github.com/prysmaticlabs/prysm@v1.4.4/beacon-chain/state/stateutil/eth1_root.go (about)

     1  package stateutil
     2  
     3  import (
     4  	"bytes"
     5  	"encoding/binary"
     6  
     7  	"github.com/pkg/errors"
     8  	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
     9  	"github.com/prysmaticlabs/prysm/shared/bytesutil"
    10  	"github.com/prysmaticlabs/prysm/shared/hashutil"
    11  	"github.com/prysmaticlabs/prysm/shared/htrutils"
    12  	"github.com/prysmaticlabs/prysm/shared/params"
    13  )
    14  
    15  // Eth1DataEncKey returns the encoded key in bytes of input `eth1Data`,
    16  // the returned key bytes can be used for caching purposes.
    17  func Eth1DataEncKey(eth1Data *ethpb.Eth1Data) []byte {
    18  	enc := make([]byte, 0, 96)
    19  	if eth1Data != nil {
    20  		if len(eth1Data.DepositRoot) > 0 {
    21  			depRoot := bytesutil.ToBytes32(eth1Data.DepositRoot)
    22  			enc = append(enc, depRoot[:]...)
    23  		}
    24  		eth1DataCountBuf := make([]byte, 8)
    25  		binary.LittleEndian.PutUint64(eth1DataCountBuf, eth1Data.DepositCount)
    26  		eth1CountRoot := bytesutil.ToBytes32(eth1DataCountBuf)
    27  		enc = append(enc, eth1CountRoot[:]...)
    28  		if len(eth1Data.BlockHash) > 0 {
    29  			blockHash := bytesutil.ToBytes32(eth1Data.BlockHash)
    30  			enc = append(enc, blockHash[:]...)
    31  		}
    32  	}
    33  	return enc
    34  }
    35  
    36  // Eth1DataRootWithHasher returns the hash tree root of input `eth1Data`.
    37  func Eth1DataRootWithHasher(hasher htrutils.HashFn, eth1Data *ethpb.Eth1Data) ([32]byte, error) {
    38  	if eth1Data == nil {
    39  		return [32]byte{}, errors.New("nil eth1 data")
    40  	}
    41  
    42  	fieldRoots := make([][]byte, 3)
    43  	for i := 0; i < len(fieldRoots); i++ {
    44  		fieldRoots[i] = make([]byte, 32)
    45  	}
    46  	if len(eth1Data.DepositRoot) > 0 {
    47  		depRoot := bytesutil.ToBytes32(eth1Data.DepositRoot)
    48  		fieldRoots[0] = depRoot[:]
    49  	}
    50  	eth1DataCountBuf := make([]byte, 8)
    51  	binary.LittleEndian.PutUint64(eth1DataCountBuf, eth1Data.DepositCount)
    52  	eth1CountRoot := bytesutil.ToBytes32(eth1DataCountBuf)
    53  	fieldRoots[1] = eth1CountRoot[:]
    54  	if len(eth1Data.BlockHash) > 0 {
    55  		blockHash := bytesutil.ToBytes32(eth1Data.BlockHash)
    56  		fieldRoots[2] = blockHash[:]
    57  	}
    58  	root, err := htrutils.BitwiseMerkleize(hasher, fieldRoots, uint64(len(fieldRoots)), uint64(len(fieldRoots)))
    59  	if err != nil {
    60  		return [32]byte{}, err
    61  	}
    62  	return root, nil
    63  }
    64  
    65  // Eth1DatasEncKey returns the encoded key in bytes of input `eth1Data`s,
    66  // the returned key bytes can be used for caching purposes.
    67  func Eth1DatasEncKey(eth1Datas []*ethpb.Eth1Data) ([32]byte, error) {
    68  	hasher := hashutil.CustomSHA256Hasher()
    69  	enc := make([]byte, len(eth1Datas)*32)
    70  	for i := 0; i < len(eth1Datas); i++ {
    71  		eth1, err := Eth1DataRootWithHasher(hasher, eth1Datas[i])
    72  		if err != nil {
    73  			return [32]byte{}, errors.Wrap(err, "could not compute eth1data merkleization")
    74  		}
    75  		copy(enc[(i*32):(i+1)*32], eth1[:])
    76  	}
    77  	hashKey := hashutil.FastSum256(enc)
    78  	return hashKey, nil
    79  }
    80  
    81  // Eth1DatasRoot returns the hash tree root of input `eth1Datas`.
    82  func Eth1DatasRoot(eth1Datas []*ethpb.Eth1Data) ([32]byte, error) {
    83  	hasher := hashutil.CustomSHA256Hasher()
    84  	eth1VotesRoots := make([][]byte, 0)
    85  	for i := 0; i < len(eth1Datas); i++ {
    86  		eth1, err := Eth1DataRootWithHasher(hasher, eth1Datas[i])
    87  		if err != nil {
    88  			return [32]byte{}, errors.Wrap(err, "could not compute eth1data merkleization")
    89  		}
    90  		eth1VotesRoots = append(eth1VotesRoots, eth1[:])
    91  	}
    92  	eth1Chunks, err := htrutils.Pack(eth1VotesRoots)
    93  	if err != nil {
    94  		return [32]byte{}, errors.Wrap(err, "could not chunk eth1 votes roots")
    95  	}
    96  
    97  	eth1VotesRootsRoot, err := htrutils.BitwiseMerkleize(
    98  		hasher,
    99  		eth1Chunks,
   100  		uint64(len(eth1Chunks)),
   101  		uint64(params.BeaconConfig().SlotsPerEpoch.Mul(uint64(params.BeaconConfig().EpochsPerEth1VotingPeriod))),
   102  	)
   103  	if err != nil {
   104  		return [32]byte{}, errors.Wrap(err, "could not compute eth1data votes merkleization")
   105  	}
   106  	eth1VotesRootBuf := new(bytes.Buffer)
   107  	if err := binary.Write(eth1VotesRootBuf, binary.LittleEndian, uint64(len(eth1Datas))); err != nil {
   108  		return [32]byte{}, errors.Wrap(err, "could not marshal eth1data votes length")
   109  	}
   110  	// We need to mix in the length of the slice.
   111  	eth1VotesRootBufRoot := make([]byte, 32)
   112  	copy(eth1VotesRootBufRoot, eth1VotesRootBuf.Bytes())
   113  	root := htrutils.MixInLength(eth1VotesRootsRoot, eth1VotesRootBufRoot)
   114  
   115  	return root, nil
   116  }