[WIP] feat/parachain: disputes coordinator

dot/parachain/available_data_fetching.go

@@ -14,7 +14,7 @@ import (
 // AvailableDataFetchingRequest represents a request to retrieve all available data for a specific candidate.
 type AvailableDataFetchingRequest struct {
 	// Hash of the candidate for which the available data is requested.
-	CandidateHash CandidateHash
+	CandidateHash parachaintypes.CandidateHash
 }
 
 // Encode returns the SCALE encoding of the AvailableDataFetchingRequest

dot/parachain/available_data_fetching_test.go

@@ -14,7 +14,7 @@ import (
 
 func TestEncodeAvailableDataFetchingRequest(t *testing.T) {
 	availableDataFetchingRequest := AvailableDataFetchingRequest{
-		CandidateHash: CandidateHash{
+		CandidateHash: parachaintypes.CandidateHash{
 			common.MustHexToHash("0x677811d2f3ded2489685468dbdb2e4fa280a249fba9356acceb2e823820e2c19"),
 		},
 	}

dot/parachain/chunk_fetching.go

@@ -13,7 +13,7 @@ import (
 // ChunkFetchingRequest represents a request to retrieve chunks of a parachain candidate
 type ChunkFetchingRequest struct {
 	// Hash of candidate we want a chunk for.
-	CandidateHash CandidateHash `scale:"1"`
+	CandidateHash parachaintypes.CandidateHash `scale:"1"`
 
 	// The index of the chunk to fetch.
 	Index parachaintypes.ValidatorIndex `scale:"2"`

dot/parachain/chunk_fetching_test.go

@@ -14,7 +14,7 @@ import (
 
 func TestEncodeChunkFetchingRequest(t *testing.T) {
 	chunkFetchingRequest := ChunkFetchingRequest{
-		CandidateHash: CandidateHash{
+		CandidateHash: parachaintypes.CandidateHash{
 			common.MustHexToHash("0x677811d2f3ded2489685468dbdb2e4fa280a249fba9356acceb2e823820e2c19"),
 		},
 		Index: parachaintypes.ValidatorIndex(8),

dot/parachain/dispute/backend.go

@@ -1,13 +1,13 @@
 package dispute
 
 import (
+	"fmt"
 	"sync"
 	"time"
 
 	"github.com/ChainSafe/gossamer/dot/parachain/dispute/types"
 	parachainTypes "github.com/ChainSafe/gossamer/dot/parachain/types"
 	"github.com/ChainSafe/gossamer/lib/common"
-	"github.com/dgraph-io/badger/v4"
 	"github.com/tidwall/btree"
 )
 
@@ -32,10 +32,14 @@ type Backend interface {
 type OverlayBackend interface {
 	Backend
 
+	// IsEmpty returns true if the overlay backend is empty.
+	IsEmpty() bool
 	// WriteToDB writes the given dispute to the database.
 	WriteToDB() error
 	// GetActiveDisputes returns the active disputes.
-	GetActiveDisputes(now int64) (*btree.BTree, error)
+	GetActiveDisputes(now uint64) (*btree.BTree, error)
+	// NoteEarliestSession prunes data in the DB based on the provided session index.
+	NoteEarliestSession(session parachainTypes.SessionIndex) error
 }
 
 // DBBackend is the backend for the dispute coordinator module that uses a database.
@@ -64,7 +68,7 @@ type syncedRecentDisputes struct {
 
 func newSyncedRecentDisputes() syncedRecentDisputes {
 	return syncedRecentDisputes{
-		BTree: btree.New(types.DisputeComparator),
+		BTree: btree.New(types.CompareDisputes),
 	}
 }
 
@@ -157,12 +161,12 @@ func (b *overlayBackend) SetCandidateVotes(session parachainTypes.SessionIndex,
 const ActiveDuration = 180 * time.Second
 
 // GetActiveDisputes returns the active disputes, if any.
-func (b *overlayBackend) GetActiveDisputes(now int64) (*btree.BTree, error) {
+func (b *overlayBackend) GetActiveDisputes(now uint64) (*btree.BTree, error) {
 	b.recentDisputes.RLock()
 	recentDisputes := b.recentDisputes.Copy()
 	b.recentDisputes.RUnlock()
 
-	activeDisputes := btree.New(types.DisputeComparator)
+	activeDisputes := btree.New(types.CompareDisputes)
 	recentDisputes.Ascend(nil, func(i interface{}) bool {
 		dispute, ok := i.(*types.Dispute)
 		if !ok {
@@ -176,7 +180,7 @@ func (b *overlayBackend) GetActiveDisputes(now int64) (*btree.BTree, error) {
 			return true
 		}
 
-		if concludedAt != nil && *concludedAt+uint64(ActiveDuration.Seconds()) > uint64(now) {
+		if concludedAt != nil && *concludedAt+uint64(ActiveDuration.Seconds()) > now {
 			activeDisputes.Set(dispute)
 		}
 
@@ -186,16 +190,64 @@ func (b *overlayBackend) GetActiveDisputes(now int64) (*btree.BTree, error) {
 	return activeDisputes, nil
 }
 
+func (b *overlayBackend) IsEmpty() bool {
+	return b.earliestSession.SessionIndex == nil && b.recentDisputes.Len() == 0 && len(b.candidateVotes.votes) == 0
+}
+
 func (b *overlayBackend) WriteToDB() error {
 	return b.inner.Write(b.earliestSession.SessionIndex, b.recentDisputes.BTree.Copy(), b.candidateVotes.votes)
 }
 
+func (b *overlayBackend) NoteEarliestSession(session parachainTypes.SessionIndex) error {
+	if b.earliestSession.SessionIndex == nil {
+		b.earliestSession.SessionIndex = &session
+		return nil
+	}
+
+	if *b.earliestSession.SessionIndex > session {
+		b.earliestSession.SessionIndex = &session
+		// clear recent disputes metadata
+		recentDisputes, err := b.GetRecentDisputes()
+		if err != nil {
+			return fmt.Errorf("get recent disputes: %w", err)
+		}
+
+		// determine new recent disputes
+		newRecentDisputes := btree.New(types.CompareDisputes)
+		recentDisputes.Ascend(nil, func(item interface{}) bool {
+			dispute := item.(*types.Dispute)
+			if dispute.Comparator.SessionIndex >= session {
+				newRecentDisputes.Set(dispute)
+			}
+			return true
+		})
+
+		// prune obsolete disputes
+		recentDisputes.Ascend(nil, func(item interface{}) bool {
+			dispute := item.(*types.Dispute)
+			if dispute.Comparator.SessionIndex < session {
+				recentDisputes.Delete(dispute)
+			}
+			return true
+		})
+
+		// update db
+		if recentDisputes.Len() > 0 {
+			if err = b.SetRecentDisputes(newRecentDisputes); err != nil {
+				return fmt.Errorf("set recent disputes: %w", err)
+			}
+		}
+	}
+
+	return nil
+}
+
 var _ OverlayBackend = (*overlayBackend)(nil)
 
 // newOverlayBackend creates a new overlayBackend.
-func newOverlayBackend(db *badger.DB) *overlayBackend {
+func newOverlayBackend(dbBackend DBBackend) *overlayBackend {
 	return &overlayBackend{
-		inner:           NewDBBackend(db),
+		inner:           dbBackend,
 		earliestSession: newSyncedEarliestSession(),
 		recentDisputes:  newSyncedRecentDisputes(),
 		candidateVotes:  newSyncedCandidateVotes(),

dot/parachain/dispute/backend_test.go

@@ -22,7 +22,8 @@ func TestOverlayBackend_EarliestSession(t *testing.T) {
 	require.NoError(t, err)
 
 	// when
-	backend := newOverlayBackend(db)
+	dbBackend := NewDBBackend(db)
+	backend := newOverlayBackend(dbBackend)
 	err = backend.SetEarliestSession(getSessionIndex(1))
 	require.NoError(t, err)
 
@@ -39,7 +40,7 @@ func TestOverlayBackend_RecentDisputes(t *testing.T) {
 	// with
 	db, err := badger.Open(badger.DefaultOptions(t.TempDir()))
 	require.NoError(t, err)
-	disputes := btree.New(types.DisputeComparator)
+	disputes := btree.New(types.CompareDisputes)
 
 	dispute1, err := types.DummyDispute(1, common.Hash{1}, types.DisputeStatusActive)
 	require.NoError(t, err)
@@ -50,7 +51,8 @@ func TestOverlayBackend_RecentDisputes(t *testing.T) {
 	disputes.Set(dispute2)
 
 	// when
-	backend := newOverlayBackend(db)
+	dbBackend := NewDBBackend(db)
+	backend := newOverlayBackend(dbBackend)
 	err = backend.SetRecentDisputes(disputes)
 	require.NoError(t, err)
 
@@ -69,7 +71,8 @@ func TestOverlayBackend_CandidateVotes(t *testing.T) {
 	candidateVotes1 := types.DummyCandidateVotes(t)
 
 	// when
-	backend := newOverlayBackend(db)
+	dbBackend := NewDBBackend(db)
+	backend := newOverlayBackend(dbBackend)
 	err = backend.SetCandidateVotes(1, common.Hash{1}, candidateVotes1)
 	require.NoError(t, err)
 
@@ -85,7 +88,7 @@ func TestOverlayBackend_GetActiveDisputes(t *testing.T) {
 	// with
 	db, err := badger.Open(badger.DefaultOptions(t.TempDir()))
 	require.NoError(t, err)
-	disputes := btree.New(types.DisputeComparator)
+	disputes := btree.New(types.CompareDisputes)
 
 	dispute1, err := types.DummyDispute(1, common.Hash{1}, types.DisputeStatusActive)
 	require.NoError(t, err)
@@ -96,12 +99,13 @@ func TestOverlayBackend_GetActiveDisputes(t *testing.T) {
 	disputes.Set(dispute2)
 
 	// when
-	backend := newOverlayBackend(db)
+	dbBackend := NewDBBackend(db)
+	backend := newOverlayBackend(dbBackend)
 	err = backend.SetRecentDisputes(disputes)
 	require.NoError(t, err)
 
 	// then
-	activeDisputes, err := backend.GetActiveDisputes(time.Now().Unix())
+	activeDisputes, err := backend.GetActiveDisputes(uint64(time.Now().Unix()))
 	require.NoError(t, err)
 	require.True(t, compareBTrees(disputes, activeDisputes))
 }
@@ -112,7 +116,8 @@ func TestOverlayBackend_Concurrency(t *testing.T) {
 	// with
 	db, err := badger.Open(badger.DefaultOptions(t.TempDir()))
 	require.NoError(t, err)
-	backend := newOverlayBackend(db)
+	dbBackend := NewDBBackend(db)
+	backend := newOverlayBackend(dbBackend)
 
 	numGoroutines := 10
 	numIterations := 1000
@@ -155,7 +160,7 @@ func TestOverlayBackend_Concurrency(t *testing.T) {
 			defer wg.Done()
 
 			for j := 0; j < numIterations; j++ {
-				disputes := btree.New(types.DisputeComparator)
+				disputes := btree.New(types.CompareDisputes)
 
 				dispute1, err := types.DummyDispute(parachainTypes.SessionIndex(j),
 					common.Hash{byte(j)},