gx publish 0.8.0

Extract non-core functionality from go-cid into go-cidutil

.gx/lastpubver

@@ -1 +1 @@
-0.7.7: QmcTcsTvfaeEBRFo1TkFgT8sRmgi1n1LTZpecfVP8fzpGD
+0.8.0: QmZFbDTY9jfSBms2MchvYM9oYRbAF19K7Pby47yDBfpPrb

.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
 
 notifications:
-  email: false
+email: false
+  

README.md

@@ -4,13 +4,15 @@ go-cid
 [![](https://img.shields.io/badge/made%20by-Protocol%20Labs-blue.svg?style=flat-square)](http://ipn.io)
 [![](https://img.shields.io/badge/project-IPFS-blue.svg?style=flat-square)](http://ipfs.io/)
 [![](https://img.shields.io/badge/freenode-%23ipfs-blue.svg?style=flat-square)](http://webchat.freenode.net/?channels=%23ipfs)
+[![](https://img.shields.io/badge/readme%20style-standard-brightgreen.svg?style=flat-square)](https://github.com/RichardLitt/standard-readme)
+[![GoDoc](https://godoc.org/github.com/ipfs/go-cid?status.svg)](https://godoc.org/github.com/ipfs/go-cid)
 [![Coverage Status](https://coveralls.io/repos/github/ipfs/go-cid/badge.svg?branch=master)](https://coveralls.io/github/ipfs/go-cid?branch=master)
 [![Travis CI](https://travis-ci.org/ipfs/go-cid.svg?branch=master)](https://travis-ci.org/ipfs/go-cid)
 
-> A package to handle content IDs in go.
+> A package to handle content IDs in Go.
 
-This is an implementation in go of the [CID spec](https://github.com/ipld/cid).
-It is used in go-ipfs and related packages to refer to a typed hunk of data.
+This is an implementation in Go of the [CID spec](https://github.com/ipld/cid).
+It is used in `go-ipfs` and related packages to refer to a typed hunk of data.
 
 
 ## Table of Contents
@@ -23,20 +25,46 @@ It is used in go-ipfs and related packages to refer to a typed hunk of data.
 
 ## Install
 
+`go-cid` is a standard Go module which can be installed with:
+
+```sh
+go get github.com/ipfs/go-cid
+```
+
+Note that `go-cid` is packaged with Gx, so it is recommended to use Gx to install and use it (see Usage section).
+
+## Usage
+
+### Using Gx and Gx-go
+
+This module is packaged with [Gx](https://github.com/whyrusleeping/gx). In order to use it in your own project it is recommended that you:
+
+```sh
+go get -u github.com/whyrusleeping/gx
+go get -u github.com/whyrusleeping/gx-go
+cd <your-project-repository>
+gx init
+gx import github.com/ipfs/go-cid
+gx install --global
+gx-go --rewrite
+```
+
+Please check [Gx](https://github.com/whyrusleeping/gx) and [Gx-go](https://github.com/whyrusleeping/gx-go) documentation for more information.
+
+### Running tests
+
+Before running tests, please run:
+
 ```sh
 make deps
 ```
 
-## Examples
+This will make sure that dependencies are rewritten to known working versions.
 
-To use CIDs, import it in your code like:
-```go
-import "github.com/ipfs/go-cid"
-```
+### Examples
 
-Then, depending on how you want to use it, something like one of the following examples should work:
+#### Parsing string input from users
 
-### Parsing string input from users
 ```go
 // Create a cid from a marshaled string
 c, err := cid.Decode("zdvgqEMYmNeH5fKciougvQcfzMcNjF3Z1tPouJ8C7pc3pe63k")
@@ -45,7 +73,8 @@ if err != nil {...}
 fmt.Println("Got CID: ", c)
 ```
 
-### Creating a CID from scratch
+#### Creating a CID from scratch
+
 ```go
 // Create a cid manually by specifying the 'prefix' parameters
 pref := cid.Prefix{
@@ -62,7 +91,8 @@ if err != nil {...}
 fmt.Println("Created CID: ", c)
 ```
 
-### Check if two CIDs match
+#### Check if two CIDs match
+
 ```go
 // To test if two cid's are equivalent, be sure to use the 'Equals' method:
 if c1.Equals(c2) {
@@ -70,7 +100,8 @@ if c1.Equals(c2) {
 }
 ```
 
-### Check if some data matches a given CID
+#### Check if some data matches a given CID
+
 ```go
 // To check if some data matches a given cid, 
 // Get your CIDs prefix, and use that to sum the data in question:

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.go

@@ -1,8 +1,28 @@
+// Package cid implements the Content-IDentifiers specification
+// (https://github.com/ipld/cid) in Go. CIDs are
+// self-describing content-addressed identifiers useful for
+// distributed information systems. CIDs are used in the IPFS
+// (https://ipfs.io) project ecosystem.
+//
+// CIDs have two major versions. A CIDv0 corresponds to a multihash of type
+// DagProtobuf, is deprecated and exists for compatibility reasons. Usually,
+// CIDv1 should be used.
+//
+// A CIDv1 has four parts:
+//
+//     <cidv1> ::= <multibase-prefix><cid-version><multicodec-packed-content-type><multihash-content-address>
+//
+// As shown above, the CID implementation relies heavily on Multiformats,
+// particularly Multibase
+// (https://github.com/multiformats/go-multibase), Multicodec
+// (https://github.com/multiformats/multicodec) and Multihash
+// implementations (https://github.com/multiformats/go-multihash).
 package cid
 
 import (
 	"bytes"
 	"encoding/binary"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"strings"
@@ -11,44 +31,136 @@ import (
 	mh "github.com/multiformats/go-multihash"
 )
 
+// UnsupportedVersionString just holds an error message
 const UnsupportedVersionString = "<unsupported cid version>"
 
+var (
+	// ErrVarintBuffSmall means that a buffer passed to the cid parser was not
+	// long enough, or did not contain an invalid cid
+	ErrVarintBuffSmall = errors.New("reading varint: buffer too small")
+
+	// ErrVarintTooBig means that the varint in the given cid was above the
+	// limit of 2^64
+	ErrVarintTooBig = errors.New("reading varint: varint bigger than 64bits" +
+		" and not supported")
+
+	// 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
+// the codes described in the authoritative document:
+// https://github.com/multiformats/multicodec/blob/master/table.csv
 const (
 	Raw = 0x55
 
 	DagProtobuf = 0x70
 	DagCBOR     = 0x71
 
-	EthereumBlock = 0x90
-	EthereumTx    = 0x91
+	GitRaw = 0x78
+
+	EthBlock           = 0x90
+	EthBlockList       = 0x91
+	EthTxTrie          = 0x92
+	EthTx              = 0x93
+	EthTxReceiptTrie   = 0x94
+	EthTxReceipt       = 0x95
+	EthStateTrie       = 0x96
+	EthAccountSnapshot = 0x97
+	EthStorageTrie     = 0x98
 	BitcoinBlock       = 0xb0
 	BitcoinTx          = 0xb1
 	ZcashBlock         = 0xc0
 	ZcashTx            = 0xc1
+	DecredBlock        = 0xe0
+	DecredTx           = 0xe1
 )
 
-func NewCidV0(h mh.Multihash) *Cid {
+// 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.
+// NewCidV1 should be used preferentially.
+func NewCidV0(mhash mh.Multihash) *Cid {
 	return &Cid{
 		version: 0,
 		codec:   DagProtobuf,
-		hash:    h,
+		hash:    mhash,
 	}
 }
 
-func NewCidV1(c uint64, h mh.Multihash) *Cid {
+// NewCidV1 returns a new Cid using the given multicodec-packed
+// content type.
+func NewCidV1(codecType uint64, mhash mh.Multihash) *Cid {
 	return &Cid{
 		version: 1,
-		codec:   c,
-		hash:    h,
+		codec:   codecType,
+		hash:    mhash,
 	}
 }
 
+// Cid represents a self-describing content adressed
+// identifier. It is formed by a Version, a Codec (which indicates
+// a multicodec-packed content type) and a Multihash.
 type Cid struct {
 	version uint64
 	codec   uint64
 	hash    mh.Multihash
 }
 
+// Parse is a short-hand function to perform Decode, Cast etc... on
+// a generic interface{} type.
 func Parse(v interface{}) (*Cid, error) {
 	switch v2 := v.(type) {
 	case string:
@@ -67,9 +179,21 @@ func Parse(v interface{}) (*Cid, error) {
 	}
 }
 
+// Decode parses a Cid-encoded string and returns a Cid object.
+// For CidV1, a Cid-encoded string is primarily a multibase string:
+//
+//     <multibase-type-code><base-encoded-string>
+//
+// The base-encoded string represents a:
+//
+// <version><codec-type><multihash>
+//
+// Decode will also detect and parse CidV0 strings. Strings
+// starting with "Qm" are considered CidV0 and treated directly
+// as B58-encoded multihashes.
 func Decode(v string) (*Cid, error) {
 	if len(v) < 2 {
-		return nil, fmt.Errorf("cid too short")
+		return nil, ErrCidTooShort
 	}
 
 	if len(v) == 46 && v[:2] == "Qm" {
@@ -89,11 +213,27 @@ func Decode(v string) (*Cid, error) {
 	return Cast(data)
 }
 
-var (
-	ErrVarintBuffSmall = errors.New("reading varint: buffer to small")
-	ErrVarintTooBig    = errors.New("reading varint: varint bigger than 64bits" +
-		" and not supported")
-)
+// 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 {
@@ -106,6 +246,17 @@ func uvError(read int) error {
 	}
 }
 
+// Cast takes a Cid data slice, parses it and returns a Cid.
+// For CidV1, the data buffer is in the form:
+//
+//     <version><codec-type><multihash>
+//
+// CidV0 are also supported. In particular, data buffers starting
+// with length 34 bytes, which starts with bytes [18,32...] are considered
+// binary multihashes.
+//
+// Please use decode when parsing a regular Cid string, as Cast does not
+// expect multibase-encoded data. Cast accepts the output of Cid.Bytes().
 func Cast(data []byte) (*Cid, error) {
 	if len(data) == 34 && data[0] == 18 && data[1] == 32 {
 		h, err := mh.Cast(data)
@@ -147,10 +298,14 @@ func Cast(data []byte) (*Cid, error) {
 	}, nil
 }
 
+// Type returns the multicodec-packed content type of a Cid.
 func (c *Cid) Type() uint64 {
 	return c.codec
 }
 
+// String returns the default string representation of a
+// Cid. Currently, Base58 is used as the encoding for the
+// multibase string.
 func (c *Cid) String() string {
 	switch c.version {
 	case 0:
@@ -167,10 +322,30 @@ 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
 }
 
+// Bytes returns the byte representation of a Cid.
+// The output of bytes can be parsed back into a Cid
+// with Cast().
 func (c *Cid) Bytes() []byte {
 	switch c.version {
 	case 0:
@@ -199,17 +374,33 @@ func (c *Cid) bytesV1() []byte {
 	return buf[:n+len(c.hash)]
 }
 
+// Equals checks that two Cids are the same.
+// In order for two Cids to be considered equal, the
+// Version, the Codec and the Multihash must match.
 func (c *Cid) Equals(o *Cid) bool {
 	return c.codec == o.codec &&
 		c.version == o.version &&
 		bytes.Equal(c.hash, o.hash)
 }
 
+// UnmarshalJSON parses the JSON representation of a Cid.
 func (c *Cid) UnmarshalJSON(b []byte) error {
 	if len(b) < 2 {
 		return fmt.Errorf("invalid cid json blob")
 	}
-	out, err := Decode(string(b[1 : len(b)-1]))
+	obj := struct {
+		CidTarget string `json:"/"`
+	}{}
+	err := json.Unmarshal(b, &obj)
+	if err != nil {
+		return err
+	}
+
+	if obj.CidTarget == "" {
+		return fmt.Errorf("cid was incorrectly formatted")
+	}
+
+	out, err := Decode(obj.CidTarget)
 	if err != nil {
 		return err
 	}
@@ -220,20 +411,30 @@ func (c *Cid) UnmarshalJSON(b []byte) error {
 	return nil
 }
 
-func (c *Cid) MarshalJSON() ([]byte, error) {
-	return []byte(fmt.Sprintf("\"%s\"", c.String())), nil
+// MarshalJSON procudes a JSON representation of a Cid, which looks as follows:
+//
+//    { "/": "<cid-string>" }
+//
+// Note that this formatting comes from the IPLD specification
+// (https://github.com/ipld/specs/tree/master/ipld)
+func (c Cid) MarshalJSON() ([]byte, error) {
+	return []byte(fmt.Sprintf("{\"/\":\"%s\"}", c.String())), nil
 }
 
+// KeyString casts the result of cid.Bytes() as a string, and returns it.
 func (c *Cid) KeyString() string {
 	return string(c.Bytes())
 }
 
+// Loggable returns a Loggable (as defined by
+// https://godoc.org/github.com/ipfs/go-log).
 func (c *Cid) Loggable() map[string]interface{} {
 	return map[string]interface{}{
 		"cid": c,
 	}
 }
 
+// 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
 	return Prefix{
@@ -244,14 +445,21 @@ func (c *Cid) Prefix() Prefix {
 	}
 }
 
-// Prefix represents all the metadata of a cid, minus any actual content information
+// Prefix represents all the metadata of a Cid,
+// 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
-	MhType   int
+	MhType   uint64
 	MhLength int
 }
 
+// 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)
 	if err != nil {
@@ -268,6 +476,9 @@ func (p Prefix) Sum(data []byte) (*Cid, error) {
 	}
 }
 
+// Bytes returns a byte representation of a Prefix. It looks like:
+//
+//     <version><codec><mh-type><mh-length>
 func (p Prefix) Bytes() []byte {
 	buf := make([]byte, 4*binary.MaxVarintLen64)
 	n := binary.PutUvarint(buf, p.Version)
@@ -277,6 +488,8 @@ func (p Prefix) Bytes() []byte {
 	return buf[:n]
 }
 
+// PrefixFromBytes parses a Prefix-byte representation onto a
+// Prefix.
 func PrefixFromBytes(buf []byte) (Prefix, error) {
 	r := bytes.NewReader(buf)
 	vers, err := binary.ReadUvarint(r)
@@ -302,7 +515,7 @@ func PrefixFromBytes(buf []byte) (Prefix, error) {
 	return Prefix{
 		Version:  vers,
 		Codec:    codec,
-		MhType:   int(mhtype),
+		MhType:   mhtype,
 		MhLength: int(mhlen),
 	}, nil
 }

cid_test.go

@@ -2,14 +2,41 @@ package cid
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
 	"math/rand"
 	"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")
@@ -24,6 +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 {
@@ -54,6 +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 {
@@ -90,6 +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)
@@ -188,3 +347,84 @@ func TestParse(t *testing.T) {
 		}
 	}
 }
+
+func TestHexDecode(t *testing.T) {
+	hexcid := "f015512209d8453505bdc6f269678e16b3e56c2a2948a41f2c792617cc9611ed363c95b63"
+	c, err := Decode(hexcid)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if c.String() != "zb2rhhFAEMepUBbGyP1k8tGfz7BSciKXP6GHuUeUsJBaK6cqG" {
+		t.Fatal("hash value failed to round trip decoding from hex")
+	}
+}
+
+func ExampleDecode() {
+	encoded := "zb2rhhFAEMepUBbGyP1k8tGfz7BSciKXP6GHuUeUsJBaK6cqG"
+	c, err := Decode(encoded)
+	if err != nil {
+		fmt.Printf("Error: %s", err)
+		return
+	}
+
+	fmt.Println(c)
+	// Output: zb2rhhFAEMepUBbGyP1k8tGfz7BSciKXP6GHuUeUsJBaK6cqG
+}
+
+func TestFromJson(t *testing.T) {
+	cval := "zb2rhhFAEMepUBbGyP1k8tGfz7BSciKXP6GHuUeUsJBaK6cqG"
+	jsoncid := []byte(`{"/":"` + cval + `"}`)
+	var c Cid
+	err := json.Unmarshal(jsoncid, &c)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if c.String() != cval {
+		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,
+	}
+}

package.json

@@ -9,15 +9,15 @@
   "gxDependencies": [
     {
       "author": "whyrusleeping",
-      "hash": "QmYDds3421prZgqKbLpEK7T9Aa2eVdQ7o3YarX1LVLdP2J",
+      "hash": "QmPnFwZ2JXKnXgMw8CdBPxn7FWh6LLdjUjxV1fKHuJnkr8",
       "name": "go-multihash",
-      "version": "1.0.0"
+      "version": "1.0.8"
     },
     {
       "author": "whyrusleeping",
-      "hash": "QmUq3H9YpcPphbRj6ct6rBgBE377A8wANP8zPMRqe1WYbf",
+      "hash": "QmSbvata2WqNkqGtZNg8MR3SKwnB8iQ7vTPJgWqB8bC5kR",
       "name": "go-multibase",
-      "version": "0.2.1"
+      "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": "0.7.7"
+  "version": "0.8.0"
 }
 

set.go

@@ -1,39 +1,49 @@
 package cid
 
+// 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 {
 	set map[string]struct{}
 }
 
+// NewSet initializes and returns a new Set.
 func NewSet() *Set {
 	return &Set{set: make(map[string]struct{})}
 }
 
+// Add puts a Cid in the Set.
 func (s *Set) Add(c *Cid) {
 	s.set[string(c.Bytes())] = struct{}{}
 }
 
+// Has returns if the Set contains a given Cid.
 func (s *Set) Has(c *Cid) bool {
 	_, ok := s.set[string(c.Bytes())]
 	return ok
 }
 
+// Remove deletes a Cid from the Set.
 func (s *Set) Remove(c *Cid) {
 	delete(s.set, string(c.Bytes()))
 }
 
+// Len returns how many elements the Set has.
 func (s *Set) Len() int {
 	return len(s.set)
 }
 
+// Keys returns the Cids in the set.
 func (s *Set) Keys() []*Cid {
 	out := make([]*Cid, 0, len(s.set))
-	for k, _ := range s.set {
+	for k := range s.set {
 		c, _ := Cast([]byte(k))
 		out = append(out, c)
 	}
 	return out
 }
 
+// Visit adds a Cid to the set only if it is
+// not in it already.
 func (s *Set) Visit(c *Cid) bool {
 	if !s.Has(c) {
 		s.Add(c)
@@ -43,8 +53,10 @@ func (s *Set) Visit(c *Cid) bool {
 	return false
 }
 
+// ForEach allows to run a custom function on each
+// Cid in the set.
 func (s *Set) ForEach(f func(c *Cid) error) error {
-	for cs, _ := range s.set {
+	for cs := range s.set {
 		c, _ := Cast([]byte(cs))
 		err := f(c)
 		if err != nil {
@@ -53,3 +65,4 @@ func (s *Set) ForEach(f func(c *Cid) error) error {
 	}
 	return nil
 }
+

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")
+	}
+}