fix(blob/service): fix getByCommitment

blob/blob.go

@@ -8,6 +8,7 @@ import (
 	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
 
 	"github.com/celestiaorg/celestia-app/pkg/appconsts"
+	"github.com/celestiaorg/celestia-app/pkg/shares"
 	"github.com/celestiaorg/celestia-app/x/blob/types"
 	"github.com/celestiaorg/nmt"
 
@@ -138,3 +139,37 @@ func (b *Blob) UnmarshalJSON(data []byte) error {
 	b.namespace = blob.Namespace
 	return nil
 }
+
+// createBlobs creates and returns blobs from the passed shares. In case if blob is incomplete, then
+// the shares of the incomplete blob will be returned.
+func createBlobs(appShares []shares.Share) ([]*Blob, []shares.Share, error) {
+	blobs := make([]*Blob, 0)
+	for {
+		if len(appShares) == 0 {
+			return blobs, nil, nil
+		}
+
+		length, err := appShares[0].SequenceLen()
+		if err != nil {
+			return nil, nil, err
+		}
+
+		amount := shares.SparseSharesNeeded(length)
+		if amount > len(appShares) {
+			return blobs, appShares, nil
+		}
+
+		b, err := parseShares(appShares[:amount])
+		if err != nil {
+			return nil, nil, err
+		}
+
+		// only 1 blob will be created bc we passed the exact amount of shares
+		blobs = append(blobs, b[0])
+
+		if amount == len(appShares) {
+			return blobs, nil, nil
+		}
+		appShares = appShares[amount:]
+	}
+}

blob/helper.go

@@ -17,16 +17,16 @@ func SharesToBlobs(rawShares []share.Share) ([]*Blob, error) {
 		return nil, ErrBlobNotFound
 	}
 
-	appShares := make([]shares.Share, 0, len(rawShares))
-	for _, shr := range rawShares {
-		bShare, err := shares.NewShare(shr)
-		if err != nil {
-			return nil, err
-		}
-		appShares = append(appShares, *bShare)
+	appShares, err := toAppShares(rawShares...)
+	if err != nil {
+		return nil, err
 	}
+	return parseShares(appShares)
+}
 
-	shareSequences, err := shares.ParseShares(appShares, true)
+// parseShares takes shares and converts them to the []*Blob.
+func parseShares(appShrs []shares.Share) ([]*Blob, error) {
+	shareSequences, err := shares.ParseShares(appShrs, true)
 	if err != nil {
 		return nil, err
 	}
@@ -84,14 +84,3 @@ func BlobsToShares(blobs ...*Blob) ([]share.Share, error) {
 	}
 	return shares.ToBytes(rawShares), nil
 }
-
-// constructAndVerifyBlob reconstruct a Blob from the passed shares and compares commitments.
-func constructAndVerifyBlob(sh []share.Share, commitment Commitment) (*Blob, bool, error) {
-	blob, err := SharesToBlobs(sh)
-	if err != nil {
-		return nil, false, err
-	}
-
-	equal := blob[0].Commitment.Equal(commitment)
-	return blob[0], equal, nil
-}

blob/service.go

@@ -198,10 +198,10 @@ func (s *Service) getByCommitment(
 	}
 
 	var (
-		rawShares = make([]share.Share, 0)
+		rawShares = make([]shares.Share, 0)
 		proofs    = make(Proof, 0)
-		amount    int
-		blobShare *shares.Share
+		// expanded specifies whether blob is expanded into multiple rows
+		expanded bool
 	)
 
 	namespacedShares, err := s.shareGetter.GetSharesByNamespace(ctx, header, namespace)
@@ -211,83 +211,38 @@ func (s *Service) getByCommitment(
 		}
 		return nil, nil, err
 	}
+
 	for _, row := range namespacedShares {
-		if len(row.Shares) == 0 {
-			break
+		appShares, err := toAppShares(row.Shares...)
+		if err != nil {
+			return nil, nil, err
 		}
-
-		rawShares = append(rawShares, row.Shares...)
+		rawShares = append(rawShares, appShares...)
 		proofs = append(proofs, row.Proof)
 
-		// reconstruct the `blobShare` from the first rawShare in range
-		// in order to get blob's length(first share will contain this info)
-		if blobShare == nil {
-			for i, shr := range rawShares {
-				bShare, err := shares.NewShare(shr)
-				if err != nil {
-					return nil, nil, err
-				}
-
-				// ensure that the first share is not a NamespacePaddingShare
-				// these shares are used to satisfy the non-interactive default rules
-				// and are not the part of the blob, so should be removed.
-				isPadding, err := bShare.IsPadding()
-				if err != nil {
-					return nil, nil, err
-				}
-				if isPadding {
-					continue
-				}
-
-				blobShare = bShare
-				// save the length.
-				length, err := blobShare.SequenceLen()
-				if err != nil {
-					return nil, nil, err
-				}
-				amount = shares.SparseSharesNeeded(length)
-				rawShares = rawShares[i:]
-				break
-			}
-		}
-
-		// move to the next row if the blob is incomplete.
-		if amount > len(rawShares) {
-			continue
-		}
-
-		blob, same, err := constructAndVerifyBlob(rawShares[:amount], commitment)
+		var blobs []*Blob
+		blobs, rawShares, err = createBlobs(rawShares)
 		if err != nil {
 			return nil, nil, err
 		}
-		if same {
-			return blob, &proofs, nil
+		for _, b := range blobs {
+			if b.Commitment.Equal(commitment) {
+				return b, &proofs, nil
+			}
+			if expanded {
+				// only the first blob in the range can be expanded
+				expanded = false
+				// leave proof only for the current row
+				proofs = proofs[len(proofs)-1:]
+			}
 		}
 
-		// drop info of the checked blob
-		rawShares = rawShares[amount:]
 		if len(rawShares) > 0 {
-			// save proof for the last row in case we have rawShares
-			proofs = proofs[len(proofs)-1:]
-		} else {
-			// otherwise clear proofs
-			proofs = nil
+			expanded = true
+			continue
 		}
-		blobShare = nil
-	}
-
-	if len(rawShares) == 0 {
-		return nil, nil, ErrBlobNotFound
-	}
-
-	blob, same, err := constructAndVerifyBlob(rawShares, commitment)
-	if err != nil {
-		return nil, nil, err
-	}
-	if same {
-		return blob, &proofs, nil
+		proofs = nil
 	}
-
 	return nil, nil, ErrBlobNotFound
 }
 
@@ -304,3 +259,25 @@ func (s *Service) getBlobs(
 	}
 	return SharesToBlobs(namespacedShares.Flatten())
 }
+
+// toAppShares converts node's raw shares to the app shares, skipping padding
+func toAppShares(shrs ...share.Share) ([]shares.Share, error) {
+	appShrs := make([]shares.Share, 0)
+	for _, shr := range shrs {
+		bShare, err := shares.NewShare(shr)
+		if err != nil {
+			return nil, err
+		}
+
+		ok, err := bShare.IsPadding()
+		if err != nil {
+			return nil, err
+		}
+		if ok {
+			continue
+		}
+
+		appShrs = append(appShrs, *bShare)
+	}
+	return appShrs, nil
+}