Struct Immutable 

pub struct Immutable<E: RStorage + Clock + Metrics, K: Array, V: VariableValue, H: CHasher, T: Translator, M: MerkleizationState<DigestOf<H>> + Send + Sync = Merkleized<H>, D: DurabilityState = Durable> { /* private fields */ }

An authenticated database that only supports adding new keyed values (no updates or deletions), where values can have varying sizes.

Implementations

impl<E: RStorage + Clock + Metrics, K: Array, V: VariableValue, H: CHasher, T: Translator, M: MerkleizationState<DigestOf<H>> + Send + Sync, D: DurabilityState> Immutable<E, K, V, H, T, M, D>

pub fn oldest_retained_loc(&self) -> Location

Return the oldest location that remains retrievable.

pub async fn get(&self, key: &K) -> Result<Option<V>, Error>

Get the value of key in the db, or None if it has no value or its corresponding operation has been pruned.

pub fn op_count(&self) -> Location

Get the number of operations that have been applied to this db, including those that are not yet committed.

pub async fn get_metadata(&self) -> Result<Option<V>, Error>

Get the metadata associated with the last commit.

impl<E: RStorage + Clock + Metrics, K: Array, V: VariableValue, H: CHasher, T: Translator, D: DurabilityState> Immutable<E, K, V, H, T, Merkleized<H>, D>

pub const fn root(&self) -> H::Digest

Return the root of the db.

pub async fn proof( &self, start_index: Location, max_ops: NonZeroU64, ) -> Result<(Proof<H::Digest>, Vec<Operation<K, V>>), Error>

Generate and return:

1. a proof of all operations applied to the db in the range starting at (and including) location start_loc, and ending at the first of either:
   • the last operation performed, or
   • the operation max_ops from the start.
2. the operations corresponding to the leaves in this range.

pub async fn historical_proof( &self, op_count: Location, start_loc: Location, max_ops: NonZeroU64, ) -> Result<(Proof<H::Digest>, Vec<Operation<K, V>>), Error>

Analogous to proof but with respect to the state of the database when it had op_count operations.

Errors

Returns crate::mmr::Error::LocationOverflow if op_count or start_loc > crate::mmr::MAX_LOCATION. Returns crate::mmr::Error::RangeOutOfBounds if op_count > number of operations, or if start_loc >= op_count. Returns Error::OperationPruned if start_loc has been pruned.

pub async fn prune(&mut self, loc: Location) -> Result<(), Error>

Prune historical operations prior to prune_loc. This does not affect the db’s root or current snapshot.

Errors

• Returns Error::PruneBeyondMinRequired if prune_loc > inactivity floor.
• Returns crate::mmr::Error::LocationOverflow if prune_loc > crate::mmr::MAX_LOCATION.

impl<E: RStorage + Clock + Metrics, K: Array, V: VariableValue, H: CHasher, T: Translator> Immutable<E, K, V, H, T, Merkleized<H>, Durable>

pub async fn init( context: E, cfg: Config<T, <Operation<K, V> as Read>::Cfg>, ) -> Result<Self, Error>

Returns an Immutable qmdb initialized from cfg. Any uncommitted log operations will be discarded and the state of the db will be as of the last committed operation.

pub async fn init_synced( context: E, cfg: Config<E, K, V, T, H::Digest, <Operation<K, V> as Read>::Cfg>, ) -> Result<Self, Error>

Returns an Immutable built from the config and sync data in cfg.

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

Sync all database state to disk. While this isn’t necessary to ensure durability of committed operations, periodic invocation may reduce memory usage and the time required to recover the database on restart.

pub async fn destroy(self) -> Result<(), Error>

Destroy the db, removing all data from disk.

pub fn into_mutable(self) -> Immutable<E, K, V, H, T, Unmerkleized, NonDurable>

Convert this database into a mutable state for batched updates.

impl<E: RStorage + Clock + Metrics, K: Array, V: VariableValue, H: CHasher, T: Translator> Immutable<E, K, V, H, T, Unmerkleized, Durable>

pub fn into_mutable(self) -> Immutable<E, K, V, H, T, Unmerkleized, NonDurable>

Convert this database into a mutable state for batched updates.

pub fn into_merkleized(self) -> Immutable<E, K, V, H, T, Merkleized<H>, Durable>

Convert to merkleized state.

impl<E: RStorage + Clock + Metrics, K: Array, V: VariableValue, H: CHasher, T: Translator> Immutable<E, K, V, H, T, Merkleized<H>, NonDurable>

pub fn into_mutable(self) -> Immutable<E, K, V, H, T, Unmerkleized, NonDurable>

Convert this database into a mutable state for batched updates.

impl<E: RStorage + Clock + Metrics, K: Array, V: VariableValue, H: CHasher, T: Translator> Immutable<E, K, V, H, T, Unmerkleized, NonDurable>

pub async fn set(&mut self, key: K, value: V) -> Result<(), Error>

Sets key to have value value, assuming key hasn’t already been assigned. The operation is reflected in the snapshot, but will be subject to rollback until the next successful commit. Attempting to set an already-set key results in undefined behavior.

Any keys that have been pruned and map to the same translated key will be dropped during this call.

pub async fn commit( self, metadata: Option<V>, ) -> Result<(Immutable<E, K, V, H, T, Unmerkleized, Durable>, Range<Location>), Error>

Commit any pending operations to the database, ensuring their durability upon return from this function. Caller can associate an arbitrary metadata value with the commit. Returns the committed database and the range of committed locations. Note that even if no operations were added since the last commit, this is a root-state changing operation.

pub fn into_merkleized( self, ) -> Immutable<E, K, V, H, T, Merkleized<H>, NonDurable>

Convert to merkleized state without committing (for read-only merkle operations).

Trait Implementations

impl<E: RStorage + Clock + Metrics, K: Array, V: VariableValue, H: CHasher, T: Translator, M: MerkleizationState<DigestOf<H>> + Send + Sync, D: DurabilityState> Gettable for Immutable<E, K, V, H, T, M, D>

type Key = K

type Value = V

type Error = Error

async fn get(&self, key: &Self::Key) -> Result<Option<Self::Value>, Self::Error>

Get the value of a key.

impl<E: RStorage + Clock + Metrics, K: Array, V: VariableValue, H: CHasher, T: Translator, M: MerkleizationState<DigestOf<H>> + Send + Sync, D: DurabilityState> LogStore for Immutable<E, K, V, H, T, M, D>

type Value = V

fn op_count(&self) -> Location

The number of operations that have been applied to this db, including those that have been pruned and those that are not yet committed.

fn inactivity_floor_loc(&self) -> Location

Return the inactivity floor location. This is the location before which all operations are known to be inactive. Operations before this point can be safely pruned.

fn is_empty(&self) -> bool

Returns true if there are no active keys in the database.

async fn get_metadata(&self) -> Result<Option<V>, Error>

Get the metadata associated with the last commit.

impl<E: RStorage + Clock + Metrics, K: Array, V: VariableValue, H: CHasher, T: Translator, D: DurabilityState> MerkleizedStore for Immutable<E, K, V, H, T, Merkleized<H>, D>

type Digest = <H as Hasher>::Digest

The digest type used for authentication.

type Operation = Operation<K, V>

The operation type stored in the log.

fn root(&self) -> Self::Digest

Returns the root digest of the authenticated store.

async fn historical_proof( &self, historical_size: Location, start_loc: Location, max_ops: NonZeroU64, ) -> Result<(Proof<Self::Digest>, Vec<Self::Operation>), Error>

Generate and return:

fn proof( &self, start_loc: Location, max_ops: NonZeroU64, ) -> impl Future<Output = Result<(Proof<Self::Digest>, Vec<Self::Operation>), Error>> + Send

Generate and return:

impl<E: RStorage + Clock + Metrics, K: Array, V: VariableValue, H: CHasher, T: Translator, D: DurabilityState> PrunableStore for Immutable<E, K, V, H, T, Merkleized<H>, D>

async fn prune(&mut self, prune_loc: Location) -> Result<(), Error>

Prune historical operations prior to loc.