fix: correctly handle symlink file sizes

The file size of a symlink is the symlink data.

go.mod

@@ -19,3 +19,5 @@ require (
 	github.com/spaolacci/murmur3 v1.1.0
 	github.com/warpfork/go-wish v0.0.0-20190328234359-8b3e70f8e830 // indirect
 )
+
+go 1.12

unixfs.go

@@ -152,13 +152,16 @@ func DataSize(data []byte) (uint64, error) {
 	if err != nil {
 		return 0, err
 	}
+	return size(pbdata)
+}
 
+func size(pbdata *pb.Data) (uint64, error) {
 	switch pbdata.GetType() {
-	case pb.Data_Directory:
+	case pb.Data_Directory, pb.Data_HAMTShard:
 		return 0, errors.New("can't get data size of directory")
 	case pb.Data_File:
 		return pbdata.GetFilesize(), nil
-	case pb.Data_Raw:
+	case pb.Data_Symlink, pb.Data_Raw:
 		return uint64(len(pbdata.GetData())), nil
 	default:
 		return 0, errors.New("unrecognized node data type")
@@ -253,10 +256,12 @@ func (n *FSNode) GetBytes() ([]byte, error) {
 	return proto.Marshal(&n.format)
 }
 
-// FileSize returns the total size of this tree. That is, the size of
-// the data in this node plus the size of all its children.
+// FileSize returns the size of the file.
 func (n *FSNode) FileSize() uint64 {
-	return n.format.GetFilesize()
+	// XXX: This needs to be able to return an error when we don't know the
+	// size.
+	size, _ := size(&n.format)
+	return size
 }
 
 // NumChildren returns the number of child blocks of this node

unixfs_test.go

@@ -123,12 +123,21 @@ func TestPBdataTools(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+}
 
-	_, sizeErr := DataSize(catSym)
-	if sizeErr == nil {
-		t.Fatal("DataSize didn't throw an error when taking the size of a Symlink.")
+func TestSymlinkFilesize(t *testing.T) {
+	path := "/ipfs/adad123123/meowgie.gif"
+	sym, err := SymlinkData(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	size, err := DataSize(sym)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if int(size) != len(path) {
+		t.Fatalf("size mismatch: %d != %d", size, len(path))
 	}
-
 }
 
 func TestMetadata(t *testing.T) {