lighthouse/eth2/state_processing/src/per_epoch_processing/inclusion_distance.rs
2019-03-17 17:47:12 +11:00

57 lines
1.8 KiB
Rust

use super::errors::InclusionError;
use super::get_attestation_participants::get_attestation_participants;
use types::*;
/// Returns the distance between the first included attestation for some validator and this
/// slot.
///
/// Spec v0.5.0
pub fn inclusion_distance(
state: &BeaconState,
attestations: &[&PendingAttestation],
validator_index: usize,
spec: &ChainSpec,
) -> Result<u64, InclusionError> {
let attestation = earliest_included_attestation(state, attestations, validator_index, spec)?;
Ok((attestation.inclusion_slot - attestation.data.slot).as_u64())
}
/// Returns the slot of the earliest included attestation for some validator.
///
/// Spec v0.5.0
pub fn inclusion_slot(
state: &BeaconState,
attestations: &[&PendingAttestation],
validator_index: usize,
spec: &ChainSpec,
) -> Result<Slot, InclusionError> {
let attestation = earliest_included_attestation(state, attestations, validator_index, spec)?;
Ok(attestation.inclusion_slot)
}
/// Finds the earliest included attestation for some validator.
///
/// Spec v0.5.0
fn earliest_included_attestation(
state: &BeaconState,
attestations: &[&PendingAttestation],
validator_index: usize,
spec: &ChainSpec,
) -> Result<PendingAttestation, InclusionError> {
let mut included_attestations = vec![];
for (i, a) in attestations.iter().enumerate() {
let participants =
get_attestation_participants(state, &a.data, &a.aggregation_bitfield, spec)?;
if participants.iter().any(|i| *i == validator_index) {
included_attestations.push(i);
}
}
let earliest_attestation_index = included_attestations
.iter()
.min_by_key(|i| attestations[**i].inclusion_slot)
.ok_or_else(|| InclusionError::NoAttestationsForValidator)?;
Ok(attestations[*earliest_attestation_index].clone())
}