add cross header settlement logic and corresponding tests

Author: AdoAdoAdo

process/track/crossHeaderSettlement.go

@@ -0,0 +1,50 @@
+package track
+
+import (
+	"bytes"
+
+	"github.com/multiversx/mx-chain-core-go/core/check"
+	"github.com/multiversx/mx-chain-core-go/data"
+)
+
+// IsSettledCrossHeader returns true if the header can no longer change: a proofed child extending
+// it is known locally, from the tracked headers or from the headers pool
+func (bbt *baseBlockTrack) IsSettledCrossHeader(header data.HeaderHandler, headerHash []byte) bool {
+	if check.IfNil(header) || len(headerHash) == 0 {
+		return false
+	}
+
+	shardID := header.GetShardID()
+	childNonce := header.GetNonce() + 1
+
+	trackedChildren, trackedChildrenHashes := bbt.GetTrackedHeadersWithNonce(shardID, childNonce)
+	if bbt.holdProofedChild(trackedChildren, trackedChildrenHashes, headerHash, shardID) {
+		return true
+	}
+
+	pooledChildren, pooledChildrenHashes, err := bbt.headersPool.GetHeadersByNonceAndShardId(childNonce, shardID)
+	if err != nil {
+		return false
+	}
+
+	return bbt.holdProofedChild(pooledChildren, pooledChildrenHashes, headerHash, shardID)
+}
+
+func (bbt *baseBlockTrack) holdProofedChild(
+	children []data.HeaderHandler,
+	childrenHashes [][]byte,
+	parentHash []byte,
+	shardID uint32,
+) bool {
+	for i, child := range children {
+		if check.IfNil(child) || !bytes.Equal(child.GetPrevHash(), parentHash) {
+			continue
+		}
+
+		if bbt.proofsPool.HasProof(shardID, childrenHashes[i]) {
+			return true
+		}
+	}
+
+	return false
+}

process/track/crossHeaderSettlement_test.go

@@ -0,0 +1,88 @@
+package track_test
+
+import (
+	"testing"
+
+	"github.com/multiversx/mx-chain-core-go/data/block"
+	"github.com/stretchr/testify/require"
+
+	"github.com/multiversx/mx-chain-go/process/track"
+)
+
+func TestBaseBlockTrack_IsSettledCrossHeader(t *testing.T) {
+	t.Parallel()
+
+	headerHash := []byte("headerHash")
+	header := &block.Header{Nonce: 5, Round: 10}
+
+	t.Run("nil header or empty hash returns false", func(t *testing.T) {
+		t.Parallel()
+
+		args, _, _ := createProofPullTrackerScaffold(true)
+		sbt, err := track.NewShardBlockTrack(args)
+		require.Nil(t, err)
+		_ = sbt.Close()
+
+		require.False(t, sbt.IsSettledCrossHeader(nil, headerHash))
+		require.False(t, sbt.IsSettledCrossHeader(header, nil))
+	})
+
+	t.Run("no child known returns false", func(t *testing.T) {
+		t.Parallel()
+
+		args, _, _ := createProofPullTrackerScaffold(true)
+		sbt, err := track.NewShardBlockTrack(args)
+		require.Nil(t, err)
+		_ = sbt.Close()
+
+		require.False(t, sbt.IsSettledCrossHeader(header, headerHash))
+	})
+
+	t.Run("tracked proofed child extending the header settles it", func(t *testing.T) {
+		t.Parallel()
+
+		args, _, _ := createProofPullTrackerScaffold(true)
+		sbt, err := track.NewShardBlockTrack(args)
+		require.Nil(t, err)
+		_ = sbt.Close()
+
+		child := &block.Header{Nonce: 6, Round: 11, PrevHash: headerHash}
+		sbt.AddTrackedHeader(child, []byte("childHash"))
+
+		// no proof for the child yet
+		require.False(t, sbt.IsSettledCrossHeader(header, headerHash))
+
+		_ = args.PoolsHolder.Proofs().AddProof(&block.HeaderProof{HeaderHash: []byte("childHash"), HeaderNonce: 6, HeaderRound: 11})
+		require.True(t, sbt.IsSettledCrossHeader(header, headerHash))
+	})
+
+	t.Run("proofed child of a sibling does not settle the header", func(t *testing.T) {
+		t.Parallel()
+
+		args, _, _ := createProofPullTrackerScaffold(true)
+		sbt, err := track.NewShardBlockTrack(args)
+		require.Nil(t, err)
+		_ = sbt.Close()
+
+		siblingChild := &block.Header{Nonce: 6, Round: 11, PrevHash: []byte("siblingHash")}
+		sbt.AddTrackedHeader(siblingChild, []byte("siblingChildHash"))
+		_ = args.PoolsHolder.Proofs().AddProof(&block.HeaderProof{HeaderHash: []byte("siblingChildHash"), HeaderNonce: 6, HeaderRound: 11})
+
+		require.False(t, sbt.IsSettledCrossHeader(header, headerHash))
+	})
+
+	t.Run("proofed child known only from the headers pool settles it", func(t *testing.T) {
+		t.Parallel()
+
+		args, _, _ := createProofPullTrackerScaffold(true)
+		sbt, err := track.NewShardBlockTrack(args)
+		require.Nil(t, err)
+		_ = sbt.Close()
+
+		child := &block.Header{Nonce: 6, Round: 11, PrevHash: headerHash}
+		args.PoolsHolder.Headers().AddHeader([]byte("childHash"), child)
+		_ = args.PoolsHolder.Proofs().AddProof(&block.HeaderProof{HeaderHash: []byte("childHash"), HeaderNonce: 6, HeaderRound: 11})
+
+		require.True(t, sbt.IsSettledCrossHeader(header, headerHash))
+	})
+}