// eXtended ETHereum package xeth import ( "bytes" "encoding/json" "fmt" "math/big" "sync" "time" "github.com/ethereum/go-ethereum/accounts" "github.com/ethereum/go-ethereum/common" "github.com/ethereum/go-ethereum/common/compiler" "github.com/ethereum/go-ethereum/core" "github.com/ethereum/go-ethereum/core/state" "github.com/ethereum/go-ethereum/core/types" "github.com/ethereum/go-ethereum/crypto" "github.com/ethereum/go-ethereum/eth" "github.com/ethereum/go-ethereum/event/filter" "github.com/ethereum/go-ethereum/logger" "github.com/ethereum/go-ethereum/logger/glog" "github.com/ethereum/go-ethereum/miner" "github.com/ethereum/go-ethereum/rlp" ) var ( filterTickerTime = 5 * time.Minute defaultGasPrice = big.NewInt(10000000000000) //150000000000 defaultGas = big.NewInt(90000) //500000 ) // byte will be inferred const ( UnknownFilterTy = iota BlockFilterTy TransactionFilterTy LogFilterTy ) func DefaultGas() *big.Int { return new(big.Int).Set(defaultGas) } func DefaultGasPrice() *big.Int { return new(big.Int).Set(defaultGasPrice) } type XEth struct { backend *eth.Ethereum frontend Frontend state *State whisper *Whisper quit chan struct{} filterManager *filter.FilterManager logMu sync.RWMutex logQueue map[int]*logQueue blockMu sync.RWMutex blockQueue map[int]*hashQueue transactionMu sync.RWMutex transactionQueue map[int]*hashQueue messagesMu sync.RWMutex messages map[int]*whisperFilter // regmut sync.Mutex // register map[string][]*interface{} // TODO improve return type solcPath string solc *compiler.Solidity agent *miner.RemoteAgent } // New creates an XEth that uses the given frontend. // If a nil Frontend is provided, a default frontend which // confirms all transactions will be used. func New(eth *eth.Ethereum, frontend Frontend) *XEth { xeth := &XEth{ backend: eth, frontend: frontend, whisper: NewWhisper(eth.Whisper()), quit: make(chan struct{}), filterManager: filter.NewFilterManager(eth.EventMux()), logQueue: make(map[int]*logQueue), blockQueue: make(map[int]*hashQueue), transactionQueue: make(map[int]*hashQueue), messages: make(map[int]*whisperFilter), agent: miner.NewRemoteAgent(), } eth.Miner().Register(xeth.agent) if frontend == nil { xeth.frontend = dummyFrontend{} } xeth.state = NewState(xeth, xeth.backend.ChainManager().TransState()) go xeth.start() go xeth.filterManager.Start() return xeth } func (self *XEth) start() { timer := time.NewTicker(2 * time.Second) done: for { select { case <-timer.C: self.logMu.Lock() for id, filter := range self.logQueue { if time.Since(filter.timeout) > filterTickerTime { self.filterManager.UninstallFilter(id) delete(self.logQueue, id) } } self.logMu.Unlock() self.blockMu.Lock() for id, filter := range self.blockQueue { if time.Since(filter.timeout) > filterTickerTime { self.filterManager.UninstallFilter(id) delete(self.blockQueue, id) } } self.blockMu.Unlock() self.transactionMu.Lock() for id, filter := range self.transactionQueue { if time.Since(filter.timeout) > filterTickerTime { self.filterManager.UninstallFilter(id) delete(self.transactionQueue, id) } } self.transactionMu.Unlock() self.messagesMu.Lock() for id, filter := range self.messages { if time.Since(filter.activity()) > filterTickerTime { self.Whisper().Unwatch(id) delete(self.messages, id) } } self.messagesMu.Unlock() case <-self.quit: break done } } } func (self *XEth) stop() { close(self.quit) } func cAddress(a []string) []common.Address { bslice := make([]common.Address, len(a)) for i, addr := range a { bslice[i] = common.HexToAddress(addr) } return bslice } func cTopics(t [][]string) [][]common.Hash { topics := make([][]common.Hash, len(t)) for i, iv := range t { topics[i] = make([]common.Hash, len(iv)) for j, jv := range iv { topics[i][j] = common.HexToHash(jv) } } return topics } func (self *XEth) RemoteMining() *miner.RemoteAgent { return self.agent } func (self *XEth) AtStateNum(num int64) *XEth { var st *state.StateDB switch num { case -2: st = self.backend.Miner().PendingState().Copy() default: if block := self.getBlockByHeight(num); block != nil { st = state.New(block.Root(), self.backend.StateDb()) } else { st = state.New(self.backend.ChainManager().GetBlockByNumber(0).Root(), self.backend.StateDb()) } } return self.WithState(st) } // applies queued transactions originating from address onto the latest state // and creates a block // only used in tests // - could be removed in favour of mining on testdag (natspec e2e + networking) // + filters func (self *XEth) ApplyTestTxs(statedb *state.StateDB, address common.Address, txc uint64) (uint64, *XEth) { block := self.backend.ChainManager().NewBlock(address) coinbase := statedb.GetStateObject(address) coinbase.SetGasPool(big.NewInt(10000000)) txs := self.backend.TxPool().GetQueuedTransactions() for i := 0; i < len(txs); i++ { for _, tx := range txs { if tx.Nonce() == txc { _, _, err := core.ApplyMessage(core.NewEnv(statedb, self.backend.ChainManager(), tx, block), tx, coinbase) if err != nil { panic(err) } txc++ } } } xeth := self.WithState(statedb) return txc, xeth } func (self *XEth) WithState(statedb *state.StateDB) *XEth { xeth := &XEth{ backend: self.backend, frontend: self.frontend, } xeth.state = NewState(xeth, statedb) return xeth } func (self *XEth) State() *State { return self.state } // subscribes to new head block events and // waits until blockchain height is greater n at any time // given the current head, waits for the next chain event // sets the state to the current head // loop is async and quit by closing the channel // used in tests and JS console debug module to control advancing private chain manually // Note: this is not threadsafe, only called in JS single process and tests func (self *XEth) UpdateState() (wait chan *big.Int) { wait = make(chan *big.Int) go func() { sub := self.backend.EventMux().Subscribe(core.ChainHeadEvent{}) var m, n *big.Int var ok bool out: for { select { case event := <-sub.Chan(): ev, ok := event.(core.ChainHeadEvent) if ok { m = ev.Block.Number() if n != nil && n.Cmp(m) < 0 { wait <- n n = nil } statedb := state.New(ev.Block.Root(), self.backend.StateDb()) self.state = NewState(self, statedb) } case n, ok = <-wait: if !ok { break out } } } sub.Unsubscribe() }() return } func (self *XEth) Whisper() *Whisper { return self.whisper } func (self *XEth) getBlockByHeight(height int64) *types.Block { var num uint64 switch height { case -2: return self.backend.Miner().PendingBlock() case -1: return self.CurrentBlock() default: if height < 0 { return nil } num = uint64(height) } return self.backend.ChainManager().GetBlockByNumber(num) } func (self *XEth) BlockByHash(strHash string) *Block { hash := common.HexToHash(strHash) block := self.backend.ChainManager().GetBlock(hash) return NewBlock(block) } func (self *XEth) EthBlockByHash(strHash string) *types.Block { hash := common.HexToHash(strHash) block := self.backend.ChainManager().GetBlock(hash) return block } func (self *XEth) EthTransactionByHash(hash string) (tx *types.Transaction, blhash common.Hash, blnum *big.Int, txi uint64) { data, _ := self.backend.ExtraDb().Get(common.FromHex(hash)) if len(data) != 0 { tx = types.NewTransactionFromBytes(data) } else { // check pending transactions tx = self.backend.TxPool().GetTransaction(common.HexToHash(hash)) } // meta var txExtra struct { BlockHash common.Hash BlockIndex uint64 Index uint64 } v, _ := self.backend.ExtraDb().Get(append(common.FromHex(hash), 0x0001)) r := bytes.NewReader(v) err := rlp.Decode(r, &txExtra) if err == nil { blhash = txExtra.BlockHash blnum = big.NewInt(int64(txExtra.BlockIndex)) txi = txExtra.Index } else { glog.V(logger.Error).Infoln(err) } return } func (self *XEth) BlockByNumber(num int64) *Block { return NewBlock(self.getBlockByHeight(num)) } func (self *XEth) EthBlockByNumber(num int64) *types.Block { return self.getBlockByHeight(num) } func (self *XEth) CurrentBlock() *types.Block { return self.backend.ChainManager().CurrentBlock() } func (self *XEth) GasLimit() *big.Int { return self.backend.ChainManager().GasLimit() } func (self *XEth) Block(v interface{}) *Block { if n, ok := v.(int32); ok { return self.BlockByNumber(int64(n)) } else if str, ok := v.(string); ok { return self.BlockByHash(str) } else if f, ok := v.(float64); ok { // Don't ask ... return self.BlockByNumber(int64(f)) } return nil } func (self *XEth) Accounts() []string { // TODO: check err? accounts, _ := self.backend.AccountManager().Accounts() accountAddresses := make([]string, len(accounts)) for i, ac := range accounts { accountAddresses[i] = common.ToHex(ac.Address) } return accountAddresses } // accessor for solidity compiler. // memoized if available, retried on-demand if not func (self *XEth) Solc() (*compiler.Solidity, error) { var err error if self.solc == nil { self.solc, err = compiler.New(self.solcPath) } return self.solc, err } // set in js console via admin interface or wrapper from cli flags func (self *XEth) SetSolc(solcPath string) (*compiler.Solidity, error) { self.solcPath = solcPath self.solc = nil return self.Solc() } func (self *XEth) DbPut(key, val []byte) bool { self.backend.ExtraDb().Put(key, val) return true } func (self *XEth) DbGet(key []byte) ([]byte, error) { val, err := self.backend.ExtraDb().Get(key) return val, err } func (self *XEth) PeerCount() int { return self.backend.PeerCount() } func (self *XEth) IsMining() bool { return self.backend.IsMining() } func (self *XEth) HashRate() int64 { return self.backend.Miner().HashRate() } func (self *XEth) EthVersion() string { return fmt.Sprintf("%d", self.backend.EthVersion()) } func (self *XEth) NetworkVersion() string { return fmt.Sprintf("%d", self.backend.NetVersion()) } func (self *XEth) WhisperVersion() string { return fmt.Sprintf("%d", self.backend.ShhVersion()) } func (self *XEth) ClientVersion() string { return self.backend.ClientVersion() } func (self *XEth) SetMining(shouldmine bool) bool { ismining := self.backend.IsMining() if shouldmine && !ismining { err := self.backend.StartMining() return err == nil } if ismining && !shouldmine { self.backend.StopMining() } return self.backend.IsMining() } func (self *XEth) IsListening() bool { return self.backend.IsListening() } func (self *XEth) Coinbase() string { eb, _ := self.backend.Etherbase() return eb.Hex() } func (self *XEth) NumberToHuman(balance string) string { b := common.Big(balance) return common.CurrencyToString(b) } func (self *XEth) StorageAt(addr, storageAddr string) string { return common.ToHex(self.State().state.GetState(common.HexToAddress(addr), common.HexToHash(storageAddr))) } func (self *XEth) BalanceAt(addr string) string { return common.ToHex(self.State().state.GetBalance(common.HexToAddress(addr)).Bytes()) } func (self *XEth) TxCountAt(address string) int { return int(self.State().state.GetNonce(common.HexToAddress(address))) } func (self *XEth) CodeAt(address string) string { return common.ToHex(self.State().state.GetCode(common.HexToAddress(address))) } func (self *XEth) CodeAtBytes(address string) []byte { return self.State().SafeGet(address).Code() } func (self *XEth) IsContract(address string) bool { return len(self.State().SafeGet(address).Code()) > 0 } func (self *XEth) SecretToAddress(key string) string { pair, err := crypto.NewKeyPairFromSec(common.FromHex(key)) if err != nil { return "" } return common.ToHex(pair.Address()) } func (self *XEth) UninstallFilter(id int) bool { defer self.filterManager.UninstallFilter(id) if _, ok := self.logQueue[id]; ok { self.logMu.Lock() defer self.logMu.Unlock() delete(self.logQueue, id) return true } if _, ok := self.blockQueue[id]; ok { self.blockMu.Lock() defer self.blockMu.Unlock() delete(self.blockQueue, id) return true } if _, ok := self.transactionQueue[id]; ok { self.transactionMu.Lock() defer self.transactionMu.Unlock() delete(self.transactionQueue, id) return true } return false } func (self *XEth) NewLogFilter(earliest, latest int64, skip, max int, address []string, topics [][]string) int { var id int filter := core.NewFilter(self.backend) filter.SetEarliestBlock(earliest) filter.SetLatestBlock(latest) filter.SetSkip(skip) filter.SetMax(max) filter.SetAddress(cAddress(address)) filter.SetTopics(cTopics(topics)) filter.LogsCallback = func(logs state.Logs) { self.logMu.Lock() defer self.logMu.Unlock() self.logQueue[id].add(logs...) } id = self.filterManager.InstallFilter(filter) self.logQueue[id] = &logQueue{timeout: time.Now()} return id } func (self *XEth) NewTransactionFilter() int { var id int filter := core.NewFilter(self.backend) filter.TransactionCallback = func(tx *types.Transaction) { self.transactionMu.Lock() defer self.transactionMu.Unlock() self.transactionQueue[id].add(tx.Hash()) } id = self.filterManager.InstallFilter(filter) self.transactionQueue[id] = &hashQueue{timeout: time.Now()} return id } func (self *XEth) NewBlockFilter() int { var id int filter := core.NewFilter(self.backend) filter.BlockCallback = func(block *types.Block, logs state.Logs) { self.blockMu.Lock() defer self.blockMu.Unlock() self.blockQueue[id].add(block.Hash()) } id = self.filterManager.InstallFilter(filter) self.blockQueue[id] = &hashQueue{timeout: time.Now()} return id } func (self *XEth) GetFilterType(id int) byte { if _, ok := self.blockQueue[id]; ok { return BlockFilterTy } else if _, ok := self.transactionQueue[id]; ok { return TransactionFilterTy } else if _, ok := self.logQueue[id]; ok { return LogFilterTy } return UnknownFilterTy } func (self *XEth) LogFilterChanged(id int) state.Logs { self.logMu.Lock() defer self.logMu.Unlock() if self.logQueue[id] != nil { return self.logQueue[id].get() } return nil } func (self *XEth) BlockFilterChanged(id int) []common.Hash { self.blockMu.Lock() defer self.blockMu.Unlock() if self.blockQueue[id] != nil { return self.blockQueue[id].get() } return nil } func (self *XEth) TransactionFilterChanged(id int) []common.Hash { self.blockMu.Lock() defer self.blockMu.Unlock() if self.transactionQueue[id] != nil { return self.transactionQueue[id].get() } return nil } func (self *XEth) Logs(id int) state.Logs { self.logMu.Lock() defer self.logMu.Unlock() filter := self.filterManager.GetFilter(id) if filter != nil { return filter.Find() } return nil } func (self *XEth) AllLogs(earliest, latest int64, skip, max int, address []string, topics [][]string) state.Logs { filter := core.NewFilter(self.backend) filter.SetEarliestBlock(earliest) filter.SetLatestBlock(latest) filter.SetSkip(skip) filter.SetMax(max) filter.SetAddress(cAddress(address)) filter.SetTopics(cTopics(topics)) return filter.Find() } // NewWhisperFilter creates and registers a new message filter to watch for // inbound whisper messages. All parameters at this point are assumed to be // HEX encoded. func (p *XEth) NewWhisperFilter(to, from string, topics [][]string) int { // Pre-define the id to be filled later var id int // Callback to delegate core whisper messages to this xeth filter callback := func(msg WhisperMessage) { p.messagesMu.RLock() // Only read lock to the filter pool defer p.messagesMu.RUnlock() p.messages[id].insert(msg) } // Initialize the core whisper filter and wrap into xeth id = p.Whisper().Watch(to, from, topics, callback) p.messagesMu.Lock() p.messages[id] = newWhisperFilter(id, p.Whisper()) p.messagesMu.Unlock() return id } // UninstallWhisperFilter disables and removes an existing filter. func (p *XEth) UninstallWhisperFilter(id int) bool { p.messagesMu.Lock() defer p.messagesMu.Unlock() if _, ok := p.messages[id]; ok { delete(p.messages, id) return true } return false } // WhisperMessages retrieves all the known messages that match a specific filter. func (self *XEth) WhisperMessages(id int) []WhisperMessage { self.messagesMu.RLock() defer self.messagesMu.RUnlock() if self.messages[id] != nil { return self.messages[id].messages() } return nil } // WhisperMessagesChanged retrieves all the new messages matched by a filter // since the last retrieval func (self *XEth) WhisperMessagesChanged(id int) []WhisperMessage { self.messagesMu.RLock() defer self.messagesMu.RUnlock() if self.messages[id] != nil { return self.messages[id].retrieve() } return nil } // func (self *XEth) Register(args string) bool { // self.regmut.Lock() // defer self.regmut.Unlock() // if _, ok := self.register[args]; ok { // self.register[args] = nil // register with empty // } // return true // } // func (self *XEth) Unregister(args string) bool { // self.regmut.Lock() // defer self.regmut.Unlock() // if _, ok := self.register[args]; ok { // delete(self.register, args) // return true // } // return false // } // // TODO improve return type // func (self *XEth) PullWatchTx(args string) []*interface{} { // self.regmut.Lock() // defer self.regmut.Unlock() // txs := self.register[args] // self.register[args] = nil // return txs // } type KeyVal struct { Key string `json:"key"` Value string `json:"value"` } func (self *XEth) EachStorage(addr string) string { var values []KeyVal object := self.State().SafeGet(addr) it := object.Trie().Iterator() for it.Next() { values = append(values, KeyVal{common.ToHex(object.Trie().GetKey(it.Key)), common.ToHex(it.Value)}) } valuesJson, err := json.Marshal(values) if err != nil { return "" } return string(valuesJson) } func (self *XEth) ToAscii(str string) string { padded := common.RightPadBytes([]byte(str), 32) return "0x" + common.ToHex(padded) } func (self *XEth) FromAscii(str string) string { if common.IsHex(str) { str = str[2:] } return string(bytes.Trim(common.FromHex(str), "\x00")) } func (self *XEth) FromNumber(str string) string { if common.IsHex(str) { str = str[2:] } return common.BigD(common.FromHex(str)).String() } func (self *XEth) PushTx(encodedTx string) (string, error) { tx := types.NewTransactionFromBytes(common.FromHex(encodedTx)) err := self.backend.TxPool().Add(tx) if err != nil { return "", err } if tx.To() == nil { addr := core.AddressFromMessage(tx) return addr.Hex(), nil } return tx.Hash().Hex(), nil } func (self *XEth) Call(fromStr, toStr, valueStr, gasStr, gasPriceStr, dataStr string) (string, error) { statedb := self.State().State() //self.eth.ChainManager().TransState() var from *state.StateObject if len(fromStr) == 0 { accounts, err := self.backend.AccountManager().Accounts() if err != nil || len(accounts) == 0 { from = statedb.GetOrNewStateObject(common.Address{}) } else { from = statedb.GetOrNewStateObject(common.BytesToAddress(accounts[0].Address)) } } else { from = statedb.GetOrNewStateObject(common.HexToAddress(fromStr)) } msg := callmsg{ from: from, to: common.HexToAddress(toStr), gas: common.Big(gasStr), gasPrice: common.Big(gasPriceStr), value: common.Big(valueStr), data: common.FromHex(dataStr), } if msg.gas.Cmp(big.NewInt(0)) == 0 { msg.gas = DefaultGas() } if msg.gasPrice.Cmp(big.NewInt(0)) == 0 { msg.gasPrice = DefaultGasPrice() } block := self.CurrentBlock() vmenv := core.NewEnv(statedb, self.backend.ChainManager(), msg, block) res, err := vmenv.Call(msg.from, msg.to, msg.data, msg.gas, msg.gasPrice, msg.value) return common.ToHex(res), err } func (self *XEth) ConfirmTransaction(tx string) bool { return self.frontend.ConfirmTransaction(tx) } func (self *XEth) Sign(fromStr, hashStr string, didUnlock bool) (string, error) { var ( from = common.HexToAddress(fromStr) hash = common.HexToHash(hashStr) ) sig, err := self.backend.AccountManager().Sign(accounts.Account{Address: from.Bytes()}, hash.Bytes()) if err == accounts.ErrLocked { if didUnlock { return "", fmt.Errorf("signer account still locked after successful unlock") } if !self.frontend.UnlockAccount(from.Bytes()) { return "", fmt.Errorf("could not unlock signer account") } // retry signing, the account should now be unlocked. return self.Sign(fromStr, hashStr, true) } else if err != nil { return "", err } return common.ToHex(sig), nil } func (self *XEth) Transact(fromStr, toStr, nonceStr, valueStr, gasStr, gasPriceStr, codeStr string) (string, error) { // this minimalistic recoding is enough (works for natspec.js) var jsontx = fmt.Sprintf(`{"params":[{"to":"%s","data": "%s"}]}`, toStr, codeStr) if !self.ConfirmTransaction(jsontx) { err := fmt.Errorf("Transaction not confirmed") return "", err } var ( from = common.HexToAddress(fromStr) to = common.HexToAddress(toStr) value = common.NewValue(valueStr) gas = common.Big(gasStr) price = common.Big(gasPriceStr) data []byte contractCreation bool ) // TODO if no_private_key then //if _, exists := p.register[args.From]; exists { // p.register[args.From] = append(p.register[args.From], args) //} else { /* account := accounts.Get(common.FromHex(args.From)) if account != nil { if account.Unlocked() { if !unlockAccount(account) { return } } result, _ := account.Transact(common.FromHex(args.To), common.FromHex(args.Value), common.FromHex(args.Gas), common.FromHex(args.GasPrice), common.FromHex(args.Data)) if len(result) > 0 { *reply = common.ToHex(result) } } else if _, exists := p.register[args.From]; exists { p.register[ags.From] = append(p.register[args.From], args) } */ // TODO: align default values to have the same type, e.g. not depend on // common.Value conversions later on if gas.Cmp(big.NewInt(0)) == 0 { gas = DefaultGas() } if price.Cmp(big.NewInt(0)) == 0 { price = DefaultGasPrice() } data = common.FromHex(codeStr) if len(toStr) == 0 { contractCreation = true } var tx *types.Transaction if contractCreation { tx = types.NewContractCreationTx(value.BigInt(), gas, price, data) } else { tx = types.NewTransactionMessage(to, value.BigInt(), gas, price, data) } state := self.backend.ChainManager().TxState() var nonce uint64 if len(nonceStr) != 0 { nonce = common.Big(nonceStr).Uint64() } else { nonce = state.NewNonce(from) } tx.SetNonce(nonce) if err := self.sign(tx, from, false); err != nil { return "", err } if err := self.backend.TxPool().Add(tx); err != nil { return "", err } if contractCreation { addr := core.AddressFromMessage(tx) glog.V(logger.Info).Infof("Tx(%x) created: %x\n", tx.Hash(), addr) return core.AddressFromMessage(tx).Hex(), nil } else { glog.V(logger.Info).Infof("Tx(%x) to: %x\n", tx.Hash(), tx.To()) } return tx.Hash().Hex(), nil } func (self *XEth) sign(tx *types.Transaction, from common.Address, didUnlock bool) error { sig, err := self.backend.AccountManager().Sign(accounts.Account{Address: from.Bytes()}, tx.Hash().Bytes()) if err == accounts.ErrLocked { if didUnlock { return fmt.Errorf("sender account still locked after successful unlock") } if !self.frontend.UnlockAccount(from.Bytes()) { return fmt.Errorf("could not unlock sender account") } // retry signing, the account should now be unlocked. return self.sign(tx, from, true) } else if err != nil { return err } tx.SetSignatureValues(sig) return nil } // callmsg is the message type used for call transations. type callmsg struct { from *state.StateObject to common.Address gas, gasPrice *big.Int value *big.Int data []byte } // accessor boilerplate to implement core.Message func (m callmsg) From() (common.Address, error) { return m.from.Address(), nil } func (m callmsg) Nonce() uint64 { return m.from.Nonce() } func (m callmsg) To() *common.Address { return &m.to } func (m callmsg) GasPrice() *big.Int { return m.gasPrice } func (m callmsg) Gas() *big.Int { return m.gas } func (m callmsg) Value() *big.Int { return m.value } func (m callmsg) Data() []byte { return m.data } type logQueue struct { logs state.Logs timeout time.Time id int } func (l *logQueue) add(logs ...*state.Log) { l.logs = append(l.logs, logs...) } func (l *logQueue) get() state.Logs { l.timeout = time.Now() tmp := l.logs l.logs = nil return tmp } type hashQueue struct { hashes []common.Hash timeout time.Time id int } func (l *hashQueue) add(hashes ...common.Hash) { l.hashes = append(l.hashes, hashes...) } func (l *hashQueue) get() []common.Hash { l.timeout = time.Now() tmp := l.hashes l.hashes = nil return tmp }