Struct Immutable 

pub struct Immutable<E: RStorage + Clock + Metrics, K: Array, V: Codec, H: CHasher, T: Translator> { /* private fields */ }

An authenticatable key-value database based on an MMR that does not allow updates or deletions of previously set keys.

Implementations

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

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

Returns an Immutable adb 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, <Variable<K, V> as Read>::Cfg>, ) -> Result<Self, Error>

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

pub fn oldest_retained_loc(&self) -> Option<u64>

Return the oldest location that remains retrievable.

pub async fn prune(&mut self, loc: u64) -> Result<(), Error>

Prunes the db of up to all operations that have location less than loc. The actual number pruned may be fewer than requested due to blob boundaries.

Panics

Panics if loc is beyond the last commit point.

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 async fn get_loc(&self, loc: u64) -> Result<Option<V>, Error>

Get the value of the operation with location loc in the db. Returns Error::OperationPruned if loc precedes the oldest retained location. The location is otherwise assumed valid.

pub async fn get_from_loc(&self, key: &K, loc: u64) -> Result<Option<V>, Error>

Get the value of the operation with location loc in the db if it matches key. Returns Error::OperationPruned if loc precedes the oldest retained location. The location is otherwise assumed valid.

pub fn op_count(&self) -> u64

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

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 fn root(&self, hasher: &mut Standard<H>) -> H::Digest

Return the root of the db.

Warning

Panics if there are uncommitted operations.

pub async fn proof( &self, start_index: u64, max_ops: NonZeroU64, ) -> Result<(Proof<H::Digest>, Vec<Variable<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.

Warning

Panics if there are uncommitted operations.

pub async fn historical_proof( &self, size: u64, start_loc: u64, max_ops: NonZeroU64, ) -> Result<(Proof<H::Digest>, Vec<Variable<K, V>>), Error>

Analogous to proof but with respect to the state of the MMR when it had size elements.

pub async fn commit(&mut self, metadata: Option<V>) -> Result<(), 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.

Failures after commit (but before sync or close) may still require reprocessing to recover the database on restart.

pub async fn get_metadata(&self) -> Result<Option<(u64, Option<V>)>, Error>

Get the location and metadata associated with the last commit, or None if no commit has been made.

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

Close the db. Operations that have not been committed will be lost.

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

Destroy the db, removing all data from disk.