53 lines
2.1 KiB
C++
53 lines
2.1 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include "rocksdb/iterator.h"
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#include "rocksdb/env.h"
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#include "table/iterator_wrapper.h"
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namespace rocksdb {
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struct ReadOptions;
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class InternalKeyComparator;
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class Arena;
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struct TwoLevelIteratorState {
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explicit TwoLevelIteratorState(bool _check_prefix_may_match)
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: check_prefix_may_match(_check_prefix_may_match) {}
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virtual ~TwoLevelIteratorState() {}
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virtual InternalIterator* NewSecondaryIterator(const Slice& handle) = 0;
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virtual bool PrefixMayMatch(const Slice& internal_key) = 0;
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// If call PrefixMayMatch()
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bool check_prefix_may_match;
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};
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// Return a new two level iterator. A two-level iterator contains an
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// index iterator whose values point to a sequence of blocks where
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// each block is itself a sequence of key,value pairs. The returned
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// two-level iterator yields the concatenation of all key/value pairs
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// in the sequence of blocks. Takes ownership of "index_iter" and
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// will delete it when no longer needed.
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//
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// Uses a supplied function to convert an index_iter value into
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// an iterator over the contents of the corresponding block.
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// arena: If not null, the arena is used to allocate the Iterator.
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// When destroying the iterator, the destructor will destroy
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// all the states but those allocated in arena.
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// need_free_iter_and_state: free `state` and `first_level_iter` if
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// true. Otherwise, just call destructor.
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extern InternalIterator* NewTwoLevelIterator(
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TwoLevelIteratorState* state, InternalIterator* first_level_iter,
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Arena* arena = nullptr, bool need_free_iter_and_state = true);
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} // namespace rocksdb
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