/
snapshot.go
167 lines (134 loc) · 3.54 KB
/
snapshot.go
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package datong
import (
"errors"
"github.com/FusionFoundation/efsn/common"
"github.com/FusionFoundation/efsn/core/types"
"github.com/FusionFoundation/efsn/crypto"
)
// Snapshot wacom
type Snapshot struct {
Selected common.Hash `json:"selected"`
Retreat []common.Hash `json:"retreat"`
TicketNumber int `json:"ticketNumber"`
}
type ticketLogType byte
const (
ticketSelect ticketLogType = iota + 1
ticketRetreat
)
type ticketLog struct {
TicketID common.Hash
Type ticketLogType
}
type snapshot struct {
logs []*ticketLog
ticketNumber int
}
func newSnapshot() *snapshot {
return &snapshot{
logs: make([]*ticketLog, 0),
}
}
func newSnapshotWithData(data []byte) (*snapshot, error) {
snap := newSnapshot()
if err := snap.SetBytes(data); err != nil {
return nil, err
}
return snap, nil
}
// NewSnapshotFromHeader wacom
func NewSnapshotFromHeader(header *types.Header) (*Snapshot, error) {
snap, err := newSnapshotWithData(getSnapDataByHeader(header))
if err != nil {
return nil, err
}
return snap.ToShow(), nil
}
func (snap *snapshot) GetVoteTicket() common.Hash {
if len(snap.logs) > 0 && snap.logs[0].Type == ticketSelect {
return snap.logs[0].TicketID
}
return common.Hash{}
}
func (snap *snapshot) AddLog(log *ticketLog) {
snap.logs = append(snap.logs, log)
}
func (snap *snapshot) SetBytes(data []byte) error {
if len(data) <= 0 {
return errors.New("Empty data")
}
realData := data[:len(data)-1]
check := data[len(data)-1]
if calcCheck(realData) != check {
return errors.New("check error")
}
snap.ticketNumber = common.BytesToInt(realData[:4])
realData = realData[4:]
dataLength := len(realData)
logLength := common.HashLength + 1
if dataLength%logLength != 0 {
return errors.New("data length error")
}
count := dataLength / logLength
snap.logs = make([]*ticketLog, count)
for i := 0; i < count; i++ {
base := logLength * i
snap.logs[i] = &ticketLog{
TicketID: common.BytesToHash(realData[base : logLength+base-1]),
Type: ticketLogType(realData[logLength+base-1]),
}
}
return nil
}
func (snap *snapshot) Bytes() []byte {
data := make([]byte, 0)
data = append(data, common.IntToBytes(snap.ticketNumber)...)
for i := 0; i < len(snap.logs); i++ {
data = append(data, snap.logs[i].TicketID[:]...)
data = append(data, byte(snap.logs[i].Type))
}
data = append(data, calcCheck(data))
return data
}
func (snap *snapshot) TicketNumber() int {
return snap.ticketNumber
}
func (snap *snapshot) SetTicketNumber(ticketNumber int) {
snap.ticketNumber = ticketNumber
}
func (snap *snapshot) ToShow() *Snapshot {
var retreat []common.Hash
if len(snap.logs) == 0 {
retreat = make([]common.Hash, 0, 0)
} else {
retreat = make([]common.Hash, 0, len(snap.logs)-1)
for i := 1; i < len(snap.logs); i++ {
if snap.logs[i].Type == ticketRetreat {
retreat = append(retreat, snap.logs[i].TicketID)
}
}
}
return &Snapshot{
Selected: snap.GetVoteTicket(),
Retreat: retreat,
TicketNumber: snap.ticketNumber,
}
}
func calcCheck(data []byte) byte {
hash := crypto.Keccak256Hash(data)
return hash[0]
}
func GenerateGenesisExtraData(old []byte, ticketNumber uint64) []byte {
snap := newSnapshot()
snap.SetTicketNumber(int(ticketNumber))
snapBytes := snap.Bytes()
extraData := make([]byte, extraVanity)
copy(extraData[:], old)
extraData = append(extraData, snapBytes...)
if len(old) >= extraVanity+extraSeal {
extraData = append(extraData, old[len(old)-extraSeal:]...)
} else {
extraData = append(extraData, make([]byte, extraSeal)...)
}
return extraData
}