path: root/cmd/ethereum/js.go

// Copyright (c) 2013-2014, Jeffrey Wilcke. All rights reserved.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
// MA 02110-1301  USA

package main

import (
    "bufio"
    "fmt"
    "io/ioutil"
    "os"
    "os/signal"
    "path"
    "strings"

    "github.com/ethereum/go-ethereum/cmd/utils"
    "github.com/ethereum/go-ethereum/core/types"
    "github.com/ethereum/go-ethereum/eth"
    "github.com/ethereum/go-ethereum/ethutil"
    "github.com/ethereum/go-ethereum/javascript"
    "github.com/ethereum/go-ethereum/state"
    "github.com/ethereum/go-ethereum/xeth"
    "github.com/obscuren/otto"
    "github.com/peterh/liner"
)

func execJsFile(ethereum *eth.Ethereum, filename string) {
    file, err := os.Open(filename)
    if err != nil {
        utils.Fatalf("%v", err)
    }
    content, err := ioutil.ReadAll(file)
    if err != nil {
        utils.Fatalf("%v", err)
    }
    re := javascript.NewJSRE(xeth.New(ethereum, nil))
    if _, err := re.Run(string(content)); err != nil {
        utils.Fatalf("Javascript Error: %v", err)
    }
}

type repl struct {
    re       *javascript.JSRE
    ethereum *eth.Ethereum
    xeth     *xeth.XEth
    prompt   string
    lr       *liner.State
}

func runREPL(ethereum *eth.Ethereum) {
    xeth := xeth.New(ethereum, nil)
    repl := &repl{
        re:       javascript.NewJSRE(xeth),
        xeth:     xeth,
        ethereum: ethereum,
        prompt:   "> ",
    }
    repl.initStdFuncs()
    if !liner.TerminalSupported() {
        repl.dumbRead()
    } else {
        lr := liner.NewLiner()
        defer lr.Close()
        lr.SetCtrlCAborts(true)
        repl.withHistory(func(hist *os.File) { lr.ReadHistory(hist) })
        repl.read(lr)
        repl.withHistory(func(hist *os.File) { hist.Truncate(0); lr.WriteHistory(hist) })
    }
}

func (self *repl) withHistory(op func(*os.File)) {
    hist, err := os.OpenFile(path.Join(self.ethereum.DataDir, "history"), os.O_RDWR|os.O_CREATE, os.ModePerm)
    if err != nil {
        fmt.Printf("unable to open history file: %v\n", err)
        return
    }
    op(hist)
    hist.Close()
}

func (self *repl) parseInput(code string) {
    defer func() {
        if r := recover(); r != nil {
            fmt.Println("[native] error", r)
        }
    }()
    value, err := self.re.Run(code)
    if err != nil {
        fmt.Println(err)
        return
    }
    self.printValue(value)
}

var indentCount = 0
var str = ""

func (self *repl) setIndent() {
    open := strings.Count(str, "{")
    open += strings.Count(str, "(")
    closed := strings.Count(str, "}")
    closed += strings.Count(str, ")")
    indentCount = open - closed
    if indentCount <= 0 {
        self.prompt = "> "
    } else {
        self.prompt = strings.Join(make([]string, indentCount*2), "..")
        self.prompt += " "
    }
}

func (self *repl) read(lr *liner.State) {
    for {
        input, err := lr.Prompt(self.prompt)
        if err != nil {
            return
        }
        if input == "" {
            continue
        }
        str += input + "\n"
        self.setIndent()
        if indentCount <= 0 {
            if input == "exit" {
                return
            }
            hist := str[:len(str)-1]
            lr.AppendHistory(hist)
            self.parseInput(str)
            str = ""
        }
    }
}

func (self *repl) dumbRead() {
    fmt.Println("Unsupported terminal, line editing will not work.")

    // process lines
    readDone := make(chan struct{})
    go func() {
        r := bufio.NewReader(os.Stdin)
    loop:
        for {
            fmt.Print(self.prompt)
            line, err := r.ReadString('\n')
            switch {
            case err != nil || line == "exit":
                break loop
            case line == "":
                continue
            default:
                self.parseInput(line + "\n")
            }
        }
        close(readDone)
    }()

    // wait for Ctrl-C
    sigc := make(chan os.Signal, 1)
    signal.Notify(sigc, os.Interrupt, os.Kill)
    defer signal.Stop(sigc)

    select {
    case <-readDone:
    case <-sigc:
        os.Stdin.Close() // terminate read
    }
}

func (self *repl) printValue(v interface{}) {
    method, _ := self.re.Vm.Get("prettyPrint")
    v, err := self.re.Vm.ToValue(v)
    if err == nil {
        val, err := method.Call(method, v)
        if err == nil {
            fmt.Printf("%v", val)
        }
    }
}

func (self *repl) initStdFuncs() {
    t, _ := self.re.Vm.Get("eth")
    eth := t.Object()
    eth.Set("connect", self.connect)
    eth.Set("stopMining", self.stopMining)
    eth.Set("startMining", self.startMining)
    eth.Set("dump", self.dump)
    eth.Set("export", self.export)
}

/*
 * The following methods are natively implemented javascript functions.
 */

func (self *repl) dump(call otto.FunctionCall) otto.Value {
    var block *types.Block

    if len(call.ArgumentList) > 0 {
        if call.Argument(0).IsNumber() {
            num, _ := call.Argument(0).ToInteger()
            block = self.ethereum.ChainManager().GetBlockByNumber(uint64(num))
        } else if call.Argument(0).IsString() {
            hash, _ := call.Argument(0).ToString()
            block = self.ethereum.ChainManager().GetBlock(ethutil.Hex2Bytes(hash))
        } else {
            fmt.Println("invalid argument for dump. Either hex string or number")
        }

        if block == nil {
            fmt.Println("block not found")

            return otto.UndefinedValue()
        }

    } else {
        block = self.ethereum.ChainManager().CurrentBlock()
    }

    statedb := state.New(block.Root(), self.ethereum.StateDb())

    v, _ := self.re.Vm.ToValue(statedb.RawDump())

    return v
}

func (self *repl) stopMining(call otto.FunctionCall) otto.Value {
    self.xeth.Miner().Stop()
    return otto.TrueValue()
}

func (self *repl) startMining(call otto.FunctionCall) otto.Value {
    self.xeth.Miner().Start()
    return otto.TrueValue()
}

func (self *repl) connect(call otto.FunctionCall) otto.Value {
    nodeURL, err := call.Argument(0).ToString()
    if err != nil {
        return otto.FalseValue()
    }
    if err := self.ethereum.SuggestPeer(nodeURL); err != nil {
        return otto.FalseValue()
    }
    return otto.TrueValue()
}

func (self *repl) export(call otto.FunctionCall) otto.Value {
    if len(call.ArgumentList) == 0 {
        fmt.Println("err: require file name")
        return otto.FalseValue()
    }

    fn, err := call.Argument(0).ToString()
    if err != nil {
        fmt.Println(err)
        return otto.FalseValue()
    }

    data := self.ethereum.ChainManager().Export()

    if err := ethutil.WriteFile(fn, data); err != nil {
        fmt.Println(err)
        return otto.FalseValue()
    }

    return otto.TrueValue()
}