Trait StorageDoubleMapKeyProvider

pub trait StorageDoubleMapKeyProvider {
    type Hasher1: StorageHasher;
    type Key1: FullCodec + Send + Sync;
    type Hasher2: StorageHasher;
    type Key2: FullCodec + Send + Sync;
    type Value: 'static + FullCodec;

    const MAP_NAME: &'static str;

    // Provided method
    fn final_key(
        pallet_prefix: &str,
        key1: &Self::Key1,
        key2: &Self::Key2,
    ) -> StorageKey { ... }
}

Can be used to access the runtime storage key of a StorageDoubleMap.

Required Associated Constants

const MAP_NAME: &'static str

The name of the variable that holds the StorageDoubleMap.

Required Associated Types

type Hasher1: StorageHasher

The same as StorageDoubleMap::Hasher1.

type Key1: FullCodec + Send + Sync

The same as StorageDoubleMap::Key1.

type Hasher2: StorageHasher

The same as StorageDoubleMap::Hasher2.

type Key2: FullCodec + Send + Sync

The same as StorageDoubleMap::Key2.

type Value: 'static + FullCodec

The same as StorageDoubleMap::Value.

Provided Methods

fn final_key( pallet_prefix: &str, key1: &Self::Key1, key2: &Self::Key2, ) -> StorageKey

This is a copy of the frame_support::storage::generator::StorageDoubleMap::storage_double_map_final_key.

We’re using it because to call storage_double_map_final_key directly, we need access to the runtime and pallet instance, which (sometimes) is impossible.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl StorageDoubleMapKeyProvider for ImportedParaHeadsKeyProvider

impl<AccountId, Reward, RewardBalance> StorageDoubleMapKeyProvider for RelayerRewardsKeyProvider<AccountId, Reward, RewardBalance>

where AccountId: 'static + Codec + EncodeLike + Send + Sync, Reward: Codec + EncodeLike + Send + Sync, RewardBalance: 'static + Codec + EncodeLike + Send + Sync,