Update to use the new string representation of a Multihash.

builder.go

@@ -34,7 +34,7 @@ func (p Prefix) WithCodec(c uint64) Builder {
 }
 
 func (p V0Builder) Sum(data []byte) (Cid, error) {
-	hash, err := mh.Sum(data, mh.SHA2_256, -1)
+	hash, err := mh.Builder{Type: mh.SHA2_256}.Sum(data)
 	if err != nil {
 		return Nil, err
 	}
@@ -53,11 +53,7 @@ func (p V0Builder) WithCodec(c uint64) Builder {
 }
 
 func (p V1Builder) Sum(data []byte) (Cid, error) {
-	mhLen := p.MhLength
-	if mhLen <= 0 {
-		mhLen = -1
-	}
-	hash, err := mh.Sum(data, p.MhType, mhLen)
+	hash, err := mh.Builder{Type: p.MhType, Length: p.MhLength}.Sum(data)
 	if err != nil {
 		return Nil, err
 	}

builder_test.go

@@ -17,7 +17,7 @@ func TestV0Builder(t *testing.T) {
 	}
 
 	// Construct c2
-	hash, err := mh.Sum(data, mh.SHA2_256, -1)
+	hash, err := mh.Builder{Type: mh.SHA2_256}.Sum(data)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -42,7 +42,7 @@ func TestV1Builder(t *testing.T) {
 	}
 
 	// Construct c2
-	hash, err := mh.Sum(data, mh.SHA2_256, -1)
+	hash, err := mh.Builder{Type: mh.SHA2_256}.Sum(data)
 	if err != nil {
 		t.Fatal(err)
 	}

cid.go

@@ -29,6 +29,7 @@ import (
 
 	mbase "github.com/multiformats/go-multibase"
 	mh "github.com/multiformats/go-multihash"
+	strbinary "github.com/multiformats/go-multihash/strbinary"
 )
 
 // UnsupportedVersionString just holds an error message
@@ -133,18 +134,18 @@ var CodecToStr = map[uint64]string{
 // compatibility with the plain-multihash format used used in IPFS.
 // NewCidV1 should be used preferentially.
 func NewCidV0(mhash mh.Multihash) Cid {
-	return Cid{string(mhash)}
+	return Cid{mhash.Binary()}
 }
 
 // NewCidV1 returns a new Cid using the given multicodec-packed
 // content type.
 func NewCidV1(codecType uint64, mhash mh.Multihash) Cid {
-	hashlen := len(mhash)
+	hashlen := len(mhash.Binary())
 	// two 8 bytes (max) numbers plus hash
 	buf := make([]byte, 2*binary.MaxVarintLen64+hashlen)
 	n := binary.PutUvarint(buf, 1)
 	n += binary.PutUvarint(buf[n:], codecType)
-	cn := copy(buf[n:], mhash)
+	cn := copy(buf[n:], mhash.Binary())
 	if cn != hashlen {
 		panic("copy hash length is inconsistent")
 	}
@@ -215,7 +216,7 @@ func Decode(v string) (Cid, error) {
 			return Nil, err
 		}
 
-		return NewCidV0(hash), nil
+		return NewCidV0(hash.Cast()), nil
 	}
 
 	_, data, err := mbase.Decode(v)
@@ -277,7 +278,7 @@ func Cast(data []byte) (Cid, error) {
 			return Nil, err
 		}
 
-		return NewCidV0(h), nil
+		return NewCidV0(h.Cast()), nil
 	}
 
 	vers, n := binary.Uvarint(data)
@@ -316,8 +317,7 @@ func (c Cid) Type() uint64 {
 	if c.Version() == 0 {
 		return DagProtobuf
 	}
-	_, n := uvarint(c.str)
-	codec, _ := uvarint(c.str[n:])
+	codec, _ := strbinary.Uvarint(c.str[1:])
 	return codec
 }
 
@@ -358,18 +358,15 @@ func (c Cid) StringOfBase(base mbase.Encoding) (string, error) {
 
 // Hash returns the multihash contained by a Cid.
 func (c Cid) Hash() mh.Multihash {
-	bytes := c.Bytes()
-
 	if c.Version() == 0 {
-		return mh.Multihash(bytes)
+		return mh.FromBinary(c.str)
 	}
 
-	// skip version length
-	_, n1 := binary.Uvarint(bytes)
-	// skip codec length
-	_, n2 := binary.Uvarint(bytes[n1:])
+	// Skip 1 byte for the Version and determine length of the Codec
+	// prefix
+	l := strbinary.UvarintLen(c.str[1:])
 
-	return mh.Multihash(bytes[n1+n2:])
+	return mh.FromBinary(c.str[1+l:])
 }
 
 // Bytes returns the byte representation of a Cid.
@@ -438,10 +435,10 @@ func (c Cid) Loggable() map[string]interface{} {
 
 // Prefix builds and returns a Prefix out of a Cid.
 func (c Cid) Prefix() Prefix {
-	dec, _ := mh.Decode(c.Hash()) // assuming we got a valid multiaddr, this will not error
+	mhType, mhLength, _ := c.Hash().Parts()
 	return Prefix{
-		MhType:   dec.Code,
-		MhLength: dec.Length,
+		MhType:   mhType,
+		MhLength: mhLength,
 		Version:  c.Version(),
 		Codec:    c.Type(),
 	}
@@ -463,7 +460,7 @@ type Prefix struct {
 // Sum uses the information in a prefix to perform a multihash.Sum()
 // and return a newly constructed Cid with the resulting multihash.
 func (p Prefix) Sum(data []byte) (Cid, error) {
-	hash, err := mh.Sum(data, p.MhType, p.MhLength)
+	hash, err := mh.Builder{Type: p.MhType, Length: p.MhLength}.Sum(data)
 	if err != nil {
 		return Nil, err
 	}

cid_test.go

@@ -1,7 +1,6 @@
 package cid
 
 import (
-	"bytes"
 	"encoding/json"
 	"fmt"
 	"math/rand"
@@ -46,7 +45,7 @@ func assertEqual(t *testing.T, a, b Cid) {
 		t.Fatal("mismatch on version")
 	}
 
-	if !bytes.Equal(a.Hash(), b.Hash()) {
+	if a.Hash() != b.Hash() {
 		t.Fatal("multihash mismatch")
 	}
 }
@@ -72,7 +71,7 @@ func TestTableForV0(t *testing.T) {
 }
 
 func TestBasicMarshaling(t *testing.T) {
-	h, err := mh.Sum([]byte("TEST"), mh.SHA3, 4)
+	h, err := mh.Builder{Type: mh.SHA3}.Sum([]byte("TEST"))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -98,7 +97,7 @@ func TestBasicMarshaling(t *testing.T) {
 }
 
 func TestBasesMarshaling(t *testing.T) {
-	h, err := mh.Sum([]byte("TEST"), mh.SHA3, 4)
+	h, err := mh.Builder{Type: mh.SHA3}.Sum([]byte("TEST"))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -198,7 +197,7 @@ func TestNewPrefixV1(t *testing.T) {
 	}
 
 	// Construct c2
-	hash, err := mh.Sum(data, mh.SHA2_256, -1)
+	hash, err := mh.Builder{Type: mh.SHA2_256}.Sum(data)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -227,7 +226,7 @@ func TestNewPrefixV0(t *testing.T) {
 	}
 
 	// Construct c2
-	hash, err := mh.Sum(data, mh.SHA2_256, -1)
+	hash, err := mh.Builder{Type: mh.SHA2_256}.Sum(data)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -243,7 +242,7 @@ func TestNewPrefixV0(t *testing.T) {
 
 func TestPrefixRoundtrip(t *testing.T) {
 	data := []byte("this is some test content")
-	hash, _ := mh.Sum(data, mh.SHA2_256, -1)
+	hash, _ := mh.Builder{Type: mh.SHA2_256}.Sum(data)
 	c := NewCidV1(DagCBOR, hash)
 
 	pref := c.Prefix()
@@ -272,7 +271,7 @@ func TestPrefixRoundtrip(t *testing.T) {
 
 func Test16BytesVarint(t *testing.T) {
 	data := []byte("this is some test content")
-	hash, _ := mh.Sum(data, mh.SHA2_256, -1)
+	hash, _ := mh.Builder{Type: mh.SHA2_256}.Sum(data)
 	c := NewCidV1(1<<63, hash)
 	_ = c.Bytes()
 }
@@ -296,10 +295,11 @@ func TestParse(t *testing.T) {
 	}
 
 	theHash := "QmdfTbBqBPQ7VNxZEYEj14VmRuZBkqFbiwReogJgS1zR1n"
-	h, err := mh.FromB58String(theHash)
+	h0, err := mh.FromB58String(theHash)
 	if err != nil {
 		t.Fatal(err)
 	}
+	h := h0.Cast()
 
 	assertions := [][]interface{}{
 		[]interface{}{NewCidV0(h), theHash},
@@ -407,7 +407,7 @@ func TestJsonRoundTrip(t *testing.T) {
 
 func BenchmarkStringV1(b *testing.B) {
 	data := []byte("this is some test content")
-	hash, _ := mh.Sum(data, mh.SHA2_256, -1)
+	hash, _ := mh.Builder{Type: mh.SHA2_256}.Sum(data)
 	cid := NewCidV1(Raw, hash)
 
 	b.ReportAllocs()

package.json

@@ -9,9 +9,9 @@
   "gxDependencies": [
     {
       "author": "whyrusleeping",
-      "hash": "QmPnFwZ2JXKnXgMw8CdBPxn7FWh6LLdjUjxV1fKHuJnkr8",
+      "hash": "QmNNAKBZusgdz5GpZh5D5RvBaSYgqfXtwB7YLsjyemkcPU",
       "name": "go-multihash",
-      "version": "1.0.8"
+      "version": "1.2.0"
     },
     {
       "author": "whyrusleeping",

set_test.go

@@ -15,7 +15,7 @@ func makeRandomCid(t *testing.T) Cid {
 		t.Fatal(err)
 	}
 
-	h, err := mh.Sum(p, mh.SHA3, 4)
+	h, err := mh.Builder{Type: mh.SHA3, Length: 4}.Sum(p)
 	if err != nil {
 		t.Fatal(err)
 	}