core/rawdb: fill in the missing method

Signed-off-by: jsvisa <delweng@gmail.com>

core/rawdb/chain_freezer.go

@@ -403,6 +403,10 @@ func (f *chainFreezer) AncientRange(kind string, start, count, maxBytes uint64)
 	return f.ancients.AncientRange(kind, start, count, maxBytes)
 }
 
+func (f *chainFreezer) AncientBytes(kind string, item, offset, length uint64) ([]byte, error) {
+	return f.ancients.AncientBytes(kind, item, offset, length)
+}
+
 func (f *chainFreezer) ModifyAncients(fn func(ethdb.AncientWriteOp) error) (int64, error) {
 	return f.ancients.ModifyAncients(fn)
 }

core/rawdb/database.go

@@ -100,6 +100,11 @@ func (db *nofreezedb) AncientRange(kind string, start, max, maxByteSize uint64)
 	return nil, errNotSupported
 }
 
+// AncientBytes retrieves a byte range [offset:offset+length] from the specified ancient item.
+func (db *nofreezedb) AncientBytes(kind string, item, offset, length uint64) ([]byte, error) {
+	return nil, errNotSupported
+}
+
 // Ancients returns an error as we don't have a backing chain freezer.
 func (db *nofreezedb) Ancients() (uint64, error) {
 	return 0, errNotSupported

core/rawdb/freezer_memory.go

@@ -412,3 +412,26 @@ func (f *MemoryFreezer) Reset() error {
 func (f *MemoryFreezer) AncientDatadir() (string, error) {
 	return "", nil
 }
+
+// AncientBytes retrieves a byte range [offset:offset+length] from the specified ancient item in memory.
+func (f *MemoryFreezer) AncientBytes(kind string, item, offset, length uint64) ([]byte, error) {
+	f.lock.RLock()
+	defer f.lock.RUnlock()
+
+	table := f.tables[kind]
+	if table == nil {
+		return nil, errUnknownTable
+	}
+	entries, err := table.retrieve(item, 1, 0)
+	if err != nil {
+		return nil, err
+	}
+	if len(entries) == 0 {
+		return nil, errOutOfBounds
+	}
+	data := entries[0]
+	if offset > uint64(len(data)) || offset+length > uint64(len(data)) {
+		return nil, fmt.Errorf("requested range out of bounds: item size %d, offset %d, length %d", len(data), offset, length)
+	}
+	return data[offset : offset+length], nil
+}

core/rawdb/table.go

@@ -62,6 +62,12 @@ func (t *table) AncientRange(kind string, start, count, maxBytes uint64) ([][]by
 	return t.db.AncientRange(kind, start, count, maxBytes)
 }
 
+// AncientBytes is a noop passthrough that just forwards the request to the underlying
+// database.
+func (t *table) AncientBytes(kind string, item, offset, length uint64) ([]byte, error) {
+	return t.db.AncientBytes(kind, item, offset, length)
+}
+
 // Ancients is a noop passthrough that just forwards the request to the underlying
 // database.
 func (t *table) Ancients() (uint64, error) {