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// 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/env.h"
#include "rocksdb/iterator.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
InternalIteratorBase<IndexValue>* NewTwoLevelIterator(
TwoLevelIteratorState* state,
InternalIteratorBase<IndexValue>* first_level_iter);
} // namespace ROCKSDB_NAMESPACE
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