moby/utils/tarsum.go
2013-08-12 22:42:29 +00:00

158 lines
3.3 KiB
Go

package utils
import (
"bytes"
"compress/gzip"
"crypto/sha256"
"encoding/hex"
"github.com/dotcloud/tar"
"hash"
"io"
"sort"
"strconv"
)
type verboseHash struct {
hash.Hash
}
func (h verboseHash) Write(buf []byte) (int, error) {
Debugf("--->%s<---", buf)
return h.Hash.Write(buf)
}
type TarSum struct {
io.Reader
tarR *tar.Reader
tarW *tar.Writer
gz *gzip.Writer
bufTar *bytes.Buffer
bufGz *bytes.Buffer
h hash.Hash
h2 verboseHash
sums []string
finished bool
first bool
}
func (ts *TarSum) encodeHeader(h *tar.Header) error {
for _, elem := range [][2]string{
{"name", h.Name},
{"mode", strconv.Itoa(int(h.Mode))},
{"uid", strconv.Itoa(h.Uid)},
{"gid", strconv.Itoa(h.Gid)},
{"size", strconv.Itoa(int(h.Size))},
{"mtime", strconv.Itoa(int(h.ModTime.UTC().Unix()))},
{"typeflag", string([]byte{h.Typeflag})},
{"linkname", h.Linkname},
{"uname", h.Uname},
{"gname", h.Gname},
{"devmajor", strconv.Itoa(int(h.Devmajor))},
{"devminor", strconv.Itoa(int(h.Devminor))},
// {"atime", strconv.Itoa(int(h.AccessTime.UTC().Unix()))},
// {"ctime", strconv.Itoa(int(h.ChangeTime.UTC().Unix()))},
} {
// Debugf("-->%s<-- -->%s<--", elem[0], elem[1])
if _, err := ts.h.Write([]byte(elem[0] + elem[1])); err != nil {
return err
}
}
return nil
}
func (ts *TarSum) Read(buf []byte) (int, error) {
if ts.gz == nil {
ts.bufTar = bytes.NewBuffer([]byte{})
ts.bufGz = bytes.NewBuffer([]byte{})
ts.tarR = tar.NewReader(ts.Reader)
ts.tarW = tar.NewWriter(ts.bufTar)
ts.gz = gzip.NewWriter(ts.bufGz)
ts.h = sha256.New()
// ts.h = verboseHash{sha256.New()}
ts.h.Reset()
ts.first = true
}
if ts.finished {
return ts.bufGz.Read(buf)
}
buf2 := make([]byte, len(buf), cap(buf))
n, err := ts.tarR.Read(buf2)
if err != nil {
if err == io.EOF {
if _, err := ts.h.Write(buf2[:n]); err != nil {
return 0, err
}
if !ts.first {
ts.sums = append(ts.sums, hex.EncodeToString(ts.h.Sum(nil)))
ts.h.Reset()
} else {
ts.first = false
}
currentHeader, err := ts.tarR.Next()
if err != nil {
if err == io.EOF {
if err := ts.gz.Close(); err != nil {
return 0, err
}
ts.finished = true
return n, nil
}
return n, err
}
if err := ts.encodeHeader(currentHeader); err != nil {
return 0, err
}
if err := ts.tarW.WriteHeader(currentHeader); err != nil {
return 0, err
}
if _, err := ts.tarW.Write(buf2[:n]); err != nil {
return 0, err
}
ts.tarW.Flush()
if _, err := io.Copy(ts.gz, ts.bufTar); err != nil {
return 0, err
}
ts.gz.Flush()
return ts.bufGz.Read(buf)
}
return n, err
}
// Filling the hash buffer
if _, err = ts.h.Write(buf2[:n]); err != nil {
return 0, err
}
// Filling the tar writter
if _, err = ts.tarW.Write(buf2[:n]); err != nil {
return 0, err
}
ts.tarW.Flush()
// Filling the gz writter
if _, err = io.Copy(ts.gz, ts.bufTar); err != nil {
return 0, err
}
ts.gz.Flush()
return ts.bufGz.Read(buf)
}
func (ts *TarSum) Sum(extra []byte) string {
sort.Strings(ts.sums)
h := sha256.New()
if extra != nil {
h.Write(extra)
}
for _, sum := range ts.sums {
Debugf("-->%s<--", sum)
h.Write([]byte(sum))
}
checksum := "tarsum+sha256:" + hex.EncodeToString(h.Sum(nil))
Debugf("checksum processed: %s", checksum)
return checksum
}