abstracted merkledag service

cli/refs.go

@@ -60,7 +60,7 @@ func refCmd(c *commander.Command, inp []string) error {
 	printRefs = func(h mh.Multihash, recursive bool) {
 		nd, err := n.GetDagNode(u.Key(h))
 		if err != nil {
-			u.PErr("error: cannot retrieve %s\n", h.B58String())
+			u.PErr("error: cannot retrieve %s (%s)\n", h.B58String(), err)
 			return
 		}
 

core/core.go

@@ -37,6 +37,9 @@ type IpfsNode struct {
 	// the block service, get/add blocks.
 	Blocks *blocks.BlockService
 
+	// the merkle dag service, get/add objects.
+	DAG *merkledag.DAGService
+
 	// the path resolution system
 	// Resolver *resolver.PathResolver
 
@@ -59,35 +62,23 @@ func NewIpfsNode(cfg *config.Config) (*IpfsNode, error) {
 		return nil, err
 	}
 
+	dag := &merkledag.DAGService{ Blocks: bs }
+
 	n := &IpfsNode{
 		Config:    cfg,
 		PeerBook:  &peer.PeerBook{},
 		Datastore: d,
 		Blocks:    bs,
+		DAG: 			 dag,
 	}
 
 	return n, nil
 }
 
 func (n *IpfsNode) AddDagNode(nd *merkledag.Node) (u.Key, error) {
-	d, err := nd.Encoded(false)
-	if err != nil {
-		return "", err
-	}
-
-	b, err := blocks.NewBlock(d)
-	if err != nil {
-		return "", err
-	}
-
-	return n.Blocks.AddBlock(b)
+	return n.DAG.Put(nd)
 }
 
 func (n *IpfsNode) GetDagNode(k u.Key) (*merkledag.Node, error) {
-	b, err := n.Blocks.GetBlock(k)
-	if err != nil {
-		return nil, err
-	}
-
-	return merkledag.Decoded(b.Data)
+	return n.DAG.Get(k)
 }

merkledag/merkledag.go

 package merkledag
 
 import (
+	"fmt"
+	blocks "github.com/jbenet/go-ipfs/blocks"
 	u "github.com/jbenet/go-ipfs/util"
 	mh "github.com/jbenet/go-multihash"
 )
@@ -79,3 +81,41 @@ func (n *Node) Key() (u.Key, error) {
 	h, err := n.Multihash()
 	return u.Key(h), err
 }
+
+// An IPFS Merkle DAG service.
+// the root is virtual (like a forest)
+// stores nodes' data in a blockService
+type DAGService struct {
+	Blocks *blocks.BlockService
+}
+
+func (n *DAGService) Put(nd *Node) (u.Key, error) {
+	if n == nil {
+		return "", fmt.Errorf("DAGService is nil")
+	}
+
+	d, err := nd.Encoded(false)
+	if err != nil {
+		return "", err
+	}
+
+	b, err := blocks.NewBlock(d)
+	if err != nil {
+		return "", err
+	}
+
+	return n.Blocks.AddBlock(b)
+}
+
+func (n *DAGService) Get(k u.Key) (*Node, error) {
+	if n == nil {
+		return nil, fmt.Errorf("DAGService is nil")
+	}
+
+	b, err := n.Blocks.GetBlock(k)
+	if err != nil {
+		return nil, err
+	}
+
+	return Decoded(b.Data)
+}