| // 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 |