Example #1
0
func skipToArMember(arReader *ar.Reader, memberPrefix string) (io.Reader, error) {
	var err error

	// find the right ar member
	var header *ar.Header
	for {
		header, err = arReader.Next()
		if err != nil {
			return nil, err
		}
		if strings.HasPrefix(header.Name, memberPrefix) {
			break
		}
	}

	// figure out what compression to use
	var dataReader io.Reader
	switch {
	case strings.HasSuffix(header.Name, ".gz"):
		dataReader, err = gzip.NewReader(arReader)
		if err != nil {
			return nil, err
		}
	case strings.HasSuffix(header.Name, ".bz2"):
		dataReader = bzip2.NewReader(arReader)
	case strings.HasSuffix(header.Name, ".xz"):
		dataReader = xzPipeReader(arReader)
	default:
		return nil, fmt.Errorf("Can not handle %s", header.Name)
	}

	return dataReader, nil
}
Example #2
0
File: ipkg.go Project: thz/kellner
// extract 'control' file from 'reader'. the contents of a 'control' file
// is a set of key-value pairs as described in
// https://www.debian.org/doc/debian-policy/ch-controlfields.html
func extractControlFromIpk(reader io.Reader) (string, error) {

	var (
		arReader  *ar.Reader
		tarReader *tar.Reader
		gzReader  *gzip.Reader
	)

	arReader = ar.NewReader(reader)
	for {
		header, err := arReader.Next()
		if err != nil && err != io.EOF {
			return "", fmt.Errorf("extracting contents: %v", err)
		} else if header == nil {
			break
		}

		// NOTE: strangeley the name of the files end with a "/" ... content error?
		if header.Name == "control.tar.gz/" || header.Name == "control.tar.gz" {
			gzReader, err = gzip.NewReader(arReader)
			if err != nil {
				return "", fmt.Errorf("analyzing control.tar.gz: %v", err)
			}
			break
		}
	}

	if gzReader == nil {
		return "", fmt.Errorf("missing control.tar.gz entry")
	}
	defer gzReader.Close()

	buffer := bytes.NewBuffer(nil)
	tarReader = tar.NewReader(gzReader)
	for {
		header, err := tarReader.Next()
		if err != nil && err != io.EOF {
			return "", fmt.Errorf("extracting control.tar.gz: %v", err)
		} else if header == nil {
			break
		}
		if header.Name != "./control" {
			continue
		}

		io.Copy(buffer, tarReader)
		break
	}

	if buffer.Len() == 0 {
		return "", fmt.Errorf("missing or empty 'control' file inside 'control.tar.gz'")
	}
	return buffer.String(), nil
}