neo-go/pkg/core/validator_state.go
2019-11-21 15:41:49 +03:00

174 lines
4.9 KiB
Go

package core
import (
"fmt"
"github.com/CityOfZion/neo-go/pkg/core/storage"
"github.com/CityOfZion/neo-go/pkg/crypto/keys"
"github.com/CityOfZion/neo-go/pkg/io"
"github.com/CityOfZion/neo-go/pkg/util"
)
// Validators is a mapping between public keys and ValidatorState.
type Validators map[*keys.PublicKey]*ValidatorState
func (v Validators) getAndUpdate(s storage.Store, publicKey *keys.PublicKey) (*ValidatorState, error) {
if validator, ok := v[publicKey]; ok {
return validator, nil
}
validatorState, err := getValidatorStateFromStore(s, publicKey)
if err != nil {
if err != storage.ErrKeyNotFound {
return nil, err
}
validatorState = &ValidatorState{PublicKey: publicKey}
}
v[publicKey] = validatorState
return validatorState, nil
}
// getValidatorsFromStore returns all validators from store.
func getValidatorsFromStore(s storage.Store) []*ValidatorState {
var validators []*ValidatorState
s.Seek(storage.STValidator.Bytes(), func(k, v []byte) {
r := io.NewBinReaderFromBuf(v)
validator := &ValidatorState{}
validator.DecodeBinary(r)
if r.Err != nil {
return
}
validators = append(validators, validator)
})
return validators
}
// getValidatorStateFromStore returns validator by publicKey.
func getValidatorStateFromStore(s storage.Store, publicKey *keys.PublicKey) (*ValidatorState, error) {
validatorState := &ValidatorState{}
key := storage.AppendPrefix(storage.STValidator, publicKey.Bytes())
if b, err := s.Get(key); err == nil {
r := io.NewBinReaderFromBuf(b)
validatorState.DecodeBinary(r)
if r.Err != nil {
return nil, fmt.Errorf("failed to decode (ValidatorState): %s", r.Err)
}
} else {
return nil, err
}
return validatorState, nil
}
// commit writes all validator states to the given Batch.
func (v Validators) commit(store storage.Store) error {
for _, validator := range v {
if err := putValidatorStateIntoStore(store, validator); err != nil {
return err
}
}
return nil
}
// putValidatorStateIntoStore puts given ValidatorState into the given store.
func putValidatorStateIntoStore(store storage.Store, vs *ValidatorState) error {
buf := io.NewBufBinWriter()
vs.EncodeBinary(buf.BinWriter)
if buf.Err != nil {
return buf.Err
}
key := storage.AppendPrefix(storage.STValidator, vs.PublicKey.Bytes())
return store.Put(key, buf.Bytes())
}
// ValidatorState holds the state of a validator.
type ValidatorState struct {
PublicKey *keys.PublicKey
Registered bool
Votes util.Fixed8
}
// RegisteredAndHasVotes returns true or false whether Validator is registered and has votes.
func (vs *ValidatorState) RegisteredAndHasVotes() bool {
return vs.Registered && vs.Votes > util.Fixed8(0)
}
// EncodeBinary encodes ValidatorState to the given BinWriter.
func (vs *ValidatorState) EncodeBinary(bw *io.BinWriter) {
vs.PublicKey.EncodeBinary(bw)
bw.WriteLE(vs.Registered)
bw.WriteLE(vs.Votes)
}
// DecodeBinary decodes ValidatorState from the given BinReader.
func (vs *ValidatorState) DecodeBinary(reader *io.BinReader) {
vs.PublicKey = &keys.PublicKey{}
vs.PublicKey.DecodeBinary(reader)
reader.ReadLE(&vs.Registered)
reader.ReadLE(&vs.Votes)
}
// GetValidatorsWeightedAverage applies weighted filter based on votes for validator and returns number of validators.
// Get back to it with further investigation in https://github.com/nspcc-dev/neo-go/issues/512.
func GetValidatorsWeightedAverage(validators []*ValidatorState) int {
return int(weightedAverage(applyWeightedFilter(validators)))
}
// applyWeightedFilter is an implementation of the filter for validators votes.
// C# reference https://github.com/neo-project/neo/blob/41caff115c28d6c7665b2a7ac72967e7ce82e921/neo/Helper.cs#L273
func applyWeightedFilter(validators []*ValidatorState) map[*ValidatorState]float64 {
var validatorsWithVotes []*ValidatorState
var amount float64
weightedVotes := make(map[*ValidatorState]float64)
start := 0.25
end := 0.75
sum := float64(0)
current := float64(0)
for _, validator := range validators {
if validator.Votes > util.Fixed8(0) {
validatorsWithVotes = append(validatorsWithVotes, validator)
amount += validator.Votes.FloatValue()
}
}
for _, validator := range validatorsWithVotes {
if current >= end {
break
}
weight := validator.Votes.FloatValue()
sum += weight
old := current
current = sum / amount
if current <= start {
continue
}
if old < start {
if current > end {
weight = (end - start) * amount
} else {
weight = (current - start) * amount
}
} else if current > end {
weight = (end - old) * amount
}
weightedVotes[validator] = weight
}
return weightedVotes
}
func weightedAverage(weightedVotes map[*ValidatorState]float64) float64 {
sumWeight := float64(0)
sumValue := float64(0)
for vState, weight := range weightedVotes {
sumWeight += weight
sumValue += vState.Votes.FloatValue() * weight
}
if sumValue == 0 || sumWeight == 0 {
return 0
}
return sumValue / sumWeight
}