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moby--moby/utils/tarsum.go

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package utils
import (
"bytes"
"compress/gzip"
"crypto/sha256"
"encoding/hex"
"github.com/dotcloud/docker/vendor/src/code.google.com/p/go/src/pkg/archive/tar"
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"hash"
"io"
"sort"
"strconv"
"strings"
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)
type TarSum struct {
io.Reader
tarR *tar.Reader
tarW *tar.Writer
gz writeCloseFlusher
bufTar *bytes.Buffer
bufGz *bytes.Buffer
h hash.Hash
sums map[string]string
currentFile string
finished bool
first bool
DisableCompression bool
}
type writeCloseFlusher interface {
io.WriteCloser
Flush() error
}
type nopCloseFlusher struct {
io.Writer
}
func (n *nopCloseFlusher) Close() error {
return nil
}
func (n *nopCloseFlusher) Flush() error {
return nil
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}
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()))},
} {
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)
if !ts.DisableCompression {
ts.gz = gzip.NewWriter(ts.bufGz)
} else {
ts.gz = &nopCloseFlusher{Writer: ts.bufGz}
}
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ts.h = sha256.New()
ts.h.Reset()
ts.first = true
ts.sums = make(map[string]string)
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}
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[ts.currentFile] = hex.EncodeToString(ts.h.Sum(nil))
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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
}
ts.currentFile = strings.TrimSuffix(strings.TrimPrefix(currentHeader.Name, "./"), "/")
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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 {
var sums []string
for _, sum := range ts.sums {
sums = append(sums, sum)
}
sort.Strings(sums)
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h := sha256.New()
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if extra != nil {
h.Write(extra)
}
for _, sum := range sums {
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Debugf("-->%s<--", sum)
h.Write([]byte(sum))
}
checksum := "tarsum+sha256:" + hex.EncodeToString(h.Sum(nil))
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Debugf("checksum processed: %s", checksum)
return checksum
}
func (ts *TarSum) GetSums() map[string]string {
return ts.sums
}