Factor out code to validate unixfs node and add unit tests.

License: MIT
Signed-off-by: Kevin Atkinson <k@kevina.org>

unixfs/io/pbdagreader.go

@@ -52,25 +52,14 @@ var _ DagReader = (*PBDagReader)(nil)
 
 // NewPBFileReader constructs a new PBFileReader.
 func NewPBFileReader(ctx context.Context, n *mdag.ProtoNode, pb *ftpb.Data, serv ipld.NodeGetter) (*PBDagReader, error) {
+	err := ValidatePB(n, pb)
+	if err != nil {
+		return nil, err
+	}
+
 	curLinks := getLinkCids(n)
 	data := pb.GetData()
 
-	// validate
-	if len(curLinks) != len(pb.Blocksizes) {
-		return nil, errors.New("unixfs ill-formed, number of links does not batch blocksize count")
-	}
-	total := uint64(len(data))
-	for _, blocksize := range pb.Blocksizes {
-		total += blocksize
-	}
-	if pb.Filesize == nil {
-		return nil, errors.New("unixfs ill-formed, filesize field missing")
-	}
-	if total != *pb.Filesize {
-		return nil, fmt.Errorf("unixfs ill-formed, actual size of %d does not match size in filesize field (%d)",
-			total, *pb.Filesize)
-	}
-
 	fctx, cancel := context.WithCancel(ctx)
 	return &PBDagReader{
 		node:     n,

unixfs/unixfs.go

@@ -5,6 +5,7 @@ package unixfs
 
 import (
 	"errors"
+	"fmt"
 
 	proto "gx/ipfs/QmZ4Qi3GaRbjcx28Sme5eMH7RQjGkt8wHxt2a65oLaeFEV/gogo-protobuf/proto"
 
@@ -258,3 +259,20 @@ func BytesForMetadata(m *Metadata) ([]byte, error) {
 func EmptyDirNode() *dag.ProtoNode {
 	return dag.NodeWithData(FolderPBData())
 }
+
+// ValidatePB validates a unixfs protonode.
+func ValidatePB(n *dag.ProtoNode, pb *pb.Data) error {
+	if len(n.Links()) != len(pb.Blocksizes) {
+		return errors.New("unixfs ill-formed, number of links does not batch blocksize count")
+	}
+	total := uint64(len(pb.GetData()))
+	for _, blocksize := range pb.Blocksizes {
+		total += blocksize
+	}
+	if total != pb.GetFilesize() {
+		return fmt.Errorf("unixfs ill-formed, actual size of %d does not match size in filesize field with value %d",
+			total, pb.GetFilesize())
+	}
+
+	return nil
+}

unixfs/unixfs_test.go

@@ -2,10 +2,12 @@ package unixfs
 
 import (
 	"bytes"
+	"encoding/hex"
 	"testing"
 
 	proto "gx/ipfs/QmZ4Qi3GaRbjcx28Sme5eMH7RQjGkt8wHxt2a65oLaeFEV/gogo-protobuf/proto"
 
+	dag "github.com/ipfs/go-ipfs/merkledag"
 	pb "github.com/ipfs/go-ipfs/unixfs/pb"
 )
 
@@ -159,3 +161,40 @@ func TestMetadata(t *testing.T) {
 	}
 
 }
+
+// originally from test/sharness/t0110-gateway-data/foofoo.block, does not have blocksize defined
+// contents: {"data":"CAIYBg==","links":[{"Cid":{"/":"QmcJw6x4bQr7oFnVnF6i8SLcJvhXjaxWvj54FYXmZ4Ct6p"},"Name":"","Size":0},{"Cid":{"/":"QmcJw6x4bQr7oFnVnF6i8SLcJvhXjaxWvj54FYXmZ4Ct6p"},"Name":"","Size":0}]}
+const noBlocksizeHex = "0A040802180612240A221220CF92FDEFCDC34CAC009C8B05EB662BE0618DB9DE55ECD42785E9EC6712F8DF6512240A221220CF92FDEFCDC34CAC009C8B05EB662BE0618DB9DE55ECD42785E9EC6712F8DF65"
+
+func TestValidatePB(t *testing.T) {
+	noBlocksize, err := hex.DecodeString(noBlocksizeHex)
+	if err != nil {
+		t.Fatal(err)
+	}
+	nd, err := dag.DecodeProtobuf(noBlocksize)
+	if err != nil {
+		t.Fatal(err)
+	}
+	fd, err := FromBytes(nd.Data())
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = ValidatePB(nd, fd)
+	if err == nil {
+		t.Fatal("invalid unixfs node (with no blocksizes) validated")
+	}
+	// give node blocksizes
+	fd.Blocksizes = []uint64{3, 3}
+	// should be ok
+	err = ValidatePB(nd, fd)
+	if err != nil {
+		t.Fatalf("valid node failed to validate: %v", err)
+	}
+	// give node incorrect filesize
+	var filesize uint64 = 8
+	fd.Filesize = &filesize
+	err = ValidatePB(nd, fd)
+	if err == nil {
+		t.Fatal("invalid unixfs node (with incorrect filesize) validated")
+	}
+}