gx publish 0.7.13

Readme/golint: improve readme with gx instructions. Make golint happy.

.gx/lastpubver

@@ -1 +1 @@
-0.7.8: QmXm6Di2T89xAeprno3x6nD6jRgtMm2wRy25DX4zc4gk8V
+0.7.13: QmZe3S3sXMWar3oPmrd8jHV8NoAWfPfLGFD8PsK3YrYpqv

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).
+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.
+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:
+### Examples
-```go
-import "github.com/ipfs/go-cid"
-```
 
-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:

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 +31,81 @@ 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")
+)
+
+// 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
+	EthBlock           = 0x90
-	EthereumTx    = 0x91
+	EthBlockList       = 0x91
-	BitcoinBlock  = 0xb0
+	EthTxTrie          = 0x92
-	BitcoinTx     = 0xb1
+	EthTx              = 0x93
-	ZcashBlock    = 0xc0
+	EthTxReceiptTrie   = 0x94
-	ZcashTx       = 0xc1
+	EthTxReceipt       = 0x95
+	EthStateTrie       = 0x96
+	EthAccountSnapshot = 0x97
+	EthStorageTrie     = 0x98
+	BitcoinBlock       = 0xb0
+	BitcoinTx          = 0xb1
+	ZcashBlock         = 0xc0
+	ZcashTx            = 0xc1
 )
 
-func NewCidV0(h mh.Multihash) *Cid {
+// 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,
+		codec:   codecType,
-		hash:    h,
+		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 +124,21 @@ 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" {
@@ -89,12 +158,6 @@ 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")
-)
-
 func uvError(read int) error {
 	switch {
 	case read == 0:
@@ -106,6 +169,17 @@ 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 +221,14 @@ 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 +245,14 @@ func (c *Cid) String() string {
 	}
 }
 
+// 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 +281,33 @@ 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 +318,30 @@ func (c *Cid) UnmarshalJSON(b []byte) error {
 	return 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
+	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 +352,19 @@ 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.
 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 +381,9 @@ 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 +393,8 @@ 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 +420,7 @@ func PrefixFromBytes(buf []byte) (Prefix, error) {
 	return Prefix{
 		Version:  vers,
 		Codec:    codec,
-		MhType:   int(mhtype),
+		MhType:   mhtype,
 		MhLength: int(mhlen),
 	}, nil
 }

cid_test.go

@@ -2,6 +2,7 @@ package cid
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
 	"math/rand"
 	"strings"
@@ -200,3 +201,29 @@ func TestHexDecode(t *testing.T) {
 		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")
+	}
+}

package.json

@@ -9,15 +9,15 @@
   "gxDependencies": [
     {
       "author": "whyrusleeping",
-      "hash": "QmYDds3421prZgqKbLpEK7T9Aa2eVdQ7o3YarX1LVLdP2J",
+      "hash": "QmVGtdTZdTFaLsaj2RwdVG8jcjNNcp1DE914DKZ2kHmXHw",
       "name": "go-multihash",
-      "version": "1.0.0"
+      "version": "1.0.4"
     },
     {
       "author": "whyrusleeping",
-      "hash": "QmXzWFN4iLdX1Vq8Sc13mET7aXsHkTyJoMbaJJD3NGRhiJ",
+      "hash": "Qme4T6BE4sQxg7ZouamF5M7Tx1ZFTqzcns7BkyQPXpoT99",
       "name": "go-multibase",
-      "version": "0.2.1"
+      "version": "0.2.4"
     }
   ],
   "gxVersion": "0.8.0",
@@ -25,6 +25,6 @@
   "license": "MIT",
   "name": "go-cid",
   "releaseCmd": "git commit -a -m \"gx publish $VERSION\"",
-  "version": "0.7.8"
+  "version": "0.7.13"
 }
 

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 {