mirror of
https://github.com/nspcc-dev/neo-go.git
synced 2024-11-27 13:58:05 +00:00
567 lines
16 KiB
Go
567 lines
16 KiB
Go
package native
|
|
|
|
import (
|
|
"crypto/elliptic"
|
|
"errors"
|
|
"math/big"
|
|
"sort"
|
|
"strings"
|
|
"sync/atomic"
|
|
|
|
"github.com/nspcc-dev/neo-go/pkg/core/blockchainer"
|
|
"github.com/nspcc-dev/neo-go/pkg/core/dao"
|
|
"github.com/nspcc-dev/neo-go/pkg/core/interop"
|
|
"github.com/nspcc-dev/neo-go/pkg/core/interop/runtime"
|
|
"github.com/nspcc-dev/neo-go/pkg/core/state"
|
|
"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
|
|
"github.com/nspcc-dev/neo-go/pkg/encoding/bigint"
|
|
"github.com/nspcc-dev/neo-go/pkg/smartcontract"
|
|
"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
|
|
"github.com/nspcc-dev/neo-go/pkg/util"
|
|
"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
|
|
)
|
|
|
|
// NEO represents NEO native contract.
|
|
type NEO struct {
|
|
nep5TokenNative
|
|
GAS *GAS
|
|
|
|
votesChanged atomic.Value
|
|
nextValidators atomic.Value
|
|
validators atomic.Value
|
|
}
|
|
|
|
// keyWithVotes is a serialized key with votes balance. It's not deserialized
|
|
// because some uses of it imply serialized-only usage and converting to
|
|
// PublicKey is quite expensive.
|
|
type keyWithVotes struct {
|
|
Key string
|
|
Votes *big.Int
|
|
}
|
|
|
|
const (
|
|
neoName = "NEO"
|
|
neoContractID = -1
|
|
// NEOTotalSupply is the total amount of NEO in the system.
|
|
NEOTotalSupply = 100000000
|
|
// prefixCandidate is a prefix used to store validator's data.
|
|
prefixCandidate = 33
|
|
// prefixVotersCount is a prefix for storing total amount of NEO of voters.
|
|
prefixVotersCount = 1
|
|
// effectiveVoterTurnout represents minimal ratio of total supply to total amount voted value
|
|
// which is require to use non-standby validators.
|
|
effectiveVoterTurnout = 5
|
|
)
|
|
|
|
var (
|
|
// nextValidatorsKey is a key used to store validators for the
|
|
// next block.
|
|
nextValidatorsKey = []byte{14}
|
|
)
|
|
|
|
// makeValidatorKey creates a key from account script hash.
|
|
func makeValidatorKey(key *keys.PublicKey) []byte {
|
|
b := key.Bytes()
|
|
// Don't create a new buffer.
|
|
b = append(b, 0)
|
|
copy(b[1:], b[0:])
|
|
b[0] = prefixCandidate
|
|
return b
|
|
}
|
|
|
|
// NewNEO returns NEO native contract.
|
|
func NewNEO() *NEO {
|
|
n := &NEO{}
|
|
nep5 := newNEP5Native(neoName)
|
|
nep5.symbol = "neo"
|
|
nep5.decimals = 0
|
|
nep5.factor = 1
|
|
nep5.onPersist = chainOnPersist(nep5.OnPersist, n.OnPersist)
|
|
nep5.incBalance = n.increaseBalance
|
|
nep5.ContractID = neoContractID
|
|
|
|
n.nep5TokenNative = *nep5
|
|
n.votesChanged.Store(true)
|
|
n.nextValidators.Store(keys.PublicKeys(nil))
|
|
n.validators.Store(keys.PublicKeys(nil))
|
|
|
|
onp := n.Methods["onPersist"]
|
|
onp.Func = getOnPersistWrapper(n.onPersist)
|
|
n.Methods["onPersist"] = onp
|
|
|
|
desc := newDescriptor("unclaimedGas", smartcontract.IntegerType,
|
|
manifest.NewParameter("account", smartcontract.Hash160Type),
|
|
manifest.NewParameter("end", smartcontract.IntegerType))
|
|
md := newMethodAndPrice(n.unclaimedGas, 3000000, smartcontract.AllowStates)
|
|
n.AddMethod(md, desc, true)
|
|
|
|
desc = newDescriptor("registerCandidate", smartcontract.BoolType,
|
|
manifest.NewParameter("pubkey", smartcontract.PublicKeyType))
|
|
md = newMethodAndPrice(n.registerCandidate, 5000000, smartcontract.AllowModifyStates)
|
|
n.AddMethod(md, desc, false)
|
|
|
|
desc = newDescriptor("unregisterCandidate", smartcontract.BoolType,
|
|
manifest.NewParameter("pubkey", smartcontract.PublicKeyType))
|
|
md = newMethodAndPrice(n.unregisterCandidate, 5000000, smartcontract.AllowModifyStates)
|
|
n.AddMethod(md, desc, false)
|
|
|
|
desc = newDescriptor("vote", smartcontract.BoolType,
|
|
manifest.NewParameter("account", smartcontract.Hash160Type),
|
|
manifest.NewParameter("pubkey", smartcontract.PublicKeyType))
|
|
md = newMethodAndPrice(n.vote, 500000000, smartcontract.AllowModifyStates)
|
|
n.AddMethod(md, desc, false)
|
|
|
|
desc = newDescriptor("getCandidates", smartcontract.ArrayType)
|
|
md = newMethodAndPrice(n.getCandidatesCall, 100000000, smartcontract.AllowStates)
|
|
n.AddMethod(md, desc, true)
|
|
|
|
desc = newDescriptor("getСommittee", smartcontract.ArrayType)
|
|
md = newMethodAndPrice(n.getCommittee, 100000000, smartcontract.AllowStates)
|
|
n.AddMethod(md, desc, true)
|
|
|
|
desc = newDescriptor("getValidators", smartcontract.ArrayType)
|
|
md = newMethodAndPrice(n.getValidators, 100000000, smartcontract.AllowStates)
|
|
n.AddMethod(md, desc, true)
|
|
|
|
desc = newDescriptor("getNextBlockValidators", smartcontract.ArrayType)
|
|
md = newMethodAndPrice(n.getNextBlockValidators, 100000000, smartcontract.AllowStates)
|
|
n.AddMethod(md, desc, true)
|
|
|
|
return n
|
|
}
|
|
|
|
// Initialize initializes NEO contract.
|
|
func (n *NEO) Initialize(ic *interop.Context) error {
|
|
if err := n.nep5TokenNative.Initialize(ic); err != nil {
|
|
return err
|
|
}
|
|
|
|
if n.nep5TokenNative.getTotalSupply(ic.DAO).Sign() != 0 {
|
|
return errors.New("already initialized")
|
|
}
|
|
|
|
h, err := getStandbyValidatorsHash(ic)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
n.mint(ic, h, big.NewInt(NEOTotalSupply))
|
|
|
|
err = ic.DAO.PutStorageItem(n.ContractID, []byte{prefixVotersCount}, &state.StorageItem{Value: []byte{}})
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// OnPersist implements Contract interface.
|
|
func (n *NEO) OnPersist(ic *interop.Context) error {
|
|
if !n.votesChanged.Load().(bool) {
|
|
return nil
|
|
}
|
|
pubs, err := n.GetValidatorsInternal(ic.Chain, ic.DAO)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
prev := n.nextValidators.Load().(keys.PublicKeys)
|
|
if len(prev) == len(pubs) {
|
|
var needUpdate bool
|
|
for i := range pubs {
|
|
if !pubs[i].Equal(prev[i]) {
|
|
needUpdate = true
|
|
break
|
|
}
|
|
}
|
|
if !needUpdate {
|
|
return nil
|
|
}
|
|
}
|
|
n.votesChanged.Store(false)
|
|
n.nextValidators.Store(pubs)
|
|
si := new(state.StorageItem)
|
|
si.Value = pubs.Bytes()
|
|
return ic.DAO.PutStorageItem(n.ContractID, nextValidatorsKey, si)
|
|
}
|
|
|
|
func (n *NEO) increaseBalance(ic *interop.Context, h util.Uint160, si *state.StorageItem, amount *big.Int) error {
|
|
acc, err := state.NEOBalanceStateFromBytes(si.Value)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if amount.Sign() == -1 && acc.Balance.Cmp(new(big.Int).Neg(amount)) == -1 {
|
|
return errors.New("insufficient funds")
|
|
}
|
|
if err := n.distributeGas(ic, h, acc); err != nil {
|
|
return err
|
|
}
|
|
if amount.Sign() == 0 {
|
|
si.Value = acc.Bytes()
|
|
return nil
|
|
}
|
|
if err := n.ModifyAccountVotes(acc, ic.DAO, amount, modifyVoteTransfer); err != nil {
|
|
return err
|
|
}
|
|
if acc.VoteTo != nil {
|
|
if err := n.modifyVoterTurnout(ic.DAO, amount); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
acc.Balance.Add(&acc.Balance, amount)
|
|
if acc.Balance.Sign() != 0 {
|
|
si.Value = acc.Bytes()
|
|
} else {
|
|
si.Value = nil
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (n *NEO) distributeGas(ic *interop.Context, h util.Uint160, acc *state.NEOBalanceState) error {
|
|
if ic.Block == nil || ic.Block.Index == 0 {
|
|
return nil
|
|
}
|
|
gen := ic.Chain.CalculateClaimable(&acc.Balance, acc.BalanceHeight, ic.Block.Index)
|
|
acc.BalanceHeight = ic.Block.Index
|
|
n.GAS.mint(ic, h, gen)
|
|
return nil
|
|
}
|
|
|
|
func (n *NEO) unclaimedGas(ic *interop.Context, args []stackitem.Item) stackitem.Item {
|
|
u := toUint160(args[0])
|
|
end := uint32(toBigInt(args[1]).Int64())
|
|
bs, err := ic.DAO.GetNEP5Balances(u)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
tr := bs.Trackers[n.ContractID]
|
|
|
|
gen := ic.Chain.CalculateClaimable(&tr.Balance, tr.LastUpdatedBlock, end)
|
|
return stackitem.NewBigInteger(gen)
|
|
}
|
|
|
|
func (n *NEO) registerCandidate(ic *interop.Context, args []stackitem.Item) stackitem.Item {
|
|
pub := toPublicKey(args[0])
|
|
ok, err := runtime.CheckKeyedWitness(ic, pub)
|
|
if err != nil {
|
|
panic(err)
|
|
} else if !ok {
|
|
return stackitem.NewBool(false)
|
|
}
|
|
err = n.RegisterCandidateInternal(ic, pub)
|
|
return stackitem.NewBool(err == nil)
|
|
}
|
|
|
|
// RegisterCandidateInternal registers pub as a new candidate.
|
|
func (n *NEO) RegisterCandidateInternal(ic *interop.Context, pub *keys.PublicKey) error {
|
|
key := makeValidatorKey(pub)
|
|
si := ic.DAO.GetStorageItem(n.ContractID, key)
|
|
if si == nil {
|
|
c := &candidate{Registered: true}
|
|
si = &state.StorageItem{Value: c.Bytes()}
|
|
} else {
|
|
c := new(candidate).FromBytes(si.Value)
|
|
c.Registered = true
|
|
si.Value = c.Bytes()
|
|
}
|
|
return ic.DAO.PutStorageItem(n.ContractID, key, si)
|
|
}
|
|
|
|
func (n *NEO) unregisterCandidate(ic *interop.Context, args []stackitem.Item) stackitem.Item {
|
|
pub := toPublicKey(args[0])
|
|
ok, err := runtime.CheckKeyedWitness(ic, pub)
|
|
if err != nil {
|
|
panic(err)
|
|
} else if !ok {
|
|
return stackitem.NewBool(false)
|
|
}
|
|
err = n.UnregisterCandidateInternal(ic, pub)
|
|
return stackitem.NewBool(err == nil)
|
|
}
|
|
|
|
// UnregisterCandidateInternal unregisters pub as a candidate.
|
|
func (n *NEO) UnregisterCandidateInternal(ic *interop.Context, pub *keys.PublicKey) error {
|
|
key := makeValidatorKey(pub)
|
|
si := ic.DAO.GetStorageItem(n.ContractID, key)
|
|
if si == nil {
|
|
return nil
|
|
}
|
|
n.validators.Store(keys.PublicKeys(nil))
|
|
c := new(candidate).FromBytes(si.Value)
|
|
if c.Votes.Sign() == 0 {
|
|
return ic.DAO.DeleteStorageItem(n.ContractID, key)
|
|
}
|
|
c.Registered = false
|
|
si.Value = c.Bytes()
|
|
return ic.DAO.PutStorageItem(n.ContractID, key, si)
|
|
}
|
|
|
|
func (n *NEO) vote(ic *interop.Context, args []stackitem.Item) stackitem.Item {
|
|
acc := toUint160(args[0])
|
|
var pub *keys.PublicKey
|
|
if _, ok := args[1].(stackitem.Null); !ok {
|
|
pub = toPublicKey(args[1])
|
|
}
|
|
err := n.VoteInternal(ic, acc, pub)
|
|
return stackitem.NewBool(err == nil)
|
|
}
|
|
|
|
// VoteInternal votes from account h for validarors specified in pubs.
|
|
func (n *NEO) VoteInternal(ic *interop.Context, h util.Uint160, pub *keys.PublicKey) error {
|
|
ok, err := runtime.CheckHashedWitness(ic, h)
|
|
if err != nil {
|
|
return err
|
|
} else if !ok {
|
|
return errors.New("invalid signature")
|
|
}
|
|
key := makeAccountKey(h)
|
|
si := ic.DAO.GetStorageItem(n.ContractID, key)
|
|
if si == nil {
|
|
return errors.New("invalid account")
|
|
}
|
|
acc, err := state.NEOBalanceStateFromBytes(si.Value)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if (acc.VoteTo == nil) != (pub == nil) {
|
|
val := &acc.Balance
|
|
if pub == nil {
|
|
val = new(big.Int).Neg(val)
|
|
}
|
|
if err := n.modifyVoterTurnout(ic.DAO, val); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
if err := n.ModifyAccountVotes(acc, ic.DAO, new(big.Int).Neg(&acc.Balance), modifyVoteOld); err != nil {
|
|
return err
|
|
}
|
|
acc.VoteTo = pub
|
|
if err := n.ModifyAccountVotes(acc, ic.DAO, &acc.Balance, modifyVoteNew); err != nil {
|
|
return err
|
|
}
|
|
si.Value = acc.Bytes()
|
|
return ic.DAO.PutStorageItem(n.ContractID, key, si)
|
|
}
|
|
|
|
const (
|
|
modifyVoteTransfer = iota
|
|
modifyVoteOld
|
|
modifyVoteNew
|
|
)
|
|
|
|
// ModifyAccountVotes modifies votes of the specified account by value (can be negative).
|
|
// typ specifies if this modify is occurring during transfer or vote (with old or new validator).
|
|
func (n *NEO) ModifyAccountVotes(acc *state.NEOBalanceState, d dao.DAO, value *big.Int, typ int) error {
|
|
n.votesChanged.Store(true)
|
|
if acc.VoteTo != nil {
|
|
key := makeValidatorKey(acc.VoteTo)
|
|
si := d.GetStorageItem(n.ContractID, key)
|
|
if si == nil {
|
|
return errors.New("invalid validator")
|
|
}
|
|
cd := new(candidate).FromBytes(si.Value)
|
|
cd.Votes.Add(&cd.Votes, value)
|
|
switch typ {
|
|
case modifyVoteOld:
|
|
if !cd.Registered && cd.Votes.Sign() == 0 {
|
|
return d.DeleteStorageItem(n.ContractID, key)
|
|
}
|
|
case modifyVoteNew:
|
|
if !cd.Registered {
|
|
return errors.New("validator must be registered")
|
|
}
|
|
}
|
|
n.validators.Store(keys.PublicKeys(nil))
|
|
si.Value = cd.Bytes()
|
|
return d.PutStorageItem(n.ContractID, key, si)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (n *NEO) getCandidates(d dao.DAO) ([]keyWithVotes, error) {
|
|
siMap, err := d.GetStorageItemsWithPrefix(n.ContractID, []byte{prefixCandidate})
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
arr := make([]keyWithVotes, 0, len(siMap))
|
|
for key, si := range siMap {
|
|
c := new(candidate).FromBytes(si.Value)
|
|
if c.Registered {
|
|
arr = append(arr, keyWithVotes{key, &c.Votes})
|
|
}
|
|
}
|
|
sort.Slice(arr, func(i, j int) bool { return strings.Compare(arr[i].Key, arr[j].Key) == -1 })
|
|
return arr, nil
|
|
}
|
|
|
|
// GetCandidates returns current registered validators list with keys
|
|
// and votes.
|
|
func (n *NEO) GetCandidates(d dao.DAO) ([]state.Validator, error) {
|
|
kvs, err := n.getCandidates(d)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
arr := make([]state.Validator, len(kvs))
|
|
for i := range kvs {
|
|
arr[i].Key, err = keys.NewPublicKeyFromBytes([]byte(kvs[i].Key), elliptic.P256())
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
arr[i].Votes = kvs[i].Votes
|
|
}
|
|
return arr, nil
|
|
}
|
|
|
|
func (n *NEO) getCandidatesCall(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
|
|
validators, err := n.getCandidates(ic.DAO)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
arr := make([]stackitem.Item, len(validators))
|
|
for i := range validators {
|
|
arr[i] = stackitem.NewStruct([]stackitem.Item{
|
|
stackitem.NewByteArray([]byte(validators[i].Key)),
|
|
stackitem.NewBigInteger(validators[i].Votes),
|
|
})
|
|
}
|
|
return stackitem.NewArray(arr)
|
|
}
|
|
|
|
// GetValidatorsInternal returns a list of current validators.
|
|
func (n *NEO) GetValidatorsInternal(bc blockchainer.Blockchainer, d dao.DAO) (keys.PublicKeys, error) {
|
|
if vals := n.validators.Load().(keys.PublicKeys); vals != nil {
|
|
return vals.Copy(), nil
|
|
}
|
|
result, err := n.GetCommitteeMembers(bc, d)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
count := bc.GetConfig().ValidatorsCount
|
|
if len(result) < count {
|
|
count = len(result)
|
|
}
|
|
result = result[:count]
|
|
sort.Sort(result)
|
|
n.validators.Store(result)
|
|
return result, nil
|
|
}
|
|
|
|
func (n *NEO) getValidators(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
|
|
result, err := n.GetValidatorsInternal(ic.Chain, ic.DAO)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
return pubsToArray(result)
|
|
}
|
|
|
|
func (n *NEO) getCommittee(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
|
|
pubs, err := n.GetCommitteeMembers(ic.Chain, ic.DAO)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
sort.Sort(pubs)
|
|
return pubsToArray(pubs)
|
|
}
|
|
|
|
func (n *NEO) modifyVoterTurnout(d dao.DAO, amount *big.Int) error {
|
|
key := []byte{prefixVotersCount}
|
|
si := d.GetStorageItem(n.ContractID, key)
|
|
if si == nil {
|
|
return errors.New("voters count not found")
|
|
}
|
|
votersCount := bigint.FromBytes(si.Value)
|
|
votersCount.Add(votersCount, amount)
|
|
si.Value = bigint.ToBytes(votersCount)
|
|
return d.PutStorageItem(n.ContractID, key, si)
|
|
}
|
|
|
|
// GetCommitteeMembers returns public keys of nodes in committee.
|
|
func (n *NEO) GetCommitteeMembers(bc blockchainer.Blockchainer, d dao.DAO) (keys.PublicKeys, error) {
|
|
key := []byte{prefixVotersCount}
|
|
si := d.GetStorageItem(n.ContractID, key)
|
|
if si == nil {
|
|
return nil, errors.New("voters count not found")
|
|
}
|
|
votersCount := bigint.FromBytes(si.Value)
|
|
// votersCount / totalSupply must be >= 0.2
|
|
votersCount.Mul(votersCount, big.NewInt(effectiveVoterTurnout))
|
|
voterTurnout := votersCount.Div(votersCount, n.getTotalSupply(d))
|
|
if voterTurnout.Sign() != 1 {
|
|
return bc.GetStandByValidators(), nil
|
|
}
|
|
cs, err := n.getCandidates(d)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
sbVals := bc.GetStandByValidators()
|
|
count := len(sbVals)
|
|
if len(cs) < count {
|
|
return sbVals, nil
|
|
}
|
|
sort.Slice(cs, func(i, j int) bool {
|
|
// The most-voted validators should end up in the front of the list.
|
|
cmp := cs[i].Votes.Cmp(cs[j].Votes)
|
|
if cmp != 0 {
|
|
return cmp > 0
|
|
}
|
|
// Ties are broken with public keys.
|
|
return strings.Compare(cs[i].Key, cs[j].Key) == -1
|
|
})
|
|
pubs := make(keys.PublicKeys, count)
|
|
for i := range pubs {
|
|
pubs[i], err = keys.NewPublicKeyFromBytes([]byte(cs[i].Key), elliptic.P256())
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
return pubs, nil
|
|
}
|
|
|
|
func (n *NEO) getNextBlockValidators(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
|
|
result, err := n.getNextBlockValidatorsInternal(ic.Chain, ic.DAO)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
return pubsToArray(result)
|
|
}
|
|
|
|
// GetNextBlockValidatorsInternal returns next block validators.
|
|
func (n *NEO) GetNextBlockValidatorsInternal(bc blockchainer.Blockchainer, d dao.DAO) (keys.PublicKeys, error) {
|
|
pubs, err := n.getNextBlockValidatorsInternal(bc, d)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return pubs.Copy(), nil
|
|
}
|
|
|
|
// getNextBlockValidatorsInternal returns next block validators.
|
|
func (n *NEO) getNextBlockValidatorsInternal(bc blockchainer.Blockchainer, d dao.DAO) (keys.PublicKeys, error) {
|
|
si := d.GetStorageItem(n.ContractID, nextValidatorsKey)
|
|
if si == nil {
|
|
return n.GetValidatorsInternal(bc, d)
|
|
}
|
|
pubs := keys.PublicKeys{}
|
|
err := pubs.DecodeBytes(si.Value)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return pubs, nil
|
|
}
|
|
|
|
func pubsToArray(pubs keys.PublicKeys) stackitem.Item {
|
|
arr := make([]stackitem.Item, len(pubs))
|
|
for i := range pubs {
|
|
arr[i] = stackitem.NewByteArray(pubs[i].Bytes())
|
|
}
|
|
return stackitem.NewArray(arr)
|
|
}
|
|
|
|
func toPublicKey(s stackitem.Item) *keys.PublicKey {
|
|
buf, err := s.TryBytes()
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
pub := new(keys.PublicKey)
|
|
if err := pub.DecodeBytes(buf); err != nil {
|
|
panic(err)
|
|
}
|
|
return pub
|
|
}
|