cmd/ethereum: new JS repl with cross-platform line editing

cmd/ethereum/js.go

@@ -18,13 +18,21 @@
 package main
 
 import (
+	"fmt"
 	"io/ioutil"
 	"os"
+	"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) {
@@ -41,3 +49,202 @@ func execJsFile(ethereum *eth.Ethereum, filename string) {
 		utils.Fatalf("Javascript Error: %v", err)
 	}
 }
+
+type repl struct {
+	re       *javascript.JSRE
+	ethereum *eth.Ethereum
+	xeth     *xeth.XEth
+	prompt   string
+	histfile *os.File
+	lr       *liner.State
+	running  bool
+}
+
+func newREPL(ethereum *eth.Ethereum) *repl {
+	hist, err := os.OpenFile(path.Join(ethereum.DataDir, "history"), os.O_RDWR|os.O_CREATE, os.ModePerm)
+	if err != nil {
+		panic(err)
+	}
+	xeth := xeth.New(ethereum)
+	repl := &repl{
+		re:       javascript.NewJSRE(xeth),
+		xeth:     xeth,
+		ethereum: ethereum,
+		prompt:   "> ",
+		histfile: hist,
+		lr:       liner.NewLiner(),
+	}
+	repl.initStdFuncs()
+	return repl
+}
+
+func (self *repl) Start() {
+	if !self.running {
+		self.running = true
+		self.lr.ReadHistory(self.histfile)
+		go self.read()
+	}
+}
+
+func (self *repl) Stop() {
+	if self.running {
+		self.running = false
+		self.histfile.Truncate(0)
+		self.lr.WriteHistory(self.histfile)
+		self.histfile.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() {
+	for {
+		input, err := self.lr.Prompt(self.prompt)
+		if err != nil {
+			return
+		}
+		if input == "" {
+			continue
+		}
+		str += input + "\n"
+		self.setIndent()
+		if indentCount <= 0 {
+			if input == "exit" {
+				self.Stop()
+				return
+			}
+			hist := str[:len(str)-1]
+			self.lr.AppendHistory(hist)
+			self.parseInput(str)
+			str = ""
+		}
+	}
+}
+
+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.Db())
+
+	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()
+}