prysm-pulse/beacon-chain/core/blocks/eth1_data.go

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package blocks
import (
"bytes"
"errors"
ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
"github.com/prysmaticlabs/prysm/shared/params"
)
// ProcessEth1DataInBlock is an operation performed on each
// beacon block to ensure the ETH1 data votes are processed
// into the beacon state.
//
// Official spec definition:
// def process_eth1_data(state: BeaconState, body: BeaconBlockBody) -> None:
// state.eth1_data_votes.append(body.eth1_data)
// if state.eth1_data_votes.count(body.eth1_data) * 2 > EPOCHS_PER_ETH1_VOTING_PERIOD * SLOTS_PER_EPOCH:
// state.latest_eth1_data = body.eth1_data
func ProcessEth1DataInBlock(beaconState *stateTrie.BeaconState, block *ethpb.BeaconBlock) (*stateTrie.BeaconState, error) {
if beaconState == nil {
return nil, errors.New("nil state")
}
if block == nil || block.Body == nil {
return nil, errors.New("nil block or block withought body")
}
if err := beaconState.AppendEth1DataVotes(block.Body.Eth1Data); err != nil {
return nil, err
}
hasSupport, err := Eth1DataHasEnoughSupport(beaconState, block.Body.Eth1Data)
if err != nil {
return nil, err
}
if hasSupport {
if err := beaconState.SetEth1Data(block.Body.Eth1Data); err != nil {
return nil, err
}
}
return beaconState, nil
}
// AreEth1DataEqual checks equality between two eth1 data objects.
func AreEth1DataEqual(a, b *ethpb.Eth1Data) bool {
if a == nil && b == nil {
return true
}
if a == nil || b == nil {
return false
}
return a.DepositCount == b.DepositCount &&
bytes.Equal(a.BlockHash, b.BlockHash) &&
bytes.Equal(a.DepositRoot, b.DepositRoot)
}
// Eth1DataHasEnoughSupport returns true when the given eth1data has more than 50% votes in the
// eth1 voting period. A vote is cast by including eth1data in a block and part of state processing
// appends eth1data to the state in the Eth1DataVotes list. Iterating through this list checks the
// votes to see if they match the eth1data.
func Eth1DataHasEnoughSupport(beaconState *stateTrie.BeaconState, data *ethpb.Eth1Data) (bool, error) {
voteCount := uint64(0)
data = stateTrie.CopyETH1Data(data)
for _, vote := range beaconState.Eth1DataVotes() {
if AreEth1DataEqual(vote, data) {
voteCount++
}
}
// If 50+% majority converged on the same eth1data, then it has enough support to update the
// state.
support := params.BeaconConfig().EpochsPerEth1VotingPeriod * params.BeaconConfig().SlotsPerEpoch
return voteCount*2 > support, nil
}