mariadb/sql/sql_trigger.h

#ifndef SQL_TRIGGER_INCLUDED
#define SQL_TRIGGER_INCLUDED

/* Copyright (C) 2004-2005 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 */

/* Forward declarations */

class Item_trigger_field;
class sp_head;
class sp_name;
class Query_tables_list;
struct TABLE_LIST;
class Query_tables_list;

/** Event on which trigger is invoked. */
enum trg_event_type
{
  TRG_EVENT_INSERT= 0,
  TRG_EVENT_UPDATE= 1,
  TRG_EVENT_DELETE= 2,
  TRG_EVENT_MAX
};

#include "table.h"                              /* GRANT_INFO */

/*
  We need this two enums here instead of sql_lex.h because
  at least one of them is used by Item_trigger_field interface.

  Time when trigger is invoked (i.e. before or after row actually
  inserted/updated/deleted).
*/
enum trg_action_time_type
{
  TRG_ACTION_BEFORE= 0, TRG_ACTION_AFTER= 1, TRG_ACTION_MAX
};


/**
  This class holds all information about triggers of table.

  QQ: Will it be merged into TABLE in the future ?
*/

class Table_triggers_list: public Sql_alloc
{
  /** Triggers as SPs grouped by event, action_time */
  sp_head *bodies[TRG_EVENT_MAX][TRG_ACTION_MAX];
  /**
    Heads of the lists linking items for all fields used in triggers
    grouped by event and action_time.
  */
  Item_trigger_field *trigger_fields[TRG_EVENT_MAX][TRG_ACTION_MAX];
  /**
    Copy of TABLE::Field array with field pointers set to TABLE::record[1]
    buffer instead of TABLE::record[0] (used for OLD values in on UPDATE
    trigger and DELETE trigger when it is called for REPLACE).
  */
  Field             **record1_field;
  /**
    During execution of trigger new_field and old_field should point to the
    array of fields representing new or old version of row correspondingly
    (so it can point to TABLE::field or to Tale_triggers_list::record1_field)
  */
  Field             **new_field;
  Field             **old_field;

  /* TABLE instance for which this triggers list object was created */
  TABLE *trigger_table;
  /**
    Names of triggers.
    Should correspond to order of triggers on definitions_list,
    used in CREATE/DROP TRIGGER for looking up trigger by name.
  */
  List<LEX_STRING>  names_list;
  /**
    List of "ON table_name" parts in trigger definitions, used for
    updating trigger definitions during RENAME TABLE.
  */
  List<LEX_STRING>  on_table_names_list;

  /**
    Grant information for each trigger (pair: subject table, trigger definer).
  */
  GRANT_INFO        subject_table_grants[TRG_EVENT_MAX][TRG_ACTION_MAX];

public:
  /**
    Field responsible for storing triggers definitions in file.
    It have to be public because we are using it directly from parser.
  */
  List<LEX_STRING>  definitions_list;
  /**
    List of sql modes for triggers
  */
  List<ulonglong> definition_modes_list;

  List<LEX_STRING>  definers_list;

  /* Character set context, used for parsing and executing triggers. */

  List<LEX_STRING> client_cs_names;
  List<LEX_STRING> connection_cl_names;
  List<LEX_STRING> db_cl_names;

  /* End of character ser context. */

  Table_triggers_list(TABLE *table_arg):
    record1_field(0), trigger_table(table_arg)
  {
    bzero((char *)bodies, sizeof(bodies));
    bzero((char *)trigger_fields, sizeof(trigger_fields));
    bzero((char *)&subject_table_grants, sizeof(subject_table_grants));
  }
  ~Table_triggers_list();

  bool create_trigger(THD *thd, TABLE_LIST *table, String *stmt_query);
  bool drop_trigger(THD *thd, TABLE_LIST *table, String *stmt_query);
  bool process_triggers(THD *thd, trg_event_type event,
                        trg_action_time_type time_type,
                        bool old_row_is_record1);

  bool get_trigger_info(THD *thd, trg_event_type event,
                        trg_action_time_type time_type,
                        LEX_STRING *trigger_name, LEX_STRING *trigger_stmt,
                        ulong *sql_mode,
                        LEX_STRING *definer,
                        LEX_STRING *client_cs_name,
                        LEX_STRING *connection_cl_name,
                        LEX_STRING *db_cl_name);

  void get_trigger_info(THD *thd,
                        int trigger_idx,
                        LEX_STRING *trigger_name,
                        ulonglong *sql_mode,
                        LEX_STRING *sql_original_stmt,
                        LEX_STRING *client_cs_name,
                        LEX_STRING *connection_cl_name,
                        LEX_STRING *db_cl_name);

  int find_trigger_by_name(const LEX_STRING *trigger_name);

  static bool check_n_load(THD *thd, const char *db, const char *table_name,
                           TABLE *table, bool names_only);
  static bool drop_all_triggers(THD *thd, char *db, char *table_name);
  static bool change_table_name(THD *thd, const char *db,
                                const char *old_table,
                                const char *new_db,
                                const char *new_table);
  bool has_triggers(trg_event_type event_type, 
                    trg_action_time_type action_time)
  {
    return (bodies[event_type][action_time] != NULL);
  }
  bool has_delete_triggers()
  {
    return (bodies[TRG_EVENT_DELETE][TRG_ACTION_BEFORE] ||
            bodies[TRG_EVENT_DELETE][TRG_ACTION_AFTER]);
  }

  void set_table(TABLE *new_table);

  void mark_fields_used(trg_event_type event);

  friend class Item_trigger_field;

  bool add_tables_and_routines_for_triggers(THD *thd,
                                            Query_tables_list *prelocking_ctx,
                                            TABLE_LIST *table_list);

private:
  bool prepare_record1_accessors(TABLE *table);
  LEX_STRING* change_table_name_in_trignames(const char *old_db_name,
                                             const char *new_db_name,
                                             LEX_STRING *new_table_name,
                                             LEX_STRING *stopper);
  bool change_table_name_in_triggers(THD *thd,
                                     const char *old_db_name,
                                     const char *new_db_name,
                                     LEX_STRING *old_table_name,
                                     LEX_STRING *new_table_name);
};

extern const LEX_STRING trg_action_time_type_names[];
extern const LEX_STRING trg_event_type_names[];

bool add_table_for_trigger(THD *thd,
                           const sp_name *trg_name,
                           bool continue_if_not_exist,
                           TABLE_LIST **table);

void build_trn_path(THD *thd, const sp_name *trg_name, LEX_STRING *trn_path);

bool check_trn_exists(const LEX_STRING *trn_path);

bool load_table_name_for_trigger(THD *thd,
                                 const sp_name *trg_name,
                                 const LEX_STRING *trn_path,
                                 LEX_STRING *tbl_name);
bool mysql_create_or_drop_trigger(THD *thd, TABLE_LIST *tables, bool create);

extern const char * const TRG_EXT;
extern const char * const TRN_EXT;

#endif /* SQL_TRIGGER_INCLUDED */