forked from ipfs/kubo
/
msgio.go
108 lines (87 loc) · 1.6 KB
/
msgio.go
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package main
import (
"flag"
"fmt"
"io"
"io/ioutil"
"os"
"strconv"
"strings"
msgio "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-msgio"
)
var Args ArgType
type ArgType struct {
Command string
Args []string
}
func (a *ArgType) Arg(i int) string {
n := i + 1
if len(a.Args) < n {
die(fmt.Sprintf("expected %d argument(s)", n))
}
return a.Args[i]
}
var usageStr = `
msgio - tool to wrap messages with msgio header
Usage
msgio header 1020 >header
cat file | msgio wrap >wrapped
Commands
header <size> output a msgio header of given size
wrap wrap incoming stream with msgio
`
func usage() {
fmt.Println(strings.TrimSpace(usageStr))
os.Exit(0)
}
func die(err string) {
fmt.Fprintf(os.Stderr, "error: %s\n", err)
os.Exit(-1)
}
func main() {
if err := run(); err != nil {
die(err.Error())
}
}
func argParse() {
flag.Usage = usage
flag.Parse()
args := flag.Args()
if l := len(args); l < 1 || l > 2 {
usage()
}
Args.Command = flag.Args()[0]
Args.Args = flag.Args()[1:]
}
func run() error {
argParse()
w := os.Stdout
r := os.Stdin
switch Args.Command {
case "header":
size, err := strconv.Atoi(Args.Arg(0))
if err != nil {
return err
}
return header(w, size)
case "wrap":
return wrap(w, r)
default:
usage()
return nil
}
}
func header(w io.Writer, size int) error {
return msgio.WriteLen(w, size)
}
func wrap(w io.Writer, r io.Reader) error {
buf, err := ioutil.ReadAll(r)
if err != nil {
return err
}
if err := msgio.WriteLen(w, len(buf)); err != nil {
return err
}
_, err = w.Write(buf)
return err
}