Expose file index in reader

reader.go

@@ -9,6 +9,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/0xsequence/ethwal/storage/stub"
 	"github.com/fatih/structs"
 
 	"github.com/0xsequence/ethwal/storage"
@@ -19,7 +20,8 @@ const firstFileIndex = 0
 const loadIndexFileTimeout = 30 * time.Second
 
 type Reader[T any] interface {
-	FilesNum() int
+	FileNum() int
+	FileIndex() *FileIndex
 	Read(ctx context.Context) (Block[T], error)
 	Seek(ctx context.Context, blockNum uint64) error
 	BlockNum() uint64
@@ -102,13 +104,27 @@ func NewReader[T any](opt Options) (Reader[T], error) {
 	}, nil
 }
 
-func (r *reader[T]) FilesNum() int {
+func (r *reader[T]) FileNum() int {
 	r.mu.Lock()
 	defer r.mu.Unlock()
 
 	return len(r.fileIndex.Files())
 }
 
+func (r *reader[T]) FileIndex() *FileIndex {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	newfiles := make([]*File, len(r.fileIndex.Files()))
+	for index, file := range r.fileIndex.Files() {
+		newfiles[index] = &File{
+			FirstBlockNum: file.FirstBlockNum,
+			LastBlockNum:  file.LastBlockNum,
+		}
+	}
+	return NewFileIndexFromFiles(stub.Stub{}, newfiles)
+}
+
 func (r *reader[T]) Read(ctx context.Context) (Block[T], error) {
 	r.mu.Lock()
 	defer r.mu.Unlock()

reader_test.go

@@ -223,7 +223,7 @@ func TestReader_Read(t *testing.T) {
 	}
 }
 
-func TestReader_NumWALFiles(t *testing.T) {
+func TestReader_FileNum(t *testing.T) {
 	testSetup(t, NewCBOREncoder, nil)
 	defer testTeardown(t)
 
@@ -238,7 +238,29 @@ func TestReader_NumWALFiles(t *testing.T) {
 	})
 	require.NoError(t, err)
 
-	assert.Equal(t, 3, rdr.FilesNum())
+	assert.Equal(t, 3, rdr.FileNum())
+
+	require.NoError(t, rdr.Close())
+}
+
+func TestReader_FileIndex(t *testing.T) {
+	testSetup(t, NewCBOREncoder, nil)
+	defer testTeardown(t)
+
+	rdr, err := NewReader[int](Options{
+		Dataset: Dataset{
+			Name:    "int-wal",
+			Path:    testPath,
+			Version: defaultDatasetVersion,
+		},
+		NewEncoder: NewCBOREncoder,
+		NewDecoder: NewCBORDecoder,
+	})
+	require.NoError(t, err)
+
+	fileIndex := rdr.FileIndex()
+	require.NotNil(t, fileIndex)
+	assert.Equal(t, 3, len(fileIndex.Files()))
 
 	require.NoError(t, rdr.Close())
 }

reader_with_filter.go

@@ -22,8 +22,12 @@ func NewReaderWithFilter[T any](reader Reader[T], filter Filter) (Reader[T], err
 	}, nil
 }
 
-func (c *readerWithFilter[T]) FilesNum() int {
-	return c.reader.FilesNum()
+func (c *readerWithFilter[T]) FileNum() int {
+	return c.reader.FileNum()
+}
+
+func (c *readerWithFilter[T]) FileIndex() *FileIndex {
+	return c.reader.FileIndex()
 }
 
 func (c *readerWithFilter[T]) Seek(ctx context.Context, blockNum uint64) error {

storage/stub/stub.go

@@ -0,0 +1,38 @@
+package stub
+
+import (
+	"context"
+	"fmt"
+	"io"
+
+	"github.com/Shopify/go-storage"
+)
+
+type Stub struct {
+}
+
+func (s Stub) Walk(ctx context.Context, path string, fn storage.WalkFn) error {
+	return nil
+}
+
+func (s Stub) Open(ctx context.Context, path string, options *storage.ReaderOptions) (*storage.File, error) {
+	return nil, fmt.Errorf("not implemented")
+}
+
+func (s Stub) Attributes(ctx context.Context, path string, options *storage.ReaderOptions) (*storage.Attributes, error) {
+	return nil, fmt.Errorf("not implemented")
+}
+
+func (s Stub) Create(ctx context.Context, path string, options *storage.WriterOptions) (io.WriteCloser, error) {
+	return nil, fmt.Errorf("not implemented")
+}
+
+func (s Stub) Delete(ctx context.Context, path string) error {
+	return nil
+}
+
+func (s Stub) URL(ctx context.Context, path string, options *storage.SignedURLOptions) (string, error) {
+	return "", nil
+}
+
+var _ storage.FS = (*Stub)(nil)