// 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 {
struct ReadOptions;
class InternalKeyComparator;
class Arena;
struct TwoLevelIteratorState {
explicit TwoLevelIteratorState(bool _check_prefix_may_match)
: check_prefix_may_match(_check_prefix_may_match) {}
virtual ~TwoLevelIteratorState() {}
virtual InternalIterator* NewSecondaryIterator(const Slice& handle) = 0;
virtual bool PrefixMayMatch(const Slice& internal_key) = 0;
virtual bool KeyReachedUpperBound(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.
// arena: If not null, the arena is used to allocate the Iterator.
// When destroying the iterator, the destructor will destroy
// all the states but those allocated in arena.
// need_free_iter_and_state: free `state` and `first_level_iter` if
// true. Otherwise, just call destructor.
extern InternalIterator* NewTwoLevelIterator(
TwoLevelIteratorState* state, InternalIterator* first_level_iter,
Arena* arena = nullptr, bool need_free_iter_and_state = true);
} // namespace rocksdb