log_buffer.h

/* Copyright (c) 2021-2022 OceanBase and/or its affiliates. All rights reserved.
miniob is licensed under Mulan PSL v2.
You can use this software according to the terms and conditions of the Mulan PSL v2.
You may obtain a copy of Mulan PSL v2 at:
         http://license.coscl.org.cn/MulanPSL2
THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
See the Mulan PSL v2 for more details. */
 
//
// Created by wangyunlai on 2024/01/31
//
 
#pragma once
 
#include "common/sys/rc.h"
#include "common/types.h"
#include "common/lang/mutex.h"
#include "common/lang/vector.h"
#include "common/lang/deque.h"
#include "common/lang/atomic.h"
#include "storage/clog/log_module.h"
#include "storage/clog/log_entry.h"
 
class LogFileWriter;
 
class LogEntryBuffer
{
public:
  LogEntryBuffer()  = default;
  ~LogEntryBuffer() = default;
 
  RC init(LSN lsn, int32_t max_bytes = 0);
 
  RC append(LSN &lsn, LogModule::Id module_id, vector<char> &&data);
  RC append(LSN &lsn, LogModule module, vector<char> &&data);
 
  RC flush(LogFileWriter &file_writer, int &count);
 
  int64_t bytes() const;
 
  int32_t entry_number() const;
 
  LSN current_lsn() const { return current_lsn_.load(); }
  LSN flushed_lsn() const { return flushed_lsn_.load(); }
 
private:
  mutex           mutex_;  
  deque<LogEntry> entries_;  
  atomic<int64_t> bytes_;    
 
  atomic<LSN> current_lsn_{0};
  atomic<LSN> flushed_lsn_{0};
 
  int32_t max_bytes_ = 4 * 1024 * 1024;  
};