fix: codec table and dag-json and dag-cbor

Codec table was missing dag-json and it had invalid code for dag-cbor.
It also had invalid string representation of dag-pb -- it was using
'protobuf' which is a totally different code.

I fixed those bugs, and added generic variants for Protobuf, JSON and
CBOR, so go-cid finally match the source of truth at
https://github.com/multiformats/multicodec/blob/master/table.csv

cid.go

@@ -51,15 +51,22 @@ var (
 // the codes described in the authoritative document:
 // https://github.com/multiformats/multicodec/blob/master/table.csv
 const (
-	Raw = 0x55
-
-	DagProtobuf = 0x70
-	DagCBOR     = 0x71
-	Libp2pKey   = 0x72
-
-	GitRaw = 0x78
-
-	DagJOSE               = 0x85
+	// core IPLD
+	Raw         = 0x55
+	DagProtobuf = 0x70   // https://ipld.io/docs/codecs/known/dag-pb/
+	DagCBOR     = 0x71   // https://ipld.io/docs/codecs/known/dag-cbor/
+	DagJSON     = 0x0129 // https://ipld.io/docs/codecs/known/dag-json/
+	Libp2pKey   = 0x72   // https://github.com/libp2p/specs/blob/master/peer-ids/peer-ids.md#peer-ids
+
+	// generic, non-dag variants
+	Protobuf = 0x50
+	CBOR     = 0x51
+	JSON     = 0x0200
+
+	// other
+	GitRaw                = 0x78
+	DagJOSE               = 0x85 // https://ipld.io/specs/codecs/dag-jose/spec/
+	DagCOSE               = 0x86
 	EthBlock              = 0x90
 	EthBlockList          = 0x91
 	EthTxTrie             = 0x92
@@ -83,11 +90,15 @@ const (
 
 // Codecs maps the name of a codec to its type
 var Codecs = map[string]uint64{
-	"v0":                      DagProtobuf,
+	"v0":                      DagProtobuf, // TODO: remove?
 	"raw":                     Raw,
-	"protobuf":                DagProtobuf,
-	"cbor":                    DagCBOR,
+	"dag-pb":                  DagProtobuf,
+	"dag-cbor":                DagCBOR,
+	"dag-json":                DagJSON,
 	"libp2p-key":              Libp2pKey,
+	"protobuf":                Protobuf,
+	"cbor":                    CBOR,
+	"json":                    JSON,
 	"git-raw":                 GitRaw,
 	"eth-block":               EthBlock,
 	"eth-block-list":          EthBlockList,
@@ -109,13 +120,19 @@ var Codecs = map[string]uint64{
 	"fil-commitment-unsealed": FilCommitmentUnsealed,
 	"fil-commitment-sealed":   FilCommitmentSealed,
 	"dag-jose":                DagJOSE,
+	"dag-cose":                DagCOSE,
 }
 
 // CodecToStr maps the numeric codec to its name
 var CodecToStr = map[uint64]string{
 	Raw:                   "raw",
-	DagProtobuf:           "protobuf",
-	DagCBOR:               "cbor",
+	DagProtobuf:           "dag-pb",
+	DagCBOR:               "dag-cbor",
+	DagJSON:               "dag-json",
+	Libp2pKey:             "libp2p-key",
+	Protobuf:              "protobuf",
+	CBOR:                  "cbor",
+	JSON:                  "json",
 	GitRaw:                "git-raw",
 	EthBlock:              "eth-block",
 	EthBlockList:          "eth-block-list",
@@ -137,6 +154,7 @@ var CodecToStr = map[uint64]string{
 	FilCommitmentUnsealed: "fil-commitment-unsealed",
 	FilCommitmentSealed:   "fil-commitment-sealed",
 	DagJOSE:               "dag-jose",
+	DagCOSE:               "dag-cose",
 }
 
 // tryNewCidV0 tries to convert a multihash into a CIDv0 CID and returns an

cid_test.go

@@ -20,9 +20,13 @@ import (
 // Makes it so changing the table accidentally has to happen twice.
 var tCodecs = map[uint64]string{
 	Raw:                   "raw",
-	DagProtobuf:           "protobuf",
-	DagCBOR:               "cbor",
+	DagProtobuf:           "dag-pb",
+	DagCBOR:               "dag-cbor",
+	DagJSON:               "dag-json",
 	Libp2pKey:             "libp2p-key",
+	Protobuf:              "protobuf",
+	CBOR:                  "cbor",
+	JSON:                  "json",
 	GitRaw:                "git-raw",
 	EthBlock:              "eth-block",
 	EthBlockList:          "eth-block-list",
@@ -44,6 +48,7 @@ var tCodecs = map[uint64]string{
 	FilCommitmentUnsealed: "fil-commitment-unsealed",
 	FilCommitmentSealed:   "fil-commitment-sealed",
 	DagJOSE:               "dag-jose",
+	DagCOSE:               "dag-cose",
 }
 
 func assertEqual(t *testing.T, a, b Cid) {