feat(header)!: introduce header.Header interface (#1304)

Most important changes in this PR:
* `tmbytes.HexBytes` replaced by `header.Hash`
* `header.Header` used in interfaces in `header` package
* `IsBefore` inlined, so we don't need to include this method in interface (it's a oneliner used once)
* `VerifyNonAdjacent` added to `Header` interface (at least for now)
* Generics introduced to avoid casting

Resolves rollkit/rollkit#575.

api/gateway/share.go

@@ -108,7 +108,7 @@ func (h *Handler) getShares(ctx context.Context, height uint64, nID namespace.ID
 	}
 	// perform request
 	shares, err := h.share.GetSharesByNamespace(ctx, header.DAH, nID)
-	return shares.Flatten(), header.Height, err
+	return shares.Flatten(), header.Height(), err
 }
 
 func dataFromShares(shares []share.Share) ([][]byte, error) {

cmd/cel-shed/header.go

@@ -7,7 +7,8 @@ import (
 
 	"github.com/spf13/cobra"
 
-	"github.com/celestiaorg/celestia-node/header/store"
+	"github.com/celestiaorg/celestia-node/header"
+	"github.com/celestiaorg/celestia-node/libs/header/store"
 	"github.com/celestiaorg/celestia-node/nodebuilder"
 	"github.com/celestiaorg/celestia-node/nodebuilder/node"
 )
@@ -54,7 +55,7 @@ Custom store path is not supported yet.`,
 			return err
 		}
 
-		hstore, err := store.NewStore(ds)
+		hstore, err := store.NewStore[*header.ExtendedHeader](ds)
 		if err != nil {
 			return err
 		}

core/fetcher.go

@@ -5,8 +5,9 @@ import (
 	"fmt"
 
 	logging "github.com/ipfs/go-log/v2"
-	tmbytes "github.com/tendermint/tendermint/libs/bytes"
 	"github.com/tendermint/tendermint/types"
+
+	libhead "github.com/celestiaorg/celestia-node/libs/header"
 )
 
 const newBlockSubscriber = "NewBlock/Events"
@@ -64,7 +65,7 @@ func (f *BlockFetcher) GetBlock(ctx context.Context, height *int64) (*types.Bloc
 	return res.Block, nil
 }
 
-func (f *BlockFetcher) GetBlockByHash(ctx context.Context, hash tmbytes.HexBytes) (*types.Block, error) {
+func (f *BlockFetcher) GetBlockByHash(ctx context.Context, hash libhead.Hash) (*types.Block, error) {
 	res, err := f.client.BlockByHash(ctx, hash)
 	if err != nil {
 		return nil, err

core/fetcher_test.go

@@ -8,8 +8,6 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"github.com/tendermint/tendermint/types"
-
-	"github.com/tendermint/tendermint/libs/bytes"
 )
 
 func TestBlockFetcher_GetBlock_and_SubscribeNewBlockEvent(t *testing.T) {
@@ -76,9 +74,7 @@ func TestBlockFetcherHeaderValues(t *testing.T) {
 	assert.Equal(t, nextBlock.LastCommit.Height, commit.Height)
 	assert.Equal(t, nextBlock.LastCommit.Signatures, commit.Signatures)
 	// compare ValidatorSet hash to the ValidatorsHash from first block height
-	hexBytes := bytes.HexBytes{}
-	err = hexBytes.Unmarshal(valSet.Hash())
-	require.NoError(t, err)
-	assert.Equal(t, nextBlock.ValidatorsHash, hexBytes)
+	hexBytes := valSet.Hash()
+	assert.Equal(t, nextBlock.ValidatorsHash.Bytes(), hexBytes)
 	require.NoError(t, fetcher.UnsubscribeNewBlockEvent(ctx))
 }

das/coordinator.go

@@ -5,13 +5,14 @@ import (
 	"sync"
 
 	"github.com/celestiaorg/celestia-node/header"
+	libhead "github.com/celestiaorg/celestia-node/libs/header"
 )
 
 // samplingCoordinator runs and coordinates sampling workers and updates current sampling state
 type samplingCoordinator struct {
 	concurrencyLimit int
 
-	getter   header.Getter
+	getter   libhead.Getter[*header.ExtendedHeader]
 	sampleFn sampleFn
 
 	state coordinatorState
@@ -37,7 +38,7 @@ type result struct {
 
 func newSamplingCoordinator(
 	params Parameters,
-	getter header.Getter,
+	getter libhead.Getter[*header.ExtendedHeader],
 	sample sampleFn,
 ) *samplingCoordinator {
 	return &samplingCoordinator{

das/coordinator_test.go

@@ -302,7 +302,7 @@ func (m *mockSampler) sample(ctx context.Context, h *header.ExtendedHeader) erro
 	m.lock.Lock()
 	defer m.lock.Unlock()
 
-	height := uint64(h.Height)
+	height := uint64(h.Height())
 	m.done[height]++
 
 	if len(m.done) > int(m.NetworkHead-m.SampleFrom) && !m.isFinished {
@@ -435,7 +435,7 @@ func (o *checkOrder) middleWare(out sampleFn) sampleFn {
 
 		if len(o.queue) > 0 {
 			// check last item in queue to be same as input
-			if o.queue[0] != uint64(h.Height) {
+			if o.queue[0] != uint64(h.Height()) {
 				o.lock.Unlock()
 				return fmt.Errorf("expected height: %v,got: %v", o.queue[0], h)
 			}
@@ -505,7 +505,7 @@ func (l *lock) releaseAll(except ...uint64) {
 func (l *lock) middleWare(out sampleFn) sampleFn {
 	return func(ctx context.Context, h *header.ExtendedHeader) error {
 		l.m.Lock()
-		ch, blocked := l.blockList[uint64(h.Height)]
+		ch, blocked := l.blockList[uint64(h.Height())]
 		l.m.Unlock()
 		if !blocked {
 			return out(ctx, h)
@@ -525,10 +525,10 @@ func onceMiddleWare(out sampleFn) sampleFn {
 	m := sync.Mutex{}
 	return func(ctx context.Context, h *header.ExtendedHeader) error {
 		m.Lock()
-		db[h.Height]++
-		if db[h.Height] > 1 {
+		db[h.Height()]++
+		if db[h.Height()] > 1 {
 			m.Unlock()
-			return fmt.Errorf("header sampled more than once: %v", h.Height)
+			return fmt.Errorf("header sampled more than once: %v", h.Height())
 		}
 		m.Unlock()
 		return out(ctx, h)

das/daser.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/celestiaorg/celestia-node/fraud"
 	"github.com/celestiaorg/celestia-node/header"
+	libhead "github.com/celestiaorg/celestia-node/libs/header"
 	"github.com/celestiaorg/celestia-node/share"
 	"github.com/celestiaorg/celestia-node/share/eds/byzantine"
 )
@@ -23,8 +24,8 @@ type DASer struct {
 
 	da     share.Availability
 	bcast  fraud.Broadcaster
-	hsub   header.Subscriber // listens for new headers in the network
-	getter header.Getter     // retrieves past headers
+	hsub   libhead.Subscriber[*header.ExtendedHeader] // listens for new headers in the network
+	getter libhead.Getter[*header.ExtendedHeader]     // retrieves past headers
 
 	sampler    *samplingCoordinator
 	store      checkpointStore
@@ -41,8 +42,8 @@ type sampleFn func(context.Context, *header.ExtendedHeader) error
 // NewDASer creates a new DASer.
 func NewDASer(
 	da share.Availability,
-	hsub header.Subscriber,
-	getter header.Getter,
+	hsub libhead.Subscriber[*header.ExtendedHeader],
+	getter libhead.Getter[*header.ExtendedHeader],
 	dstore datastore.Datastore,
 	bcast fraud.Broadcaster,
 	options ...Option,
@@ -95,7 +96,7 @@ func (d *DASer) Start(ctx context.Context) error {
 		// attempt to get head info. No need to handle error, later DASer
 		// will be able to find new head from subscriber after it is started
 		if h, err := d.getter.Head(ctx); err == nil {
-			cp.NetworkHead = uint64(h.Height)
+			cp.NetworkHead = uint64(h.Height())
 		}
 	}
 	log.Info("starting DASer from checkpoint: ", cp.String())
@@ -151,13 +152,13 @@ func (d *DASer) sample(ctx context.Context, h *header.ExtendedHeader) error {
 		var byzantineErr *byzantine.ErrByzantine
 		if errors.As(err, &byzantineErr) {
 			log.Warn("Propagating proof...")
-			sendErr := d.bcast.Broadcast(ctx, byzantine.CreateBadEncodingProof(h.Hash(), uint64(h.Height), byzantineErr))
+			sendErr := d.bcast.Broadcast(ctx, byzantine.CreateBadEncodingProof(h.Hash(), uint64(h.Height()), byzantineErr))
 			if sendErr != nil {
 				log.Errorw("fraud proof propagating failed", "err", sendErr)
 			}
 		}
 
-		log.Errorw("sampling failed", "height", h.Height, "hash", h.Hash(),
+		log.Errorw("sampling failed", "height", h.Height(), "hash", h.Hash(),
 			"square width", len(h.DAH.RowsRoots), "data root", h.DAH.Hash(), "err", err)
 		return err
 	}

das/daser_test.go

@@ -5,12 +5,6 @@ import (
 	"testing"
 	"time"
 
-	"github.com/celestiaorg/celestia-node/share/availability/full"
-	"github.com/celestiaorg/celestia-node/share/availability/light"
-	availability_test "github.com/celestiaorg/celestia-node/share/availability/test"
-
-	"github.com/tendermint/tendermint/types"
-
 	"github.com/ipfs/go-blockservice"
 	"github.com/ipfs/go-datastore"
 	ds_sync "github.com/ipfs/go-datastore/sync"
@@ -19,10 +13,14 @@ import (
 	mocknet "github.com/libp2p/go-libp2p/p2p/net/mock"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	tmbytes "github.com/tendermint/tendermint/libs/bytes"
+	"github.com/tendermint/tendermint/types"
 
 	"github.com/celestiaorg/celestia-node/fraud"
 	"github.com/celestiaorg/celestia-node/header"
+	libhead "github.com/celestiaorg/celestia-node/libs/header"
+	"github.com/celestiaorg/celestia-node/share/availability/full"
+	"github.com/celestiaorg/celestia-node/share/availability/light"
+	availability_test "github.com/celestiaorg/celestia-node/share/availability/test"
 	"github.com/celestiaorg/celestia-node/share/getters"
 )
 
@@ -232,7 +230,7 @@ func (m *mockGetter) fillSubWithHeaders(
 		randHeader := header.RandExtendedHeader(t)
 		randHeader.DataHash = dah.Hash()
 		randHeader.DAH = dah
-		randHeader.Height = int64(i + 1)
+		randHeader.RawHeader.Height = int64(i + 1)
 
 		sub.Headers[index] = randHeader
 		// also checkpointStore to mock getter for duplicate sampling
@@ -260,7 +258,7 @@ func (m *mockGetter) generateHeaders(t *testing.T, bServ blockservice.BlockServi
 		randHeader := header.RandExtendedHeader(t)
 		randHeader.DataHash = dah.Hash()
 		randHeader.DAH = dah
-		randHeader.Height = int64(i + 1)
+		randHeader.RawHeader.Height = int64(i + 1)
 
 		m.headers[int64(i+1)] = randHeader
 	}
@@ -332,6 +330,6 @@ func (m getterStub) GetVerifiedRange(
 	return nil, nil
 }
 
-func (m getterStub) Get(context.Context, tmbytes.HexBytes) (*header.ExtendedHeader, error) {
+func (m getterStub) Get(context.Context, libhead.Hash) (*header.ExtendedHeader, error) {
 	return nil, nil
 }

das/subscriber.go

@@ -4,6 +4,7 @@ import (
 	"context"
 
 	"github.com/celestiaorg/celestia-node/header"
+	libhead "github.com/celestiaorg/celestia-node/libs/header"
 )
 
 // subscriber subscribes to notifications about new headers in the network to keep
@@ -16,7 +17,7 @@ func newSubscriber() subscriber {
 	return subscriber{newDone("subscriber")}
 }
 
-func (s *subscriber) run(ctx context.Context, sub header.Subscription, emit listenFn) {
+func (s *subscriber) run(ctx context.Context, sub libhead.Subscription[*header.ExtendedHeader], emit listenFn) {
 	defer s.indicateDone()
 	defer sub.Cancel()
 
@@ -30,8 +31,8 @@ func (s *subscriber) run(ctx context.Context, sub header.Subscription, emit list
 			log.Errorw("failed to get next header", "err", err)
 			continue
 		}
-		log.Infow("new header received via subscription", "height", h.Height)
+		log.Infow("new header received via subscription", "height", h.Height())
 
-		emit(ctx, uint64(h.Height))
+		emit(ctx, uint64(h.Height()))
 	}
 }

das/worker.go

@@ -10,6 +10,7 @@ import (
 	"go.uber.org/multierr"
 
 	"github.com/celestiaorg/celestia-node/header"
+	libhead "github.com/celestiaorg/celestia-node/libs/header"
 )
 
 type worker struct {
@@ -36,7 +37,7 @@ type job struct {
 
 func (w *worker) run(
 	ctx context.Context,
-	getter header.Getter,
+	getter libhead.Getter[*header.ExtendedHeader],
 	sample sampleFn,
 	metrics *metrics,
 	resultCh chan<- result) {
@@ -59,7 +60,7 @@ func (w *worker) run(
 		}
 
 		metrics.observeGetHeader(ctx, time.Since(startGet))
-		log.Debugw("got header from header store", "height", h.Height, "hash", h.Hash(),
+		log.Debugw("got header from header store", "height", h.Height(), "hash", h.Hash(),
 			"square width", len(h.DAH.RowsRoots), "data root", h.DAH.Hash(), "finished (s)", time.Since(startGet))
 
 		startSample := time.Now()
@@ -71,10 +72,10 @@ func (w *worker) run(
 		w.setResult(curr, err)
 		metrics.observeSample(ctx, h, time.Since(startSample), err)
 		if err != nil {
-			log.Debugw("failed to sampled header", "height", h.Height, "hash", h.Hash(),
+			log.Debugw("failed to sampled header", "height", h.Height(), "hash", h.Hash(),
 				"square width", len(h.DAH.RowsRoots), "data root", h.DAH.Hash(), "err", err)
 		} else {
-			log.Debugw("sampled header", "height", h.Height, "hash", h.Hash(),
+			log.Debugw("sampled header", "height", h.Height(), "hash", h.Hash(),
 				"square width", len(h.DAH.RowsRoots), "data root", h.DAH.Hash(), "finished (s)", time.Since(startSample))
 		}
 	}

fraud/testing.go

@@ -49,10 +49,10 @@ func createStore(t *testing.T, numHeaders int) *mockStore {
 
 	for i := 0; i < numHeaders; i++ {
 		header := suite.GenExtendedHeader()
-		store.headers[header.Height] = header
+		store.headers[header.Height()] = header
 
-		if header.Height > store.headHeight {
-			store.headHeight = header.Height
+		if header.Height() > store.headHeight {
+			store.headHeight = header.Height()
 		}
 	}
 	return store

header/core/exchange.go

@@ -8,10 +8,9 @@ import (
 	"github.com/ipfs/go-blockservice"
 	logging "github.com/ipfs/go-log/v2"
 
-	tmbytes "github.com/tendermint/tendermint/libs/bytes"
-
 	"github.com/celestiaorg/celestia-node/core"
 	"github.com/celestiaorg/celestia-node/header"
+	libhead "github.com/celestiaorg/celestia-node/libs/header"
 )
 
 var log = logging.Logger("header/core")
@@ -57,7 +56,7 @@ func (ce *Exchange) GetRangeByHeight(ctx context.Context, from, amount uint64) (
 
 func (ce *Exchange) GetVerifiedRange(ctx context.Context, from *header.ExtendedHeader, amount uint64,
 ) ([]*header.ExtendedHeader, error) {
-	headers, err := ce.GetRangeByHeight(ctx, uint64(from.Height)+1, amount)
+	headers, err := ce.GetRangeByHeight(ctx, uint64(from.Height())+1, amount)
 	if err != nil {
 		return nil, err
 	}
@@ -72,7 +71,7 @@ func (ce *Exchange) GetVerifiedRange(ctx context.Context, from *header.ExtendedH
 	return headers, nil
 }
 
-func (ce *Exchange) Get(ctx context.Context, hash tmbytes.HexBytes) (*header.ExtendedHeader, error) {
+func (ce *Exchange) Get(ctx context.Context, hash libhead.Hash) (*header.ExtendedHeader, error) {
 	log.Debugw("requesting header", "hash", hash.String())
 	block, err := ce.fetcher.GetBlockByHash(ctx, hash)
 	if err != nil {

header/core/listener.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/celestiaorg/celestia-node/core"
 	"github.com/celestiaorg/celestia-node/header"
+	libhead "github.com/celestiaorg/celestia-node/libs/header"
 )
 
 // Listener is responsible for listening to Core for
@@ -20,15 +21,15 @@ import (
 // broadcasts the new `ExtendedHeader` to the header-sub gossipsub
 // network.
 type Listener struct {
-	bcast     header.Broadcaster
+	bcast     libhead.Broadcaster[*header.ExtendedHeader]
 	fetcher   *core.BlockFetcher
 	bServ     blockservice.BlockService
 	construct header.ConstructFn
 	cancel    context.CancelFunc
 }
 
 func NewListener(
-	bcast header.Broadcaster,
+	bcast libhead.Broadcaster[*header.ExtendedHeader],
 	fetcher *core.BlockFetcher,
 	bServ blockservice.BlockService,
 	construct header.ConstructFn,
@@ -98,7 +99,7 @@ func (cl *Listener) listen(ctx context.Context, sub <-chan *types.Block) {
 			// broadcast new ExtendedHeader, but if core is still syncing, notify only local subscribers
 			err = cl.bcast.Broadcast(ctx, eh, pubsub.WithLocalPublication(syncing))
 			if err != nil {
-				log.Errorw("listener: broadcasting next header", "height", eh.Height,
+				log.Errorw("listener: broadcasting next header", "height", eh.Height(),
 					"err", err)
 			}
 		case <-ctx.Done():