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+// 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 <stdint.h>
+#include <string>
+#include "db/db_impl.h"
+#include "db/dbformat.h"
+#include "db/range_del_aggregator.h"
+#include "options/cf_options.h"
+#include "rocksdb/db.h"
+#include "rocksdb/iterator.h"
+#include "util/arena.h"
+#include "util/autovector.h"
+
+namespace rocksdb {
+
+class Arena;
+class DBIter;
+
+// Return a new iterator that converts internal keys (yielded by
+// "*internal_iter") that were live at the specified "sequence" number
+// into appropriate user keys.
+extern Iterator* NewDBIterator(
+ Env* env, const ReadOptions& read_options,
+ const ImmutableCFOptions& cf_options,
+ const MutableCFOptions& mutable_cf_options,
+ const Comparator* user_key_comparator, InternalIterator* internal_iter,
+ const SequenceNumber& sequence, uint64_t max_sequential_skip_in_iterations,
+ ReadCallback* read_callback, DBImpl* db_impl = nullptr,
+ ColumnFamilyData* cfd = nullptr, bool allow_blob = false);
+
+// A wrapper iterator which wraps DB Iterator and the arena, with which the DB
+// iterator is supposed be allocated. This class is used as an entry point of
+// a iterator hierarchy whose memory can be allocated inline. In that way,
+// accessing the iterator tree can be more cache friendly. It is also faster
+// to allocate.
+class ArenaWrappedDBIter : public Iterator {
+ public:
+ virtual ~ArenaWrappedDBIter();
+
+ // Get the arena to be used to allocate memory for DBIter to be wrapped,
+ // as well as child iterators in it.
+ virtual Arena* GetArena() { return &arena_; }
+ virtual ReadRangeDelAggregator* GetRangeDelAggregator();
+
+ // Set the internal iterator wrapped inside the DB Iterator. Usually it is
+ // a merging iterator.
+ virtual void SetIterUnderDBIter(InternalIterator* iter);
+ virtual bool Valid() const override;
+ virtual void SeekToFirst() override;
+ virtual void SeekToLast() override;
+ virtual void Seek(const Slice& target) override;
+ virtual void SeekForPrev(const Slice& target) override;
+ virtual void Next() override;
+ virtual void Prev() override;
+ virtual Slice key() const override;
+ virtual Slice value() const override;
+ virtual Status status() const override;
+ virtual Status Refresh() override;
+ bool IsBlob() const;
+
+ virtual Status GetProperty(std::string prop_name, std::string* prop) override;
+
+ void Init(Env* env, const ReadOptions& read_options,
+ const ImmutableCFOptions& cf_options,
+ const MutableCFOptions& mutable_cf_options,
+ const SequenceNumber& sequence,
+ uint64_t max_sequential_skip_in_iterations, uint64_t version_number,
+ ReadCallback* read_callback, DBImpl* db_impl, ColumnFamilyData* cfd,
+ bool allow_blob, bool allow_refresh);
+
+ void StoreRefreshInfo(const ReadOptions& read_options, DBImpl* db_impl,
+ ColumnFamilyData* cfd, ReadCallback* read_callback,
+ bool allow_blob) {
+ read_options_ = read_options;
+ db_impl_ = db_impl;
+ cfd_ = cfd;
+ read_callback_ = read_callback;
+ allow_blob_ = allow_blob;
+ }
+
+ private:
+ DBIter* db_iter_;
+ Arena arena_;
+ uint64_t sv_number_;
+ ColumnFamilyData* cfd_ = nullptr;
+ DBImpl* db_impl_ = nullptr;
+ ReadOptions read_options_;
+ ReadCallback* read_callback_;
+ bool allow_blob_ = false;
+ bool allow_refresh_ = true;
+};
+
+// Generate the arena wrapped iterator class.
+// `db_impl` and `cfd` are used for reneweal. If left null, renewal will not
+// be supported.
+extern ArenaWrappedDBIter* NewArenaWrappedDbIterator(
+ Env* env, const ReadOptions& read_options,
+ const ImmutableCFOptions& cf_options,
+ const MutableCFOptions& mutable_cf_options, const SequenceNumber& sequence,
+ uint64_t max_sequential_skip_in_iterations, uint64_t version_number,
+ ReadCallback* read_callback, DBImpl* db_impl = nullptr,
+ ColumnFamilyData* cfd = nullptr, bool allow_blob = false,
+ bool allow_refresh = true);
+} // namespace rocksdb