semisync.h

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/* Copyright (C) 2007 Google Inc.
   Copyright (c) 2000, 2025, Oracle and/or its affiliates.
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.
 
   This program is designed to work with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have either included with
   the program or referenced in the documentation.
 
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License, version 2.0, for more details.
 
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 
#ifndef SEMISYNC_H
#define SEMISYNC_H
 
#include <mysql/plugin.h>
 
#include <mysql/components/services/log_builtins.h>
#include "my_io.h"
#include "my_thread.h"
#include "mysqld_error.h"
#include "sql/replication.h"
 
struct SHOW_VAR;
struct SYS_VAR;
 
/**
   This class is used to trace function calls and other process
   information
*/
class Trace {
 public:
  static const unsigned long kTraceFunction;
  static const unsigned long kTraceGeneral;
  static const unsigned long kTraceDetail;
  static const unsigned long kTraceNetWait;
 
  unsigned long trace_level_; /* the level for tracing */
 
  inline void function_enter(const char *func_name) {
    if ((trace_level_ & kTraceFunction) && log_bi)
      LogErr(INFORMATION_LEVEL, ER_SEMISYNC_TRACE_ENTER_FUNC, func_name);
  }
 
  inline int function_exit(const char *func_name, int exit_code) {
    if ((trace_level_ & kTraceFunction) && log_bi)
      LogErr(INFORMATION_LEVEL, ER_SEMISYNC_TRACE_EXIT_WITH_INT_EXIT_CODE,
             func_name, exit_code);
    return exit_code;
  }
 
  inline bool function_exit(const char *func_name, bool exit_code) {
    if ((trace_level_ & kTraceFunction) && log_bi)
      LogErr(INFORMATION_LEVEL, ER_SEMISYNC_TRACE_EXIT_WITH_BOOL_EXIT_CODE,
             func_name, exit_code ? "True" : "False");
    return exit_code;
  }
 
  inline void function_exit(const char *func_name) {
    if ((trace_level_ & kTraceFunction) && log_bi)
      LogErr(INFORMATION_LEVEL, ER_SEMISYNC_TRACE_EXIT, func_name);
  }
 
  Trace() : trace_level_(0L) {}
  Trace(unsigned long trace_level) : trace_level_(trace_level) {}
};
 
/**
   Base class for semi-sync master and slave classes
*/
class ReplSemiSyncBase : public Trace {
 public:
  static const unsigned char kSyncHeader[2]; /* three byte packet header */
 
  /* Constants in network packet header. */
  static const unsigned char kPacketMagicNum;
  static const unsigned char kPacketFlagSync;
};
 
/* The layout of a semisync slave reply packet:
   1 byte for the magic num
   8 bytes for the binlog position
   n bytes for the binlog filename, terminated with a '\0'
*/
#define REPLY_MAGIC_NUM_LEN 1
#define REPLY_BINLOG_POS_LEN 8
#define REPLY_BINLOG_NAME_LEN (FN_REFLEN + 1)
#define REPLY_MESSAGE_MAX_LENGTH \
  (REPLY_MAGIC_NUM_LEN + REPLY_BINLOG_POS_LEN + REPLY_BINLOG_NAME_LEN)
#define REPLY_MAGIC_NUM_OFFSET 0
#define REPLY_BINLOG_POS_OFFSET (REPLY_MAGIC_NUM_OFFSET + REPLY_MAGIC_NUM_LEN)
#define REPLY_BINLOG_NAME_OFFSET \
  (REPLY_BINLOG_POS_OFFSET + REPLY_BINLOG_POS_LEN)
 
/**
  Return true if the named sysvar has been defined in the server.
 
  @retval true The sysvar is defined.
  @retval false Otherwise.
*/
bool is_sysvar_defined(const char *name);
 
#endif /* SEMISYNC_H */