fix: remove invalid multicodec2string mappings (#137)

* refactor: remove Codecs table
* chore: go-cid 0.2.0

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.

This removes invalid mappings entirely.
https://github.com/multiformats/go-multicodec should be used instead.

README.md

@@ -59,10 +59,17 @@ fmt.Println("Got CID: ", c)
 #### Creating a CID from scratch
 
 ```go
+
+import (
+  cid "github.com/ipfs/go-cid"
+  mc "github.com/multiformats/go-multicodec"
+  mh "github.com/multiformats/go-multihash"
+)
+
 // Create a cid manually by specifying the 'prefix' parameters
 pref := cid.Prefix{
 	Version: 1,
-	Codec: cid.Raw,
+	Codec: mc.Raw,
 	MhType: mh.SHA2_256,
 	MhLength: -1, // default length
 }

cid.go

@@ -47,19 +47,21 @@ var (
 	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
+// Consts below are DEPRECATED and left only for legacy reasons:
+// <https://github.com/ipfs/go-cid/pull/137>
+// Modern code should use consts from go-multicodec instead:
+// <https://github.com/multiformats/go-multicodec>
 const (
-	Raw = 0x55
-
-	DagProtobuf = 0x70
-	DagCBOR     = 0x71
-	Libp2pKey   = 0x72
-
-	GitRaw = 0x78
-
-	DagJOSE               = 0x85
+	// common ones
+	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
+
+	// other
+	GitRaw                = 0x78
+	DagJOSE               = 0x85 // https://ipld.io/specs/codecs/dag-jose/spec/
 	EthBlock              = 0x90
 	EthBlockList          = 0x91
 	EthTxTrie             = 0x92
@@ -81,64 +83,6 @@ const (
 	FilCommitmentSealed   = 0xf102
 )
 
-// Codecs maps the name of a codec to its type
-var Codecs = map[string]uint64{
-	"v0":                      DagProtobuf,
-	"raw":                     Raw,
-	"protobuf":                DagProtobuf,
-	"cbor":                    DagCBOR,
-	"libp2p-key":              Libp2pKey,
-	"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,
-	"dash-block":              DashBlock,
-	"dash-tx":                 DashTx,
-	"fil-commitment-unsealed": FilCommitmentUnsealed,
-	"fil-commitment-sealed":   FilCommitmentSealed,
-	"dag-jose":                DagJOSE,
-}
-
-// 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",
-	DashBlock:             "dash-block",
-	DashTx:                "dash-tx",
-	FilCommitmentUnsealed: "fil-commitment-unsealed",
-	FilCommitmentSealed:   "fil-commitment-sealed",
-	DagJOSE:               "dag-jose",
-}
-
 // tryNewCidV0 tries to convert a multihash into a CIDv0 CID and returns an
 // error on failure.
 func tryNewCidV0(mhash mh.Multihash) (Cid, error) {

cid_test.go

@@ -15,37 +15,6 @@ import (
 	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",
-	Libp2pKey:             "libp2p-key",
-	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",
-	DashBlock:             "dash-block",
-	DashTx:                "dash-tx",
-	FilCommitmentUnsealed: "fil-commitment-unsealed",
-	FilCommitmentSealed:   "fil-commitment-sealed",
-	DagJOSE:               "dag-jose",
-}
-
 func assertEqual(t *testing.T, a, b Cid) {
 	if a.Type() != b.Type() {
 		t.Fatal("mismatch on type")
@@ -60,26 +29,6 @@ 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 TestPrefixSum(t *testing.T) {
 	// Test creating CIDs both manually and with Prefix.
 	// Tests: https://github.com/ipfs/go-cid/issues/83

version.json

@@ -1,3 +1,3 @@
 {
-  "version": "v0.1.0"
+  "version": "v0.2.0"
 }