prysm-pulse/beacon-chain/state/stateutil/eth1_root.go
2021-03-18 16:29:06 -07:00

117 lines
3.9 KiB
Go

package stateutil
import (
"bytes"
"encoding/binary"
"github.com/pkg/errors"
ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
"github.com/prysmaticlabs/prysm/shared/bytesutil"
"github.com/prysmaticlabs/prysm/shared/hashutil"
"github.com/prysmaticlabs/prysm/shared/htrutils"
"github.com/prysmaticlabs/prysm/shared/params"
)
// Eth1DataEncKey returns the encoded key in bytes of input `eth1Data`,
// the returned key bytes can be used for caching purposes.
func Eth1DataEncKey(eth1Data *ethpb.Eth1Data) []byte {
enc := make([]byte, 0, 96)
if eth1Data != nil {
if len(eth1Data.DepositRoot) > 0 {
depRoot := bytesutil.ToBytes32(eth1Data.DepositRoot)
enc = append(enc, depRoot[:]...)
}
eth1DataCountBuf := make([]byte, 8)
binary.LittleEndian.PutUint64(eth1DataCountBuf, eth1Data.DepositCount)
eth1CountRoot := bytesutil.ToBytes32(eth1DataCountBuf)
enc = append(enc, eth1CountRoot[:]...)
if len(eth1Data.BlockHash) > 0 {
blockHash := bytesutil.ToBytes32(eth1Data.BlockHash)
enc = append(enc, blockHash[:]...)
}
}
return enc
}
// Eth1DataRootWithHasher returns the hash tree root of input `eth1Data`.
func Eth1DataRootWithHasher(hasher htrutils.HashFn, eth1Data *ethpb.Eth1Data) ([32]byte, error) {
if eth1Data == nil {
return [32]byte{}, errors.New("nil eth1 data")
}
fieldRoots := make([][]byte, 3)
for i := 0; i < len(fieldRoots); i++ {
fieldRoots[i] = make([]byte, 32)
}
if len(eth1Data.DepositRoot) > 0 {
depRoot := bytesutil.ToBytes32(eth1Data.DepositRoot)
fieldRoots[0] = depRoot[:]
}
eth1DataCountBuf := make([]byte, 8)
binary.LittleEndian.PutUint64(eth1DataCountBuf, eth1Data.DepositCount)
eth1CountRoot := bytesutil.ToBytes32(eth1DataCountBuf)
fieldRoots[1] = eth1CountRoot[:]
if len(eth1Data.BlockHash) > 0 {
blockHash := bytesutil.ToBytes32(eth1Data.BlockHash)
fieldRoots[2] = blockHash[:]
}
root, err := htrutils.BitwiseMerkleize(hasher, fieldRoots, uint64(len(fieldRoots)), uint64(len(fieldRoots)))
if err != nil {
return [32]byte{}, err
}
return root, nil
}
// Eth1DataEncKey returns the encoded key in bytes of input `eth1Data`s,
// the returned key bytes can be used for caching purposes.
func Eth1DatasEncKey(eth1Datas []*ethpb.Eth1Data) ([32]byte, error) {
hasher := hashutil.CustomSHA256Hasher()
enc := make([]byte, len(eth1Datas)*32)
for i := 0; i < len(eth1Datas); i++ {
eth1, err := Eth1DataRootWithHasher(hasher, eth1Datas[i])
if err != nil {
return [32]byte{}, errors.Wrap(err, "could not compute eth1data merkleization")
}
copy(enc[(i*32):(i+1)*32], eth1[:])
}
hashKey := hashutil.FastSum256(enc)
return hashKey, nil
}
// Eth1DatasRoot returns the hash tree root of input `eth1Datas`.
func Eth1DatasRoot(eth1Datas []*ethpb.Eth1Data) ([32]byte, error) {
hasher := hashutil.CustomSHA256Hasher()
eth1VotesRoots := make([][]byte, 0)
for i := 0; i < len(eth1Datas); i++ {
eth1, err := Eth1DataRootWithHasher(hasher, eth1Datas[i])
if err != nil {
return [32]byte{}, errors.Wrap(err, "could not compute eth1data merkleization")
}
eth1VotesRoots = append(eth1VotesRoots, eth1[:])
}
eth1Chunks, err := htrutils.Pack(eth1VotesRoots)
if err != nil {
return [32]byte{}, errors.Wrap(err, "could not chunk eth1 votes roots")
}
eth1VotesRootsRoot, err := htrutils.BitwiseMerkleize(
hasher,
eth1Chunks,
uint64(len(eth1Chunks)),
uint64(params.BeaconConfig().SlotsPerEpoch.Mul(uint64(params.BeaconConfig().EpochsPerEth1VotingPeriod))),
)
if err != nil {
return [32]byte{}, errors.Wrap(err, "could not compute eth1data votes merkleization")
}
eth1VotesRootBuf := new(bytes.Buffer)
if err := binary.Write(eth1VotesRootBuf, binary.LittleEndian, uint64(len(eth1Datas))); err != nil {
return [32]byte{}, errors.Wrap(err, "could not marshal eth1data votes length")
}
// We need to mix in the length of the slice.
eth1VotesRootBufRoot := make([]byte, 32)
copy(eth1VotesRootBufRoot, eth1VotesRootBuf.Bytes())
root := htrutils.MixInLength(eth1VotesRootsRoot, eth1VotesRootBufRoot)
return root, nil
}