Struct polkadot_primitives::v2::PersistedValidationData

pub struct PersistedValidationData<H = Hash, N = BlockNumber> {
    pub parent_head: HeadData,
    pub relay_parent_number: N,
    pub relay_parent_storage_root: H,
    pub max_pov_size: u32,
}

The validation data provides information about how to create the inputs for validation of a candidate. This information is derived from the chain state and will vary from para to para, although some fields may be the same for every para.

Since this data is used to form inputs to the validation function, it needs to be persisted by the availability system to avoid dependence on availability of the relay-chain state.

Furthermore, the validation data acts as a way to authorize the additional data the collator needs to pass to the validation function. For example, the validation function can check whether the incoming messages (e.g. downward messages) were actually sent by using the data provided in the validation data using so called MQC heads.

Since the commitments of the validation function are checked by the relay-chain, secondary checkers can rely on the invariant that the relay-chain only includes para-blocks for which these checks have already been done. As such, there is no need for the validation data used to inform validators and collators about the checks the relay-chain will perform to be persisted by the availability system.

The PersistedValidationData should be relatively lightweight primarily because it is constructed during inclusion for each candidate and therefore lies on the critical path of inclusion.

Fields

parent_head: HeadData

The parent head-data.

relay_parent_number: N

The relay-chain block number this is in the context of.

relay_parent_storage_root: H

The relay-chain block storage root this is in the context of.

max_pov_size: u32

The maximum legal size of a POV block, in bytes.

Implementations

impl<H: Encode, N: Encode> PersistedValidationData<H, N>

pub fn hash(&self) -> Hash

Compute the blake2-256 hash of the persisted validation data.

Trait Implementations

impl<H: Clone, N: Clone> Clone for PersistedValidationData<H, N>

fn clone(&self) -> PersistedValidationData<H, N>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<H, N> Debug for PersistedValidationData<H, N>where H: Debug, N: Debug,

fn fmt(&self, fmt: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<H, N> Decode for PersistedValidationData<H, N>where N: Decode, H: Decode,

fn decode<__CodecInputEdqy: Input>( __codec_input_edqy: &mut __CodecInputEdqy ) -> Result<Self, Error>

Attempt to deserialise the value from input.

fn skip<I>(input: &mut I) -> Result<(), Error>where I: Input,

Attempt to skip the encoded value from input.

fn encoded_fixed_size() -> Option<usize>

Returns the fixed encoded size of the type.

impl<H: Default, N: Default> Default for PersistedValidationData<H, N>

fn default() -> PersistedValidationData<H, N>

Returns the “default value” for a type.

impl<H, N> Encode for PersistedValidationData<H, N>where N: Encode, H: Encode,

fn encode_to<__CodecOutputEdqy: Output + ?Sized>( &self, __codec_dest_edqy: &mut __CodecOutputEdqy )

Convert self to a slice and append it to the destination.

fn size_hint(&self) -> usize

If possible give a hint of expected size of the encoding.

fn encode(&self) -> Vec<u8, Global>

Convert self to an owned vector.

fn using_encoded<R, F>(&self, f: F) -> Rwhere F: FnOnce(&[u8]) -> R,

Convert self to a slice and then invoke the given closure with it.

fn encoded_size(&self) -> usize

Calculates the encoded size.

impl<H: PartialEq, N: PartialEq> PartialEq<PersistedValidationData<H, N>> for PersistedValidationData<H, N>

fn eq(&self, other: &PersistedValidationData<H, N>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<H, N> TypeInfo for PersistedValidationData<H, N>where N: TypeInfo + 'static, H: TypeInfo + 'static,

type Identity = PersistedValidationData<H, N>

The type identifying for which type info is provided.

fn type_info() -> Type

Returns the static type identifier for Self.

impl<H, N> EncodeLike<PersistedValidationData<H, N>> for PersistedValidationData<H, N>where N: Encode, H: Encode,

impl<H: Eq, N: Eq> Eq for PersistedValidationData<H, N>

impl<H, N> StructuralEq for PersistedValidationData<H, N>

impl<H, N> StructuralPartialEq for PersistedValidationData<H, N>