Struct MemoryStore 

pub struct MemoryStore { /* private fields */ }

A store with no file.

It keeps what redb keeps - one value per path, written as MessagePack - in a sorted map, and nothing outlives it: there is no buffer, no background thread and nothing to flush, so every commit has landed by the time it is asked for. What it refuses is what redb refuses, which is less than any other engine here, so a store that falls back to it keeps taking every write it took on disk.

The bookkeeping lives beside the values - the version each line stands at, the schemas recorded, the migration log, the format record, which namespaces were seeded - so a migration runs over it the way it runs over a file.

Implementations

impl MemoryStore

pub fn open( config: &StoreConfig, migrations: MigrationSet, ) -> StorageResult<(Self, MigrationReport)>

An empty store, under the limits and read settings config names, with migrations run over it. Nothing else in config applies: there is no file to reach or to save.

Trait Implementations

impl Clone for MemoryStore

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for MemoryStore

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

Formats the value using the given formatter.

impl StoreBackend for MemoryStore

fn get_raw(&self, path: &StorePath) -> StorageResult<Option<Vec<u8>>>

fn set_erased( &self, path: &StorePath, value: &dyn Serialize, by: Writer, ) -> StorageResult<()>

fn set_owned_erased( &self, path: StorePath, value: &dyn Serialize, by: Writer, ) -> StorageResult<()>

fn get_erased( &self, path: &StorePath, f: &mut dyn FnMut(&mut dyn Deserializer<'_>) -> StorageResult<()>, ) -> StorageResult<bool>

Runs f against a deserializer positioned at path, in the backend’s own format. Ok(false) means the key is absent and f never ran.

fn decode_erased( &self, bytes: &[u8], f: &mut dyn FnMut(&mut dyn Deserializer<'_>) -> StorageResult<()>, ) -> StorageResult<()>

Same, for bytes carried by a crate::StoreEvent.

fn delete_with_source( &self, path: &StorePath, source: Option<Uuid>, ) -> StorageResult<()>

fn delete(&self, path: &StorePath) -> StorageResult<()>

fn delete_prefix_with_source( &self, prefix: &StorePath, source: Option<Uuid>, ) -> StorageResult<()>

Removes every key under prefix, emitting one crate::StoreOp::DeletePrefix instead of a Delete per key.

fn scan_prefix( &self, prefix: &StorePath, ) -> StorageResult<Vec<(StorePath, Vec<u8>)>>

Every key under prefix, sorted by key on every backend.

fn scan_keys(&self, prefix: &StorePath) -> StorageResult<Vec<StorePath>>

The keys under prefix, sorted, without reading their values.

fn parallel_reads(&self) -> bool

Whether this store was asked to read large collections on more than one core - StoreConfig::parallel_reads.

fn files_layout(&self) -> Option<StoreLayout>

Where this store keeps what it keeps.

fn save_now(&self) -> StorageResult<()>

Writes everything buffered and says whether it landed.

fn close(&self) -> StorageResult<()>

Writes what is buffered, stops the background threads and lets go of the file.

fn is_closed(&self) -> bool

Whether StoreBackend::close has already run.

fn subscribe( &self, kind: SubscriptionKind, callback: StoreCallback, ) -> SubscriptionId

Registers callback for the changes kind names, under an id from SubscriptionId::next.

fn unsubscribe(&self, id: SubscriptionId) -> bool

Removes the subscription id names, and says whether this store held it. An id another store handed out is never held here.

fn flush_prefix(&self, _prefix: &StorePath) -> StorageResult<()>

Gets what is buffered under prefix onto disk.

fn flush_async(&self) -> Commit

Commits without blocking; the future resolves once a flush has landed.

fn is_initialized(&self, namespace: &StorePath) -> StorageResult<bool>

fn set_initialized( &self, namespace: &StorePath, state: InitState, ) -> StorageResult<()>

Records whether namespace has been seeded.

fn record_schema( &self, at: &StorePath, schema: &SchemaSnapshot, ) -> StorageResult<()>

Writes down the places a declaration claims, at the prefix it claims them under.

fn delete_prefix(&self, prefix: &StorePath) -> StorageResult<()>

fn visit_prefix( &self, prefix: &StorePath, visit: &mut dyn FnMut(PathRef<'_>, &[u8]) -> StorageResult<()>, ) -> StorageResult<()>

Hands every entry under prefix to visit, in the order a scan lists.

fn persist_health(&self) -> Option<Arc<PersistHealth>>

How this store’s background saving is faring, and who is listening.

fn save_async(&self) -> Commit

Writes everything buffered, as StoreBackend::save_now does, and resolves with how that write ended - without blocking the thread that awaits it.

fn close_async(&self) -> Commit

Closes the store, as StoreBackend::close does, and resolves with what the closing write did - without blocking the thread that awaits it.

fn mark_initialized(&self, namespace: &StorePath) -> StorageResult<()>