mirror of https://github.com/facebook/rocksdb.git
115 lines
4.4 KiB
C++
115 lines
4.4 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 <stdint.h>
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#include <string>
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#include "db/db_impl/db_impl.h"
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#include "db/db_iter.h"
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#include "db/dbformat.h"
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#include "db/range_del_aggregator.h"
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#include "memory/arena.h"
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#include "options/cf_options.h"
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#include "rocksdb/db.h"
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#include "rocksdb/iterator.h"
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#include "util/autovector.h"
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namespace ROCKSDB_NAMESPACE {
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class Arena;
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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 to 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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// When using the class's Iterator interface, the behavior is exactly
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// the same as the inner DBIter.
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class ArenaWrappedDBIter : public Iterator {
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public:
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virtual ~ArenaWrappedDBIter() { db_iter_->~DBIter(); }
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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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virtual ReadRangeDelAggregator* GetRangeDelAggregator() {
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return db_iter_->GetRangeDelAggregator();
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}
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const ReadOptions& GetReadOptions() { return read_options_; }
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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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db_iter_->SetIter(iter);
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}
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bool Valid() const override { return db_iter_->Valid(); }
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void SeekToFirst() override { db_iter_->SeekToFirst(); }
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void SeekToLast() override { db_iter_->SeekToLast(); }
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// 'target' does not contain timestamp, even if user timestamp feature is
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// enabled.
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void Seek(const Slice& target) override { db_iter_->Seek(target); }
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void SeekForPrev(const Slice& target) override {
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db_iter_->SeekForPrev(target);
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}
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void Next() override { db_iter_->Next(); }
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void Prev() override { db_iter_->Prev(); }
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Slice key() const override { return db_iter_->key(); }
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Slice value() const override { return db_iter_->value(); }
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Status status() const override { return db_iter_->status(); }
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Slice timestamp() const override { return db_iter_->timestamp(); }
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bool IsBlob() const { return db_iter_->IsBlob(); }
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Status GetProperty(std::string prop_name, std::string* prop) override;
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Status Refresh() override;
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void Init(Env* env, const ReadOptions& read_options,
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const ImmutableCFOptions& cf_options,
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const MutableCFOptions& mutable_cf_options,
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const SequenceNumber& sequence,
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uint64_t max_sequential_skip_in_iterations, uint64_t version_number,
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ReadCallback* read_callback, DBImpl* db_impl, ColumnFamilyData* cfd,
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bool allow_blob, bool allow_refresh);
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// Store some parameters so we can refresh the iterator at a later point
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// with these same params
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void StoreRefreshInfo(DBImpl* db_impl, ColumnFamilyData* cfd,
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ReadCallback* read_callback, bool allow_blob) {
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db_impl_ = db_impl;
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cfd_ = cfd;
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read_callback_ = read_callback;
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allow_blob_ = allow_blob;
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}
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private:
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DBIter* db_iter_;
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Arena arena_;
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uint64_t sv_number_;
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ColumnFamilyData* cfd_ = nullptr;
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DBImpl* db_impl_ = nullptr;
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ReadOptions read_options_;
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ReadCallback* read_callback_;
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bool allow_blob_ = false;
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bool allow_refresh_ = true;
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};
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// Generate the arena wrapped iterator class.
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// `db_impl` and `cfd` are used for reneweal. If left null, renewal will not
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// be supported.
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extern ArenaWrappedDBIter* NewArenaWrappedDbIterator(
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Env* env, const ReadOptions& read_options,
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const ImmutableCFOptions& cf_options,
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const MutableCFOptions& mutable_cf_options, const SequenceNumber& sequence,
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uint64_t max_sequential_skip_in_iterations, uint64_t version_number,
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ReadCallback* read_callback, DBImpl* db_impl = nullptr,
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ColumnFamilyData* cfd = nullptr, bool allow_blob = false,
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bool allow_refresh = true);
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} // namespace ROCKSDB_NAMESPACE
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