Struct pallet_payment::NMapKey

pub struct NMapKey<Hasher, KeyType>(_);

A type used exclusively by storage maps as their key type.

The final key generated has the following form:

Hasher1(encode(key1))
    ++ Hasher2(encode(key2))
    ++ ...
    ++ HasherN(encode(keyN))

Trait Implementations

impl<H, K> KeyGenerator for Key<H, K>where
    H: StorageHasher,
    K: FullCodec + StaticTypeInfo,

type Key = K

type KArg = (K,)

type HashFn = Box<dyn FnOnce(&[u8]) -> Vec<u8, Global> + 'static, Global>

type HArg = (<Key<H, K> as KeyGenerator>::HashFn,)

const HASHER_METADATA: &'static [StorageHasher] = &[H::METADATA]

fn final_key<KArg>(key: KArg) -> Vec<u8, Global> where
    KArg: EncodeLikeTuple<<Key<H, K> as KeyGenerator>::KArg> + TupleToEncodedIter,

Given a key tuple, calculate the final key by encoding each element individually and hashing them using the corresponding hasher in the KeyGenerator.

fn migrate_key<KArg>(
    key: &KArg,
    hash_fns: <Key<H, K> as KeyGenerator>::HArg
) -> Vec<u8, Global> where
    KArg: EncodeLikeTuple<<Key<H, K> as KeyGenerator>::KArg> + TupleToEncodedIter,

Given a key tuple, migrate the keys from using the old hashers as given by hash_fns to using the newer hashers as specified by this KeyGenerator.

impl<H, K> KeyGeneratorMaxEncodedLen for Key<H, K>where
    H: StorageHasher,
    K: FullCodec + MaxEncodedLen + StaticTypeInfo,

fn key_max_encoded_len() -> usize

impl<H, K> ReversibleKeyGenerator for Key<H, K>where
    H: ReversibleStorageHasher,
    K: FullCodec + StaticTypeInfo,

type ReversibleHasher = H

fn decode_final_key(
    key_material: &[u8]
) -> Result<(<Key<H, K> as KeyGenerator>::Key, &[u8]), Error>