Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 29 insertions, 0 deletions

diff --git a/src/rocksdb/file/readahead_raf.h b/src/rocksdb/file/readahead_raf.h
new file mode 100644
index 000000000..dfaf2b4fa
--- /dev/null
+++ b/src/rocksdb/file/readahead_raf.h
@@ -0,0 +1,29 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#pragma once
+#include <memory>
+
+#include "rocksdb/rocksdb_namespace.h"
+
+namespace ROCKSDB_NAMESPACE {
+class FSRandomAccessFile;
+// This file provides the following main abstractions:
+// SequentialFileReader : wrapper over Env::SequentialFile
+// RandomAccessFileReader : wrapper over Env::RandomAccessFile
+// WritableFileWriter : wrapper over Env::WritableFile
+// In addition, it also exposed NewReadaheadRandomAccessFile, NewWritableFile,
+// and ReadOneLine primitives.
+
+// NewReadaheadRandomAccessFile provides a wrapper over RandomAccessFile to
+// always prefetch additional data with every read. This is mainly used in
+// Compaction Table Readers.
+std::unique_ptr<FSRandomAccessFile> NewReadaheadRandomAccessFile(
+    std::unique_ptr<FSRandomAccessFile>&& file, size_t readahead_size);
+}  // namespace ROCKSDB_NAMESPACE