Struct cw_storage_plus::MultiIndex

pub struct MultiIndex<'a, K, T> { /* fields omitted */ }

MultiIndex stores (namespace, index_name, idx_value, pk) -> b“pk_len“. Allows many values per index, and references pk. The associated primary key value is stored in the main (pk_namespace) map, which stores (namespace, pk_namespace, pk) -> value.

The stored pk_len is used to recover the pk from the index namespace, and perform the secondary load of the associated value from the main map.

The MultiIndex definition must include a field for the pk. That is, the MultiIndex K value is always a n-tuple (n >= 2) and its last element must be the pk. The index function must therefore put the pk as last element, when generating the index.

Implementations

impl<'a, K, T> MultiIndex<'a, K, T> where
    T: Serialize + DeserializeOwned + Clone, 

pub fn new(
    idx_fn: fn(_: &T, _: Vec<u8>) -> K,
    pk_namespace: &'a str,
    idx_namespace: &'a str
) -> Self

impl<'a, K, T> MultiIndex<'a, K, T> where
    T: Serialize + DeserializeOwned + Clone,
    K: PrimaryKey<'a>, 

pub fn prefix(&self, p: K::Prefix) -> Prefix<T>

pub fn sub_prefix(&self, p: K::SubPrefix) -> Prefix<T>

pub fn index_key(&self, k: K) -> Vec<u8>

impl<'a, K, T> MultiIndex<'a, K, T> where
    T: Serialize + DeserializeOwned + Clone,
    K: PrimaryKey<'a>,
    K::SubPrefix: EmptyPrefix, 

pub fn range<'c>(
    &'c self,
    store: &'c dyn Storage,
    min: Option<Bound>,
    max: Option<Bound>,
    order: Order
) -> Box<dyn Iterator<Item = StdResult<Pair<T>>> + 'c> where
    T: 'c, 

pub fn keys<'c>(
    &'c self,
    store: &'c dyn Storage,
    min: Option<Bound>,
    max: Option<Bound>,
    order: Order
) -> Box<dyn Iterator<Item = Vec<u8>> + 'c>

Trait Implementations

impl<'a, K, T> Index<T> for MultiIndex<'a, K, T> where
    T: Serialize + DeserializeOwned + Clone,
    K: PrimaryKey<'a>, 

fn save(&self, store: &mut dyn Storage, pk: &[u8], data: &T) -> StdResult<()>

fn remove(
    &self,
    store: &mut dyn Storage,
    pk: &[u8],
    old_data: &T
) -> StdResult<()>