gx publish 0.7.25

add a streaming CID set

.gx/lastpubver

@@ -1 +1 @@
-0.7.14: QmTJRF2HyQfqXc9BBWVu9ZoumjAs7KsbvYaE6fRrzzoDRF
+0.7.25: QmYjnkEL7i731PirfVH1sis89evN7jt4otSHw5D2xXXwUV

.travis.yml

@@ -1,24 +1,24 @@
-os:
-  - linux
-  - osx
+sudo: false
+
 
 language: go
-
 go:
-    - 1.7
-
-install: true
-
-before_install:
-  - make deps
-
+  - 'tip'
+  
+install:
+  - go get github.com/whyrusleeping/gx
+  - go get github.com/whyrusleeping/gx-go
+  - gx install --global
 script:
-  - go vet
-  - $GOPATH/bin/goveralls -service="travis-ci"
+  - gx test -v -race -coverprofile=coverage.txt -covermode=atomic .
+  
+after_success:
+  - bash <(curl -s https://codecov.io/bash)
 
 cache:
-    directories:
-        - $GOPATH/src/gx
+  directories:
+    - $GOPATH/src/gx
 
 notifications:
-  email: false
+email: false
+  

builder.go

@@ -0,0 +1,74 @@
+package cid
+
+import (
+	mh "github.com/multiformats/go-multihash"
+)
+
+type Builder interface {
+	Sum(data []byte) (*Cid, error)
+	GetCodec() uint64
+	WithCodec(uint64) Builder
+}
+
+type V0Builder struct{}
+
+type V1Builder struct {
+	Codec    uint64
+	MhType   uint64
+	MhLength int // MhLength <= 0 means the default length
+}
+
+func (p Prefix) GetCodec() uint64 {
+	return p.Codec
+}
+
+func (p Prefix) WithCodec(c uint64) Builder {
+	if c == p.Codec {
+		return p
+	}
+	p.Codec = c
+	if c != DagProtobuf {
+		p.Version = 1
+	}
+	return p
+}
+
+func (p V0Builder) Sum(data []byte) (*Cid, error) {
+	hash, err := mh.Sum(data, mh.SHA2_256, -1)
+	if err != nil {
+		return nil, err
+	}
+	return NewCidV0(hash), nil
+}
+
+func (p V0Builder) GetCodec() uint64 {
+	return DagProtobuf
+}
+
+func (p V0Builder) WithCodec(c uint64) Builder {
+	if c == DagProtobuf {
+		return p
+	}
+	return V1Builder{Codec: c, MhType: mh.SHA2_256}
+}
+
+func (p V1Builder) Sum(data []byte) (*Cid, error) {
+	mhLen := p.MhLength
+	if mhLen <= 0 {
+		mhLen = -1
+	}
+	hash, err := mh.Sum(data, p.MhType, mhLen)
+	if err != nil {
+		return nil, err
+	}
+	return NewCidV1(p.Codec, hash), nil
+}
+
+func (p V1Builder) GetCodec() uint64 {
+	return p.Codec
+}
+
+func (p V1Builder) WithCodec(c uint64) Builder {
+	p.Codec = c
+	return p
+}

builder_test.go

@@ -0,0 +1,92 @@
+package cid
+
+import (
+	"testing"
+
+	mh "github.com/multiformats/go-multihash"
+)
+
+func TestV0Builder(t *testing.T) {
+	data := []byte("this is some test content")
+
+	// Construct c1
+	format := V0Builder{}
+	c1, err := format.Sum(data)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Construct c2
+	hash, err := mh.Sum(data, mh.SHA2_256, -1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	c2 := NewCidV0(hash)
+
+	if !c1.Equals(c2) {
+		t.Fatal("cids mismatch")
+	}
+	if c1.Prefix() != c2.Prefix() {
+		t.Fatal("prefixes mismatch")
+	}
+}
+
+func TestV1Builder(t *testing.T) {
+	data := []byte("this is some test content")
+
+	// Construct c1
+	format := V1Builder{Codec: DagCBOR, MhType: mh.SHA2_256}
+	c1, err := format.Sum(data)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Construct c2
+	hash, err := mh.Sum(data, mh.SHA2_256, -1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	c2 := NewCidV1(DagCBOR, hash)
+
+	if !c1.Equals(c2) {
+		t.Fatal("cids mismatch")
+	}
+	if c1.Prefix() != c2.Prefix() {
+		t.Fatal("prefixes mismatch")
+	}
+}
+
+func TestCodecChange(t *testing.T) {
+	t.Run("Prefix-CidV0", func(t *testing.T) {
+		p := Prefix{Version: 0, Codec: DagProtobuf, MhType: mh.SHA2_256, MhLength: mh.DefaultLengths[mh.SHA2_256]}
+		testCodecChange(t, p)
+	})
+	t.Run("Prefix-CidV1", func(t *testing.T) {
+		p := Prefix{Version: 1, Codec: DagProtobuf, MhType: mh.SHA2_256, MhLength: mh.DefaultLengths[mh.SHA2_256]}
+		testCodecChange(t, p)
+	})
+	t.Run("V0Builder", func(t *testing.T) {
+		testCodecChange(t, V0Builder{})
+	})
+	t.Run("V1Builder", func(t *testing.T) {
+		testCodecChange(t, V1Builder{Codec: DagProtobuf, MhType: mh.SHA2_256})
+	})
+}
+
+func testCodecChange(t *testing.T, b Builder) {
+	data := []byte("this is some test content")
+
+	if b.GetCodec() != DagProtobuf {
+		t.Fatal("original builder not using Protobuf codec")
+	}
+
+	b = b.WithCodec(Raw)
+	c, err := b.Sum(data)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if c.Type() != Raw {
+		t.Fatal("new cid codec did not change to Raw")
+	}
+}

cid-fmt/main.go

@@ -0,0 +1,128 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	c "github.com/ipfs/go-cid"
+
+	mb "github.com/multiformats/go-multibase"
+)
+
+func usage() {
+	fmt.Fprintf(os.Stderr, "usage: %s [-b multibase-code] [-v cid-version] <fmt-str> <cid> ...\n\n", os.Args[0])
+	fmt.Fprintf(os.Stderr, "<fmt-str> is either 'prefix' or a printf style format string:\n%s", c.FormatRef)
+	os.Exit(2)
+}
+
+func main() {
+	if len(os.Args) < 2 {
+		usage()
+	}
+	newBase := mb.Encoding(-1)
+	var verConv func(cid *c.Cid) (*c.Cid, error)
+	args := os.Args[1:]
+outer:
+	for {
+		switch args[0] {
+		case "-b":
+			if len(args) < 2 {
+				usage()
+			}
+			encoder, err := mb.EncoderByName(args[1])
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "Error: %s\n", err.Error())
+				os.Exit(2)
+			}
+			newBase = encoder.Encoding()
+			args = args[2:]
+		case "-v":
+			if len(args) < 2 {
+				usage()
+			}
+			switch args[1] {
+			case "0":
+				verConv = toCidV0
+			case "1":
+				verConv = toCidV1
+			default:
+				fmt.Fprintf(os.Stderr, "Error: Invalid cid version: %s\n", args[1])
+				os.Exit(2)
+			}
+			args = args[2:]
+		default:
+			break outer
+		}
+	}
+	if len(args) < 2 {
+		usage()
+	}
+	fmtStr := args[0]
+	switch fmtStr {
+	case "prefix":
+		fmtStr = "%P"
+	default:
+		if strings.IndexByte(fmtStr, '%') == -1 {
+			fmt.Fprintf(os.Stderr, "Error: Invalid format string: %s\n", fmtStr)
+			os.Exit(2)
+		}
+	}
+	for _, cidStr := range args[1:] {
+		cid, err := c.Decode(cidStr)
+		if err != nil {
+			fmt.Fprintf(os.Stdout, "!INVALID_CID!\n")
+			errorMsg("%s: %v", cidStr, err)
+			// Don't abort on a bad cid
+			continue
+		}
+		base := newBase
+		if newBase == -1 {
+			base, _ = c.ExtractEncoding(cidStr)
+		}
+		if verConv != nil {
+			cid, err = verConv(cid)
+			if err != nil {
+				fmt.Fprintf(os.Stdout, "!ERROR!\n")
+				errorMsg("%s: %v", cidStr, err)
+				// Don't abort on a bad conversion
+				continue
+			}
+		}
+		str, err := c.Format(fmtStr, base, cid)
+		switch err.(type) {
+		case c.FormatStringError:
+			fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+			os.Exit(2)
+		default:
+			fmt.Fprintf(os.Stdout, "!ERROR!\n")
+			errorMsg("%s: %v", cidStr, err)
+			// Don't abort on cid specific errors
+			continue
+		case nil:
+			// no error
+		}
+		fmt.Fprintf(os.Stdout, "%s\n", str)
+	}
+	os.Exit(exitCode)
+}
+
+var exitCode = 0
+
+func errorMsg(fmtStr string, a ...interface{}) {
+	fmt.Fprintf(os.Stderr, "Error: ")
+	fmt.Fprintf(os.Stderr, fmtStr, a...)
+	fmt.Fprintf(os.Stderr, "\n")
+	exitCode = 1
+}
+
+func toCidV0(cid *c.Cid) (*c.Cid, error) {
+	if cid.Type() != c.DagProtobuf {
+		return nil, fmt.Errorf("can't convert non-protobuf nodes to cidv0")
+	}
+	return c.NewCidV0(cid.Hash()), nil
+}
+
+func toCidV1(cid *c.Cid) (*c.Cid, error) {
+	return c.NewCidV1(cid.Type(), cid.Hash()), nil
+}

cid-fmt/main_test.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"fmt"
+	"testing"
+
+	c "github.com/ipfs/go-cid"
+)
+
+func TestCidConv(t *testing.T) {
+	cidv0 := "QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn"
+	cidv1 := "zdj7WbTaiJT1fgatdet9Ei9iDB5hdCxkbVyhyh8YTUnXMiwYi"
+	cid, err := c.Decode(cidv0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	cid, err = toCidV1(cid)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if cid.String() != cidv1 {
+		t.Fatal("conversion failure")
+	}
+	cid, err = toCidV0(cid)
+	if err != nil {
+		t.Fatal(err)
+	}
+	cidStr := cid.String()
+	if cidStr != cidv0 {
+		t.Error(fmt.Sprintf("conversion failure, expected: %s; but got: %s", cidv0, cidStr))
+	}
+}
+
+func TestBadCidConv(t *testing.T) {
+	// this cid is a raw leaf and should not be able to convert to cidv0
+	cidv1 := "zb2rhhzX7uSKrtQ2ZZXFAabKiKFYZrJqKY2KE1cJ8yre2GSWZ"
+	cid, err := c.Decode(cidv1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	cid, err = toCidV0(cid)
+	if err == nil {
+		t.Fatal("expected failure")
+	}
+}

cid.go

@@ -47,6 +47,10 @@ var (
 	// ErrCidTooShort means that the cid passed to decode was not long
 	// enough to be a valid Cid
 	ErrCidTooShort = errors.New("cid too short")
+
+	// ErrInvalidEncoding means that selected encoding is not supported
+	// by this Cid version
+	ErrInvalidEncoding = errors.New("invalid base encoding")
 )
 
 // These are multicodec-packed content types. The should match
@@ -73,8 +77,57 @@ const (
 	BitcoinTx          = 0xb1
 	ZcashBlock         = 0xc0
 	ZcashTx            = 0xc1
+	DecredBlock        = 0xe0
+	DecredTx           = 0xe1
 )
 
+// Codecs maps the name of a codec to its type
+var Codecs = map[string]uint64{
+	"v0":                   DagProtobuf,
+	"raw":                  Raw,
+	"protobuf":             DagProtobuf,
+	"cbor":                 DagCBOR,
+	"git-raw":              GitRaw,
+	"eth-block":            EthBlock,
+	"eth-block-list":       EthBlockList,
+	"eth-tx-trie":          EthTxTrie,
+	"eth-tx":               EthTx,
+	"eth-tx-receipt-trie":  EthTxReceiptTrie,
+	"eth-tx-receipt":       EthTxReceipt,
+	"eth-state-trie":       EthStateTrie,
+	"eth-account-snapshot": EthAccountSnapshot,
+	"eth-storage-trie":     EthStorageTrie,
+	"bitcoin-block":        BitcoinBlock,
+	"bitcoin-tx":           BitcoinTx,
+	"zcash-block":          ZcashBlock,
+	"zcash-tx":             ZcashTx,
+	"decred-block":         DecredBlock,
+	"decred-tx":            DecredTx,
+}
+
+// CodecToStr maps the numeric codec to its name
+var CodecToStr = map[uint64]string{
+	Raw:                "raw",
+	DagProtobuf:        "protobuf",
+	DagCBOR:            "cbor",
+	GitRaw:             "git-raw",
+	EthBlock:           "eth-block",
+	EthBlockList:       "eth-block-list",
+	EthTxTrie:          "eth-tx-trie",
+	EthTx:              "eth-tx",
+	EthTxReceiptTrie:   "eth-tx-receipt-trie",
+	EthTxReceipt:       "eth-tx-receipt",
+	EthStateTrie:       "eth-state-trie",
+	EthAccountSnapshot: "eth-account-snapshot",
+	EthStorageTrie:     "eth-storage-trie",
+	BitcoinBlock:       "bitcoin-block",
+	BitcoinTx:          "bitcoin-tx",
+	ZcashBlock:         "zcash-block",
+	ZcashTx:            "zcash-tx",
+	DecredBlock:        "decred-block",
+	DecredTx:           "decred-tx",
+}
+
 // NewCidV0 returns a Cid-wrapped multihash.
 // They exist to allow IPFS to work with Cids while keeping
 // compatibility with the plain-multihash format used used in IPFS.
@@ -160,6 +213,28 @@ func Decode(v string) (*Cid, error) {
 	return Cast(data)
 }
 
+// Extract the encoding from a Cid.  If Decode on the same string did
+// not return an error neither will this function.
+func ExtractEncoding(v string) (mbase.Encoding, error) {
+	if len(v) < 2 {
+		return -1, ErrCidTooShort
+	}
+
+	if len(v) == 46 && v[:2] == "Qm" {
+		return mbase.Base58BTC, nil
+	}
+
+	encoding := mbase.Encoding(v[0])
+
+	// check encoding is valid
+	_, err := mbase.NewEncoder(encoding)
+	if err != nil {
+		return -1, err
+	}
+
+	return encoding, nil
+}
+
 func uvError(read int) error {
 	switch {
 	case read == 0:
@@ -247,6 +322,22 @@ func (c *Cid) String() string {
 	}
 }
 
+// String returns the string representation of a Cid
+// encoded is selected base
+func (c *Cid) StringOfBase(base mbase.Encoding) (string, error) {
+	switch c.version {
+	case 0:
+		if base != mbase.Base58BTC {
+			return "", ErrInvalidEncoding
+		}
+		return c.hash.B58String(), nil
+	case 1:
+		return mbase.Encode(base, c.bytesV1())
+	default:
+		panic("not possible to reach this point")
+	}
+}
+
 // Hash returns the multihash contained by a Cid.
 func (c *Cid) Hash() mh.Multihash {
 	return c.hash
@@ -326,7 +417,7 @@ func (c *Cid) UnmarshalJSON(b []byte) error {
 //
 // Note that this formatting comes from the IPLD specification
 // (https://github.com/ipld/specs/tree/master/ipld)
-func (c *Cid) MarshalJSON() ([]byte, error) {
+func (c Cid) MarshalJSON() ([]byte, error) {
 	return []byte(fmt.Sprintf("{\"/\":\"%s\"}", c.String())), nil
 }
 
@@ -358,6 +449,8 @@ func (c *Cid) Prefix() Prefix {
 // that is, the Version, the Codec, the Multihash type
 // and the Multihash length. It does not contains
 // any actual content information.
+// NOTE: The use -1 in MhLength to mean default length is deprecated,
+//   use the V0Builder or V1Builder structures instead
 type Prefix struct {
 	Version  uint64
 	Codec    uint64

cid_test.go

@@ -8,9 +8,35 @@ import (
 	"strings"
 	"testing"
 
+	mbase "github.com/multiformats/go-multibase"
 	mh "github.com/multiformats/go-multihash"
 )
 
+// Copying the "silly test" idea from
+// https://github.com/multiformats/go-multihash/blob/7aa9f26a231c6f34f4e9fad52bf580fd36627285/multihash_test.go#L13
+// Makes it so changing the table accidentally has to happen twice.
+var tCodecs = map[uint64]string{
+	Raw:                "raw",
+	DagProtobuf:        "protobuf",
+	DagCBOR:            "cbor",
+	GitRaw:             "git-raw",
+	EthBlock:           "eth-block",
+	EthBlockList:       "eth-block-list",
+	EthTxTrie:          "eth-tx-trie",
+	EthTx:              "eth-tx",
+	EthTxReceiptTrie:   "eth-tx-receipt-trie",
+	EthTxReceipt:       "eth-tx-receipt",
+	EthStateTrie:       "eth-state-trie",
+	EthAccountSnapshot: "eth-account-snapshot",
+	EthStorageTrie:     "eth-storage-trie",
+	BitcoinBlock:       "bitcoin-block",
+	BitcoinTx:          "bitcoin-tx",
+	ZcashBlock:         "zcash-block",
+	ZcashTx:            "zcash-tx",
+	DecredBlock:        "decred-block",
+	DecredTx:           "decred-tx",
+}
+
 func assertEqual(t *testing.T, a, b *Cid) {
 	if a.codec != b.codec {
 		t.Fatal("mismatch on type")
@@ -25,6 +51,26 @@ func assertEqual(t *testing.T, a, b *Cid) {
 	}
 }
 
+func TestTable(t *testing.T) {
+	if len(tCodecs) != len(Codecs)-1 {
+		t.Errorf("Item count mismatch in the Table of Codec. Should be %d, got %d", len(tCodecs)+1, len(Codecs))
+	}
+
+	for k, v := range tCodecs {
+		if Codecs[v] != k {
+			t.Errorf("Table mismatch: 0x%x %s", k, v)
+		}
+	}
+}
+
+// The table returns cid.DagProtobuf for "v0"
+// so we test it apart
+func TestTableForV0(t *testing.T) {
+	if Codecs["v0"] != DagProtobuf {
+		t.Error("Table mismatch: Codecs[\"v0\"] should resolve to DagProtobuf (0x70)")
+	}
+}
+
 func TestBasicMarshaling(t *testing.T) {
 	h, err := mh.Sum([]byte("TEST"), mh.SHA3, 4)
 	if err != nil {
@@ -55,6 +101,60 @@ func TestBasicMarshaling(t *testing.T) {
 	assertEqual(t, cid, out2)
 }
 
+func TestBasesMarshaling(t *testing.T) {
+	h, err := mh.Sum([]byte("TEST"), mh.SHA3, 4)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cid := &Cid{
+		codec:   7,
+		version: 1,
+		hash:    h,
+	}
+
+	data := cid.Bytes()
+
+	out, err := Cast(data)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	assertEqual(t, cid, out)
+
+	testBases := []mbase.Encoding{
+		mbase.Base16,
+		mbase.Base32,
+		mbase.Base32hex,
+		mbase.Base32pad,
+		mbase.Base32hexPad,
+		mbase.Base58BTC,
+		mbase.Base58Flickr,
+		mbase.Base64pad,
+		mbase.Base64urlPad,
+		mbase.Base64url,
+		mbase.Base64,
+	}
+
+	for _, b := range testBases {
+		s, err := cid.StringOfBase(b)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if s[0] != byte(b) {
+			t.Fatal("Invalid multibase header")
+		}
+
+		out2, err := Decode(s)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		assertEqual(t, cid, out2)
+	}
+}
+
 func TestEmptyString(t *testing.T) {
 	_, err := Decode("")
 	if err == nil {
@@ -91,6 +191,64 @@ func TestV0ErrorCases(t *testing.T) {
 	}
 }
 
+func TestNewPrefixV1(t *testing.T) {
+	data := []byte("this is some test content")
+
+	// Construct c1
+	prefix := NewPrefixV1(DagCBOR, mh.SHA2_256)
+	c1, err := prefix.Sum(data)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if c1.Prefix() != prefix {
+		t.Fatal("prefix not preserved")
+	}
+
+	// Construct c2
+	hash, err := mh.Sum(data, mh.SHA2_256, -1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	c2 := NewCidV1(DagCBOR, hash)
+
+	if !c1.Equals(c2) {
+		t.Fatal("cids mismatch")
+	}
+	if c1.Prefix() != c2.Prefix() {
+		t.Fatal("prefixes mismatch")
+	}
+}
+
+func TestNewPrefixV0(t *testing.T) {
+	data := []byte("this is some test content")
+
+	// Construct c1
+	prefix := NewPrefixV0(mh.SHA2_256)
+	c1, err := prefix.Sum(data)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if c1.Prefix() != prefix {
+		t.Fatal("prefix not preserved")
+	}
+
+	// Construct c2
+	hash, err := mh.Sum(data, mh.SHA2_256, -1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	c2 := NewCidV0(hash)
+
+	if !c1.Equals(c2) {
+		t.Fatal("cids mismatch")
+	}
+	if c1.Prefix() != c2.Prefix() {
+		t.Fatal("prefixes mismatch")
+	}
+}
+
 func TestPrefixRoundtrip(t *testing.T) {
 	data := []byte("this is some test content")
 	hash, _ := mh.Sum(data, mh.SHA2_256, -1)
@@ -227,3 +385,46 @@ func TestFromJson(t *testing.T) {
 		t.Fatal("json parsing failed")
 	}
 }
+
+func TestJsonRoundTrip(t *testing.T) {
+	exp, err := Decode("zb2rhhFAEMepUBbGyP1k8tGfz7BSciKXP6GHuUeUsJBaK6cqG")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Verify it works for a *Cid.
+	enc, err := json.Marshal(exp)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var actual Cid
+	err = json.Unmarshal(enc, &actual)
+	if !exp.Equals(&actual) {
+		t.Fatal("cids not equal for *Cid")
+	}
+
+	// Verify it works for a Cid.
+	enc, err = json.Marshal(*exp)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var actual2 Cid
+	err = json.Unmarshal(enc, &actual2)
+	if !exp.Equals(&actual2) {
+		t.Fatal("cids not equal for Cid")
+	}
+}
+
+func BenchmarkStringV1(b *testing.B) {
+	data := []byte("this is some test content")
+	hash, _ := mh.Sum(data, mh.SHA2_256, -1)
+	cid := NewCidV1(Raw, hash)
+	b.ResetTimer()
+	count := 0
+	for i := 0; i < b.N; i++ {
+		count += len(cid.String())
+	}
+	if count != 49*b.N {
+		b.FailNow()
+	}
+}

codecov.yml

@@ -0,0 +1,3 @@
+coverage:
+  range: "50...100"
+comment: off

deprecated.go

@@ -0,0 +1,28 @@
+package cid
+
+import (
+	mh "github.com/multiformats/go-multihash"
+)
+
+// NewPrefixV0 returns a CIDv0 prefix with the specified multihash type.
+// DEPRECATED: Use V0Builder
+func NewPrefixV0(mhType uint64) Prefix {
+	return Prefix{
+		MhType:   mhType,
+		MhLength: mh.DefaultLengths[mhType],
+		Version:  0,
+		Codec:    DagProtobuf,
+	}
+}
+
+// NewPrefixV1 returns a CIDv1 prefix with the specified codec and multihash
+// type.
+// DEPRECATED: Use V1Builder
+func NewPrefixV1(codecType uint64, mhType uint64) Prefix {
+	return Prefix{
+		MhType:   mhType,
+		MhLength: mh.DefaultLengths[mhType],
+		Version:  1,
+		Codec:    codecType,
+	}
+}

format.go

@@ -0,0 +1,151 @@
+package cid
+
+import (
+	"bytes"
+	"fmt"
+
+	mb "github.com/multiformats/go-multibase"
+	mh "github.com/multiformats/go-multihash"
+)
+
+// FormatRef is a string documenting the format string for the Format function
+const FormatRef = `
+   %% literal %
+   %b multibase name
+   %B multibase code
+   %v version string
+   %V version number
+   %c codec name
+   %C codec code
+   %h multihash name
+   %H multihash code
+   %L hash digest length
+   %m multihash encoded in base %b (with multibase prefix)
+   %M multihash encoded in base %b without multibase prefix
+   %d hash digest encoded in base %b (with multibase prefix)
+   %D hash digest encoded in base %b without multibase prefix
+   %s cid string encoded in base %b (1)
+   %S cid string encoded in base %b without multibase prefix
+   %P cid prefix: %v-%c-%h-%L
+
+(1) For CID version 0 the multibase must be base58btc and no prefix is
+used.  For Cid version 1 the multibase prefix is included.
+`
+
+// Format formats a cid according to the format specificer as
+// documented in the FormatRef constant
+func Format(fmtStr string, base mb.Encoding, cid *Cid) (string, error) {
+	p := cid.Prefix()
+	var out bytes.Buffer
+	var err error
+	encoder, err := mb.NewEncoder(base)
+	if err != nil {
+		return "", err
+	}
+	for i := 0; i < len(fmtStr); i++ {
+		if fmtStr[i] != '%' {
+			out.WriteByte(fmtStr[i])
+			continue
+		}
+		i++
+		if i >= len(fmtStr) {
+			return "", FormatStringError{"premature end of format string", ""}
+		}
+		switch fmtStr[i] {
+		case '%':
+			out.WriteByte('%')
+		case 'b': // base name
+			out.WriteString(baseToString(base))
+		case 'B': // base code
+			out.WriteByte(byte(base))
+		case 'v': // version string
+			fmt.Fprintf(&out, "cidv%d", p.Version)
+		case 'V': // version num
+			fmt.Fprintf(&out, "%d", p.Version)
+		case 'c': // codec name
+			out.WriteString(codecToString(p.Codec))
+		case 'C': // codec code
+			fmt.Fprintf(&out, "%d", p.Codec)
+		case 'h': // hash fun name
+			out.WriteString(hashToString(p.MhType))
+		case 'H': // hash fun code
+			fmt.Fprintf(&out, "%d", p.MhType)
+		case 'L': // hash length
+			fmt.Fprintf(&out, "%d", p.MhLength)
+		case 'm', 'M': // multihash encoded in base %b
+			out.WriteString(encode(encoder, cid.Hash(), fmtStr[i] == 'M'))
+		case 'd', 'D': // hash digest encoded in base %b
+			dec, err := mh.Decode(cid.Hash())
+			if err != nil {
+				return "", err
+			}
+			out.WriteString(encode(encoder, dec.Digest, fmtStr[i] == 'D'))
+		case 's': // cid string encoded in base %b
+			str, err := cid.StringOfBase(base)
+			if err != nil {
+				return "", err
+			}
+			out.WriteString(str)
+		case 'S': // cid string without base prefix
+			out.WriteString(encode(encoder, cid.Bytes(), true))
+		case 'P': // prefix
+			fmt.Fprintf(&out, "cidv%d-%s-%s-%d",
+				p.Version,
+				codecToString(p.Codec),
+				hashToString(p.MhType),
+				p.MhLength,
+			)
+		default:
+			return "", FormatStringError{"unrecognized specifier in format string", fmtStr[i-1 : i+1]}
+		}
+
+	}
+	return out.String(), err
+}
+
+// FormatStringError is the error return from Format when the format
+// string is ill formed
+type FormatStringError struct {
+	Message   string
+	Specifier string
+}
+
+func (e FormatStringError) Error() string {
+	if e.Specifier == "" {
+		return e.Message
+	} else {
+		return fmt.Sprintf("%s: %s", e.Message, e.Specifier)
+	}
+}
+
+func baseToString(base mb.Encoding) string {
+	baseStr, ok := mb.EncodingToStr[base]
+	if !ok {
+		return fmt.Sprintf("base?%c", base)
+	}
+	return baseStr
+}
+
+func codecToString(num uint64) string {
+	name, ok := CodecToStr[num]
+	if !ok {
+		return fmt.Sprintf("codec?%d", num)
+	}
+	return name
+}
+
+func hashToString(num uint64) string {
+	name, ok := mh.Codes[num]
+	if !ok {
+		return fmt.Sprintf("hash?%d", num)
+	}
+	return name
+}
+
+func encode(base mb.Encoder, data []byte, strip bool) string {
+	str := base.Encode(data)
+	if strip {
+		return str[1:]
+	}
+	return str
+}

format_test.go

@@ -0,0 +1,73 @@
+package cid
+
+import (
+	"fmt"
+	"testing"
+
+	mb "github.com/multiformats/go-multibase"
+)
+
+func TestFmt(t *testing.T) {
+	cids := map[string]string{
+		"cidv0": "QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn",
+		"cidv1": "zdj7WfLr9DhLrb1hsoSi4fSdjjxuZmeqgEtBPWxMLtPbDNbFD",
+	}
+	tests := []struct {
+		cidId   string
+		newBase mb.Encoding
+		fmtStr  string
+		result  string
+	}{
+		{"cidv0", -1, "%P", "cidv0-protobuf-sha2-256-32"},
+		{"cidv0", -1, "%b-%v-%c-%h-%L", "base58btc-cidv0-protobuf-sha2-256-32"},
+		{"cidv0", -1, "%s", "QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn"},
+		{"cidv0", -1, "%S", "QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn"},
+		{"cidv0", -1, "ver#%V/#%C/#%H/%L", "ver#0/#112/#18/32"},
+		{"cidv0", -1, "%m", "zQmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn"},
+		{"cidv0", -1, "%M", "QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn"},
+		{"cidv0", -1, "%d", "z72gdmFAgRzYHkJzKiL8MgMMRW3BTSCGyDHroPxJbxMJn"},
+		{"cidv0", -1, "%D", "72gdmFAgRzYHkJzKiL8MgMMRW3BTSCGyDHroPxJbxMJn"},
+		{"cidv0", 'B', "%S", "CIQFTFEEHEDF6KLBT32BFAGLXEZL4UWFNWM4LFTLMXQBCERZ6CMLX3Y"},
+		{"cidv0", 'B', "%B%S", "BCIQFTFEEHEDF6KLBT32BFAGLXEZL4UWFNWM4LFTLMXQBCERZ6CMLX3Y"},
+		{"cidv1", -1, "%P", "cidv1-protobuf-sha2-256-32"},
+		{"cidv1", -1, "%b-%v-%c-%h-%L", "base58btc-cidv1-protobuf-sha2-256-32"},
+		{"cidv1", -1, "%s", "zdj7WfLr9DhLrb1hsoSi4fSdjjxuZmeqgEtBPWxMLtPbDNbFD"},
+		{"cidv1", -1, "%S", "dj7WfLr9DhLrb1hsoSi4fSdjjxuZmeqgEtBPWxMLtPbDNbFD"},
+		{"cidv1", -1, "ver#%V/#%C/#%H/%L", "ver#1/#112/#18/32"},
+		{"cidv1", -1, "%m", "zQmYFbmndVP7QqAVWyKhpmMuQHMaD88pkK57RgYVimmoh5H"},
+		{"cidv1", -1, "%M", "QmYFbmndVP7QqAVWyKhpmMuQHMaD88pkK57RgYVimmoh5H"},
+		{"cidv1", -1, "%d", "zAux4gVVsLRMXtsZ9fd3tFEZN4jGYB6kP37fgoZNTc11H"},
+		{"cidv1", -1, "%D", "Aux4gVVsLRMXtsZ9fd3tFEZN4jGYB6kP37fgoZNTc11H"},
+		{"cidv1", 'B', "%s", "BAFYBEIETJGSRL3EQPQPCABV3G6IUBYTSIFVQ24XRRHD3JUETSKLTGQ7DJA"},
+		{"cidv1", 'B', "%S", "AFYBEIETJGSRL3EQPQPCABV3G6IUBYTSIFVQ24XRRHD3JUETSKLTGQ7DJA"},
+		{"cidv1", 'B', "%B%S", "BAFYBEIETJGSRL3EQPQPCABV3G6IUBYTSIFVQ24XRRHD3JUETSKLTGQ7DJA"},
+	}
+	for _, tc := range tests {
+		name := fmt.Sprintf("%s/%s", tc.cidId, tc.fmtStr)
+		if tc.newBase != -1 {
+			name = fmt.Sprintf("%s/%c", name, tc.newBase)
+		}
+		cidStr := cids[tc.cidId]
+		t.Run(name, func(t *testing.T) {
+			testFmt(t, cidStr, tc.newBase, tc.fmtStr, tc.result)
+		})
+	}
+}
+
+func testFmt(t *testing.T, cidStr string, newBase mb.Encoding, fmtStr string, result string) {
+	cid, err := Decode(cidStr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	base := newBase
+	if newBase == -1 {
+		base, _ = ExtractEncoding(cidStr)
+	}
+	str, err := Format(fmtStr, base, cid)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if str != result {
+		t.Error(fmt.Sprintf("expected: %s; but got: %s", result, str))
+	}
+}

package.json

@@ -9,15 +9,15 @@
   "gxDependencies": [
     {
       "author": "whyrusleeping",
-      "hash": "QmVGtdTZdTFaLsaj2RwdVG8jcjNNcp1DE914DKZ2kHmXHw",
+      "hash": "QmPnFwZ2JXKnXgMw8CdBPxn7FWh6LLdjUjxV1fKHuJnkr8",
       "name": "go-multihash",
-      "version": "1.0.4"
+      "version": "1.0.8"
     },
     {
       "author": "whyrusleeping",
-      "hash": "Qme4T6BE4sQxg7ZouamF5M7Tx1ZFTqzcns7BkyQPXpoT99",
+      "hash": "QmSbvata2WqNkqGtZNg8MR3SKwnB8iQ7vTPJgWqB8bC5kR",
       "name": "go-multibase",
-      "version": "0.2.4"
+      "version": "0.2.7"
     }
   ],
   "gxVersion": "0.8.0",
@@ -25,6 +25,6 @@
   "license": "MIT",
   "name": "go-cid",
   "releaseCmd": "git commit -a -m \"gx publish $VERSION\"",
-  "version": "0.7.14"
+  "version": "0.7.25"
 }
 

set.go

@@ -1,5 +1,9 @@
 package cid
 
+import (
+	"context"
+)
+
 // Set is a implementation of a set of Cids, that is, a structure
 // to which holds a single copy of every Cids that is added to it.
 type Set struct {
@@ -65,3 +69,34 @@ func (s *Set) ForEach(f func(c *Cid) error) error {
 	}
 	return nil
 }
+
+// StreamingSet is an extension of Set which allows to implement back-pressure
+// for the Visit function
+type StreamingSet struct {
+	Set *Set
+	New chan *Cid
+}
+
+// NewStreamingSet initializes and returns new Set.
+func NewStreamingSet() *StreamingSet {
+	return &StreamingSet{
+		Set: NewSet(),
+		New: make(chan *Cid),
+	}
+}
+
+// Visitor creates new visitor which adds a Cids to the set and emits them to
+// the set.New channel
+func (s *StreamingSet) Visitor(ctx context.Context) func(c *Cid) bool {
+	return func(c *Cid) bool {
+		if s.Set.Visit(c) {
+			select {
+			case s.New <- c:
+			case <-ctx.Done():
+			}
+			return true
+		}
+
+		return false
+	}
+}

set_test.go

@@ -0,0 +1,92 @@
+package cid
+
+import (
+	"crypto/rand"
+	"errors"
+	"testing"
+
+	mh "github.com/multiformats/go-multihash"
+)
+
+func makeRandomCid(t *testing.T) *Cid {
+	p := make([]byte, 256)
+	_, err := rand.Read(p)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	h, err := mh.Sum(p, mh.SHA3, 4)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cid := &Cid{
+		codec:   7,
+		version: 1,
+		hash:    h,
+	}
+
+	return cid
+}
+
+func TestSet(t *testing.T) {
+	cid := makeRandomCid(t)
+	cid2 := makeRandomCid(t)
+	s := NewSet()
+
+	s.Add(cid)
+
+	if !s.Has(cid) {
+		t.Error("should have the CID")
+	}
+
+	if s.Len() != 1 {
+		t.Error("should report 1 element")
+	}
+
+	keys := s.Keys()
+
+	if len(keys) != 1 || !keys[0].Equals(cid) {
+		t.Error("key should correspond to Cid")
+	}
+
+	if s.Visit(cid) {
+		t.Error("visit should return false")
+	}
+
+	foreach := []*Cid{}
+	foreachF := func(c *Cid) error {
+		foreach = append(foreach, c)
+		return nil
+	}
+
+	if err := s.ForEach(foreachF); err != nil {
+		t.Error(err)
+	}
+
+	if len(foreach) != 1 {
+		t.Error("ForEach should have visited 1 element")
+	}
+
+	foreachErr := func(c *Cid) error {
+		return errors.New("test")
+	}
+
+	if err := s.ForEach(foreachErr); err == nil {
+		t.Error("Should have returned an error")
+	}
+
+	if !s.Visit(cid2) {
+		t.Error("should have visited a new Cid")
+	}
+
+	if s.Len() != 2 {
+		t.Error("len should be 2 now")
+	}
+
+	s.Remove(cid2)
+
+	if s.Len() != 1 {
+		t.Error("len should be 1 now")
+	}
+}