rocksdb/table/two_level_iterator.h
sdong fdf882ded2 Replace namespace name "rocksdb" with ROCKSDB_NAMESPACE (#6433)
Summary:
When dynamically linking two binaries together, different builds of RocksDB from two sources might cause errors. To provide a tool for user to solve the problem, the RocksDB namespace is changed to a flag which can be overridden in build time.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6433

Test Plan: Build release, all and jtest. Try to build with ROCKSDB_NAMESPACE with another flag.

Differential Revision: D19977691

fbshipit-source-id: aa7f2d0972e1c31d75339ac48478f34f6cfcfb3e
2020-02-20 12:09:57 -08:00

44 lines
1.7 KiB
C++

// 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 "rocksdb/iterator.h"
#include "rocksdb/env.h"
#include "table/iterator_wrapper.h"
namespace ROCKSDB_NAMESPACE {
struct ReadOptions;
class InternalKeyComparator;
// TwoLevelIteratorState expects iterators are not created using the arena
struct TwoLevelIteratorState {
TwoLevelIteratorState() {}
virtual ~TwoLevelIteratorState() {}
virtual InternalIteratorBase<IndexValue>* NewSecondaryIterator(
const BlockHandle& handle) = 0;
};
// Return a new two level iterator. A two-level iterator contains an
// index iterator whose values point to a sequence of blocks where
// each block is itself a sequence of key,value pairs. The returned
// two-level iterator yields the concatenation of all key/value pairs
// in the sequence of blocks. Takes ownership of "index_iter" and
// will delete it when no longer needed.
//
// Uses a supplied function to convert an index_iter value into
// an iterator over the contents of the corresponding block.
// Note: this function expects first_level_iter was not created using the arena
extern InternalIteratorBase<IndexValue>* NewTwoLevelIterator(
TwoLevelIteratorState* state,
InternalIteratorBase<IndexValue>* first_level_iter);
} // namespace ROCKSDB_NAMESPACE