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rocksdb/table/two_level_iterator.h

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1.7 KiB

// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same 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 {
struct ReadOptions;
class InternalKeyComparator;
struct TwoLevelIteratorState {
explicit TwoLevelIteratorState(bool check_prefix_may_match)
: check_prefix_may_match(check_prefix_may_match) {}
virtual ~TwoLevelIteratorState() {}
virtual Iterator* NewSecondaryIterator(const Slice& handle) = 0;
virtual bool PrefixMayMatch(const Slice& internal_key) = 0;
// If call PrefixMayMatch()
bool check_prefix_may_match;
};
// 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.
extern Iterator* NewTwoLevelIterator(TwoLevelIteratorState* state,
Iterator* first_level_iter);
} // namespace rocksdb