package remotecontext import ( "archive/tar" "crypto/sha256" "hash" "os" "github.com/docker/docker/pkg/archive" "github.com/docker/docker/pkg/tarsum" ) // NewFileHash returns new hash that is used for the builder cache keys func NewFileHash(path, name 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 } } hdr, err := archive.FileInfoHeader(name, fi, link) if err != nil { return nil, err } if err := archive.ReadSecurityXattrToTarHeader(path, hdr); err != nil { return nil, err } 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() tarsum.WriteV1Header(tsh.hdr, tsh.Hash) }