feat: vm: allow raw "cbor" in state and use the new go-multicodec

1. Switch to go-multicodec as the source of multicodec code information.
This gives us a central, generated source of multicodec codes.
2. Use this library inside the VM and shapshot logic to consistently
allow CBOR, in addition to DagCBOR.
3. Remove the hard-coded CBOR constant.

chain/store/snapshot.go

@@ -15,7 +15,7 @@ import (
 	"github.com/ipld/go-car"
 	carutil "github.com/ipld/go-car/util"
 	carv2 "github.com/ipld/go-car/v2"
-	mh "github.com/multiformats/go-multihash"
+	"github.com/multiformats/go-multicodec"
 	cbg "github.com/whyrusleeping/cbor-gen"
 	"go.uber.org/atomic"
 	"golang.org/x/sync/errgroup"
@@ -369,14 +369,16 @@ func (s *walkScheduler) Wait() error {
 }
 
 func (s *walkScheduler) enqueueIfNew(task walkTask) {
-	if task.c.Prefix().MhType == mh.IDENTITY {
+	if multicodec.Code(task.c.Prefix().MhType) == multicodec.Identity {
 		//log.Infow("ignored", "cid", todo.c.String())
 		return
 	}
 
-	// This lets through RAW and CBOR blocks, the only two types that we
-	// end up writing to the exported CAR.
-	if task.c.Prefix().Codec != cid.Raw && task.c.Prefix().Codec != cid.DagCBOR {
+	// This lets through RAW, CBOR, and DagCBOR blocks, the only types that we end up writing to
+	// the exported CAR.
+	switch multicodec.Code(task.c.Prefix().Codec) {
+	case multicodec.Cbor, multicodec.DagCbor, multicodec.Raw:
+	default:
 		//log.Infow("ignored", "cid", todo.c.String())
 		return
 	}
@@ -450,7 +452,8 @@ func (s *walkScheduler) processTask(t walkTask, workerN int) error {
 	// We exported the ipld block. If it wasn't a CBOR block, there's nothing
 	// else to do and we can bail out early as it won't have any links
 	// etc.
-	if t.c.Prefix().Codec != cid.DagCBOR || t.c.Prefix().MhType == mh.IDENTITY {
+	if multicodec.Code(t.c.Prefix().Codec) != multicodec.DagCbor ||
+		multicodec.Code(t.c.Prefix().MhType) == multicodec.Identity {
 		return nil
 	}
 
@@ -683,14 +686,13 @@ func (cs *ChainStore) WalkSnapshot(ctx context.Context, ts *types.TipSet, inclRe
 				prefix := c.Prefix()
 
 				// Don't include identity CIDs.
-				if prefix.MhType == mh.IDENTITY {
+				if multicodec.Code(prefix.MhType) == multicodec.Identity {
 					continue
 				}
 
-				// We only include raw and dagcbor, for now.
-				// Raw for "code" CIDs.
-				switch prefix.Codec {
-				case cid.Raw, cid.DagCBOR:
+				// We only include raw, cbor, and dagcbor, for now.
+				switch multicodec.Code(prefix.Codec) {
+				case multicodec.Cbor, multicodec.DagCbor, multicodec.Raw:
 				default:
 					continue
 				}
@@ -722,7 +724,7 @@ func (cs *ChainStore) WalkSnapshot(ctx context.Context, ts *types.TipSet, inclRe
 }
 
 func recurseLinks(ctx context.Context, bs bstore.Blockstore, walked *cid.Set, root cid.Cid, in []cid.Cid) ([]cid.Cid, error) {
-	if root.Prefix().Codec != cid.DagCBOR {
+	if multicodec.Code(root.Prefix().Codec) != multicodec.DagCbor {
 		return in, nil
 	}
 

chain/vm/vm.go

@@ -11,7 +11,7 @@ import (
 	"github.com/ipfs/go-cid"
 	cbor "github.com/ipfs/go-ipld-cbor"
 	logging "github.com/ipfs/go-log/v2"
-	mh "github.com/multiformats/go-multihash"
+	"github.com/multiformats/go-multicodec"
 	cbg "github.com/whyrusleeping/cbor-gen"
 	"go.opencensus.io/stats"
 	"go.opencensus.io/trace"
@@ -38,7 +38,6 @@ import (
 )
 
 const MaxCallDepth = 4096
-const CborCodec = 0x51
 
 var (
 	log            = logging.Logger("vm")
@@ -128,7 +127,7 @@ func (bs *gasChargingBlocks) Put(ctx context.Context, blk block.Block) error {
 func (vm *LegacyVM) makeRuntime(ctx context.Context, msg *types.Message, parent *Runtime) *Runtime {
 	paramsCodec := uint64(0)
 	if len(msg.Params) > 0 {
-		paramsCodec = CborCodec
+		paramsCodec = uint64(multicodec.Cbor)
 	}
 	rt := &Runtime{
 		ctx:         ctx,
@@ -380,7 +379,7 @@ func (vm *LegacyVM) send(ctx context.Context, msg *types.Message, parent *Runtim
 
 	retCodec := uint64(0)
 	if len(ret) > 0 {
-		retCodec = CborCodec
+		retCodec = uint64(multicodec.Cbor)
 	}
 	rt.executionTrace.MsgRct = types.ReturnTrace{
 		ExitCode:    aerrors.RetCode(err),
@@ -695,15 +694,15 @@ func (vm *LegacyVM) ActorStore(ctx context.Context) adt.Store {
 }
 
 func linksForObj(blk block.Block, cb func(cid.Cid)) error {
-	switch blk.Cid().Prefix().Codec {
-	case cid.DagCBOR:
+	switch multicodec.Code(blk.Cid().Prefix().Codec) {
+	case multicodec.DagCbor:
 		err := cbg.ScanForLinks(bytes.NewReader(blk.RawData()), cb)
 		if err != nil {
 			return xerrors.Errorf("cbg.ScanForLinks: %w", err)
 		}
 		return nil
-	case cid.Raw:
-		// We implicitly have all children of raw blocks.
+	case multicodec.Raw, multicodec.Cbor:
+		// We implicitly have all children of raw/cbor blocks.
 		return nil
 	default:
 		return xerrors.Errorf("vm flush copy method only supports dag cbor")
@@ -803,14 +802,17 @@ func copyRec(ctx context.Context, from, to blockstore.Blockstore, root cid.Cid,
 		}
 
 		prefix := link.Prefix()
-		if prefix.Codec == cid.FilCommitmentSealed || prefix.Codec == cid.FilCommitmentUnsealed {
+		codec := multicodec.Code(prefix.Codec)
+		switch codec {
+		case multicodec.FilCommitmentSealed, cid.FilCommitmentUnsealed:
 			return
 		}
 
 		// We always have blocks inlined into CIDs, but we may not have their children.
-		if prefix.MhType == mh.IDENTITY {
+		if multicodec.Code(prefix.MhType) == multicodec.Identity {
 			// Unless the inlined block has no children.
-			if prefix.Codec == cid.Raw {
+			switch codec {
+			case multicodec.Raw, multicodec.Cbor:
 				return
 			}
 		} else {

go.mod

@@ -123,6 +123,7 @@ require (
 	github.com/multiformats/go-multiaddr v0.9.0
 	github.com/multiformats/go-multiaddr-dns v0.3.1
 	github.com/multiformats/go-multibase v0.2.0
+	github.com/multiformats/go-multicodec v0.9.0
 	github.com/multiformats/go-multihash v0.2.3
 	github.com/multiformats/go-varint v0.0.7
 	github.com/open-rpc/meta-schema v0.0.0-20201029221707-1b72ef2ea333
@@ -278,7 +279,6 @@ require (
 	github.com/mr-tron/base58 v1.2.0 // indirect
 	github.com/multiformats/go-base36 v0.2.0 // indirect
 	github.com/multiformats/go-multiaddr-fmt v0.1.0 // indirect
-	github.com/multiformats/go-multicodec v0.9.0 // indirect
 	github.com/multiformats/go-multistream v0.4.1 // indirect
 	github.com/nikkolasg/hexjson v0.1.0 // indirect
 	github.com/nkovacs/streamquote v1.0.0 // indirect