implement symlinks in unixfs, first draft

License: MIT
Signed-off-by: Jeromy <jeromyj@gmail.com>

commands/files/linkfile.go

@@ -0,0 +1,50 @@
+package files
+
+import (
+	"io"
+	"os"
+	"strings"
+)
+
+type Symlink struct {
+	name   string
+	path   string
+	Target string
+	stat   os.FileInfo
+
+	reader io.Reader
+}
+
+func NewLinkFile(name, path, target string, stat os.FileInfo) File {
+	return &Symlink{
+		name:   name,
+		path:   path,
+		Target: target,
+		stat:   stat,
+		reader: strings.NewReader(target),
+	}
+}
+
+func (lf *Symlink) IsDirectory() bool {
+	return false
+}
+
+func (lf *Symlink) NextFile() (File, error) {
+	return nil, io.EOF
+}
+
+func (f *Symlink) FileName() string {
+	return f.name
+}
+
+func (f *Symlink) Close() error {
+	return nil
+}
+
+func (f *Symlink) FullPath() string {
+	return f.path
+}
+
+func (f *Symlink) Read(b []byte) (int, error) {
+	return f.reader.Read(b)
+}

commands/files/multipartfile.go

@@ -1,6 +1,7 @@
 package files
 
 import (
+	"io/ioutil"
 	"mime"
 	"mime/multipart"
 	"net/http"
@@ -30,6 +31,17 @@ func NewFileFromPart(part *multipart.Part) (File, error) {
 	}
 
 	contentType := part.Header.Get(contentTypeHeader)
+	if contentType == "symlink" {
+		out, err := ioutil.ReadAll(part)
+		if err != nil {
+			return nil, err
+		}
+
+		return &Symlink{
+			Target: string(out),
+			name:   f.FileName(),
+		}, nil
+	}
 
 	var params map[string]string
 	var err error

commands/files/serialfile.go

@@ -84,10 +84,25 @@ func (f *serialFile) NextFile() (File, error) {
 	// open the next file
 	fileName := fp.Join(f.name, stat.Name())
 	filePath := fp.Join(f.path, stat.Name())
+	st, err := os.Lstat(filePath)
+	if err != nil {
+		return nil, err
+	}
+
+	if st.Mode()&os.ModeSymlink != 0 {
+		f.current = nil
+		target, err := os.Readlink(filePath)
+		if err != nil {
+			return nil, err
+		}
+		return NewLinkFile(fileName, filePath, target, st), nil
+	}
+
 	file, err := os.Open(filePath)
 	if err != nil {
 		return nil, err
 	}
+
 	f.current = file
 
 	// recursively call the constructor on the next file

commands/http/multifilereader.go

@@ -64,13 +64,23 @@ func (mfr *MultiFileReader) Read(buf []byte) (written int, err error) {
 
 		// handle starting a new file part
 		if !mfr.closed {
-			if file.IsDirectory() {
+
+			var contentType string
+			if s, ok := file.(*files.Symlink); ok {
+				mfr.currentFile = s
+
+				// TODO(why): this is a hack. pick a real contentType
+				contentType = "symlink"
+			} else if file.IsDirectory() {
 				// if file is a directory, create a multifilereader from it
 				// (using 'multipart/mixed')
-				mfr.currentFile = NewMultiFileReader(file, false)
+				nmfr := NewMultiFileReader(file, false)
+				mfr.currentFile = nmfr
+				contentType = fmt.Sprintf("multipart/mixed; boundary=%s", nmfr.Boundary())
 			} else {
 				// otherwise, use the file as a reader to read its contents
 				mfr.currentFile = file
+				contentType = "application/octet-stream"
 			}
 
 			// write the boundary and headers
@@ -83,12 +93,7 @@ func (mfr *MultiFileReader) Read(buf []byte) (written int, err error) {
 				header.Set("Content-Disposition", fmt.Sprintf("file; filename=\"%s\"", filename))
 			}
 
-			if file.IsDirectory() {
-				boundary := mfr.currentFile.(*MultiFileReader).Boundary()
-				header.Set("Content-Type", fmt.Sprintf("multipart/mixed; boundary=%s", boundary))
-			} else {
-				header.Set("Content-Type", "application/octet-stream")
-			}
+			header.Set("Content-Type", contentType)
 
 			_, err := mfr.mpWriter.CreatePart(header)
 			if err != nil {

core/commands/add.go

@@ -143,6 +143,7 @@ remains to be implemented.
 					return nil // done
 				}
 
+				log.Errorf("FILE: %#v", file)
 				if _, err := fileAdder.addFile(file); err != nil {
 					return err
 				}
@@ -359,6 +360,23 @@ func (params *adder) addFile(file files.File) (*dag.Node, error) {
 		return params.addDir(file)
 	}
 
+	if s, ok := file.(*files.Symlink); ok {
+		log.Error("SYMLINK: ", s)
+		log.Error(s.Target)
+		log.Error(s.FileName())
+		dagnode := &dag.Node{
+			Data: ft.SymlinkData(s.Target),
+		}
+
+		_, err := params.node.DAG.Add(dagnode)
+		if err != nil {
+			return nil, err
+		}
+
+		err = params.addNode(dagnode, s.FileName())
+		return dagnode, err
+	}
+
 	// if the progress flag was specified, wrap the file so that we can send
 	// progress updates to the client (over the output channel)
 	var reader io.Reader = file

fuse/readonly/readonly_unix.go

@@ -7,6 +7,8 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"syscall"
+	"time"
 
 	fuse "github.com/ipfs/go-ipfs/Godeps/_workspace/src/bazil.org/fuse"
 	fs "github.com/ipfs/go-ipfs/Godeps/_workspace/src/bazil.org/fuse/fs"
@@ -58,6 +60,8 @@ func (s *Root) Lookup(ctx context.Context, name string) (fs.Node, error) {
 		return nil, fuse.ENOENT
 	}
 
+	log.Error("RESOLVE: ", name)
+	ctx, _ = context.WithTimeout(ctx, time.Second/2)
 	nd, err := s.Ipfs.Resolver.ResolvePath(ctx, path.Path(name))
 	if err != nil {
 		// todo: make this error more versatile.
@@ -118,6 +122,13 @@ func (s *Node) Attr(ctx context.Context, a *fuse.Attr) error {
 			Uid:    uint32(os.Getuid()),
 			Gid:    uint32(os.Getgid()),
 		}
+	case ftpb.Data_Symlink:
+		*a = fuse.Attr{
+			Mode: 0777 | os.ModeSymlink,
+			Size: uint64(len(s.cached.GetData())),
+			Uid:  uint32(os.Getuid()),
+			Gid:  uint32(os.Getgid()),
+		}
 
 	default:
 		return fmt.Errorf("Invalid data type - %s", s.cached.GetType())
@@ -155,6 +166,13 @@ func (s *Node) ReadDirAll(ctx context.Context) ([]fuse.Dirent, error) {
 	return nil, fuse.ENOENT
 }
 
+func (s *Node) Readlink(ctx context.Context, req *fuse.ReadlinkRequest) (string, error) {
+	if s.cached.GetType() != ftpb.Data_Symlink {
+		return "", fuse.Errno(syscall.EINVAL)
+	}
+	return string(s.cached.GetData()), nil
+}
+
 func (s *Node) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
 
 	k, err := s.Nd.Key()
@@ -204,6 +222,7 @@ type roNode interface {
 	fs.HandleReader
 	fs.Node
 	fs.NodeStringLookuper
+	fs.NodeReadlinker
 }
 
 var _ roNode = (*Node)(nil)

unixfs/format.go

@@ -77,6 +77,20 @@ func WrapData(b []byte) []byte {
 	return out
 }
 
+func SymlinkData(path string) []byte {
+	pbdata := new(pb.Data)
+	typ := pb.Data_Symlink
+	pbdata.Data = []byte(path)
+	pbdata.Type = &typ
+
+	out, err := proto.Marshal(pbdata)
+	if err != nil {
+		panic(err)
+	}
+
+	return out
+}
+
 func UnwrapData(data []byte) ([]byte, error) {
 	pbdata := new(pb.Data)
 	err := proto.Unmarshal(data, pbdata)

unixfs/io/dagreader.go

@@ -17,6 +17,8 @@ import (
 
 var ErrIsDir = errors.New("this dag node is a directory")
 
+var ErrCantReadSymlinks = errors.New("cannot currently read symlinks")
+
 // DagReader provides a way to easily read the data contained in a dag.
 type DagReader struct {
 	serv mdag.DAGService
@@ -79,6 +81,8 @@ func NewDagReader(ctx context.Context, n *mdag.Node, serv mdag.DAGService) (*Dag
 			return nil, err
 		}
 		return NewDagReader(ctx, child, serv)
+	case ftpb.Data_Symlink:
+		return nil, ErrCantReadSymlinks
 	default:
 		return nil, ft.ErrUnrecognizedType
 	}
@@ -130,6 +134,8 @@ func (dr *DagReader) precalcNextBuf(ctx context.Context) error {
 		return nil
 	case ftpb.Data_Metadata:
 		return errors.New("Shouldnt have had metadata object inside file")
+	case ftpb.Data_Symlink:
+		return errors.New("shouldnt have had symlink inside file")
 	default:
 		return ft.ErrUnrecognizedType
 	}

unixfs/pb/unixfs.pb.go

@@ -14,7 +14,7 @@ It has these top-level messages:
 */
 package unixfs_pb
 
-import proto "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/gogo/protobuf/proto"
+import proto "github.com/gogo/protobuf/proto"
 import math "math"
 
 // Reference imports to suppress errors if they are not otherwise used.
@@ -28,6 +28,7 @@ const (
 	Data_Directory Data_DataType = 1
 	Data_File      Data_DataType = 2
 	Data_Metadata  Data_DataType = 3
+	Data_Symlink   Data_DataType = 4
 )
 
 var Data_DataType_name = map[int32]string{
@@ -35,12 +36,14 @@ var Data_DataType_name = map[int32]string{
 	1: "Directory",
 	2: "File",
 	3: "Metadata",
+	4: "Symlink",
 }
 var Data_DataType_value = map[string]int32{
 	"Raw":       0,
 	"Directory": 1,
 	"File":      2,
 	"Metadata":  3,
+	"Symlink":   4,
 }
 
 func (x Data_DataType) Enum() *Data_DataType {

unixfs/pb/unixfs.proto

@@ -6,6 +6,7 @@ message Data {
 		Directory = 1;
 		File = 2;
 		Metadata = 3;
+		Symlink = 4;
 	}
 
 	required DataType Type = 1;