// Diff produces an archive of the changes between the specified
// layer and its parent layer which may be "".
func (gdw *NaiveDiffDriver) Diff(id, parent string) (arch archive.Archive, err error) {
driver := gdw.ProtoDriver
layerFs, err := driver.Get(id, "")
if err != nil {
return nil, err
}
defer func() {
if err != nil {
driver.Put(id)
}
}()
if parent == "" {
archive, err := archive.Tar(layerFs, archive.Uncompressed)
if err != nil {
return nil, err
}
return ioutils.NewReadCloserWrapper(archive, func() error {
err := archive.Close()
driver.Put(id)
return err
}), nil
}
parentFs, err := driver.Get(parent, "")
if err != nil {
return nil, err
}
defer driver.Put(parent)
changes, err := archive.ChangesDirs(layerFs, parentFs)
if err != nil {
return nil, err
}
archive, err := archive.ExportChanges(layerFs, changes, gdw.uidMaps, gdw.gidMaps)
if err != nil {
return nil, err
}
return ioutils.NewReadCloserWrapper(archive, func() error {
err := archive.Close()
driver.Put(id)
return err
}), nil
}
func (bufPool *BufioReaderPool) NewReadCloserWrapper(buf *bufio.Reader, r io.Reader) io.ReadCloser {
return ioutils.NewReadCloserWrapper(r, func() error {
if readCloser, ok := r.(io.ReadCloser); ok {
return readCloser.Close()
}
return nil
})
}
// DecompressStream decompress the archive and returns a ReaderCloser with the decompressed archive.
func DecompressStream(archive io.Reader) (io.ReadCloser, error) {
p := pools.BufioReader32KPool
buf := p.Get(archive)
bs, err := buf.Peek(10)
if err != nil {
return nil, err
}
compression := DetectCompression(bs)
switch compression {
case Uncompressed:
readBufWrapper := p.NewReadCloserWrapper(buf, buf)
return readBufWrapper, nil
case Gzip:
gzReader, err := gzip.NewReader(buf)
if err != nil {
return nil, err
}
readBufWrapper := p.NewReadCloserWrapper(buf, gzReader)
return readBufWrapper, nil
case Bzip2:
bz2Reader := bzip2.NewReader(buf)
readBufWrapper := p.NewReadCloserWrapper(buf, bz2Reader)
return readBufWrapper, nil
case Xz:
xzReader, chdone, err := xzDecompress(buf)
if err != nil {
return nil, err
}
readBufWrapper := p.NewReadCloserWrapper(buf, xzReader)
return ioutils.NewReadCloserWrapper(readBufWrapper, func() error {
<-chdone
return readBufWrapper.Close()
}), nil
default:
return nil, fmt.Errorf("Unsupported compression format %s", (&compression).Extension())
}
}