path: root/xeth/xeth.go

// 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
    dappStorePre     = []byte("dapp-")
)

// byte will be inferred
const (
    UnknownFilterTy = iota
    BlockFilterTy
    TransactionFilterTy
    LogFilterTy
)

func DefaultGas() *big.Int { return new(big.Int).Set(defaultGas) }

func (self *XEth) DefaultGasPrice() *big.Int {
    if self.gpo == nil {
        self.gpo = eth.NewGasPriceOracle(self.backend)
    }
    return self.gpo.SuggestPrice()
}

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

    agent *miner.RemoteAgent

    gpo *eth.GasPriceOracle
}

func NewTest(eth *eth.Ethereum, frontend Frontend) *XEth {
    return &XEth{
        backend:  eth,
        frontend: frontend,
    }
}

// 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(ethereum *eth.Ethereum, frontend Frontend) *XEth {
    xeth := &XEth{
        backend:          ethereum,
        frontend:         frontend,
        quit:             make(chan struct{}),
        filterManager:    filter.NewFilterManager(ethereum.EventMux()),
        logQueue:         make(map[int]*logQueue),
        blockQueue:       make(map[int]*hashQueue),
        transactionQueue: make(map[int]*hashQueue),
        messages:         make(map[int]*whisperFilter),
        agent:            miner.NewRemoteAgent(),
    }
    if ethereum.Whisper() != nil {
        xeth.whisper = NewWhisper(ethereum.Whisper())
    }
    ethereum.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) {
    chain := self.backend.ChainManager()
    header := chain.CurrentBlock().Header()
    coinbase := statedb.GetStateObject(address)
    coinbase.SetGasLimit(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, header), 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,
        gpo:      self.gpo,
    }

    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) {
    // Due to increasing return params and need to determine if this is from transaction pool or
    // some chain, this probably needs to be refactored for more expressiveness
    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, dberr := self.backend.ExtraDb().Get(append(common.FromHex(hash), 0x0001))
    // TODO check specifically for ErrNotFound
    if dberr != nil {
        return
    }
    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) GetBlockReceipts(bhash common.Hash) (receipts types.Receipts, err error) {
    return self.backend.BlockProcessor().GetBlockReceipts(bhash)
}

func (self *XEth) GetTxReceipt(txhash common.Hash) (receipt *types.Receipt, err error) {
    _, bhash, _, txi := self.EthTransactionByHash(common.ToHex(txhash[:]))
    var receipts types.Receipts
    receipts, err = self.backend.BlockProcessor().GetBlockReceipts(bhash)
    if err == nil {
        if txi < uint64(len(receipts)) {
            receipt = receipts[txi]
        } else {
            err = fmt.Errorf("Invalid tx index")
        }
    }
    return
}

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 { // JSON numbers are represented as float64
        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] = ac.Address.Hex()
    }
    return accountAddresses
}

// accessor for solidity compiler.
// memoized if available, retried on-demand if not
func (self *XEth) Solc() (*compiler.Solidity, error) {
    return self.backend.Solc()
}

// set in js console via admin interface or wrapper from cli flags
func (self *XEth) SetSolc(solcPath string) (*compiler.Solidity, error) {
    self.backend.SetSolc(solcPath)
    return self.Solc()
}

// store DApp value in extra database
func (self *XEth) DbPut(key, val []byte) bool {
    self.backend.ExtraDb().Put(append(dappStorePre, key...), val)
    return true
}

// retrieve DApp value from extra database
func (self *XEth) DbGet(key []byte) ([]byte, error) {
    val, err := self.backend.ExtraDb().Get(append(dappStorePre, 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, threads int) bool {
    ismining := self.backend.IsMining()
    if shouldmine && !ismining {
        err := self.backend.StartMining(threads)
        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 self.State().state.GetState(common.HexToAddress(addr), common.HexToHash(storageAddr)).Hex()
}

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)
        glog.V(logger.Info).Infof("Tx(%x) created: %x\n", tx.Hash(), addr)
        return addr.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) Call(fromStr, toStr, valueStr, gasStr, gasPriceStr, dataStr string) (string, string, error) {
    statedb := self.State().State().Copy()
    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(accounts[0].Address)
        }
    } else {
        from = statedb.GetOrNewStateObject(common.HexToAddress(fromStr))
    }

    from.SetBalance(common.MaxBig)
    from.SetGasLimit(self.backend.ChainManager().GasLimit())
    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 = self.DefaultGasPrice()
    }

    header := self.CurrentBlock().Header()
    vmenv := core.NewEnv(statedb, self.backend.ChainManager(), msg, header)

    res, gas, err := core.ApplyMessage(vmenv, msg, from)
    return common.ToHex(res), gas.String(), err
}

func (self *XEth) ConfirmTransaction(tx string) bool {
    return self.frontend.ConfirmTransaction(tx)
}

func (self *XEth) doSign(from common.Address, hash common.Hash, didUnlock bool) ([]byte, error) {
    sig, err := self.backend.AccountManager().Sign(accounts.Account{Address: from}, hash.Bytes())
    if err == accounts.ErrLocked {
        if didUnlock {
            return nil, fmt.Errorf("signer account still locked after successful unlock")
        }
        if !self.frontend.UnlockAccount(from.Bytes()) {
            return nil, fmt.Errorf("could not unlock signer account")
        }
        // retry signing, the account should now be unlocked.
        return self.doSign(from, hash, true)
    } else if err != nil {
        return nil, err
    }
    return sig, nil
}

func (self *XEth) Sign(fromStr, hashStr string, didUnlock bool) (string, error) {
    var (
        from = common.HexToAddress(fromStr)
        hash = common.HexToHash(hashStr)
    )
    sig, err := self.doSign(from, hash, didUnlock)
    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.Big(valueStr)
        gas              *big.Int
        price            *big.Int
        data             []byte
        contractCreation bool
    )

    if len(gasStr) == 0 {
        gas = DefaultGas()
    } else {
        gas = common.Big(gasStr)
    }

    if len(gasPriceStr) == 0 {
        price = self.DefaultGasPrice()
    } else {
        price = common.Big(gasPriceStr)
    }

    data = common.FromHex(codeStr)
    if len(toStr) == 0 {
        contractCreation = true
    }

    // 2015-05-18 Is this still needed?
    // 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
    var nonce uint64
    if len(nonceStr) != 0 {
        nonce = common.Big(nonceStr).Uint64()
    } else {
        state := self.backend.TxPool().State()
        nonce = state.GetNonce(from)
    }
    var tx *types.Transaction
    if contractCreation {
        tx = types.NewContractCreation(nonce, value, gas, price, data)
    } else {
        tx = types.NewTransaction(nonce, to, value, gas, price, data)
    }

    signed, err := self.sign(tx, from, false)
    if err != nil {
        return "", err
    }
    if err = self.backend.TxPool().Add(signed); err != nil {
        return "", err
    }

    if contractCreation {
        addr := core.AddressFromMessage(tx)
        glog.V(logger.Info).Infof("Tx(%x) created: %x\n", tx.Hash(), addr)
        return addr.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) (*types.Transaction, error) {
    hash := tx.Hash()
    sig, err := self.doSign(from, hash, didUnlock)
    if err != nil {
        return tx, err
    }
    return tx.WithSignature(sig)
}

// 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
}