~drizzle-trunk/drizzle/development

/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-

 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:

 *

 *  Copyright (C) 2009 Sun Microsystems

 *

 *  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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

 */

/*

  This class is shared between different table objects. There is one

  instance of table share per one table in the database.

*/

class TableShare

{

public:

  TableShare() 

  {

    init();

  }                    /* Remove gcc warning */

  /** Category of this table. */

  enum_table_category table_category;

  uint32_t open_count;			/* Number of tables in open list */

  /* The following is copied to each Table on OPEN */

  Field **field;

  Field **found_next_number_field;

  Field *timestamp_field;               /* Used only during open */

  KEY  *key_info;			/* data of keys in database */

  uint	*blob_field;			/* Index to blobs in Field arrray*/

  /* hash of field names (contains pointers to elements of field array) */

  HASH	name_hash;			/* hash of field names */

  MEM_ROOT mem_root;

  TYPELIB keynames;			/* Pointers to keynames */

  TYPELIB fieldnames;			/* Pointer to fieldnames */

  TYPELIB *intervals;			/* pointer to interval info */

  pthread_mutex_t mutex;                /* For locking the share  */

  pthread_cond_t cond;			/* To signal that share is ready */

  TableShare *next,		/* Link to unused shares */

    **prev;

  unsigned char	*default_values;		/* row with default values */

  LEX_STRING comment;			/* Comment about table */

  const CHARSET_INFO *table_charset; /* Default charset of string fields */

  MY_BITMAP all_set;

  /*

    Key which is used for looking-up table in table cache and in the list

    of thread's temporary tables. Has the form of:

      "database_name\0table_name\0" + optional part for temporary tables.

    Note that all three 'table_cache_key', 'db' and 'table_name' members

    must be set (and be non-zero) for tables in table cache. They also

    should correspond to each other.

    To ensure this one can use set_table_cache() methods.

  */

  LEX_STRING table_cache_key;

  LEX_STRING db;                        /* Pointer to db */

  LEX_STRING table_name;                /* Table name (for open) */

  LEX_STRING path;	/* Path to .frm file (from datadir) */

  LEX_STRING normalized_path;		/* unpack_filename(path) */

  LEX_STRING connect_string;

  uint32_t   avg_row_length;		/* create information */

  uint32_t   block_size;                   /* create information */

  uint32_t   mysql_version;

  uint32_t   version;

  uint32_t   timestamp_offset;		/* Set to offset+1 of record */

  uint32_t   reclength;			/* Recordlength */

  uint32_t   stored_rec_length;         /* Stored record length*/

  enum row_type row_type;		/* How rows are stored */

  ha_rows min_rows;		/* create information */

  ha_rows max_rows;		/* create information */

  StorageEngine *storage_engine;			/* storage engine plugin */

  inline StorageEngine *db_type() const	/* table_type for handler */

  {

    return storage_engine;

  }

  enum tmp_table_type tmp_table;

  enum ha_choice page_checksum;

  uint32_t ref_count;       /* How many Table objects uses this */

  uint32_t blob_ptr_size;			/* 4 or 8 */

  uint32_t key_block_size;			/* create key_block_size, if used */

  uint32_t null_bytes;

  uint32_t last_null_bit_pos;

  uint32_t fields;				/* Number of fields */

  uint32_t rec_buff_length;                 /* Size of table->record[] buffer */

  uint32_t keys, key_parts;

  uint32_t max_key_length, max_unique_length, total_key_length;

  uint32_t uniques;                         /* Number of UNIQUE index */

  uint32_t null_fields;			/* number of null fields */

  uint32_t blob_fields;			/* number of blob fields */

  uint32_t timestamp_field_offset;		/* Field number for timestamp field */

  uint32_t varchar_fields;                  /* number of varchar fields */

  uint32_t db_create_options;		/* Create options from database */

  uint32_t db_options_in_use;		/* Options in use */

  uint32_t db_record_offset;		/* if HA_REC_IN_SEQ */

  uint32_t rowid_field_offset;		/* Field_nr +1 to rowid field */

  /* Index of auto-updated TIMESTAMP field in field array */

  uint32_t primary_key;

  uint32_t next_number_index;               /* autoincrement key number */

  uint32_t next_number_key_offset;          /* autoinc keypart offset in a key */

  uint32_t next_number_keypart;             /* autoinc keypart number in a key */

  uint32_t error, open_errno, errarg;       /* error from open_table_def() */

  uint32_t column_bitmap_size;

  bool db_low_byte_first;		/* Portable row format */

  bool crashed;

  bool name_lock, replace_with_name_lock;

  bool waiting_on_cond;                 /* Protection against free */

  /*

     Set of keys in use, implemented as a Bitmap.

     Excludes keys disabled by ALTER Table ... DISABLE KEYS.

  */

  key_map keys_in_use;

  key_map keys_for_keyread;

  /*

    Set share's table cache key and update its db and table name appropriately.

    SYNOPSIS

      set_table_cache_key()

        key_buff    Buffer with already built table cache key to be

                    referenced from share.

        key_length  Key length.

    NOTES

      Since 'key_buff' buffer will be referenced from share it should has same

      life-time as share itself.

      This method automatically ensures that TableShare::table_name/db have

      appropriate values by using table cache key as their source.

  */

  void set_table_cache_key(char *key_buff, uint32_t key_length)

  {

    table_cache_key.str= key_buff;

    table_cache_key.length= key_length;

    /*

      Let us use the fact that the key is "db/0/table_name/0" + optional

      part for temporary tables.

    */

    db.str=            table_cache_key.str;

    db.length=         strlen(db.str);

    table_name.str=    db.str + db.length + 1;

    table_name.length= strlen(table_name.str);

  }

  /*

    Set share's table cache key and update its db and table name appropriately.

    SYNOPSIS

      set_table_cache_key()

        key_buff    Buffer to be used as storage for table cache key

                    (should be at least key_length bytes).

        key         Value for table cache key.

        key_length  Key length.

    NOTE

      Since 'key_buff' buffer will be used as storage for table cache key

      it should has same life-time as share itself.

  */

  void set_table_cache_key(char *key_buff, const char *key, uint32_t key_length)

  {

    memcpy(key_buff, key, key_length);

    set_table_cache_key(key_buff, key_length);

  }

  inline bool honor_global_locks()

  {

    return (table_category == TABLE_CATEGORY_USER);

  }

  /*

    Initialize share for temporary tables

    SYNOPSIS

    init()

    share	Share to fill

    key		Table_cache_key, as generated from create_table_def_key.

    must start with db name.

    key_length	Length of key

    table_name	Table name

    path	Path to file (possible in lower case) without .frm

    NOTES

    This is different from alloc_table_share() because temporary tables

    don't have to be shared between threads or put into the table def

    cache, so we can do some things notable simpler and faster

    If table is not put in session->temporary_tables (happens only when

    one uses OPEN TEMPORARY) then one can specify 'db' as key and

    use key_length= 0 as neither table_cache_key or key_length will be used).

  */

  void init()

  {

    init("", 0, "", "");

  }

  void init(const char *new_table_name,

            const char *new_path)

  {

    init("", 0, new_table_name, new_path);

  }

  void init(const char *key,

            uint32_t key_length, const char *new_table_name,

            const char *new_path)

  {

    memset(this, 0, sizeof(TableShare));

    init_sql_alloc(&mem_root, TABLE_ALLOC_BLOCK_SIZE, 0);

    table_category=         TABLE_CATEGORY_TEMPORARY;

    tmp_table=              INTERNAL_TMP_TABLE;

    db.str=                 (char*) key;

    db.length=		 strlen(key);

    table_cache_key.str=    (char*) key;

    table_cache_key.length= key_length;

    table_name.str=         (char*) new_table_name;

    table_name.length=      strlen(new_table_name);

    path.str=               (char*) new_path;

    normalized_path.str=    (char*) new_path;

    path.length= normalized_path.length= strlen(new_path);

    return;

  }

  /*

    Free table share and memory used by it

    SYNOPSIS

    free_table_share()

    share		Table share

    NOTES

    share->mutex must be locked when we come here if it's not a temp table

  */

  void free_table_share()

  {

    MEM_ROOT new_mem_root;

    assert(ref_count == 0);

    /*

      If someone is waiting for this to be deleted, inform it about this.

      Don't do a delete until we know that no one is refering to this anymore.

    */

    if (tmp_table == NO_TMP_TABLE)

    {

      /* share->mutex is locked in release_table_share() */

      while (waiting_on_cond)

      {

        pthread_cond_broadcast(&cond);

        pthread_cond_wait(&cond, &mutex);

      }

      /* No thread refers to this anymore */

      pthread_mutex_unlock(&mutex);

      pthread_mutex_destroy(&mutex);

      pthread_cond_destroy(&cond);

    }

    hash_free(&name_hash);

    storage_engine= NULL;

    /* We must copy mem_root from share because share is allocated through it */

    memcpy(&new_mem_root, &mem_root, sizeof(new_mem_root));

    free_root(&new_mem_root, MYF(0));                 // Free's share

    return;

  }

};