mirror of
https://gitlab.com/pulsechaincom/prysm-pulse.git
synced 2024-12-25 12:57:18 +00:00
83 lines
2.8 KiB
Go
83 lines
2.8 KiB
Go
package helpers
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import (
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"github.com/pkg/errors"
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pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
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ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
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"github.com/prysmaticlabs/prysm/shared/bls"
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"github.com/prysmaticlabs/prysm/shared/params"
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)
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var (
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// ErrAttestationDataSlotNilState is returned when a nil state argument
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// is provided to AttestationDataSlot.
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ErrAttestationDataSlotNilState = errors.New("nil state provided for AttestationDataSlot")
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// ErrAttestationDataSlotNilData is returned when a nil attestation data
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// argument is provided to AttestationDataSlot.
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ErrAttestationDataSlotNilData = errors.New("nil data provided for AttestationDataSlot")
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)
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// AttestationDataSlot returns current slot of AttestationData for given state
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//
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// Spec pseudocode definition:
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// def get_attestation_data_slot(state: BeaconState, data: AttestationData) -> Slot:
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// """
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// Return the slot corresponding to the attestation ``data``.
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// """
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// committee_count = get_committee_count(state, data.target.epoch)
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// offset = (data.crosslink.shard + SHARD_COUNT - get_start_shard(state, data.target.epoch)) % SHARD_COUNT
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// return Slot(compute_start_slot_of_epoch(data.target.epoch) + offset // (committee_count // SLOTS_PER_EPOCH))
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func AttestationDataSlot(state *pb.BeaconState, data *ethpb.AttestationData) (uint64, error) {
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if state == nil {
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return 0, ErrAttestationDataSlotNilState
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}
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if data == nil {
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return 0, ErrAttestationDataSlotNilData
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}
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committeeCount, err := CommitteeCount(state, data.Target.Epoch)
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if err != nil {
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return 0, err
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}
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epochStartShardNumber, err := StartShard(state, data.Target.Epoch)
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if err != nil { // This should never happen if CommitteeCount was successful
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return 0, errors.Wrap(err, "could not determine epoch start shard")
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}
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offset := (data.Crosslink.Shard + params.BeaconConfig().ShardCount -
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epochStartShardNumber) % params.BeaconConfig().ShardCount
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return StartSlot(data.Target.Epoch) + (offset / (committeeCount / params.BeaconConfig().SlotsPerEpoch)), nil
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}
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// AggregateAttestation aggregates attestations a1 and a2 together.
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func AggregateAttestation(a1 *ethpb.Attestation, a2 *ethpb.Attestation) (*ethpb.Attestation, error) {
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baseAtt := a1
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newAtt := a2
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if a2.AggregationBits.Count() > a1.AggregationBits.Count() {
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baseAtt = a2
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newAtt = a1
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}
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if baseAtt.AggregationBits.Contains(newAtt.AggregationBits) {
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return baseAtt, nil
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}
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newBits := baseAtt.AggregationBits.Or(newAtt.AggregationBits)
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newSig, err := bls.SignatureFromBytes(newAtt.Signature)
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if err != nil {
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return nil, err
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}
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baseSig, err := bls.SignatureFromBytes(baseAtt.Signature)
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if err != nil {
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return nil, err
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}
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aggregatedSig := bls.AggregateSignatures([]*bls.Signature{baseSig, newSig})
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baseAtt.Signature = aggregatedSig.Marshal()
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baseAtt.AggregationBits = newBits
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return baseAtt, nil
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}
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