Trait bp_header_chain::ChainWithGrandpa

pub trait ChainWithGrandpa: Chain {
    const WITH_CHAIN_GRANDPA_PALLET_NAME: &'static str;
    const MAX_AUTHORITIES_COUNT: u32;
    const REASONABLE_HEADERS_IN_JUSTIFICATION_ANCESTRY: u32;
    const MAX_MANDATORY_HEADER_SIZE: u32;
    const AVERAGE_HEADER_SIZE: u32;
}

Substrate-based chain that is using direct GRANDPA finality.

Keep in mind that parachains are relying on relay chain GRANDPA, so they should not implement this trait.

Required Associated Constants

const WITH_CHAIN_GRANDPA_PALLET_NAME: &'static str

Name of the bridge GRANDPA pallet (used in construct_runtime macro call) that is deployed at some other chain to bridge with this ChainWithGrandpa.

We assume that all chains that are bridging with this ChainWithGrandpa are using the same name.

const MAX_AUTHORITIES_COUNT: u32

Max number of GRANDPA authorities at the chain.

This is a strict constant. If bridged chain will have more authorities than that, the GRANDPA bridge pallet may halt.

const REASONABLE_HEADERS_IN_JUSTIFICATION_ANCESTRY: u32

Max reasonable number of headers in votes_ancestries vector of the GRANDPA justification.

This isn’t a strict limit. The relay may submit justifications with more headers in its ancestry and the pallet will accept such justification. The limit is only used to compute maximal refund amount and submitting justifications which exceed the limit, may be costly to submitter.

const MAX_MANDATORY_HEADER_SIZE: u32

Maximal size of the mandatory chain header. Mandatory header is the header that enacts new GRANDPA authorities set (so it has large digest inside).

This isn’t a strict limit. The relay may submit larger headers and the pallet will accept the call. The limit is only used to compute maximal refund amount and doing calls which exceed the limit, may be costly to submitter.

const AVERAGE_HEADER_SIZE: u32

Average size of the chain header. We don’t expect to see there headers that change GRANDPA authorities set (GRANDPA will probably be able to finalize at least one additional header per session on non test chains), so this is average size of headers that aren’t changing the set.

This isn’t a strict limit. The relay may submit justifications with larger headers and the pallet will accept the call. However, if the total size of all submit_finality_proof arguments exceeds the maximal size, computed using this average size, relayer will only get partial refund.

We expect some headers on production chains that are above this size. But they are rare and if rellayer cares about its profitability, we expect it’ll select other headers for submission.

Object Safety

This trait is not object safe.

Implementors

impl<T> ChainWithGrandpa for T

where T: Chain + UnderlyingChainProvider, T::Chain: ChainWithGrandpa,

const WITH_CHAIN_GRANDPA_PALLET_NAME: &'static str = <T::Chain as ChainWithGrandpa>::WITH_CHAIN_GRANDPA_PALLET_NAME

const MAX_AUTHORITIES_COUNT: u32 = <T::Chain as ChainWithGrandpa>::MAX_AUTHORITIES_COUNT

const REASONABLE_HEADERS_IN_JUSTIFICATION_ANCESTRY: u32 = <T::Chain as ChainWithGrandpa>::REASONABLE_HEADERS_IN_JUSTIFICATION_ANCESTRY

const MAX_MANDATORY_HEADER_SIZE: u32 = <T::Chain as ChainWithGrandpa>::MAX_MANDATORY_HEADER_SIZE

const AVERAGE_HEADER_SIZE: u32 = <T::Chain as ChainWithGrandpa>::AVERAGE_HEADER_SIZE