Struct StateStore 

pub struct StateStore { /* private fields */ }

Thread-safe state store with transition logging.

All reads and writes go through this store. Every write produces a StateTransition record for audit and replay. Optionally backed by a JSONL journal file for durability across process restarts (see StateStore::durable).

Implementations

impl StateStore

pub fn new() -> StateStore

pub async fn lock_proposal_execution(&self) -> MutexGuard<'_, ()>

Shared proposal-transaction guard. Hold this across proposal execution, including rollback and replanning; actions inside the guarded proposal may still execute concurrently according to their DAG.

pub fn durable(path: impl Into<PathBuf>) -> Result<StateStore, Error>

Open a durable, JSONL-backed StateStore. If the file exists, its transitions are replayed (last-write-wins per key, with TTLs honored) to rebuild current state. Subsequent writes append to the same file.

Returns an error only on filesystem-level failures (parent directory missing, permission denied, etc.). Malformed lines inside the journal are skipped with a warning rather than failing the open — agent persistence shouldn’t refuse to start over a single bad line.

pub fn sync(&self) -> Result<(), Error>

Fsync the journal writer. Call after a batch of writes when you need durability guarantees beyond best-effort flush.

pub fn reap_expired(&self, now: DateTime<Utc>) -> Result<Vec<String>, Error>

Drop expired keys (per ttl_secs on their last write) and rewrite the journal as a compacted snapshot of the surviving state. Returns the keys that were reaped.

TTL semantics: a ttl_secs of 0 means “expired immediately” — the key is reapable on the next call. There is no “0 = forever” sentinel; use set (no TTL) for keys that should never auto-expire.

Latest-write-wins: a key rewritten WITHOUT a TTL after a TTL’d write is NOT reaped — the more recent write effectively cancels the TTL.

Single-pass over the transitions log via a key→latest index, so cost is O(n) in journal length (not O(n²)).

pub fn reap_expired_scoped( &self, now: DateTime<Utc>, tenant: Option<&str>, ) -> Result<Vec<String>, Error>

Reap only the expired keys in one tenant’s namespace (EPIC E / E3). tenant = Some(id) reaps tenant:<id>:*; tenant = None reaps only the unscoped namespace. This is the per-tenant counterpart to Self::reap_expired (which reaps across all tenants): it lets a per-tenant reaping budget expire one tenant’s TTL’d keys without touching another tenant’s — so one tenant’s memory pressure can’t evict another’s state.

pub fn get(&self, key: &str) -> Option<Value>

pub fn get_or(&self, key: &str, default: Value) -> Value

pub fn exists(&self, key: &str) -> bool

pub fn set(&self, key: &str, value: Value, action_id: &str) -> StateTransition

pub fn set_with_ttl( &self, key: &str, value: Value, action_id: &str, ttl_secs: u64, ) -> StateTransition

Set a key with a TTL (seconds from now). reap_expired drops the key once the deadline passes; re-setting the key without a TTL (set) cancels the TTL.

ttl_secs == 0 means “expire immediately” (reapable on the next reap_expired call). It is NOT a “no expiry” sentinel — use the plain set(...) method for keys that should never auto-expire. This differs from the Unix/Redis convention; the distinction matters because a TTL passed from untrusted input could otherwise silently mean “forever” when the caller intended “never store.”

pub fn set_batch( &self, entries: Vec<(String, Value)>, action_id: &str, ) -> Vec<StateTransition>

Apply several writes as ONE atomic mutation boundary (Parslee-ai/car#1140). The state lock is held across every entry, so a concurrent reader observes the complete old state or the complete new state — never a prefix of the batch — and the journal receives the whole batch as a single line ([BatchTransitionRecord]), giving replay after an interrupted append the same old-or-complete guarantee.

Entries apply in the order given; a duplicated key’s later entry wins, each bumping the key’s version. An empty batch is a no-op. A single-entry batch behaves exactly like Self::set, journal line shape included.

pub fn version(&self, key: &str) -> Option<u64>

Current version of key (number of writes/deletes applied to it), or None if it was never written. Used by the transactional conflict checker to detect stale reads (survey §5.2.4).

pub fn versions(&self) -> HashMap<String, u64>

Snapshot of all key versions — the version map an action’s assumptions are checked against.

pub fn versioned_snapshot( &self, ) -> (HashMap<String, Value>, HashMap<String, u64>)

Atomic snapshot of both the current values and the current versions, taken under a single consistent lock acquisition (state then versions, matching the write path) so the two maps can’t tear — a caller never sees a value from version N+1 paired with version N (neo review N2). This is the pair the transactional conflict checker (car_verify::check_transaction) should consume.

pub fn delete(&self, key: &str, action_id: &str) -> Option<StateTransition>

pub fn snapshot(&self) -> HashMap<String, Value>

Deep clone of current state.

pub fn restore( &self, snapshot: HashMap<String, Value>, transition_count: usize, ) -> Result<RestoreDurability, Error>

Restore state from a snapshot, truncating transitions. For durable stores the restored snapshot replaces the JSONL journal before the in-memory state is published; failures leave the current state intact.

pub fn snapshot_scoped(&self, tenant: Option<&str>) -> HashMap<String, Value>

Snapshot only the keys belonging to one tenant’s namespace (Parslee-ai/car#187 / EPIC E task E2). tenant = Some(id) captures tenant:<id>:*; tenant = None captures the unscoped (non-tenant:) namespace. Keys are returned in their full (prefixed) form so the result round-trips through Self::restore_scoped. This is the per-tenant counterpart to Self::snapshot, which captures all tenants and so can’t be used for a tenant-isolated rollback.

pub fn restore_scoped( &self, tenant: Option<&str>, snapshot: HashMap<String, Value>, transition_count: usize, ) -> Result<RestoreDurability, Error>

Restore a single tenant’s namespace from a scoped snapshot, leaving every other tenant’s keys untouched (EPIC E / E2). Existing keys in the target namespace are dropped and replaced by snapshot; keys outside it are preserved. Fixes the cross-tenant clobber where a rollback via the unscoped Self::restore wiped concurrent tenants’ state.

The transition log is FILTERED, not truncated (linus review C-5): only this tenant’s post-snapshot transitions are discarded. Truncating shared history dropped transitions concurrent tenants committed after transition_count, which both falsified the audit trail and let reap_expired* treat another tenant’s stale TTL’d transition as latest — deleting a live key. transition_count is the log length captured when this tenant’s snapshot was taken.

pub fn transition_count(&self) -> usize

pub fn transitions(&self) -> Vec<StateTransition>

pub fn transitions_since(&self, index: usize) -> Vec<StateTransition>

pub fn keys(&self) -> Vec<String>

pub fn replace_all(&self, snapshot: HashMap<String, Value>)

Replace the entire state map without recording transitions. Used by checkpoint restore to avoid synthetic transition history. Also clears the transitions log so callers of transitions_since() don’t see stale history from the discarded state.

pub fn scoped<'a>(&'a self, tenant: Option<&'a str>) -> ScopedStateView<'a>

Build a tenant-scoped view over this store (Parslee-ai/car#187 phase 3 enforcement).

All reads / writes go through tenant:<tenant_id>:<key> so distinct tenants can’t see each other’s keys. tenant = None returns a view that hits the unscoped (legacy) namespace — callers that don’t yet have a RuntimeScope get pre-#187 behaviour automatically.

Cheap to construct; holds a &self borrow plus the tenant string. The view’s methods take the parking-lot lock the same way the unscoped methods do.

Trait Implementations

impl Default for StateStore

fn default() -> StateStore

Returns the “default value” for a type.

impl StateView for StateStore

fn get_value(&self, key: &str) -> Option<Value>

Get a value by key. Returns None if the key doesn’t exist.

fn key_exists(&self, key: &str) -> bool

Check if a key exists in state.

fn is_unknown(&self, _key: &str) -> bool

Whether a key’s value is unknown (symbolic analysis only). Returns false by default — runtime state is always known.