path: root/rpc/api.go

package rpc

import (
    "encoding/json"
    "fmt"
    "math/big"
    "path"
    "strings"
    "sync"
    "time"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/core"
    "github.com/ethereum/go-ethereum/core/types"
    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/ethdb"
    "github.com/ethereum/go-ethereum/event"
    "github.com/ethereum/go-ethereum/event/filter"
    "github.com/ethereum/go-ethereum/state"
    "github.com/ethereum/go-ethereum/xeth"
)

var (
    defaultGasPrice  = big.NewInt(150000000000)
    defaultGas       = big.NewInt(500000)
    filterTickerTime = 5 * time.Minute
)

type EthereumApi struct {
    eth    *xeth.XEth
    xethMu sync.RWMutex
    mux    *event.TypeMux

    quit          chan struct{}
    filterManager *filter.FilterManager

    logMut sync.RWMutex
    logs   map[int]*logFilter

    messagesMut sync.RWMutex
    messages    map[int]*whisperFilter
    // Register keeps a list of accounts and transaction data
    regmut   sync.Mutex
    register map[string][]*NewTxArgs

    db common.Database
}

func NewEthereumApi(eth *xeth.XEth, dataDir string) *EthereumApi {
    db, _ := ethdb.NewLDBDatabase(path.Join(dataDir, "dapps"))
    api := &EthereumApi{
        eth:           eth,
        mux:           eth.Backend().EventMux(),
        quit:          make(chan struct{}),
        filterManager: filter.NewFilterManager(eth.Backend().EventMux()),
        logs:          make(map[int]*logFilter),
        messages:      make(map[int]*whisperFilter),
        db:            db,
    }
    go api.filterManager.Start()
    go api.start()

    return api
}

func (self *EthereumApi) xethWithStateNum(num int64) *xeth.XEth {
    chain := self.xeth().Backend().ChainManager()
    var block *types.Block

    if num < 0 {
        num = chain.CurrentBlock().Number().Int64() + num + 1
    }
    block = chain.GetBlockByNumber(uint64(num))

    var st *state.StateDB
    if block != nil {
        st = state.New(block.Root(), self.xeth().Backend().StateDb())
    } else {
        st = chain.State()
    }
    return self.xeth().WithState(st)
}

func (self *EthereumApi) start() {
    timer := time.NewTicker(filterTickerTime)
done:
    for {
        select {
        case <-timer.C:
            self.logMut.Lock()
            self.messagesMut.Lock()
            for id, filter := range self.logs {
                if time.Since(filter.timeout) > 20*time.Second {
                    self.filterManager.UninstallFilter(id)
                    delete(self.logs, id)
                }
            }

            for id, filter := range self.messages {
                if time.Since(filter.timeout) > 20*time.Second {
                    self.xeth().Whisper().Unwatch(id)
                    delete(self.messages, id)
                }
            }
            self.logMut.Unlock()
            self.messagesMut.Unlock()
        case <-self.quit:
            break done
        }
    }
}

func (self *EthereumApi) stop() {
    close(self.quit)
}

// func (self *EthereumApi) Register(args string, reply *interface{}) error {
//  self.regmut.Lock()
//  defer self.regmut.Unlock()

//  if _, ok := self.register[args]; ok {
//      self.register[args] = nil // register with empty
//  }
//  return nil
// }

// func (self *EthereumApi) Unregister(args string, reply *interface{}) error {
//  self.regmut.Lock()
//  defer self.regmut.Unlock()

//  delete(self.register, args)

//  return nil
// }

// func (self *EthereumApi) WatchTx(args string, reply *interface{}) error {
//  self.regmut.Lock()
//  defer self.regmut.Unlock()

//  txs := self.register[args]
//  self.register[args] = nil

//  *reply = txs
//  return nil
// }

func (self *EthereumApi) NewFilter(args *FilterOptions, reply *interface{}) error {
    var id int
    filter := core.NewFilter(self.xeth().Backend())
    filter.SetOptions(toFilterOptions(args))
    filter.LogsCallback = func(logs state.Logs) {
        self.logMut.Lock()
        defer self.logMut.Unlock()

        self.logs[id].add(logs...)
    }
    id = self.filterManager.InstallFilter(filter)
    self.logs[id] = &logFilter{timeout: time.Now()}

    *reply = common.ToHex(big.NewInt(int64(id)).Bytes())

    return nil
}

func (self *EthereumApi) UninstallFilter(id int, reply *interface{}) error {
    if _, ok := self.logs[id]; ok {
        delete(self.logs, id)
    }

    self.filterManager.UninstallFilter(id)
    *reply = true
    return nil
}

func (self *EthereumApi) NewFilterString(args *FilterStringArgs, reply *interface{}) error {
    var id int
    filter := core.NewFilter(self.xeth().Backend())

    callback := func(block *types.Block) {
        self.logMut.Lock()
        defer self.logMut.Unlock()

        self.logs[id].add(&state.StateLog{})
    }

    switch args.Word {
    case "pending":
        filter.PendingCallback = callback
    case "latest":
        filter.BlockCallback = callback
    default:
        return NewValidationError("Word", "Must be `latest` or `pending`")
    }

    id = self.filterManager.InstallFilter(filter)
    self.logs[id] = &logFilter{timeout: time.Now()}
    *reply = common.ToHex(big.NewInt(int64(id)).Bytes())

    return nil
}

func (self *EthereumApi) FilterChanged(id int, reply *interface{}) error {
    self.logMut.Lock()
    defer self.logMut.Unlock()

    if self.logs[id] != nil {
        *reply = NewLogsRes(self.logs[id].get())
    }

    return nil
}

func (self *EthereumApi) Logs(id int, reply *interface{}) error {
    self.logMut.Lock()
    defer self.logMut.Unlock()

    filter := self.filterManager.GetFilter(id)
    if filter != nil {
        *reply = NewLogsRes(filter.Find())
    }

    return nil
}

func (self *EthereumApi) AllLogs(args *FilterOptions, reply *interface{}) error {
    filter := core.NewFilter(self.xeth().Backend())
    filter.SetOptions(toFilterOptions(args))

    *reply = NewLogsRes(filter.Find())

    return nil
}

func (p *EthereumApi) Transact(args *NewTxArgs, reply *interface{}) (err error) {
    // 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 args.Gas.Cmp(big.NewInt(0)) == 0 {
        args.Gas = defaultGas
    }

    if args.GasPrice.Cmp(big.NewInt(0)) == 0 {
        args.GasPrice = defaultGasPrice
    }

    *reply, err = p.xeth().Transact(args.From, args.To, args.Value.String(), args.Gas.String(), args.GasPrice.String(), args.Data)
    if err != nil {
        fmt.Println("err:", err)
        return err
    }

    return nil
}

func (p *EthereumApi) Call(args *NewTxArgs, reply *interface{}) error {
    result, err := p.xethWithStateNum(args.BlockNumber).Call(args.From, args.To, args.Value.String(), args.Gas.String(), args.GasPrice.String(), args.Data)
    if err != nil {
        return err
    }

    *reply = result
    return nil
}

func (p *EthereumApi) GetStorageAt(args *GetStorageAtArgs, reply *interface{}) error {
    if err := args.requirements(); err != nil {
        return err
    }

    state := p.xethWithStateNum(args.BlockNumber).State().SafeGet(args.Address)
    value := state.StorageString(args.Key)

    var hx string
    if strings.Index(args.Key, "0x") == 0 {
        hx = string([]byte(args.Key)[2:])
    } else {
        // Convert the incoming string (which is a bigint) into hex
        i, _ := new(big.Int).SetString(args.Key, 10)
        hx = common.Bytes2Hex(i.Bytes())
    }
    rpclogger.Debugf("GetStateAt(%s, %s)\n", args.Address, hx)
    *reply = map[string]string{args.Key: value.Str()}
    return nil
}

func (p *EthereumApi) NewWhisperFilter(args *WhisperFilterArgs, reply *interface{}) error {
    var id int
    opts := new(xeth.Options)
    opts.From = args.From
    opts.To = args.To
    opts.Topics = args.Topics
    opts.Fn = func(msg xeth.WhisperMessage) {
        p.messagesMut.Lock()
        defer p.messagesMut.Unlock()
        p.messages[id].add(msg) // = append(p.messages[id], msg)
    }
    id = p.xeth().Whisper().Watch(opts)
    p.messages[id] = &whisperFilter{timeout: time.Now()}
    *reply = common.ToHex(big.NewInt(int64(id)).Bytes())
    return nil
}

func (self *EthereumApi) MessagesChanged(id int, reply *interface{}) error {
    self.messagesMut.Lock()
    defer self.messagesMut.Unlock()

    if self.messages[id] != nil {
        *reply = self.messages[id].get()
    }

    return nil
}

func (p *EthereumApi) WhisperPost(args *WhisperMessageArgs, reply *interface{}) error {
    err := p.xeth().Whisper().Post(args.Payload, args.To, args.From, args.Topics, args.Priority, args.Ttl)
    if err != nil {
        return err
    }

    *reply = true
    return nil
}

func (p *EthereumApi) GetBlockByHash(blockhash string, includetx bool) (*BlockRes, error) {
    block := p.xeth().EthBlockByHash(blockhash)
    br := NewBlockRes(block)
    br.fullTx = includetx
    return br, nil
}

func (p *EthereumApi) GetBlockByNumber(blocknum int64, includetx bool) (*BlockRes, error) {
    block := p.xeth().EthBlockByNumber(blocknum)
    br := NewBlockRes(block)
    br.fullTx = includetx
    return br, nil
}

func (p *EthereumApi) GetBlockTransactionCountByHash(blockhash string) (int64, error) {
    block := p.xeth().EthBlockByHash(blockhash)
    br := NewBlockRes(block)
    return int64(len(br.Transactions)), nil
}

func (p *EthereumApi) GetBlockTransactionCountByNumber(blocknum int64) (int64, error) {
    block := p.xeth().EthBlockByNumber(blocknum)
    br := NewBlockRes(block)
    return int64(len(br.Transactions)), nil
}

func (p *EthereumApi) GetBlockUncleCountByHash(blockhash string) (int64, error) {
    block := p.xeth().EthBlockByHash(blockhash)
    br := NewBlockRes(block)
    return int64(len(br.Uncles)), nil
}

func (p *EthereumApi) GetBlockUncleCountByNumber(blocknum int64) (int64, error) {
    block := p.xeth().EthBlockByNumber(blocknum)
    br := NewBlockRes(block)
    return int64(len(br.Uncles)), nil
}

func (p *EthereumApi) GetRequestReply(req *RpcRequest, reply *interface{}) error {
    // Spec at https://github.com/ethereum/wiki/wiki/Generic-JSON-RPC
    rpclogger.Debugf("%s %s", req.Method, req.Params)
    switch req.Method {
    case "web3_sha3":
        args := new(Sha3Args)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }
        *reply = common.ToHex(crypto.Sha3(common.FromHex(args.Data)))
    case "web3_clientVersion":
        *reply = p.xeth().Backend().Version()
    case "net_version":
        return NewNotImplementedError(req.Method)
    case "net_listening":
        *reply = p.xeth().IsListening()
    case "net_peerCount":
        *reply = common.ToHex(big.NewInt(int64(p.xeth().PeerCount())).Bytes())
    case "eth_coinbase":
        // TODO handling of empty coinbase due to lack of accounts
        res := p.xeth().Coinbase()
        if res == "0x" || res == "0x0" {
            *reply = nil
        } else {
            *reply = res
        }
    case "eth_mining":
        *reply = p.xeth().IsMining()
    case "eth_gasPrice":
        *reply = common.ToHex(defaultGasPrice.Bytes())
    case "eth_accounts":
        *reply = p.xeth().Accounts()
    case "eth_blockNumber":
        *reply = common.ToHex(p.xeth().Backend().ChainManager().CurrentBlock().Number().Bytes())
    case "eth_getBalance":
        args := new(GetBalanceArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }

        if err := args.requirements(); err != nil {
            return err
        }

        *reply = common.ToHex(p.xethWithStateNum(args.BlockNumber).State().SafeGet(args.Address).Balance().Bytes())
    case "eth_getStorage", "eth_storageAt":
        args := new(GetStorageArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }

        if err := args.requirements(); err != nil {
            return err
        }

        *reply = p.xethWithStateNum(args.BlockNumber).State().SafeGet(args.Address).Storage()
    case "eth_getStorageAt":
        args := new(GetStorageAtArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }
        return p.GetStorageAt(args, reply)
    case "eth_getTransactionCount":
        args := new(GetTxCountArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }

        err := args.requirements()
        if err != nil {
            return err
        }

        *reply = p.xethWithStateNum(args.BlockNumber).TxCountAt(args.Address)
    case "eth_getBlockTransactionCountByHash":
        args := new(GetBlockByHashArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }

        v, err := p.GetBlockTransactionCountByHash(args.BlockHash)
        if err != nil {
            return err
        }
        *reply = common.ToHex(big.NewInt(v).Bytes())
    case "eth_getBlockTransactionCountByNumber":
        args := new(GetBlockByNumberArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }

        v, err := p.GetBlockTransactionCountByNumber(args.BlockNumber)
        if err != nil {
            return err
        }
        *reply = common.ToHex(big.NewInt(v).Bytes())
    case "eth_getUncleCountByBlockHash":
        args := new(GetBlockByHashArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }

        v, err := p.GetBlockUncleCountByHash(args.BlockHash)
        if err != nil {
            return err
        }
        *reply = common.ToHex(big.NewInt(v).Bytes())
    case "eth_getUncleCountByBlockNumber":
        args := new(GetBlockByNumberArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }

        v, err := p.GetBlockUncleCountByNumber(args.BlockNumber)
        if err != nil {
            return err
        }
        *reply = common.ToHex(big.NewInt(v).Bytes())
    case "eth_getData", "eth_getCode":
        args := new(GetDataArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }
        if err := args.requirements(); err != nil {
            return err
        }
        *reply = p.xethWithStateNum(args.BlockNumber).CodeAt(args.Address)
    case "eth_sendTransaction", "eth_transact":
        args := new(NewTxArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }
        return p.Transact(args, reply)
    case "eth_call":
        args := new(NewTxArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }
        return p.Call(args, reply)
    case "eth_flush":
        return NewNotImplementedError(req.Method)
    case "eth_getBlockByHash":
        args := new(GetBlockByHashArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }

        v, err := p.GetBlockByHash(args.BlockHash, args.Transactions)
        if err != nil {
            return err
        }
        *reply = v
    case "eth_getBlockByNumber":
        args := new(GetBlockByNumberArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }

        v, err := p.GetBlockByNumber(args.BlockNumber, args.Transactions)
        if err != nil {
            return err
        }
        *reply = v
    case "eth_getTransactionByHash":
        // HashIndexArgs used, but only the "Hash" part we need.
        args := new(HashIndexArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
        }
        tx := p.xeth().EthTransactionByHash(hash)
        if tx != nil {
            *reply = NewTransactionRes(tx)
        }
    case "eth_getTransactionByBlockHashAndIndex":
        args := new(HashIndexArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }

        v, err := p.GetBlockByHash(args.Hash, true)
        if err != nil {
            return err
        }
        if args.Index > int64(len(v.Transactions)) || args.Index < 0 {
            return NewValidationError("Index", "does not exist")
        }
        *reply = v.Transactions[args.Index]
    case "eth_getTransactionByBlockNumberAndIndex":
        args := new(BlockNumIndexArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }

        v, err := p.GetBlockByNumber(args.BlockNumber, true)
        if err != nil {
            return err
        }
        if args.Index > int64(len(v.Transactions)) || args.Index < 0 {
            return NewValidationError("Index", "does not exist")
        }
        *reply = v.Transactions[args.Index]
    case "eth_getUncleByBlockHashAndIndex":
        args := new(HashIndexArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }

        v, err := p.GetBlockByHash(args.Hash, false)
        if err != nil {
            return err
        }
        if args.Index > int64(len(v.Uncles)) || args.Index < 0 {
            return NewValidationError("Index", "does not exist")
        }

        uncle, err := p.GetBlockByHash(common.ToHex(v.Uncles[args.Index]), false)
        if err != nil {
            return err
        }
        *reply = uncle
    case "eth_getUncleByBlockNumberAndIndex":
        args := new(BlockNumIndexArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }

        v, err := p.GetBlockByNumber(args.BlockNumber, true)
        if err != nil {
            return err
        }
        if args.Index > int64(len(v.Uncles)) || args.Index < 0 {
            return NewValidationError("Index", "does not exist")
        }

        uncle, err := p.GetBlockByHash(common.ToHex(v.Uncles[args.Index]), false)
        if err != nil {
            return err
        }
        *reply = uncle
    case "eth_getCompilers":
        c := []string{""}
        *reply = c
    case "eth_compileSolidity", "eth_compileLLL", "eth_compileSerpent":
        return NewNotImplementedError(req.Method)
    case "eth_newFilter":
        args := new(FilterOptions)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }
        return p.NewFilter(args, reply)
    case "eth_newBlockFilter":
        args := new(FilterStringArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }
        return p.NewFilterString(args, reply)
    case "eth_uninstallFilter":
        args := new(FilterIdArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }
        return p.UninstallFilter(args.Id, reply)
    case "eth_getFilterChanges":
        args := new(FilterIdArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }
        return p.FilterChanged(args.Id, reply)
    case "eth_getFilterLogs":
        args := new(FilterIdArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }
        return p.Logs(args.Id, reply)
    case "eth_getLogs":
        args := new(FilterOptions)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }
        return p.AllLogs(args, reply)
    case "eth_getWork", "eth_submitWork":
        return NewNotImplementedError(req.Method)
    case "db_putString":
        args := new(DbArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }

        if err := args.requirements(); err != nil {
            return err
        }

        p.db.Put([]byte(args.Database+args.Key), []byte(args.Value))
        *reply = true
    case "db_getString":
        args := new(DbArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }

        if err := args.requirements(); err != nil {
            return err
        }

        res, _ := p.db.Get([]byte(args.Database + args.Key))
        *reply = string(res)
    case "db_putHex", "db_getHex":
        return NewNotImplementedError(req.Method)
    case "shh_post":
        args := new(WhisperMessageArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }
        return p.WhisperPost(args, reply)
    case "shh_newIdentity":
        *reply = p.xeth().Whisper().NewIdentity()
    // case "shh_removeIdentity":
    //  args := new(WhisperIdentityArgs)
    //  if err := json.Unmarshal(req.Params, &args); err != nil {
    //      return err
    //  }
    //  *reply = p.xeth().Whisper().RemoveIdentity(args.Identity)
    case "shh_hasIdentity":
        args := new(WhisperIdentityArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }
        *reply = p.xeth().Whisper().HasIdentity(args.Identity)
    case "shh_newGroup", "shh_addToGroup":
        return NewNotImplementedError(req.Method)
    case "shh_newFilter":
        args := new(WhisperFilterArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }
        return p.NewWhisperFilter(args, reply)
    case "shh_uninstallFilter":
        args := new(FilterIdArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }

        if _, ok := p.messages[args.Id]; ok {
            delete(p.messages, args.Id)
        }

        *reply = true
    case "shh_getFilterChanges":
        args := new(FilterIdArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }
        return p.MessagesChanged(args.Id, reply)
    case "shh_getMessages":
        args := new(FilterIdArgs)
        if err := json.Unmarshal(req.Params, &args); err != nil {
            return err
        }
        *reply = p.xeth().Whisper().Messages(id)
    // case "eth_register":
    //  args, err := req.ToRegisterArgs()
    //  if err != nil {
    //      return err
    //  }
    //  return p.Register(args, reply)
    // case "eth_unregister":
    //  args, err := req.ToRegisterArgs()
    //  if err != nil {
    //      return err
    //  }
    //  return p.Unregister(args, reply)
    // case "eth_watchTx":
    //  args, err := req.ToWatchTxArgs()
    //  if err != nil {
    //      return err
    //  }
    //  return p.WatchTx(args, reply)
    default:
        return NewNotImplementedError(req.Method)
    }

    rpclogger.DebugDetailf("Reply: %T %s", reply, reply)
    return nil
}

func (self *EthereumApi) xeth() *xeth.XEth {
    self.xethMu.RLock()
    defer self.xethMu.RUnlock()

    return self.eth
}

func toFilterOptions(options *FilterOptions) core.FilterOptions {
    var opts core.FilterOptions

    // Convert optional address slice/string to byte slice
    if str, ok := options.Address.(string); ok {
        opts.Address = [][]byte{common.FromHex(str)}
    } else if slice, ok := options.Address.([]interface{}); ok {
        bslice := make([][]byte, len(slice))
        for i, addr := range slice {
            if saddr, ok := addr.(string); ok {
                bslice[i] = common.FromHex(saddr)
            }
        }
        opts.Address = bslice
    }

    opts.Earliest = options.Earliest
    opts.Latest = options.Latest

    topics := make([][][]byte, len(options.Topics))
    for i, topicDat := range options.Topics {
        if slice, ok := topicDat.([]interface{}); ok {
            topics[i] = make([][]byte, len(slice))
            for j, topic := range slice {
                topics[i][j] = common.FromHex(topic.(string))
            }
        } else if str, ok := topicDat.(string); ok {
            topics[i] = make([][]byte, 1)
            topics[i][0] = common.FromHex(str)
        }
    }
    opts.Topics = topics

    return opts
}

type whisperFilter struct {
    messages []xeth.WhisperMessage
    timeout  time.Time
    id       int
}

func (w *whisperFilter) add(msgs ...xeth.WhisperMessage) {
    w.messages = append(w.messages, msgs...)
}
func (w *whisperFilter) get() []xeth.WhisperMessage {
    w.timeout = time.Now()
    tmp := w.messages
    w.messages = nil
    return tmp
}

type logFilter struct {
    logs    state.Logs
    timeout time.Time
    id      int
}

func (l *logFilter) add(logs ...state.Log) {
    l.logs = append(l.logs, logs...)
}

func (l *logFilter) get() state.Logs {
    l.timeout = time.Now()
    tmp := l.logs
    l.logs = nil
    return tmp
}