YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.

//  This source code is licensed under the BSD-style license found in the

//  LICENSE file in the root directory of this source tree. An additional grant

//  of patent rights can be found in the PATENTS file in the same directory.

//

// The following only applies to changes made to this file as part of YugaByte development.

//

// Portions Copyright (c) YugaByte, Inc.

//

// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except

// in compliance with the License.  You may obtain a copy of the License at

//

// http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software distributed under the License

// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express

// or implied.  See the License for the specific language governing permissions and limitations

// under the License.

//

#pragma once

#include <stddef.h>

#include <stdint.h>

#include <stdio.h>

#include <string.h>

#include <limits>

#include <memory>

#include <stack>

#include <string>

#include <unordered_map>

#include <vector>

#include "yb/rocksdb/db/dbformat.h"

#include "yb/rocksdb/env.h"

#include "yb/rocksdb/listener.h"

#include "yb/rocksdb/options.h"

#include "yb/rocksdb/status.h"

#include "yb/rocksdb/types.h"

namespace rocksdb {

class MergeContext;

class GetContext {

 public:

  enum GetState {

    kNotFound,

    kFound,

    kDeleted,

    kCorrupt,

    kMerge  // saver contains the current merge result (the operands)

  };

  GetContext(const Comparator* ucmp, const MergeOperator* merge_operator,

             Logger* logger, Statistics* statistics, GetState init_state,

             const Slice& user_key, std::string* ret_value, bool* value_found,

             MergeContext* merge_context, Env* env,

             SequenceNumber* seq = nullptr);

  void MarkKeyMayExist();

  // Records this key, value, and any meta-data (such as sequence number and

  // state) into this GetContext.

  //

  // Returns True if more keys need to be read (due to merges) or

  //         False if the complete value has been found.

  bool SaveValue(const ParsedInternalKey& parsed_key, const Slice& value);

  // Simplified version of the previous function. Should only be used when we

  // know that the operation is a Put.

  void SaveValue(const Slice& value, SequenceNumber seq);

  GetState State() const { return state_; }

  // If a non-null string is passed, all the SaveValue calls will be

  // logged into the string. The operations can then be replayed on

  // another GetContext with replayGetContextLog.

  void SetReplayLog(std::string* replay_log) { replay_log_ = replay_log; }

  // Do we need to fetch the SequenceNumber for this key?

  bool NeedToReadSequence() const { return (seq_ != nullptr); }

 private:

  const Comparator* ucmp_;

  const MergeOperator* merge_operator_;

  // the merge operations encountered;

  Logger* logger_;

  Statistics* statistics_;

  GetState state_;

  Slice user_key_;

  std::string* value_;

  bool* value_found_;  // Is value set correctly? Used by KeyMayExist

  MergeContext* merge_context_;

  Env* env_;

  // If a key is found, seq_ will be set to the SequenceNumber of most recent

  // write to the key or kMaxSequenceNumber if unknown

  SequenceNumber* seq_;

  std::string* replay_log_;

};

void replayGetContextLog(const Slice& replay_log, const Slice& user_key,

                         GetContext* get_context);

}  // namespace rocksdb