Function newReader

docker/internal/tarfile/reader.go:96–125

newReader creates a Reader for the specified path and removeOnClose flag. The caller should call .Close() on the returned archive when done.

(path string, removeOnClose bool)

// newReader creates a Reader for the specified path and removeOnClose flag.
// The caller should call .Close() on the returned archive when done.
func newReader(path string, removeOnClose bool) (*Reader, error) {
	// This is a valid enough archive, except Manifest is not yet filled.
	r := Reader{
		path:          path,
		removeOnClose: removeOnClose,
	}
	succeeded := false
	defer func() {
		if !succeeded {
			r.Close()
		}
	}()

	// We initialize Manifest immediately when constructing the Reader instead
	// of later on-demand because every caller will need the data, and because doing it now
	// removes the need to synchronize the access/creation of the data if the archive is later
	// used from multiple goroutines to access different images.

	// FIXME? Do we need to deal with the legacy format?
	bytes, err := r.readTarComponent(manifestFileName, iolimits.MaxTarFileManifestSize)
	if err != nil {
		return nil, err
	}
	if err := json.Unmarshal(bytes, &r.Manifest); err != nil {
		return nil, fmt.Errorf("decoding tar manifest.json: %w", err)
	}

	succeeded = true
	return &r, nil
}

// Close removes resources associated with an initialized Reader, if any.
func (r *Reader) Close() error {