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Filename : client_plugin.h
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/* Copyright (C) 2010 - 2012 Sergei Golubchik and Monty Program Ab
                 2014, 2022 MariaDB Corporation AB

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.
   
   This library 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
   Library General Public License for more details.
   
   You should have received a copy of the GNU Library General Public
   License along with this library; if not see <http://www.gnu.org/licenses>
   or write to the Free Software Foundation, Inc., 
   51 Franklin St., Fifth Floor, Boston, MA 02110, USA */

/**
  @file

  MySQL Client Plugin API

  This file defines the API for plugins that work on the client side
*/
#ifndef MYSQL_CLIENT_PLUGIN_INCLUDED
#define MYSQL_CLIENT_PLUGIN_INCLUDED

#ifndef MYSQL_ABI_CHECK
#include <stdarg.h>
#include <stdlib.h>
#endif


#ifndef PLUGINDIR
#define PLUGINDIR "lib/plugin"
#endif

#define plugin_declarations_sym "_mysql_client_plugin_declaration_"

/* known plugin types */
#define MYSQL_CLIENT_PLUGIN_RESERVED         0 
#define MYSQL_CLIENT_PLUGIN_RESERVED2        1
#define MYSQL_CLIENT_AUTHENTICATION_PLUGIN   2 /* authentication   */

#define MYSQL_CLIENT_AUTHENTICATION_PLUGIN_INTERFACE_VERSION  0x0100
#define MYSQL_CLIENT_MAX_PLUGINS             3

/* Connector/C specific plugin types */
#define MARIADB_CLIENT_REMOTEIO_PLUGIN       100 /* communication IO */
#define MARIADB_CLIENT_PVIO_PLUGIN           101
#define MARIADB_CLIENT_TRACE_PLUGIN          102
#define MARIADB_CLIENT_CONNECTION_PLUGIN     103
#define MARIADB_CLIENT_COMPRESSION_PLUGIN    104

#define MARIADB_CLIENT_REMOTEIO_PLUGIN_INTERFACE_VERSION 0x0100
#define MARIADB_CLIENT_PVIO_PLUGIN_INTERFACE_VERSION 0x0100
#define MARIADB_CLIENT_TRACE_PLUGIN_INTERFACE_VERSION 0x0100
#define MARIADB_CLIENT_CONNECTION_PLUGIN_INTERFACE_VERSION 0x0100
#define MARIADB_CLIENT_COMPRESSION_PLUGIN_INTERFACE_VERSION 0x0100

#define MARIADB_CLIENT_MAX_PLUGINS             5

#define mysql_declare_client_plugin(X)          \
     struct st_mysql_client_plugin_ ## X        \
        _mysql_client_plugin_declaration_ = {   \
          MYSQL_CLIENT_ ## X ## _PLUGIN,        \
          MYSQL_CLIENT_ ## X ## _PLUGIN_INTERFACE_VERSION,
#define mysql_end_client_plugin             }

#if defined _WIN32
#  define MARIADB_CLIENT_PLUGIN_EXPORT __declspec(dllexport)
#elif defined(__GNUC__) || defined(__clang__)
#  define MARIADB_CLIENT_PLUGIN_EXPORT __attribute__((visibility("default")))
#else
#  define MARIADB_CLIENT_PLUGIN_EXPORT
#endif

/* generic plugin header structure */
#ifndef MYSQL_CLIENT_PLUGIN_HEADER
#define MYSQL_CLIENT_PLUGIN_HEADER                      \
  int type;                                             \
  unsigned int interface_version;                       \
  const char *name;                                     \
  const char *author;                                   \
  const char *desc;                                     \
  unsigned int version[3];                              \
  const char *license;                                  \
  void *mysql_api;                                      \
  int (*init)(char *, size_t, int, va_list);            \
  int (*deinit)(void);                                  \
  int (*options)(const char *option, const void *);

struct st_mysql_client_plugin
{
  MYSQL_CLIENT_PLUGIN_HEADER
};
#endif

struct st_mysql;

/********* connection handler plugin specific declarations **********/

typedef struct st_ma_connection_plugin
{
  MYSQL_CLIENT_PLUGIN_HEADER
  /* functions */
  MYSQL *(*connect)(MYSQL *mysql, const char *host,
                    const char *user, const char *passwd,
		                const char *db, unsigned int port,
                    const char *unix_socket, unsigned long clientflag);
  void (*close)(MYSQL *mysql);
  int (*set_optionsv)(MYSQL *mysql, unsigned int option, ...);
  int (*set_connection)(MYSQL *mysql,enum enum_server_command command,
                        const char *arg,
                        size_t length, my_bool skipp_check, void *opt_arg);
  my_bool (*reconnect)(MYSQL *mysql);
  int (*reset)(MYSQL *mysql);
} MARIADB_CONNECTION_PLUGIN;

#define MARIADB_DB_DRIVER(a) ((a)->ext_db)

/*******************  Communication IO plugin *****************/
#include <ma_pvio.h>

typedef struct st_mariadb_client_plugin_PVIO
{
  MYSQL_CLIENT_PLUGIN_HEADER
  struct st_ma_pvio_methods *methods;
} MARIADB_PVIO_PLUGIN;

/******** authentication plugin specific declarations *********/
#include <mysql/plugin_auth.h>

struct st_mysql_client_plugin_AUTHENTICATION
{
  MYSQL_CLIENT_PLUGIN_HEADER
  int (*authenticate_user)(MYSQL_PLUGIN_VIO *vio, struct st_mysql *mysql);
};

/******** trace plugin *******/
struct st_mysql_client_plugin_TRACE
{
  MYSQL_CLIENT_PLUGIN_HEADER
};

#include <ma_compress.h>

typedef struct st_mariadb_client_plugin_COMPRESS
{
  MYSQL_CLIENT_PLUGIN_HEADER
  ma_compress_ctx *(*init_ctx)(int compression_level);
  void (*free_ctx)(ma_compress_ctx *ctx);
  my_bool (*compress)(ma_compress_ctx *ctx, void *dst, size_t *dst_len, void *source, size_t source_len);
  my_bool (*decompress)(ma_compress_ctx *ctx, void *dst, size_t *dst_len, void *source, size_t *source_len);
} MARIADB_COMPRESSION_PLUGIN;

/**
  type of the mysql_authentication_dialog_ask function

  @param mysql          mysql
  @param type           type of the input
                        1 - ordinary string input
                        2 - password string
  @param prompt         prompt
  @param buf            a buffer to store the use input
  @param buf_len        the length of the buffer

  @retval               a pointer to the user input string.
                        It may be equal to 'buf' or to 'mysql->password'.
                        In all other cases it is assumed to be an allocated
                        string, and the "dialog" plugin will free() it.
*/
typedef char *(*mysql_authentication_dialog_ask_t)(struct st_mysql *mysql,
                      int type, const char *prompt, char *buf, int buf_len);

/********************** remote IO plugin **********************/
#ifdef HAVE_REMOTEIO
#include <mariadb/ma_io.h>

/* Remote IO plugin */
typedef struct st_mysql_client_plugin_REMOTEIO
{
  MYSQL_CLIENT_PLUGIN_HEADER
  struct st_rio_methods *methods;
} MARIADB_REMOTEIO_PLUGIN;
#endif

/******** using plugins ************/

/**
  loads a plugin and initializes it

  @param mysql  MYSQL structure. only MYSQL_PLUGIN_DIR option value is used,
                and last_errno/last_error, for error reporting
  @param name   a name of the plugin to load
  @param type   type of plugin that should be loaded, -1 to disable type check
  @param argc   number of arguments to pass to the plugin initialization
                function
  @param ...    arguments for the plugin initialization function

  @retval
  a pointer to the loaded plugin, or NULL in case of a failure
*/
struct st_mysql_client_plugin *
mysql_load_plugin(struct st_mysql *mysql, const char *name, int type,
                  int argc, ...);

/**
  loads a plugin and initializes it, taking va_list as an argument

  This is the same as mysql_load_plugin, but take va_list instead of
  a list of arguments.

  @param mysql  MYSQL structure. only MYSQL_PLUGIN_DIR option value is used,
                and last_errno/last_error, for error reporting
  @param name   a name of the plugin to load
  @param type   type of plugin that should be loaded, -1 to disable type check
  @param argc   number of arguments to pass to the plugin initialization
                function
  @param args   arguments for the plugin initialization function

  @retval
  a pointer to the loaded plugin, or NULL in case of a failure
*/
struct st_mysql_client_plugin * STDCALL
mysql_load_plugin_v(struct st_mysql *mysql, const char *name, int type,
                    int argc, va_list args);

/**
  finds an already loaded plugin by name, or loads it, if necessary

  @param mysql  MYSQL structure. only MYSQL_PLUGIN_DIR option value is used,
                and last_errno/last_error, for error reporting
  @param name   a name of the plugin to load
  @param type   type of plugin that should be loaded

  @retval
  a pointer to the plugin, or NULL in case of a failure
*/
struct st_mysql_client_plugin * STDCALL
mysql_client_find_plugin(struct st_mysql *mysql, const char *name, int type);

/**
  adds a plugin structure to the list of loaded plugins

  This is useful if an application has the necessary functionality
  (for example, a special load data handler) statically linked into
  the application binary. It can use this function to register the plugin
  directly, avoiding the need to factor it out into a shared object.

  @param mysql  MYSQL structure. It is only used for error reporting
  @param plugin an st_mysql_client_plugin structure to register

  @retval
  a pointer to the plugin, or NULL in case of a failure
*/
struct st_mysql_client_plugin * STDCALL
mysql_client_register_plugin(struct st_mysql *mysql,
                             struct st_mysql_client_plugin *plugin);

extern struct st_mysql_client_plugin *mysql_client_builtins[];

#endif