refactor!(shwap/store): decouple Q1Q4 and ODS files

share/empty.go

@@ -11,10 +11,16 @@ import (
 	"github.com/celestiaorg/rsmt2d"
 )
 
+// EmptyEDSDataHash returns DataHash of the empty block EDS.
+func EmptyEDSDataHash() DataHash {
+	initEmpty()
+	return emptyBlockDataHash
+}
+
 // EmptyEDSRoots returns AxisRoots of the empty block EDS.
 func EmptyEDSRoots() *AxisRoots {
 	initEmpty()
-	return emptyBlockRoot
+	return emptyBlockRoots
 }
 
 // EmptyEDS returns the EDS of the empty block data square.
@@ -30,17 +36,18 @@ func EmptyBlockShares() []Share {
 }
 
 var (
-	emptyMu          sync.Mutex
-	emptyBlockRoot   *AxisRoots
-	emptyBlockEDS    *rsmt2d.ExtendedDataSquare
-	emptyBlockShares []Share
+	emptyMu            sync.Mutex
+	emptyBlockDataHash DataHash
+	emptyBlockRoots    *AxisRoots
+	emptyBlockEDS      *rsmt2d.ExtendedDataSquare
+	emptyBlockShares   []Share
 )
 
 // initEmpty enables lazy initialization for constant empty block data.
 func initEmpty() {
 	emptyMu.Lock()
 	defer emptyMu.Unlock()
-	if emptyBlockRoot != nil {
+	if emptyBlockRoots != nil {
 		return
 	}
 
@@ -54,16 +61,16 @@ func initEmpty() {
 	}
 	emptyBlockEDS = eds
 
-	emptyBlockRoot, err = NewAxisRoots(eds)
+	emptyBlockRoots, err = NewAxisRoots(eds)
 	if err != nil {
 		panic(fmt.Errorf("failed to create empty DAH: %w", err))
 	}
 	minDAH := da.MinDataAvailabilityHeader()
-	if !bytes.Equal(minDAH.Hash(), emptyBlockRoot.Hash()) {
+	if !bytes.Equal(minDAH.Hash(), emptyBlockRoots.Hash()) {
 		panic(fmt.Sprintf("mismatch in calculated minimum DAH and minimum DAH from celestia-app, "+
-			"expected %s, got %s", minDAH.String(), emptyBlockRoot.String()))
+			"expected %s, got %s", minDAH.String(), emptyBlockRoots.String()))
 	}
 
 	// precompute Hash, so it's cached internally to avoid potential races
-	emptyBlockRoot.Hash()
+	emptyBlockDataHash = emptyBlockRoots.Hash()
 }

share/new_eds/accessor.go

@@ -10,6 +10,9 @@ import (
 	"github.com/celestiaorg/celestia-node/share/shwap"
 )
 
+// EmptyAccessor is an accessor of an empty EDS block.
+var EmptyAccessor = &Rsmt2D{ExtendedDataSquare: share.EmptyEDS()}
+
 // Accessor is an interface for accessing extended data square data.
 type Accessor interface {
 	// Size returns square size of the Accessor.

share/root.go

@@ -38,7 +38,7 @@ func (dh DataHash) String() string {
 
 // IsEmptyEDS check whether DataHash corresponds to the root of an empty block EDS.
 func (dh DataHash) IsEmptyEDS() bool {
-	return bytes.Equal(EmptyEDSRoots().Hash(), dh)
+	return bytes.Equal(EmptyEDSDataHash(), dh)
 }
 
 // NewSHA256Hasher returns a new instance of a SHA-256 hasher.

store/file/file.go

@@ -0,0 +1,8 @@
+package file
+
+const (
+	// writeBufferSize defines buffer size for optimized batched writes into the file system.
+	// TODO(@Wondertan): Consider making it configurable
+	writeBufferSize = 64 << 10
+	filePermissions = 0o600
+)

store/file/header.go

@@ -2,7 +2,6 @@ package file
 
 import (
 	"encoding/binary"
-	"errors"
 	"fmt"
 	"io"
 
@@ -37,17 +36,14 @@ type fileType uint8
 
 const (
 	ods fileType = iota
-	q1q4
+	q4
 )
 
 func readHeader(r io.Reader) (*headerV0, error) {
 	// read first byte to determine the fileVersion
 	var version headerVersion
 	err := binary.Read(r, binary.LittleEndian, &version)
 	if err != nil {
-		if errors.Is(err, io.EOF) {
-			return nil, ErrEmptyFile
-		}
 		return nil, fmt.Errorf("readHeader: %w", err)
 	}
 
@@ -70,6 +66,14 @@ func writeHeader(w io.Writer, h *headerV0) error {
 	return err
 }
 
+func (h *headerV0) SquareSize() int {
+	return int(h.squareSize)
+}
+
+func (h *headerV0) ShareSize() int {
+	return int(h.shareSize)
+}
+
 func (h *headerV0) Size() int {
 	// header size + 1 byte for header fileVersion
 	return headerVOSize + 1