path: root/ethereum/javascript_runtime.go

package main

import (
    "fmt"
    "github.com/ethereum/eth-go"
    "github.com/ethereum/eth-go/ethchain"
    "github.com/ethereum/eth-go/ethpub"
    "github.com/ethereum/eth-go/ethutil"
    "github.com/obscuren/otto"
    "io/ioutil"
    "os"
    "path/filepath"
)

type JSRE struct {
    ethereum *eth.Ethereum
    vm       *otto.Otto
    lib      *ethpub.PEthereum

    blockChan  chan ethutil.React
    changeChan chan ethutil.React
    quitChan   chan bool

    objectCb map[string][]otto.Value
}

func NewJSRE(ethereum *eth.Ethereum) *JSRE {
    re := &JSRE{
        ethereum,
        otto.New(),
        ethpub.NewPEthereum(ethereum),
        make(chan ethutil.React, 1),
        make(chan ethutil.React, 1),
        make(chan bool),
        make(map[string][]otto.Value),
    }

    // Init the JS lib
    re.vm.Run(jsLib)

    // We have to make sure that, whoever calls this, calls "Stop"
    go re.mainLoop()

    re.Bind("eth", &JSEthereum{re.lib, re.vm})

    re.initStdFuncs()

    return re
}

func (self *JSRE) Bind(name string, v interface{}) {
    self.vm.Set(name, v)
}

func (self *JSRE) Run(code string) (otto.Value, error) {
    return self.vm.Run(code)
}

func (self *JSRE) Require(file string) error {
    if len(filepath.Ext(file)) == 0 {
        file += ".js"
    }

    fh, err := os.Open(file)
    if err != nil {
        return err
    }

    content, _ := ioutil.ReadAll(fh)
    self.Run("exports = {};(function() {" + string(content) + "})();")

    return nil
}

func (self *JSRE) Stop() {
    // Kill the main loop
    self.quitChan <- true

    close(self.blockChan)
    close(self.quitChan)
    close(self.changeChan)
}

func (self *JSRE) mainLoop() {
    // Subscribe to events
    reactor := self.ethereum.Reactor()
    reactor.Subscribe("newBlock", self.blockChan)

out:
    for {
        select {
        case <-self.quitChan:
            break out
        case block := <-self.blockChan:
            if _, ok := block.Resource.(*ethchain.Block); ok {
            }
        case object := <-self.changeChan:
            if stateObject, ok := object.Resource.(*ethchain.StateObject); ok {
                for _, cb := range self.objectCb[ethutil.Hex(stateObject.Address())] {
                    val, _ := self.vm.ToValue(ethpub.NewPStateObject(stateObject))
                    cb.Call(cb, val)
                }
            } else if storageObject, ok := object.Resource.(*ethchain.StorageState); ok {
                for _, cb := range self.objectCb[ethutil.Hex(storageObject.StateAddress)+ethutil.Hex(storageObject.Address)] {
                    val, _ := self.vm.ToValue(ethpub.NewPStorageState(storageObject))
                    cb.Call(cb, val)
                }
            }
        }
    }
}

func (self *JSRE) initStdFuncs() {
    t, _ := self.vm.Get("eth")
    eth := t.Object()
    eth.Set("watch", self.watch)
    eth.Set("addPeer", self.addPeer)
    eth.Set("require", self.require)
}

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

// eth.watch
func (self JSRE) watch(call otto.FunctionCall) otto.Value {
    addr, _ := call.Argument(0).ToString()
    var storageAddr string
    var cb otto.Value
    var storageCallback bool
    if len(call.ArgumentList) > 2 {
        storageCallback = true
        storageAddr, _ = call.Argument(1).ToString()
        cb = call.Argument(2)
    } else {
        cb = call.Argument(1)
    }

    if storageCallback {
        self.objectCb[addr+storageAddr] = append(self.objectCb[addr+storageAddr], cb)

        event := "storage:" + string(ethutil.FromHex(addr)) + ":" + string(ethutil.FromHex(storageAddr))
        self.ethereum.Reactor().Subscribe(event, self.changeChan)
    } else {
        self.objectCb[addr] = append(self.objectCb[addr], cb)

        event := "object:" + string(ethutil.FromHex(addr))
        self.ethereum.Reactor().Subscribe(event, self.changeChan)
    }

    return otto.UndefinedValue()
}

func (self *JSRE) addPeer(call otto.FunctionCall) otto.Value {
    host, err := call.Argument(0).ToString()
    if err != nil {
        return otto.FalseValue()
    }
    self.ethereum.ConnectToPeer(host)

    return otto.TrueValue()
}

func (self *JSRE) require(call otto.FunctionCall) otto.Value {
    file, err := call.Argument(0).ToString()
    if err != nil {
        return otto.UndefinedValue()
    }
    if err := self.Require(file); err != nil {
        fmt.Println("err:", err)
        return otto.UndefinedValue()
    }

    t, _ := self.vm.Get("exports")

    return t
}