Rework package structure for unixfs and subpackage

cc @jbenet

unixfs/format.go

@@ -0,0 +1,119 @@
+// Package format implements a data format for files in the ipfs filesystem
+// It is not the only format in ipfs, but it is the one that the filesystem assumes
+package unixfs
+
+import (
+	"errors"
+
+	"github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/goprotobuf/proto"
+)
+
+var ErrMalformedFileFormat = errors.New("malformed data in file format")
+var ErrInvalidDirLocation = errors.New("found directory node in unexpected place")
+var ErrUnrecognizedType = errors.New("unrecognized node type")
+
+func FromBytes(data []byte) (*PBData, error) {
+	pbdata := new(PBData)
+	err := proto.Unmarshal(data, pbdata)
+	if err != nil {
+		return nil, err
+	}
+	return pbdata, nil
+}
+
+func FilePBData(data []byte, totalsize uint64) []byte {
+	pbfile := new(PBData)
+	typ := PBData_File
+	pbfile.Type = &typ
+	pbfile.Data = data
+	pbfile.Filesize = proto.Uint64(totalsize)
+
+	data, err := proto.Marshal(pbfile)
+	if err != nil {
+		// This really shouldnt happen, i promise
+		// The only failure case for marshal is if required fields
+		// are not filled out, and they all are. If the proto object
+		// gets changed and nobody updates this function, the code
+		// should panic due to programmer error
+		panic(err)
+	}
+	return data
+}
+
+// Returns Bytes that represent a Directory
+func FolderPBData() []byte {
+	pbfile := new(PBData)
+	typ := PBData_Directory
+	pbfile.Type = &typ
+
+	data, err := proto.Marshal(pbfile)
+	if err != nil {
+		//this really shouldnt happen, i promise
+		panic(err)
+	}
+	return data
+}
+
+func WrapData(b []byte) []byte {
+	pbdata := new(PBData)
+	typ := PBData_Raw
+	pbdata.Data = b
+	pbdata.Type = &typ
+
+	out, err := proto.Marshal(pbdata)
+	if err != nil {
+		// This shouldnt happen. seriously.
+		panic(err)
+	}
+
+	return out
+}
+
+func UnwrapData(data []byte) ([]byte, error) {
+	pbdata := new(PBData)
+	err := proto.Unmarshal(data, pbdata)
+	if err != nil {
+		return nil, err
+	}
+	return pbdata.GetData(), nil
+}
+
+func DataSize(data []byte) (uint64, error) {
+	pbdata := new(PBData)
+	err := proto.Unmarshal(data, pbdata)
+	if err != nil {
+		return 0, err
+	}
+
+	switch pbdata.GetType() {
+	case PBData_Directory:
+		return 0, errors.New("Cant get data size of directory!")
+	case PBData_File:
+		return pbdata.GetFilesize(), nil
+	case PBData_Raw:
+		return uint64(len(pbdata.GetData())), nil
+	default:
+		return 0, errors.New("Unrecognized node data type!")
+	}
+}
+
+type MultiBlock struct {
+	Data       []byte
+	blocksizes []uint64
+	subtotal   uint64
+}
+
+func (mb *MultiBlock) AddBlockSize(s uint64) {
+	mb.subtotal += s
+	mb.blocksizes = append(mb.blocksizes, s)
+}
+
+func (mb *MultiBlock) GetBytes() ([]byte, error) {
+	pbn := new(PBData)
+	t := PBData_File
+	pbn.Type = &t
+	pbn.Filesize = proto.Uint64(uint64(len(mb.Data)) + mb.subtotal)
+	pbn.Blocksizes = mb.blocksizes
+	pbn.Data = mb.Data
+	return proto.Marshal(pbn)
+}