buildkit/cache/contenthash/filehash.go

95 lines
2.1 KiB
Go

package contenthash
import (
"archive/tar"
"crypto/sha256"
"hash"
"os"
"path/filepath"
"time"
"github.com/tonistiigi/fsutil"
)
// NewFileHash returns new hash that is used for the builder cache keys
func NewFileHash(path string, fi os.FileInfo) (hash.Hash, error) {
var link string
if fi.Mode()&os.ModeSymlink != 0 {
var err error
link, err = os.Readlink(path)
if err != nil {
return nil, err
}
}
stat := &fsutil.Stat{
Mode: uint32(fi.Mode()),
Size_: fi.Size(),
ModTime: fi.ModTime().UnixNano(),
Linkname: link,
}
if err := setUnixOpt(path, fi, stat); err != nil {
return nil, err
}
return NewFromStat(stat)
}
func NewFromStat(stat *fsutil.Stat) (hash.Hash, error) {
fi := &statInfo{stat}
hdr, err := tar.FileInfoHeader(fi, stat.Linkname)
if err != nil {
return nil, err
}
hdr.Name = "" // note: empty name is different from current has in docker build. Name is added on recursive directory scan instead
hdr.Mode = int64(chmodWindowsTarEntry(os.FileMode(hdr.Mode)))
hdr.Devmajor = stat.Devmajor
hdr.Devminor = stat.Devminor
if len(stat.Xattrs) > 0 {
hdr.Xattrs = make(map[string]string, len(stat.Xattrs))
for k, v := range stat.Xattrs {
hdr.Xattrs[k] = string(v)
}
}
// fmt.Printf("hdr: %#v\n", hdr)
tsh := &tarsumHash{hdr: hdr, Hash: sha256.New()}
tsh.Reset() // initialize header
return tsh, nil
}
type tarsumHash struct {
hash.Hash
hdr *tar.Header
}
// Reset resets the Hash to its initial state.
func (tsh *tarsumHash) Reset() {
// comply with hash.Hash and reset to the state hash had before any writes
tsh.Hash.Reset()
WriteV1TarsumHeaders(tsh.hdr, tsh.Hash)
}
type statInfo struct {
*fsutil.Stat
}
func (s *statInfo) Name() string {
return filepath.Base(s.Stat.Path)
}
func (s *statInfo) Size() int64 {
return s.Stat.Size_
}
func (s *statInfo) Mode() os.FileMode {
return os.FileMode(s.Stat.Mode)
}
func (s *statInfo) ModTime() time.Time {
return time.Unix(s.Stat.ModTime/1e9, s.Stat.ModTime%1e9)
}
func (s *statInfo) IsDir() bool {
return s.Mode().IsDir()
}
func (s *statInfo) Sys() interface{} {
return s.Stat
}