Loop Once Over state.LatestAttestations in Epoch Processing (#2342)

* single loop for extracting attestations

* complete

beacon-chain/core/epoch/epoch_operations.go

@@ -5,134 +5,15 @@
 package epoch
 
 import (
-	"bytes"
 	"fmt"
 	"math"
 
-	block "github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/validators"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	b "github.com/prysmaticlabs/prysm/shared/bytesutil"
 )
 
-// CurrentAttestations returns the pending attestations from current epoch.
-//
-// Spec pseudocode definition:
-//   return [a for a in state.latest_attestations if current_epoch ==
-//   	slot_to_epoch(a.data.slot)]
-//  (Note: this is the set of attestations of slots in the epoch
-//  current_epoch, not attestations that got included in the chain
-//  during the epoch current_epoch.)
-func CurrentAttestations(state *pb.BeaconState) []*pb.PendingAttestation {
-	var currentEpochAttestations []*pb.PendingAttestation
-	currentEpoch := helpers.CurrentEpoch(state)
-
-	for _, attestation := range state.LatestAttestations {
-		if currentEpoch == helpers.SlotToEpoch(attestation.Data.Slot) {
-			currentEpochAttestations = append(currentEpochAttestations, attestation)
-		}
-	}
-	return currentEpochAttestations
-}
-
-// CurrentEpochBoundaryAttestations returns the pending attestations from
-// the epoch's boundary block.
-//
-// Spec pseudocode definition:
-//   return [a for a in current_epoch_attestations if a.data.epoch_boundary_root ==
-//   	get_block_root(state, get_epoch_start_slot(current_epoch))
-func CurrentEpochBoundaryAttestations(
-	state *pb.BeaconState,
-	currentEpochAttestations []*pb.PendingAttestation,
-) ([]*pb.PendingAttestation, error) {
-	var boundaryAttestations []*pb.PendingAttestation
-	for _, attestation := range currentEpochAttestations {
-		boundaryBlockRoot, err := block.BlockRoot(state, helpers.StartSlot(helpers.CurrentEpoch(state)))
-		if err != nil {
-			return nil, err
-		}
-
-		attestationData := attestation.Data
-		sameRoot := bytes.Equal(attestationData.EpochBoundaryRootHash32, boundaryBlockRoot)
-		if sameRoot {
-			boundaryAttestations = append(boundaryAttestations, attestation)
-		}
-	}
-	return boundaryAttestations, nil
-}
-
-// PrevAttestations returns the attestations of the previous epoch
-// (state.slot - 2 * SLOTS_PER_EPOCH...state.slot - EPOCH_LENGTH).
-//
-// Spec pseudocode definition:
-//   return [a for a in state.latest_attestations if
-//   	previous_epoch == slot_to_epoch(a.data.slot)].
-func PrevAttestations(state *pb.BeaconState) []*pb.PendingAttestation {
-	var prevEpochAttestations []*pb.PendingAttestation
-	prevEpoch := helpers.PrevEpoch(state)
-
-	for _, attestation := range state.LatestAttestations {
-		if prevEpoch == helpers.SlotToEpoch(attestation.Data.Slot) {
-			prevEpochAttestations = append(prevEpochAttestations, attestation)
-		}
-	}
-
-	return prevEpochAttestations
-}
-
-// PrevEpochBoundaryAttestations returns the boundary attestations
-// at the start of the previous epoch.
-//
-// Spec pseudocode definition:
-//   return [a for a in previous_epoch_attestations
-// 	 if a.epoch_boundary_root == get_block_root(state, get_epoch_start_slot(previous_epoch)]
-func PrevEpochBoundaryAttestations(
-	state *pb.BeaconState,
-	prevEpochAttestations []*pb.PendingAttestation,
-) ([]*pb.PendingAttestation, error) {
-	var prevEpochBoundaryAttestations []*pb.PendingAttestation
-
-	prevBoundaryBlockRoot, err := block.BlockRoot(state,
-		helpers.StartSlot(helpers.PrevEpoch(state)))
-	if err != nil {
-		return nil, err
-	}
-
-	for _, attestation := range prevEpochAttestations {
-		if bytes.Equal(attestation.Data.EpochBoundaryRootHash32, prevBoundaryBlockRoot) {
-			prevEpochBoundaryAttestations = append(prevEpochBoundaryAttestations, attestation)
-		}
-	}
-	return prevEpochBoundaryAttestations, nil
-}
-
-// PrevHeadAttestations returns the pending attestations from
-// the canonical beacon chain.
-//
-// Spec pseudocode definition:
-//   return [a for a in previous_epoch_attestations
-//   if a.data.beacon_block_root == get_block_root(state, a.data.slot)]
-func PrevHeadAttestations(
-	state *pb.BeaconState,
-	prevEpochAttestations []*pb.PendingAttestation,
-) ([]*pb.PendingAttestation, error) {
-
-	var headAttestations []*pb.PendingAttestation
-	for _, attestation := range prevEpochAttestations {
-		canonicalBlockRoot, err := block.BlockRoot(state, attestation.Data.Slot)
-		if err != nil {
-			return nil, err
-		}
-
-		attestationData := attestation.Data
-		if bytes.Equal(attestationData.BeaconBlockRootHash32, canonicalBlockRoot) {
-			headAttestations = append(headAttestations, attestation)
-		}
-	}
-	return headAttestations, nil
-}
-
 // TotalBalance returns the total balance at stake of the validators
 // from the shard committee regardless of validators attested or not.
 //