swarm/hash: Custom multihash implementation (#633)

* swarm/hash: Custom multihash implementation

* swarm/hash, swarm/storage: Delint and fix comments

* swarm/storage: Rebase cleanup

* swarm/multihash: Rename package to multihash

* swarm/multihash, swarm/storage: Remove redundant error formatting

* swarm/multihash: Add missing files

* swarm/storage: Fix error string bug

* swarm/api: Remove sprintf in error

swarm/api/api.go

@@ -365,19 +365,14 @@ func (self *Api) Get(manifestAddr storage.Address, path string) (reader storage.
 				}
 
 				// validate that data as multihash
-				decodedMultihash, err := multihash.Decode(rsrcData)
+				decodedMultihash, err := multihash.FromMultihash(rsrcData)
 				if err != nil {
-					apiGetInvalid.Inc(1)
-					status = http.StatusInternalServerError
-					log.Warn(fmt.Sprintf("could not decode resource multihash: %v", err))
-					return reader, mimeType, status, nil, err
-				} else if decodedMultihash.Code != multihash.KECCAK_256 {
 					apiGetInvalid.Inc(1)
 					status = http.StatusUnprocessableEntity
-					log.Warn(fmt.Sprintf("invalid resource multihash code: %x", decodedMultihash.Code))
+					log.Warn("invalid resource multihash", "err", err)
 					return reader, mimeType, status, nil, err
 				}
-				manifestAddr = storage.Address(decodedMultihash.Digest)
+				manifestAddr = storage.Address(decodedMultihash)
 				log.Trace("resource is multihash", "key", manifestAddr)
 
 				// get the manifest the multihash digest points to

swarm/api/http/server_test.go

@@ -117,10 +117,7 @@ func TestBzzResourceMultihash(t *testing.T) {
 		t.Fatal(err)
 	}
 	s := common.FromHex(string(b))
-	mh, err := multihash.Encode(s, multihash.KECCAK_256)
-	if err != nil {
-		t.Fatal(err)
-	}
+	mh := multihash.ToMultihash(s)
 
 	mhHex := hexutil.Encode(mh)
 	log.Info("added data", "manifest", string(b), "data", common.ToHex(mh))