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/*
* Copyright (c) SAS Institute, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package rpmutils
import (
"bytes"
"compress/bzip2"
"compress/gzip"
"fmt"
"io"
"github.com/ulikunitz/xz/lzma"
"github.com/xi2/xz"
)
// Wrap RPM payload with uncompress reader, assumes that header has
// already been read.
func uncompressRpmPayloadReader(r io.Reader, hdr *RpmHeader) (io.Reader, error) {
// Check to make sure payload format is a cpio archive. If the tag does
// not exist, assume archive is cpio.
if hdr.HasTag(PAYLOADFORMAT) {
val, err := hdr.GetString(PAYLOADFORMAT)
if err != nil {
return nil, err
}
if val != "cpio" {
return nil, fmt.Errorf("Unknown payload format %s", val)
}
}
// Check to see how the payload was compressed. If the tag does not
// exist, check if it is gzip, if not it is uncompressed.
var compression string
if hdr.HasTag(PAYLOADCOMPRESSOR) {
val, err := hdr.GetString(PAYLOADCOMPRESSOR)
if err != nil {
return nil, err
}
compression = val
} else {
// peek at the start of the payload to see if it's compressed
b := make([]byte, 2)
_, err := io.ReadFull(r, b)
if err != nil {
return nil, err
}
if b[0] == 0x1f && b[1] == 0x8b {
compression = "gzip"
} else {
compression = "uncompressed"
}
// splice the peeked bytes back in
r = io.MultiReader(bytes.NewReader(b), r)
}
switch compression {
case "zstd":
return newZstdReader(r)
case "gzip":
return gzip.NewReader(r)
case "bzip2":
return bzip2.NewReader(r), nil
case "lzma":
return lzma.NewReader(r)
case "xz":
return xz.NewReader(r, 0)
case "uncompressed":
// prevent ExpandPayload from closing the underlying file
return noCloseWrapper{r}, nil
default:
return nil, fmt.Errorf("Unknown compression type %s", compression)
}
}
type noCloseWrapper struct {
r io.Reader
}
func (w noCloseWrapper) Read(d []byte) (int, error) {
return w.r.Read(d)
}
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