state.go

package types

import (
	"fmt"
	"time"

	// TODO(tzdybal): copy to local project?
	tmstate "github.com/tendermint/tendermint/proto/tendermint/state"
	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
	tmversion "github.com/tendermint/tendermint/proto/tendermint/version"
	"github.com/tendermint/tendermint/types"
	"github.com/tendermint/tendermint/version"
)

// InitStateVersion sets the Consensus.Block and Software versions,
// but leaves the Consensus.App version blank.
// The Consensus.App version will be set during the Handshake, once
// we hear from the app what protocol version it is running.
var InitStateVersion = tmstate.Version{
	Consensus: tmversion.Consensus{
		Block: version.BlockProtocol,
		App:   0,
	},
	Software: version.TMCoreSemVer,
}

// State contains information about current state of the blockchain.
type State struct {
	Version tmstate.Version

	// immutable
	ChainID       string
	InitialHeight int64 // should be 1, not 0, when starting from height 1

	// LastBlockHeight=0 at genesis (ie. block(H=0) does not exist)
	LastBlockHeight int64
	LastBlockID     types.BlockID
	LastBlockTime   time.Time

	// SLStateIndex identifies the Settlement Layer state index we're synced with
	SLStateIndex uint64

	// In the MVP implementation, there will be only one Validator
	NextValidators              *types.ValidatorSet
	Validators                  *types.ValidatorSet
	LastValidators              *types.ValidatorSet
	LastHeightValidatorsChanged int64

	// Consensus parameters used for validating blocks.
	// Changes returned by EndBlock and updated after Commit.
	ConsensusParams                  tmproto.ConsensusParams
	LastHeightConsensusParamsChanged int64

	// Merkle root of the results from executing prev block
	LastResultsHash [32]byte

	// LastStore height is the last height we've saved to the store.
	LastStoreHeight uint64

	// BaseHeight is the height of the first block we have in store after pruning.
	BaseHeight uint64

	// the latest AppHash we've received from calling abci.Commit()
	AppHash [32]byte
}

// NewFromGenesisDoc reads blockchain State from genesis.
func NewFromGenesisDoc(genDoc *types.GenesisDoc) (State, error) {
	err := genDoc.ValidateAndComplete()
	if err != nil {
		return State{}, fmt.Errorf("in genesis doc: %w", err)
	}

	var validatorSet, nextValidatorSet *types.ValidatorSet
	validatorSet = types.NewValidatorSet(nil)
	nextValidatorSet = types.NewValidatorSet(nil)

	s := State{
		Version:       InitStateVersion,
		ChainID:       genDoc.ChainID,
		InitialHeight: genDoc.InitialHeight,

		LastBlockHeight: 0,
		LastBlockID:     types.BlockID{},
		LastBlockTime:   genDoc.GenesisTime,

		NextValidators:              nextValidatorSet,
		Validators:                  validatorSet,
		LastValidators:              types.NewValidatorSet(nil),
		LastHeightValidatorsChanged: genDoc.InitialHeight,

		ConsensusParams:                  *genDoc.ConsensusParams,
		LastHeightConsensusParamsChanged: genDoc.InitialHeight,

		BaseHeight: 0,
	}
	copy(s.AppHash[:], genDoc.AppHash)

	return s, nil
}

func (s *State) IsGenesis() bool {
	return s.LastBlockHeight == 0
}