nimbus-eth2/beacon_chain/block_pools/spec_cache.nim

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# beacon_chain
# Copyright (c) 2018-2020 Status Research & Development GmbH
# Licensed and distributed under either of
# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
# at your option. This file may not be copied, modified, or distributed except according to those terms.
import
std/[algorithm, sequtils, sets],
../spec/[beaconstate, datatypes, presets, validator],
block_pools_types
# Spec functions implemented based on cached values instead of the full state
func count_active_validators*(epochInfo: EpochRef): uint64 =
epochInfo.shuffled_active_validator_indices.lenu64
func get_committee_count_per_slot*(epochInfo: EpochRef): uint64 =
get_committee_count_per_slot(count_active_validators(epochInfo))
func get_beacon_committee*(
epochRef: EpochRef, slot: Slot, index: CommitteeIndex): seq[ValidatorIndex] =
# Return the beacon committee at ``slot`` for ``index``.
let
committees_per_slot = get_committee_count_per_slot(epochRef)
compute_committee(
epochRef.shuffled_active_validator_indices,
(slot mod SLOTS_PER_EPOCH) * committees_per_slot +
index.uint64,
committees_per_slot * SLOTS_PER_EPOCH
)
# https://github.com/ethereum/eth2.0-specs/blob/v0.12.2/specs/phase0/beacon-chain.md#get_attesting_indices
func get_attesting_indices*(epochRef: EpochRef,
data: AttestationData,
bits: CommitteeValidatorsBits):
HashSet[ValidatorIndex] =
get_attesting_indices(
bits,
get_beacon_committee(epochRef, data.slot, data.index.CommitteeIndex))
# https://github.com/ethereum/eth2.0-specs/blob/v0.12.2/specs/phase0/beacon-chain.md#get_indexed_attestation
func get_indexed_attestation*(epochRef: EpochRef, attestation: Attestation): IndexedAttestation =
# Return the indexed attestation corresponding to ``attestation``.
let
attesting_indices =
get_attesting_indices(
epochRef, attestation.data, attestation.aggregation_bits)
IndexedAttestation(
attesting_indices:
List[uint64, Limit MAX_VALIDATORS_PER_COMMITTEE].init(
sorted(mapIt(attesting_indices, it.uint64), system.cmp)),
data: attestation.data,
signature: attestation.signature
)