Struct trie_db::Lookup

pub struct Lookup<'a, 'cache, L: TrieLayout, Q: Query<L::Hash>> {
    pub db: &'a dyn HashDBRef<L::Hash, DBValue>,
    pub query: Q,
    pub hash: TrieHash<L>,
    pub cache: Option<&'cache mut dyn TrieCache<L::Codec>>,
    pub recorder: Option<&'cache mut dyn TrieRecorder<TrieHash<L>>>,
}

Trie lookup helper object.

Fields

db: &'a dyn HashDBRef<L::Hash, DBValue>

database to query from.

query: Q

Query object to record nodes and transform data.

hash: TrieHash<L>

Hash to start at

cache: Option<&'cache mut dyn TrieCache<L::Codec>>

Optional cache that should be used to speed up the lookup.

recorder: Option<&'cache mut dyn TrieRecorder<TrieHash<L>>>

Optional recorder that will be called to record all trie accesses.

Implementations

impl<'a, 'cache, L, Q> Lookup<'a, 'cache, L, Q>where L: TrieLayout, Q: Query<L::Hash>,

pub fn lookup_first_descendant( self, full_key: &[u8], nibble_key: NibbleSlice<'_> ) -> Result<Option<MerkleValue<TrieHash<L>>>, TrieHash<L>, CError<L>>

Look up the merkle value (hash) of the node that is the closest descendant for the provided key.

When the provided key leads to a node, then the merkle value (hash) of that node is returned. However, if the key does not lead to a node, then the merkle value of the closest descendant is returned. None if no such descendant exists.

pub fn look_up( self, full_key: &[u8], nibble_key: NibbleSlice<'_> ) -> Result<Option<Q::Item>, TrieHash<L>, CError<L>>

Look up the given nibble_key.

If the value is found, it will be passed to the given function to decode or copy.

The given full_key should be the full key to the data that is requested. This will be used when there is a cache to potentially speed up the lookup.

pub fn look_up_hash( self, full_key: &[u8], nibble_key: NibbleSlice<'_> ) -> Result<Option<TrieHash<L>>, TrieHash<L>, CError<L>>

Look up the value hash for the given nibble_key.

The given full_key should be the full key to the data that is requested. This will be used when there is a cache to potentially speed up the lookup.