fix(share): return fixed data size in blockstore (#3634)

(cherry picked from commit 9fd66a5)

share/eds/blockstore.go

@@ -4,6 +4,9 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"os"
+
+	share_ipld "github.com/celestiaorg/celestia-node/share/ipld"
 
 	bstore "github.com/ipfs/boxo/blockstore"
 	"github.com/ipfs/boxo/datastore/dshelp"
@@ -14,6 +17,8 @@ import (
 	ipld "github.com/ipfs/go-ipld-format"
 )
 
+var enableFixedDataSize = os.Getenv("CELESTIA_CONST_DATA_SIZE") == "1"
+
 var _ bstore.Blockstore = (*blockstore)(nil)
 
 var (
@@ -80,6 +85,13 @@ func (bs *blockstore) Get(ctx context.Context, cid cid.Cid) (blocks.Block, error
 }
 
 func (bs *blockstore) GetSize(ctx context.Context, cid cid.Cid) (int, error) {
+	if enableFixedDataSize {
+		// For now we return a fixed result, which is a max of possible values (see above).
+		// Motivation behind such behavior is described here:
+		// https://github.com/celestiaorg/celestia-node/issues/3630
+		return share_ipld.LeafNodeSize, nil
+	}
+
 	blockstr, err := bs.getReadOnlyBlockstore(ctx, cid)
 	if err == nil {
 		defer closeAndLog("blockstore", blockstr)

share/ipld/nmt.go

@@ -39,11 +39,11 @@ const (
 	// NmtHashSize is the size of a digest created by an NMT in bytes.
 	NmtHashSize = 2*share.NamespaceSize + sha256.Size
 
-	// innerNodeSize is the size of data in inner nodes.
-	innerNodeSize = NmtHashSize * 2
+	// InnerNodeSize is the size of data in inner nodes.
+	InnerNodeSize = NmtHashSize * 2
 
-	// leafNodeSize is the size of data in leaf nodes.
-	leafNodeSize = share.NamespaceSize + appconsts.ShareSize
+	// LeafNodeSize is the size of data in leaf nodes.
+	LeafNodeSize = share.NamespaceSize + appconsts.ShareSize
 
 	// cidPrefixSize is the size of the prepended buffer of the CID encoding
 	// for NamespacedSha256. For more information, see:
@@ -100,12 +100,12 @@ func (n nmtNode) Links() []*ipld.Link {
 	switch len(n.RawData()) {
 	default:
 		panic(fmt.Sprintf("unexpected size %v", len(n.RawData())))
-	case innerNodeSize:
+	case InnerNodeSize:
 		leftCid := MustCidFromNamespacedSha256(n.RawData()[:NmtHashSize])
 		rightCid := MustCidFromNamespacedSha256(n.RawData()[NmtHashSize:])
 
 		return []*ipld.Link{{Cid: leftCid}, {Cid: rightCid}}
-	case leafNodeSize:
+	case LeafNodeSize:
 		return nil
 	}
 }