prysm-pulse/beacon-chain/core/state/transition.go
2018-12-27 23:19:32 -06:00

107 lines
3.8 KiB
Go

package state
import (
"fmt"
"github.com/gogo/protobuf/proto"
b "github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
"github.com/prysmaticlabs/prysm/beacon-chain/core/randao"
pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
"github.com/prysmaticlabs/prysm/shared/params"
)
// ExecuteStateTransition defines the procedure for a state transition function.
// Spec:
// We now define the state transition function. At a high level the state transition is made up of two parts:
// - The per-slot transitions, which happens every slot, and only affects a parts of the state.
// - The per-epoch transitions, which happens at every epoch boundary (i.e. state.slot % EPOCH_LENGTH == 0), and affects the entire state.
// The per-slot transitions generally focus on verifying aggregate signatures and saving temporary records relating to the per-slot
// activity in the BeaconState. The per-epoch transitions focus on the validator registry, including adjusting balances and activating
// and exiting validators, as well as processing crosslinks and managing block justification/finalization.
func ExecuteStateTransition(
beaconState *pb.BeaconState,
block *pb.BeaconBlock,
prevBlockRoot [32]byte,
) (*pb.BeaconState, error) {
var err error
newState := proto.Clone(beaconState).(*pb.BeaconState)
currentSlot := newState.GetSlot()
newState.Slot = currentSlot + 1
newState, err = randao.UpdateRandaoLayers(newState, newState.GetSlot())
if err != nil {
return nil, fmt.Errorf("unable to update randao layer %v", err)
}
newState = randao.UpdateRandaoMixes(newState)
newState = b.ProcessBlockRoots(newState, prevBlockRoot)
newHashes, err := CalculateNewBlockHashes(newState, block, currentSlot)
if err != nil {
return nil, fmt.Errorf("unable to calculate recent blockhashes")
}
newState.LatestBlockRootHash32S = newHashes
if block != nil {
newState, err = ProcessBlock(newState, block)
if err != nil {
return nil, fmt.Errorf("unable to process block: %v", err)
}
if newState.GetSlot()%params.BeaconConfig().EpochLength == 0 {
newState = NewEpochTransition(newState)
}
}
return newState, nil
}
// ProcessBlock creates a new, modified beacon state by applying block operation
// transformations as defined in the Ethereum Serenity specification, including processing proposer slashings,
// processing block attestations, and more.
func ProcessBlock(state *pb.BeaconState, block *pb.BeaconBlock) (*pb.BeaconState, error) {
newState := proto.Clone(state).(*pb.BeaconState)
if block.GetSlot() != state.GetSlot() {
return nil, fmt.Errorf(
"block.slot != state.slot, block.slot = %d, state.slot = %d",
block.GetSlot(),
newState.GetSlot(),
)
}
// TODO(#781): Verify Proposer Signature.
var err error
newState = b.ProcessPOWReceiptRoots(newState, block)
newState, err = b.ProcessBlockRandao(newState, block)
if err != nil {
return nil, fmt.Errorf("could not verify and process block randao: %v", err)
}
newState, err = b.ProcessProposerSlashings(newState, block)
if err != nil {
return nil, fmt.Errorf("could not verify block proposer slashings: %v", err)
}
newState, err = b.ProcessCasperSlashings(newState, block)
if err != nil {
return nil, fmt.Errorf("could not verify block casper slashings: %v", err)
}
newState, err = b.ProcessBlockAttestations(newState, block)
if err != nil {
return nil, fmt.Errorf("could not process block attestations: %v", err)
}
// TODO(#781): Process block validator deposits.
newState, err = b.ProcessValidatorExits(newState, block)
if err != nil {
return nil, fmt.Errorf("could not process validator exits: %v", err)
}
return newState, nil
}
// NewEpochTransition describes the per epoch operations that are performed on the
// beacon state.
func NewEpochTransition(state *pb.BeaconState) *pb.BeaconState {
// TODO(#1074): This will encompass all the related logic to epoch transitions.
return state
}