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
79 lines
2.9 KiB
C++
79 lines
2.9 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 <stdint.h>
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#include "rocksdb/db.h"
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#include "rocksdb/iterator.h"
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#include "db/dbformat.h"
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#include "util/arena.h"
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#include "util/autovector.h"
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namespace rocksdb {
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class Arena;
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class DBIter;
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class InternalIterator;
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// Return a new iterator that converts internal keys (yielded by
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// "*internal_iter") that were live at the specified "sequence" number
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// into appropriate user keys.
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extern Iterator* NewDBIterator(Env* env, const ImmutableCFOptions& options,
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const Comparator* user_key_comparator,
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InternalIterator* internal_iter,
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const SequenceNumber& sequence,
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uint64_t max_sequential_skip_in_iterations,
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const Slice* iterate_upper_bound = nullptr);
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// A wrapper iterator which wraps DB Iterator and the arena, with which the DB
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// iterator is supposed be allocated. This class is used as an entry point of
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// a iterator hierarchy whose memory can be allocated inline. In that way,
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// accessing the iterator tree can be more cache friendly. It is also faster
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// to allocate.
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class ArenaWrappedDBIter : public Iterator {
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public:
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virtual ~ArenaWrappedDBIter();
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// Get the arena to be used to allocate memory for DBIter to be wrapped,
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// as well as child iterators in it.
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virtual Arena* GetArena() { return &arena_; }
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// Set the DB Iterator to be wrapped
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virtual void SetDBIter(DBIter* iter);
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// Set the internal iterator wrapped inside the DB Iterator. Usually it is
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// a merging iterator.
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virtual void SetIterUnderDBIter(InternalIterator* iter);
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virtual bool Valid() const override;
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virtual void SeekToFirst() override;
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virtual void SeekToLast() override;
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virtual void Seek(const Slice& target) override;
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virtual void Next() override;
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virtual void Prev() override;
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virtual Slice key() const override;
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virtual Slice value() const override;
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virtual Status status() const override;
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void RegisterCleanup(CleanupFunction function, void* arg1, void* arg2);
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private:
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DBIter* db_iter_;
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Arena arena_;
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};
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// Generate the arena wrapped iterator class.
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extern ArenaWrappedDBIter* NewArenaWrappedDbIterator(
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Env* env, const ImmutableCFOptions& options,
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const Comparator* user_key_comparator,
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const SequenceNumber& sequence, uint64_t max_sequential_skip_in_iterations,
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const Slice* iterate_upper_bound = nullptr);
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} // namespace rocksdb
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