mariadb/sql/examples/ha_example.h

/* Copyright (C) 2003 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; either version 2 of the License, or
  (at your option) any later version.

  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 */

/* 
  Please read ha_exmple.cc before reading this file.
  Please keep in mind that the example storage engine implements all methods
  that are required to be implemented. handler.h has a full list of methods
  that you can implement.
*/

#ifdef __GNUC__
#pragma interface			/* gcc class implementation */
#endif

/*
  EXAMPLE_SHARE is a structure that will be shared amoung all open handlers
  The example implements the minimum of what you will probably need.
*/
typedef struct st_example_share {
  char *table_name;
  uint table_name_length,use_count;
  pthread_mutex_t mutex;
  THR_LOCK lock;
} EXAMPLE_SHARE;

/*
  Class definition for the storage engine
*/
class ha_example: public handler
{
  THR_LOCK_DATA lock;      /* MySQL lock */
  EXAMPLE_SHARE *share;    /* Shared lock info */

public:
  ha_example(TABLE *table): handler(table)
  {
  }
  ~ha_example() 
  {
  }
  /* The name that will be used for display purposes */
  const char *table_type() const { return "EXAMPLE"; } 
  /* The name of the index type that will be used for display */
  const char *index_type(uint inx) { return "NONE"; }
  const char **bas_ext() const;
  /* 
    This is a list of flags that says what the storage engine 
    implements. The current table flags are documented in
    table_flags.
  */
  ulong table_flags() const
  {
    return 0;
  }
  /* 
    This is a list of flags that says how the storage engine 
    implements indexes. The current index flags are documented in
    handler.h. If you do not implement indexes, just return zero 
    here.
  */
  ulong index_flags(uint inx) const
  {
    return 0;
  }
  /* 
    unireg.cc will call the following to make sure that the storage engine can
    handle the data it is about to send.
  */
  uint max_record_length() const { return HA_MAX_REC_LENGTH; }
  uint max_keys()          const { return 0; }
  uint max_key_parts()     const { return 0; }
  uint max_key_length()    const { return 0; }
  /*
    Called in test_quick_select to determine if indexes should be used.
  */
  virtual double scan_time() { return (double) (records+deleted) / 20.0+10; }
  /* 
    The next method will never be called if you do not implement indexes.
  */
  virtual double read_time(ha_rows rows) { return (double) rows /  20.0+1; }

  /* 
    Everything below are methods that we implment in ha_example.cc.
  */
  int open(const char *name, int mode, uint test_if_locked);
  int close(void);
  int write_row(byte * buf);
  int update_row(const byte * old_data, byte * new_data);
  int delete_row(const byte * buf);
  int index_read(byte * buf, const byte * key,
                 uint key_len, enum ha_rkey_function find_flag);
  int index_read_idx(byte * buf, uint idx, const byte * key,
                     uint key_len, enum ha_rkey_function find_flag);
  int index_next(byte * buf);
  int index_prev(byte * buf);
  int index_first(byte * buf);
  int index_last(byte * buf);
  int rnd_init(bool scan=1);
  int rnd_next(byte *buf);
  int rnd_pos(byte * buf, byte *pos);
  void position(const byte *record);
  void info(uint);
  int extra(enum ha_extra_function operation);
  int reset(void);
  int external_lock(THD *thd, int lock_type);
  int delete_all_rows(void);
  ha_rows records_in_range(uint inx, key_range *min_key,
                           key_range *max_key);
  int delete_table(const char *from);
  int rename_table(const char * from, const char * to);
  int create(const char *name, TABLE *form, HA_CREATE_INFO *create_info);

  THR_LOCK_DATA **store_lock(THD *thd, THR_LOCK_DATA **to,
                             enum thr_lock_type lock_type);
};