wrapper_functions.h

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/* Copyright (c) 2014, 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 */
 
/**
  @file
 
  @brief Contains wrapper functions for memory allocation and deallocation.
  This includes generic functions to be called from the binlogevent library,
  which call the appropriate corresponding function, depending on whether
  the library is compiled independently, or with the MySQL server.
*/
 
#ifndef MYSQL_BINLOG_EVENT_WRAPPER_FUNCTIONS_H
#define MYSQL_BINLOG_EVENT_WRAPPER_FUNCTIONS_H
 
#ifndef STANDALONE_BINLOG
#define HAVE_MYSYS 1
#endif
 
#ifdef HAVE_MYSYS
#include "my_config.h"
#include "my_sys.h"
#include "mysql/service_mysql_alloc.h"
 
extern PSI_memory_key key_memory_log_event;
#else
#include <cassert>
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <stdlib.h>
#include <string.h>
 
#endif
 
#if !defined(NDEBUG)
 
#include "my_dbug.h"
 
#ifdef HAVE_MYSYS
#define BAPI_ASSERT(x) assert(x)
#define BAPI_PRINT(name, params) DBUG_PRINT(name, params)
#define BAPI_ENTER(x) DBUG_ENTER(x)
#define BAPI_RETURN(x) DBUG_RETURN(x)
#define BAPI_TRACE DBUG_TRACE
#define BAPI_VOID_RETURN DBUG_VOID_RETURN
#define BAPI_LOG(x, y) DBUG_LOG(x, y)
#define BAPI_VAR(v) DBUG_VAR(v)
#else
#define BAPI_ASSERT(x) assert(x)
#define BAPI_PRINT(name, params) \
  do {                           \
  } while (0)
#define BAPI_ENTER(x) \
  do {                \
  } while (0)
#define BAPI_RETURN(x) return (x)
#define BAPI_TRACE \
  do {             \
  } while (0)
#define BAPI_VOID_RETURN return
#define BAPI_LOG(x, y) \
  do {                 \
  } while (0)
#define BAPI_VAR(v) ""
#endif
#else
#define BAPI_ASSERT(x) \
  do {                 \
  } while (0)
#define BAPI_PRINT(name, params) \
  do {                           \
  } while (0)
#define BAPI_ENTER(x) \
  do {                \
  } while (0)
#define BAPI_RETURN(x) return (x)
#define BAPI_TRACE \
  do {             \
  } while (0)
#define BAPI_VOID_RETURN return
#define BAPI_LOG(x, y) \
  do {                 \
  } while (0)
#define BAPI_VAR(v) ""
#endif
 
namespace mysql::binlog::event {
 
#ifndef HAVE_STRNDUP
/**
  The strndup() function returns a pointer to a new string which is a duplicate
  of the string s, but it only copies at most n bytes. If s is longer than n,
  only n bytes are copied, and a terminating null byte ('\0') is added.
  Memory for the new string is obtained with malloc,
  and can be freed with free.
  @param  s  The string whose copy we want to create
  @param  n  Number of bytes to be copied
 
  @return    The duplicated string, or NULL if insufficient memory was
  available.
*/
inline char *strndup(const char *s, size_t n) {
  char *result;
  size_t len = strlen(s);
 
  if (n < len) len = n;
 
  result = (char *)malloc(len + 1);
  if (!result) return nullptr;
 
  result[len] = '\0';
  return (char *)memcpy(result, s, len);
}
#endif
 
/**
  This is a wrapper function, and returns a pointer to a new string which is
  a duplicate of the input string. The terminating Null character is added.
 
  If compiled with MySQL server,the strndup function from the mysys library is
  called, which allow instrumenting memory allocated. Else, the standard
  string function is called.
 
  @param destination The string to be duplicated
  @param n           The number of bytes to be copied
 
  @return The duplicated string, or NULL if insufficient memory was available.
*/
inline const char *bapi_strndup(const char *destination, size_t n) {
#ifdef HAVE_MYSYS
  /* Call the function in mysys library, required for memory instrumentation */
  return my_strndup(key_memory_log_event, destination, n, MYF(MY_WME));
#else
  return strndup(destination, n);
#endif
}
 
/**
  This is a wrapper function, and returns a pointer to a new memory with the
  contents copied from the input memory pointer, up to a given length
 
  @param source Pointer to the buffer from which data is to be copied
  @param len Length up to which the source should be copied
 
  @return dest pointer to a new memory if allocation was successful
          NULL otherwise
*/
inline void *bapi_memdup(const void *source, size_t len) {
  void *dest;
#ifdef HAVE_MYSYS
  /* Call the function in mysys library, required for memory instrumentation */
  dest = my_memdup(key_memory_log_event, source, len, MYF(MY_WME));
#else
  dest = malloc(len);
  if (dest) memcpy(dest, source, len);
#endif
  return dest;
}
 
/**
  This is a wrapper function in order to allocate memory from the heap
  in the binlogevent library.
 
  If compiled with the MySQL server, and memory is allocated using memory
  allocating methods from the mysys library, my_malloc is called. Otherwise,
  the standard malloc() is called from the function.
 
  @param size         Size of the memory to be allocated.
  @param flags        flags to pass to MySQL server my_malloc functions
  @return Void pointer to the allocated chunk of memory
*/
inline void *bapi_malloc(size_t size, int flags [[maybe_unused]]) {
  void *dest = nullptr;
#ifdef HAVE_MYSYS
  dest = my_malloc(key_memory_log_event, size, MYF(flags));
#else
  dest = malloc(size);
#endif
  return dest;
}
 
/**
  This is a wrapper function in order to free the memory allocated from the heap
  in the binlogevent library.
 
  If compiled with the MySQL server, and memory is allocated using memory
  allocating methods from the mysys library, my_free is called. Otherwise,
  the standard free() is called from the function.
 
  @param ptr Pointer to the memory which is to be freed.
*/
inline void bapi_free(void *ptr) {
#ifdef HAVE_MYSYS
  return my_free(ptr);
#else
  return free(ptr);
#endif
}
 
}  // namespace mysql::binlog::event
 
#endif  // MYSQL_BINLOG_EVENT_WRAPPER_FUNCTIONS_H