path: root/cmd/rlpdump/main.go

// Copyright 2015 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum 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 3 of the License, or
// (at your option) any later version.
//
// go-ethereum 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 go-ethereum. If not, see <http://www.gnu.org/licenses/>.

// rlpdump is a pretty-printer for RLP data.
package main

import (
    "bytes"
    "encoding/hex"
    "flag"
    "fmt"
    "io"
    "os"
    "strings"

    "github.com/ethereum/go-ethereum/rlp"
)

var (
    hexMode = flag.String("hex", "", "dump given hex data")
    noASCII = flag.Bool("noascii", false, "don't print ASCII strings readably")
    single  = flag.Bool("single", false, "print only the first element, discard the rest")
)

func init() {
    flag.Usage = func() {
        fmt.Fprintln(os.Stderr, "Usage:", os.Args[0], "[-noascii] [-hex <data>] [filename]")
        flag.PrintDefaults()
        fmt.Fprintln(os.Stderr, `
Dumps RLP data from the given file in readable form.
If the filename is omitted, data is read from stdin.`)
    }
}

func main() {
    flag.Parse()

    var r io.Reader
    switch {
    case *hexMode != "":
        data, err := hex.DecodeString(*hexMode)
        if err != nil {
            die(err)
        }
        r = bytes.NewReader(data)

    case flag.NArg() == 0:
        r = os.Stdin

    case flag.NArg() == 1:
        fd, err := os.Open(flag.Arg(0))
        if err != nil {
            die(err)
        }
        defer fd.Close()
        r = fd

    default:
        fmt.Fprintln(os.Stderr, "Error: too many arguments")
        flag.Usage()
        os.Exit(2)
    }

    s := rlp.NewStream(r, 0)
    for {
        if err := dump(s, 0); err != nil {
            if err != io.EOF {
                die(err)
            }
            break
        }
        fmt.Println()
        if *single {
            break
        }
    }
}

func dump(s *rlp.Stream, depth int) error {
    kind, size, err := s.Kind()
    if err != nil {
        return err
    }
    switch kind {
    case rlp.Byte, rlp.String:
        str, err := s.Bytes()
        if err != nil {
            return err
        }
        if len(str) == 0 || !*noASCII && isASCII(str) {
            fmt.Printf("%s%q", ws(depth), str)
        } else {
            fmt.Printf("%s%x", ws(depth), str)
        }
    case rlp.List:
        s.List()
        defer s.ListEnd()
        if size == 0 {
            fmt.Print(ws(depth) + "[]")
        } else {
            fmt.Println(ws(depth) + "[")
            for i := 0; ; i++ {
                if i > 0 {
                    fmt.Print(",\n")
                }
                if err := dump(s, depth+1); err == rlp.EOL {
                    break
                } else if err != nil {
                    return err
                }
            }
            fmt.Print(ws(depth) + "]")
        }
    }
    return nil
}

func isASCII(b []byte) bool {
    for _, c := range b {
        if c < 32 || c > 126 {
            return false
        }
    }
    return true
}

func ws(n int) string {
    return strings.Repeat("  ", n)
}

func die(args ...interface{}) {
    fmt.Fprintln(os.Stderr, args...)
    os.Exit(1)
}