merkledag

coding.go

+package merkledag
+
+import (
+  "fmt"
+  mh "github.com/jbenet/go-multihash"
+)
+
+// for now, we use a PBNode intermediate thing.
+// because native go objects are nice.
+
+func (n *Node) Unmarshal(encoded []byte) error {
+  var pbn PBNode
+  if err := pbn.Unmarshal(encoded), err != nil {
+    return fmt.Errorf("Unmarshal failed. %v", err)
+  }
+
+  pbnl := pbn.Links()
+  n.Links = make([]*Link, len(pbnl))
+  for i, l := range(pbnl) {
+    n.Links[i] = &Link{Name: l.GetName(), Size: l.GetSize()}
+    n.Links[i].Hash, err := mh.Cast(l.GetHash())
+    if err != nil {
+      return fmt.Errorf("Link hash is not valid multihash. %v", err)
+    }
+  }
+
+  n.Data = pbn.GetData()
+  return nil
+}
+
+func (n *Node) MarshalTo(encoded []byte) error {
+  pbn := n.getPBNode()
+  if err := pbn.MarshalTo(encoded), err != nil {
+    return fmt.Errorf("Marshal failed. %v", err)
+  }
+  return nil
+}
+
+func (n *Node) Marshal() ([]byte, error) {
+  pbn := n.getPBNode()
+  data, err := pbn.Marshal()
+  if err != nil {
+    return data, fmt.Errorf("Marshal failed. %v", err)
+  }
+  return data, nil
+}
+
+func (n *Node) getPBNode() *PBNode {
+  pbn := &PBNode{}
+  pbn.Links = make([]*PBLink, len(n.Links))
+  for i, l := range(n.Links) {
+    pbn.Links[i] = &PBLink{}
+    n.Links[i].Name = &l.Name
+    n.Links[i].Size = l.Size
+    n.Links[i].Hash = &[]byte(l.Hash)
+  }
+
+  pbn.Data = &n.Data
+  return pbn, nil
+}
+

merkledag.go

+package merkledag
+
+import (
+  mh "github.com/jbenet/go-multihash"
+)
+
+// A node in the IPFS Merkle DAG.
+// nodes have opaque data and a set of navigable links.
+type Node {
+  Links []*Link
+  Data []byte
+}
+
+
+// An IPFS Merkle DAG Link
+type Link {
+  // utf string name. should be unique per object
+  Name string // utf8
+
+  // cumulative size of target object
+  Size uint64
+
+  // multihash of the target object
+  Hash mh.Multihash
+}
+
+
+type EncodedNode []byte
+
+
+func (n *Node) Size() uint64 {
+  uint64 s = len(n.Encode())
+  for _, l := range(n.Links) {
+    s += l.Size
+  }
+}

merkledag.proto

+package merkledag
+
+import "code.google.com/p/gogoprotobuf/gogoproto/gogo.proto";
+
+option (gogoproto.gostring_all) = true;
+option (gogoproto.equal_all) = true;
+option (gogoproto.verbose_equal_all) = true;
+option (gogoproto.goproto_stringer_all) = false;
+option (gogoproto.stringer_all) =  true;
+option (gogoproto.populate_all) = true;
+option (gogoproto.testgen_all) = true;
+option (gogoproto.benchgen_all) = true;
+option (gogoproto.marshaler_all) = true;
+option (gogoproto.sizer_all) = true;
+option (gogoproto.unmarshaler_all) = true;
+
+
+// An IPFS MerkleDAG Node
+message PBNode {
+
+  // refs to other objects
+  repeated Link Links = 2;
+
+  // opaque user data
+  optional bytes Data = 1;
+}
+
+
+// An IPFS MerkleDAG Link
+message PBLink {
+
+  // multihash of the target object
+  optional bytes Hash = 1;
+
+  // utf string name. should be unique per object
+  optional string Name = 2;
+
+  // cumulative size of target object
+  optional uint64 Size = 3;
+}