/* Copyright (C) 2005 MySQL AB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   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 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#ifndef _sql_plugin_h
#define _sql_plugin_h

class sys_var;
enum SHOW_COMP_OPTION { SHOW_OPTION_YES, SHOW_OPTION_NO, SHOW_OPTION_DISABLED};

#include <my_sys.h>

#ifdef DBUG_OFF
#define plugin_ref_to_int(A) A
#define plugin_int_to_ref(A) A
#else
#define plugin_ref_to_int(A) (A ? A[0] : NULL)
#define plugin_int_to_ref(A) &(A)
#endif

/*
  the following flags are valid for plugin_init()
*/
#define PLUGIN_INIT_SKIP_DYNAMIC_LOADING 1
#define PLUGIN_INIT_SKIP_PLUGIN_TABLE    2
#define PLUGIN_INIT_SKIP_INITIALIZATION  4

#define INITIAL_LEX_PLUGIN_LIST_SIZE    16

typedef enum enum_mysql_show_type SHOW_TYPE;
typedef struct st_mysql_show_var SHOW_VAR;
typedef struct st_mysql_lex_string LEX_STRING;

#define MYSQL_ANY_PLUGIN         -1

/*
  different values of st_plugin_int::state
  though they look like a bitmap, plugin may only
  be in one of those eigenstates, not in a superposition of them :)
  It's a bitmap, because it makes it easier to test
  "whether the state is one of those..."
*/
#define PLUGIN_IS_FREED         1
#define PLUGIN_IS_DELETED       2
#define PLUGIN_IS_UNINITIALIZED 4
#define PLUGIN_IS_READY         8
#define PLUGIN_IS_DYING         16
#define PLUGIN_IS_DISABLED      32

/* A handle for the dynamic library containing a plugin or plugins. */

struct st_plugin_dl
{
  LEX_STRING dl;
  void *handle;
  struct st_mysql_plugin *plugins;
  int version;
  uint ref_count;            /* number of plugins loaded from the library */
};

/* A handle of a plugin */

struct st_plugin_int
{
  LEX_STRING name;
  struct st_mysql_plugin *plugin;
  struct st_plugin_dl *plugin_dl;
  uint state;
  uint ref_count;               /* number of threads using the plugin */
  void *data;                   /* plugin type specific, e.g. handlerton */
  MEM_ROOT mem_root;            /* memory for dynamic plugin structures */
  sys_var *system_vars;         /* server variables for this plugin */
  bool is_mandatory;            /* If true then plugin must not fail to load */
};


/*
  See intern_plugin_lock() for the explanation for the
  conditionally defined plugin_ref type
*/
#ifdef DBUG_OFF
typedef struct st_plugin_int *plugin_ref;
#define plugin_decl(pi) ((pi)->plugin)
#define plugin_dlib(pi) ((pi)->plugin_dl)
#define plugin_data(pi,cast) ((cast)((pi)->data))
#define plugin_name(pi) (&((pi)->name))
#define plugin_state(pi) ((pi)->state)
#define plugin_equals(p1,p2) ((p1) == (p2))
#else
typedef struct st_plugin_int **plugin_ref;
#define plugin_decl(pi) ((pi)[0]->plugin)
#define plugin_dlib(pi) ((pi)[0]->plugin_dl)
#define plugin_data(pi,cast) ((cast)((pi)[0]->data))
#define plugin_name(pi) (&((pi)[0]->name))
#define plugin_state(pi) ((pi)[0]->state)
#define plugin_equals(p1,p2) ((p1) && (p2) && (p1)[0] == (p2)[0])
#endif

typedef int (*plugin_type_init)(struct st_plugin_int *);

extern char *opt_plugin_load;
extern char *opt_plugin_dir_ptr;
extern char opt_plugin_dir[FN_REFLEN];
extern const LEX_STRING plugin_type_names[];

extern int plugin_init(int *argc, char **argv, int init_flags);
extern void plugin_shutdown(void);
void add_plugin_options(DYNAMIC_ARRAY *options, MEM_ROOT *mem_root);
extern bool plugin_is_ready(const LEX_STRING *name, int type);
#define my_plugin_lock_by_name(A,B,C) plugin_lock_by_name(A,B,C CALLER_INFO)
#define my_plugin_lock_by_name_ci(A,B,C) plugin_lock_by_name(A,B,C ORIG_CALLER_INFO)
#define my_plugin_lock(A,B) plugin_lock(A,B CALLER_INFO)
#define my_plugin_lock_ci(A,B) plugin_lock(A,B ORIG_CALLER_INFO)
extern plugin_ref plugin_lock(THD *thd, plugin_ref *ptr CALLER_INFO_PROTO);
extern plugin_ref plugin_lock_by_name(THD *thd, const LEX_STRING *name,
                                      int type CALLER_INFO_PROTO);
extern void plugin_unlock(THD *thd, plugin_ref plugin);
extern void plugin_unlock_list(THD *thd, plugin_ref *list, uint count);
extern bool mysql_install_plugin(THD *thd, const LEX_STRING *name,
                                 const LEX_STRING *dl);
extern bool mysql_uninstall_plugin(THD *thd, const LEX_STRING *name);
extern bool plugin_register_builtin(struct st_mysql_plugin *plugin);
extern void plugin_thdvar_init(THD *thd);
extern void plugin_thdvar_cleanup(THD *thd);
extern SHOW_COMP_OPTION plugin_status(const char *name, int len, size_t type);

typedef my_bool (plugin_foreach_func)(THD *thd,
                                      plugin_ref plugin,
                                      void *arg);
#define plugin_foreach(A,B,C,D) plugin_foreach_with_mask(A,B,C,PLUGIN_IS_READY,D)
extern bool plugin_foreach_with_mask(THD *thd, plugin_foreach_func *func,
                                     int type, uint state_mask, void *arg);
#endif