feat(blob): extend blob struct with index field

blob/blob.go

@@ -99,6 +99,10 @@ type Blob struct {
 	// the celestia-node's namespace type
 	// this is to avoid converting to and from app's type
 	namespace share.Namespace
+
+	// index represents index of the first share in the eds.
+	// before data is being published, the index set by default to -1.
+	index int
 }
 
 // NewBlobV0 constructs a new blob from the provided Namespace and data.
@@ -127,19 +131,25 @@ func NewBlob(shareVersion uint8, namespace share.Namespace, data []byte) (*Blob,
 	if err != nil {
 		return nil, err
 	}
-	return &Blob{Blob: blob, Commitment: com, namespace: namespace}, nil
+	return &Blob{Blob: blob, Commitment: com, namespace: namespace, index: -1}, nil
 }
 
 // Namespace returns blob's namespace.
 func (b *Blob) Namespace() share.Namespace {
 	return b.namespace
 }
 
+// Index returns the index  of the first share in the eds.
+func (b *Blob) Index() int {
+	return b.index
+}
+
 type jsonBlob struct {
 	Namespace    share.Namespace `json:"namespace"`
 	Data         []byte          `json:"data"`
 	ShareVersion uint32          `json:"share_version"`
 	Commitment   Commitment      `json:"commitment"`
+	Index        int             `json:"index"`
 }
 
 func (b *Blob) MarshalJSON() ([]byte, error) {
@@ -148,6 +158,7 @@ func (b *Blob) MarshalJSON() ([]byte, error) {
 		Data:         b.Data,
 		ShareVersion: b.ShareVersion,
 		Commitment:   b.Commitment,
+		Index:        b.index,
 	}
 	return json.Marshal(blob)
 }
@@ -165,6 +176,7 @@ func (b *Blob) UnmarshalJSON(data []byte) error {
 	b.Blob.ShareVersion = blob.ShareVersion
 	b.Commitment = blob.Commitment
 	b.namespace = blob.Namespace
+	b.index = blob.Index
 	return nil
 }
 

blob/blob_test.go

@@ -1,7 +1,7 @@
 package blob
 
 import (
-	"reflect"
+	"bytes"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -67,7 +67,8 @@ func TestBlob(t *testing.T) {
 
 				newBlob := &Blob{}
 				require.NoError(t, newBlob.UnmarshalJSON(data))
-				require.True(t, reflect.DeepEqual(blob[0], newBlob))
+				require.True(t, bytes.Equal(blob[0].Blob.Data, newBlob.Data))
+				require.True(t, bytes.Equal(blob[0].Commitment, newBlob.Commitment))
 			},
 		},
 	}

blob/service.go

@@ -251,6 +251,18 @@ func (s *Service) getByCommitment(
 
 	getCtx, getSharesSpan := tracer.Start(ctx, "get-shares-by-namespace")
 
+	// ensure that requested namespace can be found inside the DAH before retrieving it.
+	offset := -1
+	for i, row := range header.DAH.RowRoots {
+		if !namespace.IsOutsideRange(row, row) {
+			offset = i
+			break
+		}
+	}
+	if offset == -1 {
+		return nil, nil, ErrBlobNotFound
+	}
+
 	namespacedShares, err := s.shareGetter.GetSharesByNamespace(getCtx, header, namespace)
 	if err != nil {
 		if errors.Is(err, share.ErrNotFound) {
@@ -291,9 +303,10 @@ func (s *Service) getByCommitment(
 		if err != nil {
 			return nil, nil, err
 		}
+
 		for _, b := range blobs {
 			if b.Commitment.Equal(commitment) {
-				span.AddEvent("blob reconstructed")
+				b.index = offset*len(header.DAH.RowRoots) + proofs[0].Start()
 				return b, &proofs, nil
 			}
 			// Falling under this flag means that the data from the last row
@@ -303,15 +316,18 @@ func (s *Service) getByCommitment(
 			// to the current row and have a single proof.
 			if spansMultipleRows {
 				spansMultipleRows = false
-				// leave proof only for the current row
+				// move offset to the current row index.
+				offset += len(proofs) - 1
+				// leave proof only for the current row.
 				proofs = proofs[len(proofs)-1:]
 			}
 		}
-
 		if len(rawShares) > 0 {
 			spansMultipleRows = true
 			continue
 		}
+		// moving to the next row.
+		offset++
 		proofs = nil
 	}