Trait hash_db::HashDB [−][src]
Trait modelling datastore keyed by a hash defined by the Hasher
.
Required methods
fn get(&self, key: &H::Out, prefix: Prefix<'_>) -> Option<T>
[src]
Look up a given hash into the bytes that hash to it, returning None if the hash is not known.
fn contains(&self, key: &H::Out, prefix: Prefix<'_>) -> bool
[src]
Check for the existance of a hash-key.
fn insert(&mut self, prefix: Prefix<'_>, value: &[u8]) -> H::Out
[src]
Insert a datum item into the DB and return the datum’s hash for a later lookup. Insertions
are counted and the equivalent number of remove()
s must be performed before the data
is considered dead.
fn emplace(&mut self, key: H::Out, prefix: Prefix<'_>, value: T)
[src]
Like insert()
, except you provide the key and the data is all moved.
fn remove(&mut self, key: &H::Out, prefix: Prefix<'_>)
[src]
Remove a datum previously inserted. Insertions can be “owed” such that the same number of
insert()
s may happen without the data being eventually being inserted into the DB.
It can be “owed” more than once.