forked from vbatts/tar-split
/
disasm.go
63 lines (57 loc) · 1.42 KB
/
disasm.go
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package main
import (
"compress/gzip"
"io"
"os"
"github.com/bmoylan/tar-split/tar/asm"
"github.com/bmoylan/tar-split/tar/storage"
"github.com/sirupsen/logrus"
"github.com/urfave/cli"
)
// CommandDisasm provides the disasm command.
func CommandDisasm(c *cli.Context) {
if len(c.Args()) != 1 {
logrus.Fatalf("please specify tar to be disabled <NAME|->")
}
if len(c.String("output")) == 0 {
logrus.Fatalf("--output filename must be set")
}
// Set up the tar input stream
var inputStream io.Reader
if c.Args()[0] == "-" {
inputStream = os.Stdin
} else {
fh, err := os.Open(c.Args()[0])
if err != nil {
logrus.Fatal(err)
}
defer safeClose(fh)
inputStream = fh
}
// Set up the metadata storage
mf, err := os.OpenFile(c.String("output"), os.O_CREATE|os.O_WRONLY|os.O_TRUNC, os.FileMode(0600))
if err != nil {
logrus.Fatal(err)
}
defer safeClose(mf)
mfz := gzip.NewWriter(mf)
defer safeClose(mfz)
metaPacker := storage.NewJSONPacker(mfz)
// we're passing nil here for the file putter, because the ApplyDiff will
// handle the extraction of the archive
its, err := asm.NewInputTarStream(inputStream, metaPacker, nil)
if err != nil {
logrus.Fatal(err)
}
var out io.Writer
if c.Bool("no-stdout") {
out = io.Discard
} else {
out = os.Stdout
}
i, err := io.Copy(out, its)
if err != nil {
logrus.Fatal(err)
}
logrus.Infof("created %s from %s (read %d bytes)", c.String("output"), c.Args()[0], i)
}