Replace root hash by root content id

dagger/merkledag.nim

@@ -1,10 +1,10 @@
-import pkg/libp2p/multihash
-
-export multihash
+import pkg/libp2p
 
 type
   MerkleDag* = object
     data*: seq[byte]
 
-proc rootHash*(dag: MerkleDag): MultiHash =
-  MultiHash.digest("sha2-256", dag.data).get()
+proc rootId*(dag: MerkleDag): Cid =
+  let codec = multiCodec("dag-pb")
+  let hash =  MultiHash.digest("sha2-256", dag.data).get()
+  Cid.init(CIDv0, codec, hash).get()

dagger/repo.nim

@@ -1,21 +1,22 @@
 import std/tables
 import std/hashes
+import pkg/libp2p
 import ./merkledag
 
 export merkledag
 
 type
   Repo* = ref object
-    storage: Table[MultiHash, MerkleDag]
+    storage: Table[Cid, MerkleDag]
 
-proc hash(multihash: MultiHash): Hash =
-  hash($multihash)
+proc hash(id: Cid): Hash =
+  hash($id)
 
 proc store*(repo: Repo, dag: MerkleDag) =
-  repo.storage[dag.rootHash] = dag
+  repo.storage[dag.rootId] = dag
 
-proc contains*(repo: Repo, hash: MultiHash): bool =
-  repo.storage.hasKey(hash)
+proc contains*(repo: Repo, id: Cid): bool =
+  repo.storage.hasKey(id)
 
-proc retrieve*(repo: Repo, hash: MultiHash): MerkleDag =
-  repo.storage[hash]
+proc retrieve*(repo: Repo, id: Cid): MerkleDag =
+  repo.storage[id]

tests/dagger/testMerkleDag.nim

@@ -1,11 +1,12 @@
 import std/unittest
+import pkg/libp2p
 import pkg/dagger/merkledag
 
 suite "Merkle DAG":
 
-  test "has a root hash":
+  test "has a content id":
     let dag1 = MerkleDag(data: @[1'u8, 2'u8, 3'u8])
     let dag2 = MerkleDag(data: @[4'u8, 5'u8, 6'u8])
     let dag3 = MerkleDag(data: @[4'u8, 5'u8, 6'u8])
-    check dag1.rootHash != dag2.rootHash
-    check dag2.rootHash == dag3.rootHash
+    check dag1.rootId != dag2.rootId
+    check dag2.rootId == dag3.rootId

tests/dagger/testRepo.nim

@@ -12,11 +12,11 @@ suite "repo":
   test "stores Merkle DAGs":
     repo.store(dag)
 
-  test "retrieves Merkle DAGs by their root hash":
+  test "retrieves Merkle DAGs by their root id":
     repo.store(dag)
-    check repo.retrieve(dag.rootHash) == dag
+    check repo.retrieve(dag.rootId) == dag
 
-  test "knows which hashes are stored":
-    check repo.contains(dag.rootHash) == false
+  test "knows which ids are stored":
+    check repo.contains(dag.rootId) == false
     repo.store(dag)
-    check repo.contains(dag.rootHash) == true
+    check repo.contains(dag.rootId) == true