Struct InMemoryStore 

pub struct InMemoryStore { /* private fields */ }

Single-node in-memory store: atomic counters behind a short transaction mutex that serializes check-and-spend so multi-key spends stay atomic.

Implementations

impl InMemoryStore

pub fn new() -> Self

Create an empty store.

Trait Implementations

impl Debug for InMemoryStore

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

Formats the value using the given formatter.

impl Default for InMemoryStore

fn default() -> InMemoryStore

Returns the “default value” for a type.

impl StateStore for InMemoryStore

fn refund(&self, key: &str, amount: u64)

Round-33 F1: saturating refund. saturating_sub on i64 keeps the value non-negative even under concurrent remove_prefix or a duplicate refund; the transaction lock keeps the load/store pair atomic with respect to other spend / add operations on the same key.

Round-34 F1: NEVER resurrect a cell that a concurrent remove_prefix already dropped. The prior implementation used self.cell(key) which materialises a fresh 0 AtomicI64 in the DashMap via entry().or_insert_with(...). Under the round-33 lost-claim-plus-idle-close ordering (mcp_call’s sandbox-gate debit races with the reconciler’s clear_budget_state), the refund path would create a permanent 0-cell for a sealed session that no future remove_prefix would ever collect — attacker-driven memory growth. Skip the refund silently when the cell is gone; the “budget spent” state is already whatever the caller wanted (probably 0) and there’s nothing to compensate.

fn add(&self, key: &str, delta: u64) -> Result<u64, StateError>

Add delta to key, returning the new value.

fn get(&self, key: &str) -> Result<u64, StateError>

Read the current value of key (0 if absent).

fn try_spend( &self, key: &str, amount: u64, limit: u64, ) -> Result<bool, StateError>

Atomically spend amount from the remaining budget limit - spent(key). Returns Ok(true) and records the spend if the full amount fits, Ok(false) (recording nothing) otherwise.

fn try_spend_many(&self, spends: &[Spend]) -> Result<Option<usize>, StateError>

Atomically validate and commit every spend, or commit none. Returns the index of the first dimension that would exceed its limit.

fn remove(&self, key: &str)

Remove a key (session cleanup).

fn remove_prefix(&self, prefix: &str)

Remove every key beginning with prefix (whole-session cleanup at finalization). Backends with native expiry (e.g. Redis TTLs) may leave this as the default no-op; in-process backends must implement it or session-keyed counters accumulate for the process lifetime.