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kubo/unixfs/archive/tar/writer.go
Jeromy 479761ec6a change batch fetching methods of dagserv
License: MIT
Signed-off-by: Jeromy <jeromyj@gmail.com>
2016-02-20 10:27:07 -08:00

125 lines
2.7 KiB
Go

package tar
import (
"archive/tar"
"io"
"path"
"time"
proto "gx/ipfs/QmZ4Qi3GaRbjcx28Sme5eMH7RQjGkt8wHxt2a65oLaeFEV/gogo-protobuf/proto"
cxt "gx/ipfs/QmZy2y8t9zQH2a1b8q2ZSLKp17ATuJoCNxxyMFG5qFExpt/go-net/context"
mdag "github.com/ipfs/go-ipfs/merkledag"
ft "github.com/ipfs/go-ipfs/unixfs"
uio "github.com/ipfs/go-ipfs/unixfs/io"
upb "github.com/ipfs/go-ipfs/unixfs/pb"
)
// Writer is a utility structure that helps to write
// unixfs merkledag nodes as a tar archive format.
// It wraps any io.Writer.
type Writer struct {
Dag mdag.DAGService
TarW *tar.Writer
ctx cxt.Context
}
// NewWriter wraps given io.Writer.
func NewWriter(ctx cxt.Context, dag mdag.DAGService, archive bool, compression int, w io.Writer) (*Writer, error) {
return &Writer{
Dag: dag,
TarW: tar.NewWriter(w),
ctx: ctx,
}, nil
}
func (w *Writer) writeDir(nd *mdag.Node, fpath string) error {
if err := writeDirHeader(w.TarW, fpath); err != nil {
return err
}
for i, ng := range mdag.GetDAG(w.ctx, w.Dag, nd) {
child, err := ng.Get(w.ctx)
if err != nil {
return err
}
npath := path.Join(fpath, nd.Links[i].Name)
if err := w.WriteNode(child, npath); err != nil {
return err
}
}
return nil
}
func (w *Writer) writeFile(nd *mdag.Node, pb *upb.Data, fpath string) error {
if err := writeFileHeader(w.TarW, fpath, pb.GetFilesize()); err != nil {
return err
}
dagr := uio.NewDataFileReader(w.ctx, nd, pb, w.Dag)
if _, err := dagr.WriteTo(w.TarW); err != nil {
return err
}
w.TarW.Flush()
return nil
}
func (w *Writer) WriteNode(nd *mdag.Node, fpath string) error {
pb := new(upb.Data)
if err := proto.Unmarshal(nd.Data, pb); err != nil {
return err
}
switch pb.GetType() {
case upb.Data_Metadata:
fallthrough
case upb.Data_Directory:
return w.writeDir(nd, fpath)
case upb.Data_Raw:
fallthrough
case upb.Data_File:
return w.writeFile(nd, pb, fpath)
case upb.Data_Symlink:
return writeSymlinkHeader(w.TarW, string(pb.GetData()), fpath)
default:
return ft.ErrUnrecognizedType
}
}
func (w *Writer) Close() error {
return w.TarW.Close()
}
func writeDirHeader(w *tar.Writer, fpath string) error {
return w.WriteHeader(&tar.Header{
Name: fpath,
Typeflag: tar.TypeDir,
Mode: 0777,
ModTime: time.Now(),
// TODO: set mode, dates, etc. when added to unixFS
})
}
func writeFileHeader(w *tar.Writer, fpath string, size uint64) error {
return w.WriteHeader(&tar.Header{
Name: fpath,
Size: int64(size),
Typeflag: tar.TypeReg,
Mode: 0644,
ModTime: time.Now(),
// TODO: set mode, dates, etc. when added to unixFS
})
}
func writeSymlinkHeader(w *tar.Writer, target, fpath string) error {
return w.WriteHeader(&tar.Header{
Name: fpath,
Linkname: target,
Mode: 0777,
Typeflag: tar.TypeSymlink,
})
}