internal/era,cmd: add number method to era iterator to get the current block number

cmd/era/main.go

@@ -248,7 +248,6 @@ func verify(ctx *cli.Context) error {
 func checkAccumulator(e *era.Era) error {
 	var (
 		err    error
-		start  = e.Start()
 		want   common.Hash
 		td     *big.Int
 		tds    = make([]*big.Int, 0)
@@ -271,15 +270,15 @@ func checkAccumulator(e *era.Era) error {
 	//   * the accumulator is correct by recomputing it locally,
 	//     which verifies the blocks are all correct (via hash)
 	//   * the receipts root matches the value in the block
-	for j := 0; it.Next(); j++ {
+	for it.Next() {
 		// next() walks the block index, so we're able to
 		// implicitly verify it.
 		if it.Error() != nil {
-			return fmt.Errorf("error reading block %d: %w", start+uint64(j), err)
+			return fmt.Errorf("error reading block %d: %w", it.Number(), err)
 		}
 		block, receipts, err := it.BlockAndReceipts()
 		if it.Error() != nil {
-			return fmt.Errorf("error reading block %d: %w", start+uint64(j), err)
+			return fmt.Errorf("error reading block %d: %w", it.Number(), err)
 		}
 		tr := types.DeriveSha(block.Transactions(), trie.NewStackTrie(nil))
 		if tr != block.TxHash() {

cmd/utils/cmd.go

@@ -293,32 +293,31 @@ func ImportHistory(chain *core.BlockChain, db ethdb.Database, dir string, networ
 			if err != nil {
 				return fmt.Errorf("error making era reader: %w", err)
 			}
-			for j := 0; it.Next(); j++ {
+			for it.Next() {
-				n := i*era.MaxEra1Size + j
 				block, err := it.Block()
 				if err != nil {
-					return fmt.Errorf("error reading block %d: %w", n, err)
+					return fmt.Errorf("error reading block %d: %w", it.Number(), err)
 				}
 				if block.Number().BitLen() == 0 {
 					continue // skip genesis
 				}
 				receipts, err := it.Receipts()
 				if err != nil {
-					return fmt.Errorf("error reading receipts %d: %w", n, err)
+					return fmt.Errorf("error reading receipts %d: %w", it.Number(), err)
 				}
 				if status, err := chain.HeaderChain().InsertHeaderChain([]*types.Header{block.Header()}, start, forker); err != nil {
-					return fmt.Errorf("error inserting header %d: %w", n, err)
+					return fmt.Errorf("error inserting header %d: %w", it.Number(), err)
 				} else if status != core.CanonStatTy {
-					return fmt.Errorf("error inserting header %d, not canon: %v", n, status)
+					return fmt.Errorf("error inserting header %d, not canon: %v", it.Number(), status)
 				}
 				if _, err := chain.InsertReceiptChain([]*types.Block{block}, []types.Receipts{receipts}, 2^64-1); err != nil {
-					return fmt.Errorf("error inserting body %d: %w", n, err)
+					return fmt.Errorf("error inserting body %d: %w", it.Number(), err)
 				}
 				imported += 1
 
 				// Give the user some feedback that something is happening.
 				if time.Since(reported) >= 8*time.Second {
-					log.Info("Importing Era files", "head", n, "imported", imported, "elapsed", common.PrettyDuration(time.Since(start)))
+					log.Info("Importing Era files", "head", it.Number(), "imported", imported, "elapsed", common.PrettyDuration(time.Since(start)))
 					imported = 0
 					reported = time.Now()
 				}

internal/era/iterator.go

@@ -43,6 +43,11 @@ func (it *Iterator) Next() bool {
 	return it.inner.Next()
 }
 
+// Number returns the current number block the iterator will return.
+func (it *Iterator) Number() uint64 {
+	return it.inner.next - 1
+}
+
 // Error returns the error status of the iterator.
 func (it *Iterator) Error() error {
 	return it.inner.Error()
@@ -145,6 +150,11 @@ func (it *RawIterator) Next() bool {
 	return true
 }
 
+// Number returns the current number block the iterator will return.
+func (it *RawIterator) Number() uint64 {
+	return it.next - 1
+}
+
 // Error returns the error status of the iterator.
 func (it *RawIterator) Error() error {
 	if it.err == io.EOF {