// 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).

#pragma once

#include <ctime>

#include "memory/arena.h"

#include "port/sys_time.h"

#include "rocksdb/env.h"

#include "util/autovector.h"

namespace ROCKSDB_NAMESPACE {

class Logger;

// A class to buffer info log entries and flush them in the end.

class LogBuffer {

 public:

  // log_level: the log level for all the logs

  // info_log:  logger to write the logs to

  LogBuffer(const InfoLogLevel log_level, Logger* info_log);

  // Add a log entry to the buffer. Use default max_log_size.

  // max_log_size indicates maximize log size, including some metadata.

  void AddLogToBuffer(size_t max_log_size, const char* format, va_list ap);

  size_t IsEmpty() const { return logs_.empty(); }

  // Flush all buffered log to the info log.

  void FlushBufferToLog();

  static const size_t kDefaultMaxLogSize = 512;

 private:

  // One log entry with its timestamp

  struct BufferedLog {

    port::TimeVal now_tv;  // Timestamp of the log

    char message[1];       // Beginning of log message

  };

  const InfoLogLevel log_level_;

  Logger* info_log_;

  Arena arena_;

  autovector<BufferedLog*> logs_;

};

// Add log to the LogBuffer for a delayed info logging. It can be used when

// we want to add some logs inside a mutex.

// max_log_size indicates maximize log size, including some metadata.

void LogToBuffer(LogBuffer* log_buffer, size_t max_log_size, const char* format,

                 ...);

// Same as previous function, but with default max log size.

void LogToBuffer(LogBuffer* log_buffer, const char* format, ...);

}  // namespace ROCKSDB_NAMESPACE