first when a non-default policy or scope keys are needed. remove acts on an existing target only: a tombstone for a name the engine never registered is a wiring error, not a silent no-op.

Implementations

impl SnapshotManager

pub fn register(&self, name: &str, options: SnapshotOptions) -> Result<()>

Register a snapshot target with its options (replaces any existing registration of the same name — its cache is reset). Returns an error when the options are invalid (see SnapshotOptions::validate).

pub fn upsert( &self, name: &str, scope: &str, rev: u64, data: Vars, ) -> Result<()>

Feed a new value for name/scope. Auto-registers the target with SnapshotOptions::default when missing, so the write only fails when those options are rejected (see SnapshotOptions::validate). Revisions are monotonic per scope: a value whose rev is not newer than the cached one is ignored (a stale revision cannot roll the scope back).

pub fn remove(&self, name: &str, scope: &str) -> Result<()>

Remove the value of name/scope (tombstone). Fails when the target is not registered — there is nothing to tombstone, and a caller that believes it deleted a target should hear about the mismatch.

pub fn read(&self, name: &str, scope: &str) -> Option<SnapshotEntry>

Current value of name/scope, if any.

pub fn list(&self, name: &str) -> Vec<(String, SnapshotEntry)>

All current values of one snapshot target: (scope, entry) pairs.

Trait Implementations

impl Clone for SnapshotManager

fn clone(&self) -> SnapshotManager

Returns a duplicate of the value.

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

Performs copy-assignment from source.