Struct OverlayStorage 

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

Thread-safe overlay storage that wraps a base storage. All writes go to an in-memory HashMap overlay. Reads check overlay first, then fall through to base. Deletes are tracked as tombstones in the overlay.

This is useful for transaction profiling where we need to read from the database but not persist any mutations.

Implementations

impl<K, V> OverlayStorage<K, V>

where K: Clone + Eq + Hash + Send + Sync + 'static, V: Clone + Send + Sync + 'static,

pub fn new(base: Box<dyn Storage<K, V>>) -> Self

Create a new overlay wrapping the given base storage

impl<K, V> OverlayStorage<K, V>

where K: Serialize + for<'de> Deserialize<'de> + Clone + Eq + Hash + Send + Sync + 'static, V: Serialize + for<'de> Deserialize<'de> + Clone + Send + Sync + 'static,

pub fn wrap(base: Box<dyn Storage<K, V>>) -> Box<dyn Storage<K, V>>

Create a boxed overlay from a base storage. This is a convenience method for wrapping storage fields.

Trait Implementations

impl<K, V> Storage<K, V> for OverlayStorage<K, V>

where K: Serialize + for<'de> Deserialize<'de> + Clone + Eq + Hash + Send + Sync + 'static, V: Serialize + for<'de> Deserialize<'de> + Clone + Send + Sync + 'static,

fn store(&mut self, key: K, value: V) -> StorageResult<()>

fn get(&self, key: &K) -> StorageResult<Option<V>>

fn take(&mut self, key: &K) -> StorageResult<Option<V>>

fn clear(&mut self) -> StorageResult<()>

fn keys(&self) -> StorageResult<Vec<K>>

fn into_iter(&self) -> StorageResult<Box<dyn Iterator<Item = (K, V)> + '_>>

fn count(&self) -> StorageResult<u64>

Returns the number of entries in the storage.

fn shutdown(&self)

Explicitly shutdown the storage, performing any cleanup like WAL checkpoint. This should be called before the application exits to ensure data is persisted. Default implementation does nothing.

fn clone_box(&self) -> Box<dyn Storage<K, V>>

fn contains_key(&self, key: &K) -> StorageResult<bool>