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35ad531be3
Summary: Separate a new class InternalIterator from class Iterator, when the look-up is done internally, which also means they operate on key with sequence ID and type. This change will enable potential future optimizations but for now InternalIterator's functions are still the same as Iterator's. At the same time, separate the cleanup function to a separate class and let both of InternalIterator and Iterator inherit from it. Test Plan: Run all existing tests. Reviewers: igor, yhchiang, anthony, kradhakrishnan, IslamAbdelRahman, rven Reviewed By: rven Subscribers: leveldb, dhruba Differential Revision: https://reviews.facebook.net/D48549
53 lines
2.1 KiB
C++
53 lines
2.1 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same 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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