From 5852134849fcb46ba4591777457b148ecd144ca2 Mon Sep 17 00:00:00 2001
From: Elad <theman@elad.im>
Date: Wed, 6 Mar 2019 20:13:44 +0700
Subject: [PATCH] contracts/ens: cid sanity tests

---
 contracts/ens/ens.go      | 26 +++++++++++++---
 contracts/ens/ens_test.go | 63 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+), 4 deletions(-)

diff --git a/contracts/ens/ens.go b/contracts/ens/ens.go
index 3930ae4fb0..2a761542d5 100644
--- a/contracts/ens/ens.go
+++ b/contracts/ens/ens.go
@@ -25,12 +25,15 @@ import (
 	"encoding/binary"
 	"strings"
 
+	mh "github.com/multiformats/go-multihash"
+
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/contracts/ens/contract"
 	"github.com/ethereum/go-ethereum/contracts/ens/fallback_contract"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ipfs/go-cid"
 )
 
 var (
@@ -262,6 +265,14 @@ func (ens *ENS) SetContentHash(name string, hash []byte) (*types.Transaction, er
 }
 
 func decodeMultiCodec(b []byte) (common.Hash, error) {
+
+	// Create a cid from a marshaled string
+	c, err := cid.Decode(string(b))
+	if err != nil {
+		return common.Hash{}, err
+	}
+
+	return common.Hash{}, nil
 	/* from the EIP documentation
 	   storage system: Swarm (0xe4)
 	   CID version: 1 (0x01)
@@ -274,9 +285,16 @@ func decodeMultiCodec(b []byte) (common.Hash, error) {
 
 }
 
-func encodeMultiCodec(h common.Hash) []byte {
-	b := []byte{0xe4, 0x01, 0x01, 0x1b, 0x20}
+// encodeCid encodes a swarm hash into an IPLD CID
+func encodeCid(h common.Hash) (cid.Cid, error) {
+	b := []byte{0x1b, 0x20}     //0x1b = keccak256 (should be changed to bmt), 0x20 = 32 bytes hash length
+	b = append(b, h.Bytes()...) // append actual hash bytes
+	multi, err := mh.Cast(b)
+	if err != nil {
+		return cid.Cid{}, err
+	}
 
-	b = append(b, h.Bytes()...)
-	return b
+	c := cid.NewCidV1(cid.Raw, multi) //todo: cid.Raw should be swarm manifest
+
+	return c, nil
 }
diff --git a/contracts/ens/ens_test.go b/contracts/ens/ens_test.go
index 764a575cb7..4c7bfcda79 100644
--- a/contracts/ens/ens_test.go
+++ b/contracts/ens/ens_test.go
@@ -17,6 +17,8 @@
 package ens
 
 import (
+	"bytes"
+	"fmt"
 	"math/big"
 	"testing"
 
@@ -27,6 +29,7 @@ import (
 	"github.com/ethereum/go-ethereum/contracts/ens/fallback_contract"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/crypto"
+	mh "github.com/multiformats/go-multihash"
 )
 
 var (
@@ -120,3 +123,63 @@ func TestENS(t *testing.T) {
 	}
 	t.Fatal("todo: try to set old contract with new multicodec stuff and assert fail, set new contract with multicodec stuff, encode, decode and assert returns correct hash")
 }
+
+func TestCIDSanity(t *testing.T) {
+	for _, v := range []struct {
+		name    string
+		hashStr string
+		fail    bool
+	}{
+		{
+			name:    "hash OK, should not fail",
+			hashStr: "d1de9994b4d039f6548d191eb26786769f580809256b4685ef316805265ea162",
+			fail:    false,
+		},
+		{
+			name:    "hash empty , should fail",
+			hashStr: "",
+			fail:    true,
+		},
+	} {
+		t.Run(v.name, func(t *testing.T) {
+			hash := common.HexToHash(v.hashStr)
+			cc, err := encodeCid(hash)
+			if err != nil {
+				if v.fail {
+					return
+				}
+				t.Fatal(err)
+			}
+
+			if cc.Prefix().MhLength != 32 {
+				t.Fatal("w00t")
+			}
+			fmt.Println(cc.Hash())
+			decoded, err := mh.Decode(cc.Hash())
+			if err != nil {
+				t.Fatal(err)
+			}
+			if decoded.Length != 32 {
+				t.Fatal("invalid length")
+			}
+			if !bytes.Equal(decoded.Digest, hash[:]) {
+				t.Fatalf("hashes not equal")
+			}
+
+			if decoded.Length != 32 {
+				t.Fatal("wrong length")
+			}
+			fmt.Println("Created CID: ", cc)
+
+		})
+
+		/*c, err := cid.Decode("zdvgqEMYmNeH5fKciougvQcfzMcNjF3Z1tPouJ8C7pc3pe63k")
+		if err != nil {
+			t.Fatal("Error decoding CID")
+		}
+
+		fmt.Sprintf("Got CID: %v", c)
+		fmt.Println("Got CID:", c.Prefix())
+		*/
+	}
+}