heap.h

/*
   Copyright (c) 2000, 2024, 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
*/

/* This file should be included when using heap_database_functions */
/* Author: Michael Widenius */

/**
  @file include/heap.h
*/

#ifndef _heap_h
#define _heap_h

#ifndef _my_base_h
#include "my_base.h"
#endif

#include <sys/types.h>
#include <time.h>

#include "my_compare.h"
#include "my_inttypes.h"
#include "my_list.h"
#include "my_tree.h"
#include "thr_lock.h"

/* defines used by heap-funktions */

#define HP_MAX_LEVELS 4 /* 128^5 records is enough */
#define HP_PTRS_IN_NOD 128

/* struct used with heap_funktions */

struct HEAPINFO /* Struct from heap_info */
{
  ulong records; /* Records in database */
  ulong deleted; /* Deleted records in database */
  ulong max_records;
  ulonglong data_length;
  ulonglong index_length;
  uint reclength; /* Length of one record */
  int errkey;
  ulonglong auto_increment;
  time_t create_time;
};

/* Structs used by heap-database-handler */

struct HP_PTRS {
  uchar *blocks[HP_PTRS_IN_NOD]; /* pointers to HP_PTRS or records */
};

struct st_level_info {
  /* Number of unused slots in *last_blocks HP_PTRS block (0 for 0th level) */
  uint free_ptrs_in_block{0};

  /*
    Maximum number of records that can be 'contained' inside of each element
    of last_blocks array. For level 0 - 1, for level 1 - HP_PTRS_IN_NOD, for
    level 2 - HP_PTRS_IN_NOD^2 and so forth.
  */
  ulong records_under_level{0};

  /*
    Ptr to last allocated HP_PTRS (or records buffer for level 0) on this
    level.
  */
  HP_PTRS *last_blocks{nullptr};
};

/*
  Heap table records and hash index entries are stored in HP_BLOCKs.
  HP_BLOCK is used as a 'growable array' of fixed-size records. Size of record
  is recbuffer bytes.
  The internal representation is as follows:
  HP_BLOCK is a hierarchical structure of 'blocks'.
  A block at level 0 is an array records_in_block records.
  A block at higher level is an HP_PTRS structure with pointers to blocks at
  lower levels.
  At the highest level there is one top block. It is stored in HP_BLOCK::root.

  See hp_find_block for a description of how record pointer is obtained from
  its index.
  See hp_get_new_block
*/

struct HP_BLOCK {
  HP_PTRS *root{nullptr}; /* Top-level block */
  struct st_level_info level_info[HP_MAX_LEVELS + 1];
  uint levels{0};           /* number of used levels */
  uint records_in_block{0}; /* Records in one heap-block */
  uint recbuffer{0};        /* Length of one saved record */
  ulong last_allocated{0};  /* number of records there is allocated space for */
};

struct HP_INFO; /* For reference */

struct HP_KEYDEF /* Key definition with open */
{
  uint flag{0};       /* HA_NOSAME | HA_NULL_PART_KEY */
  uint keysegs{0};    /* Number of key-segment */
  uint length{0};     /* Length of key (automatic) */
  uint8 algorithm{0}; /* HASH / BTREE */
  HA_KEYSEG *seg{nullptr};
  HP_BLOCK block; /* Where keys are saved */
  /*
    Number of buckets used in hash table. Used only to provide
    #records estimates for heap key scans.
  */
  ha_rows hash_buckets{0};
  TREE rb_tree;
  int (*write_key)(HP_INFO *info, HP_KEYDEF *keyinfo, const uchar *record,
                   uchar *recpos){nullptr};
  int (*delete_key)(HP_INFO *info, HP_KEYDEF *keyinfo, const uchar *record,
                    uchar *recpos, int flag){nullptr};
  uint (*get_key_length)(HP_KEYDEF *keydef, const uchar *key){nullptr};
};

struct HP_SHARE {
  HP_BLOCK block;
  HP_KEYDEF *keydef;
  ulong min_records, max_records; /* Params to open */
  ulonglong data_length, index_length, max_table_size;
  uint key_stat_version; /* version to indicate insert/delete */
  uint records;          /* records */
  uint blength;          /* records rounded up to 2^n */
  uint deleted;          /* Deleted records in database */
  uint reclength;        /* Length of one record */
  uint changed;
  uint keys, max_key_length;
  uint currently_disabled_keys; /* saved value from "keys" when disabled */
  uint open_count;
  uchar *del_link; /* Link to next block with del. rec */
  char *name;      /* Name of "memory-file" */
  time_t create_time;
  THR_LOCK lock;
  bool delete_on_close;
  LIST open_list;
  uint auto_key;
  uint auto_key_type; /* real type of the auto key segment */
  ulonglong auto_increment;
};

struct HASH_INFO;

struct HP_INFO {
  HP_SHARE *s;
  uchar *current_ptr;
  HASH_INFO *current_hash_ptr;
  ulong current_record, next_block;
  int lastinx, errkey;
  int mode; /* Mode of file (READONLY..) */
  uint opt_flag, update;
  uchar *lastkey; /* Last used key with rkey */
  uchar *recbuf;  /* Record buffer for rb-tree keys */
  enum ha_rkey_function last_find_flag;
  TREE_ELEMENT *parents[MAX_TREE_HEIGHT + 1];
  TREE_ELEMENT **last_pos;
  uint lastkey_len;
  bool implicit_emptied;
  THR_LOCK_DATA lock;
  LIST open_list;
};

typedef uchar *HEAP_PTR;

struct HP_HEAP_POSITION {
  HEAP_PTR ptr{nullptr};
  ulong record_no{0}; /* Number of current record in table scan order (starting
                      at 0) */
};

struct HP_CREATE_INFO {
  HP_KEYDEF *keydef;
  ulong max_records;
  ulong min_records;
  uint auto_key; /* keynr [1 - maxkey] for auto key */
  uint auto_key_type;
  uint keys;
  uint reclength;
  ulonglong max_table_size;
  ulonglong auto_increment;
  bool with_auto_increment;
  bool single_instance;
  bool delete_on_close;
  /*
    TRUE if heap_create should 'pin' the created share by setting
    open_count to 1. Is only looked at if not internal_table.
  */
  bool pin_share;
};

/* Prototypes for heap-functions */

extern HP_INFO *heap_open(const char *name, int mode);
extern HP_INFO *heap_open_from_share(HP_SHARE *share, int mode);
extern HP_INFO *heap_open_from_share_and_register(HP_SHARE *share, int mode);
extern void heap_release_share(HP_SHARE *share, bool single_instance);
extern int heap_close(HP_INFO *info);
extern int heap_write(HP_INFO *info, const uchar *buff);
extern int heap_update(HP_INFO *info, const uchar *old, const uchar *newdata);
extern int heap_rrnd(HP_INFO *info, uchar *buf, HP_HEAP_POSITION *pos);
extern int heap_scan_init(HP_INFO *info);
extern int heap_scan(HP_INFO *info, uchar *record);
extern int heap_delete(HP_INFO *info, const uchar *buff);
extern int heap_info(HP_INFO *info, HEAPINFO *x, int flag);
extern int heap_create(const char *name, HP_CREATE_INFO *create_info,
                       HP_SHARE **share, bool *created_new_share);
extern int heap_delete_table(const char *name);
extern void heap_drop_table(HP_INFO *info);
extern int heap_extra(HP_INFO *info, enum ha_extra_function function);
extern int heap_reset(HP_INFO *info);
extern int heap_rename(const char *old_name, const char *new_name);
extern int heap_panic(enum ha_panic_function flag);
extern int heap_rsame(HP_INFO *info, uchar *record, int inx);
extern int heap_rnext(HP_INFO *info, uchar *record);
extern int heap_rprev(HP_INFO *info, uchar *record);
extern int heap_rfirst(HP_INFO *info, uchar *record, int inx);
extern int heap_rlast(HP_INFO *info, uchar *record, int inx);
extern void heap_clear(HP_INFO *info);
extern void heap_clear_keys(HP_INFO *info);
extern int heap_disable_indexes(HP_INFO *info);
extern int heap_enable_indexes(HP_INFO *info);
extern int heap_indexes_are_disabled(HP_INFO *info);
extern void heap_update_auto_increment(HP_INFO *info, const uchar *record);
ha_rows hp_rb_records_in_range(HP_INFO *info, int inx, key_range *min_key,
                               key_range *max_key);
int hp_panic(enum ha_panic_function flag);
int heap_rkey(HP_INFO *info, uchar *record, int inx, const uchar *key,
              key_part_map keypart_map, enum ha_rkey_function find_flag);
extern uchar *heap_find(HP_INFO *info, int inx, const uchar *key);
extern int heap_check_heap(HP_INFO *info, bool print_status);
extern void heap_position(HP_INFO *info, HP_HEAP_POSITION *pos);

#endif