prysm-pulse/beacon-chain/state/v1/proofs.go

48 lines
1.6 KiB
Go

package v1
import (
"encoding/binary"
"github.com/pkg/errors"
"github.com/prysmaticlabs/prysm/beacon-chain/state/fieldtrie"
"github.com/prysmaticlabs/prysm/encoding/bytesutil"
)
const (
finalizedRootIndex = uint64(105) // Precomputed value.
)
// FinalizedRootGeneralizedIndex for the beacon state.
func FinalizedRootGeneralizedIndex() uint64 {
return finalizedRootIndex
}
// CurrentSyncCommitteeProof from the state's Merkle trie representation.
func (*BeaconState) CurrentSyncCommitteeProof() ([][]byte, error) {
return nil, errors.New("CurrentSyncCommitteeProof() unsupported for v1 beacon state")
}
// NextSyncCommitteeProof from the state's Merkle trie representation.
func (*BeaconState) NextSyncCommitteeProof() ([][]byte, error) {
return nil, errors.New("NextSyncCommitteeProof() unsupported for v1 beacon state")
}
// FinalizedRootProof crafts a Merkle proof for the finalized root
// contained within the finalized checkpoint of a beacon state.
func (b *BeaconState) FinalizedRootProof() ([][]byte, error) {
b.lock.RLock()
defer b.lock.RUnlock()
cpt := b.state.FinalizedCheckpoint
// The epoch field of a finalized checkpoint is the neighbor
// index of the finalized root field in its Merkle tree representation
// of the checkpoint. This neighbor is the first element added to the proof.
epochBuf := make([]byte, 8)
binary.LittleEndian.PutUint64(epochBuf, uint64(cpt.Epoch))
epochRoot := bytesutil.ToBytes32(epochBuf)
proof := make([][]byte, 0)
proof = append(proof, epochRoot[:])
branch := fieldtrie.ProofFromMerkleLayers(b.merkleLayers, finalizedCheckpoint)
proof = append(proof, branch...)
return proof, nil
}