/
main.go
208 lines (174 loc) · 4 KB
/
main.go
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package main
import (
"bytes"
"flag"
"fmt"
"io"
"io/ioutil"
"os"
"strings"
mh "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-multihash"
)
var usage = `usage: %s [options] [FILE]
Print or check multihash checksums.
With no FILE, or when FILE is -, read standard input.
Options:
`
// flags
var encodings = []string{"raw", "hex", "base58", "base64"}
var algorithms = []string{"sha1", "sha2-256", "sha2-512", "sha3"}
var encoding string
var algorithm string
var algorithmCode int
var length int
var checkRaw string
var checkMh mh.Multihash
var inputFilename string
var quiet bool
// joined names
var algoStr string
var encStr string
func init() {
flag.Usage = func() {
fmt.Fprintf(os.Stderr, usage, os.Args[0])
flag.PrintDefaults()
}
algoStr = "one of: " + strings.Join(algorithms, ", ")
flag.StringVar(&algorithm, "algorithm", "sha2-256", algoStr)
flag.StringVar(&algorithm, "a", "sha2-256", algoStr+" (shorthand)")
encStr = "one of: " + strings.Join(encodings, ", ")
flag.StringVar(&encoding, "encoding", "base58", encStr)
flag.StringVar(&encoding, "e", "base58", encStr+" (shorthand)")
checkStr := "check checksum matches"
flag.StringVar(&checkRaw, "check", "", checkStr)
flag.StringVar(&checkRaw, "c", "", checkStr+" (shorthand)")
lengthStr := "checksums length in bits (truncate). -1 is default"
flag.IntVar(&length, "length", -1, lengthStr)
flag.IntVar(&length, "l", -1, lengthStr+" (shorthand)")
quietStr := "quiet output (no newline on checksum, no error text)"
flag.BoolVar(&quiet, "quiet", false, quietStr)
flag.BoolVar(&quiet, "q", false, quietStr+" (shorthand)")
}
func strIn(a string, set []string) bool {
for _, s := range set {
if s == a {
return true
}
}
return false
}
func parseFlags() error {
flag.Parse()
if !strIn(algorithm, algorithms) {
return fmt.Errorf("algorithm '%s' not %s", algorithm, algoStr)
}
var found bool
algorithmCode, found = mh.Names[algorithm]
if !found {
return fmt.Errorf("algorithm '%s' not found (lib error, pls report).")
}
if !strIn(encoding, encodings) {
return fmt.Errorf("encoding '%s' not %s", encoding, encStr)
}
if checkRaw != "" {
var err error
checkMh, err = Decode(encoding, checkRaw)
if err != nil {
return fmt.Errorf("fail to decode check '%s': %s", checkRaw, err)
}
}
if length >= 0 {
if length%8 != 0 {
return fmt.Errorf("length must be multiple of 8")
}
length = length / 8
if length > mh.DefaultLengths[algorithmCode] {
length = mh.DefaultLengths[algorithmCode]
}
}
return nil
}
func getInput() (io.ReadCloser, error) {
args := flag.Args()
switch {
case len(args) < 1:
inputFilename = "-"
return os.Stdin, nil
case args[0] == "-":
inputFilename = "-"
return os.Stdin, nil
default:
inputFilename = args[0]
f, err := os.Open(args[0])
if err != nil {
return nil, fmt.Errorf("failed to open '%s': %s", args[0], err)
}
return f, nil
}
}
func check(h1 mh.Multihash, r io.Reader) error {
h2, err := hash(r)
if err != nil {
return err
}
if !bytes.Equal(h1, h2) {
if quiet {
os.Exit(1)
}
return fmt.Errorf("computed checksum did not match (-q for no output)")
}
if !quiet {
fmt.Println("OK checksums match (-q for no output)")
}
return nil
}
func hash(r io.Reader) (mh.Multihash, error) {
b, err := ioutil.ReadAll(r)
if err != nil {
return nil, err
}
return mh.Sum(b, algorithmCode, length)
}
func printHash(r io.Reader) error {
h, err := hash(r)
if err != nil {
return err
}
s, err := Encode(encoding, h)
if err != nil {
return err
}
if quiet {
fmt.Print(s)
} else {
fmt.Println(s)
}
return nil
}
func main() {
checkErr := func(err error) {
if err != nil {
die("error: ", err)
}
}
err := parseFlags()
checkErr(err)
inp, err := getInput()
checkErr(err)
if checkMh != nil {
err = check(checkMh, inp)
checkErr(err)
} else {
err = printHash(inp)
checkErr(err)
}
inp.Close()
}
func die(v ...interface{}) {
if !quiet {
fmt.Fprint(os.Stderr, v...)
fmt.Fprint(os.Stderr, "\n")
}
// flag.Usage()
os.Exit(1)
}