feat(blob): introduce structure of blob

blob/blob.go

@@ -0,0 +1,55 @@
+package blob
+
+import (
+	"github.com/celestiaorg/celestia-app/x/blob/types"
+	"github.com/celestiaorg/nmt"
+	"github.com/celestiaorg/nmt/namespace"
+)
+
+// Commitment is a Merkle Root of the subtree built from shares of the Blob.
+// It is computed by splitting the blob into shares and building the Merkle subtree to be included after Submit.
+type Commitment []byte
+
+// Proof is a collection of nmt.Proofs that verifies the inclusion of the data.
+type Proof []nmt.Proof
+
+// Blob represents any application-specific binary data that anyone can submit to Celestia.
+type Blob struct {
+	*types.Blob
+
+	commitment Commitment
+}
+
+// NewBlob constructs a new blob from the provided namespace.ID and data.
+func NewBlob(nID namespace.ID, data []byte) (*Blob, error) {
+	blob, err := types.NewBlob(nID, data)
+	if err != nil {
+		return nil, err
+	}
+
+	com, err := types.CreateCommitment(blob)
+	if err != nil {
+		return nil, err
+	}
+	return &Blob{Blob: blob, commitment: com}, nil
+}
+
+// NamespaceID returns blobs namespaceId.
+func (b *Blob) NamespaceID() []byte {
+	return b.Blob.NamespaceId
+}
+
+// Data returns blobs raw data.
+func (b *Blob) Data() []byte {
+	return b.Blob.Data
+}
+
+// Commitment returns the commitment of current blob.
+func (b *Blob) Commitment() Commitment {
+	return b.commitment
+}
+
+// Version is the format that was used to encode Blob data and namespaceID into shares.
+func (b *Blob) Version() uint32 {
+	return b.Blob.ShareVersion
+}