mariadb/sql/sql_class.h

/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult 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 */


/* Classes in mysql */

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

// TODO: create log.h and move all the log header stuff there

class Query_log_event;
class Load_log_event;
class Slave_log_event;
class sp_rcontext;

enum enum_enable_or_disable { LEAVE_AS_IS, ENABLE, DISABLE };
enum enum_ha_read_modes { RFIRST, RNEXT, RPREV, RLAST, RKEY };
enum enum_duplicates { DUP_ERROR, DUP_REPLACE, DUP_IGNORE, DUP_UPDATE };
enum enum_log_type { LOG_CLOSED, LOG_NORMAL, LOG_NEW, LOG_BIN };
enum enum_delay_key_write { DELAY_KEY_WRITE_NONE, DELAY_KEY_WRITE_ON,
			    DELAY_KEY_WRITE_ALL };

// log info errors
#define LOG_INFO_EOF -1
#define LOG_INFO_IO  -2
#define LOG_INFO_INVALID -3
#define LOG_INFO_SEEK -4
#define LOG_INFO_PURGE_NO_ROTATE -5
#define LOG_INFO_MEM -6
#define LOG_INFO_FATAL -7
#define LOG_INFO_IN_USE -8

struct st_relay_log_info;

typedef struct st_log_info
{
  char log_file_name[FN_REFLEN];
  my_off_t index_file_offset, index_file_start_offset;
  my_off_t pos;
  bool fatal; // if the purge happens to give us a negative offset
  pthread_mutex_t lock;
  st_log_info():fatal(0) { pthread_mutex_init(&lock, MY_MUTEX_INIT_FAST);}
  ~st_log_info() { pthread_mutex_destroy(&lock);}
} LOG_INFO;

typedef struct st_user_var_events
{
  user_var_entry *user_var_event;
  char *value;
  ulong length;
  Item_result type;
  uint charset_number;
} BINLOG_USER_VAR_EVENT;

class Log_event;

class MYSQL_LOG {
 private:
  pthread_mutex_t LOCK_log, LOCK_index;
  pthread_cond_t update_cond;
  ulonglong bytes_written;
  time_t last_time,query_start;
  IO_CACHE log_file;
  IO_CACHE index_file;
  char *name;
  char time_buff[20],db[NAME_LEN+1];
  char log_file_name[FN_REFLEN],index_file_name[FN_REFLEN];
  // current file sequence number for load data infile binary logging
  uint file_id;
  uint open_count;				// For replication
  volatile enum_log_type log_type;
  enum cache_type io_cache_type;
  bool write_error,inited;
  /*
    For binlog - if log name can never change we should not try to rotate it
    or write any rotation events. The user should use FLUSH MASTER instead
    of FLUSH LOGS for purging.
  */
  bool no_rotate;
  bool need_start_event;
  bool no_auto_events; // for relay binlog
  friend class Log_event;

public:
  MYSQL_LOG();
  ~MYSQL_LOG();
  void reset_bytes_written()
  {
    bytes_written = 0;
  }
  void harvest_bytes_written(ulonglong* counter)
  {
#ifndef DBUG_OFF
    char buf1[22],buf2[22];
#endif	
    DBUG_ENTER("harvest_bytes_written");
    (*counter)+=bytes_written;
    DBUG_PRINT("info",("counter: %s  bytes_written: %s", llstr(*counter,buf1),
		       llstr(bytes_written,buf2)));
    bytes_written=0;
    DBUG_VOID_RETURN;
  }
  void signal_update() { pthread_cond_broadcast(&update_cond);}
  void wait_for_update(THD* thd);
  void set_need_start_event() { need_start_event = 1; }
  void init(enum_log_type log_type_arg,
	    enum cache_type io_cache_type_arg = WRITE_CACHE,
	    bool no_auto_events_arg = 0);
  void cleanup();
  bool open(const char *log_name,enum_log_type log_type,
	    const char *new_name, const char *index_file_name_arg,
	    enum cache_type io_cache_type_arg,
	    bool no_auto_events_arg);
  void new_file(bool need_lock= 1);
  bool write(THD *thd, enum enum_server_command command,
	     const char *format,...);
  bool write(THD *thd, const char *query, uint query_length,
	     time_t query_start=0);
  bool write(Log_event* event_info); // binary log write
  bool write(THD *thd, IO_CACHE *cache);

  /*
    v stands for vector
    invoked as appendv(buf1,len1,buf2,len2,...,bufn,lenn,0)
  */
  bool appendv(const char* buf,uint len,...);
  bool append(Log_event* ev);
  
  int generate_new_name(char *new_name,const char *old_name);
  void make_log_name(char* buf, const char* log_ident);
  bool is_active(const char* log_file_name);
  int update_log_index(LOG_INFO* linfo);
  int purge_logs(THD* thd, const char* to_log);
  int purge_logs_before_date(THD* thd, time_t purge_time);
  int purge_first_log(struct st_relay_log_info* rli); 
  bool reset_logs(THD* thd);
  // if we are exiting, we also want to close the index file
  void close(bool exiting = 0);

  // iterating through the log index file
  int find_log_pos(LOG_INFO* linfo, const char* log_name,
		   bool need_mutex);
  int find_next_log(LOG_INFO* linfo, bool need_mutex);
  int get_current_log(LOG_INFO* linfo);
  uint next_file_id();

  inline bool is_open() { return log_type != LOG_CLOSED; }
  inline char* get_index_fname() { return index_file_name;}
  inline char* get_log_fname() { return log_file_name; }
  inline pthread_mutex_t* get_log_lock() { return &LOCK_log; }
  inline IO_CACHE* get_log_file() { return &log_file; }

  inline void lock_index() { pthread_mutex_lock(&LOCK_index);}
  inline void unlock_index() { pthread_mutex_unlock(&LOCK_index);}
  inline IO_CACHE *get_index_file() { return &index_file;}
  inline uint32 get_open_count() { return open_count; }
};

/* character conversion tables */

class CONVERT;
CONVERT *get_convert_set(const char *name_ptr);

class CONVERT
{
  const uchar *from_map,*to_map;
  void convert_array(const uchar *mapping,uchar *buff,uint length);
public:
  const char *name;
  uint numb;
  CONVERT(const char *name_par,uchar *from_par,uchar *to_par, uint number)
    :from_map(from_par),to_map(to_par),name(name_par),numb(number) {}
  friend CONVERT *get_convert_set(const char *name_ptr);
  inline void convert(char *a,uint length)
  {
    convert_array(from_map, (uchar*) a,length);
  }
  char *store_dest(char *to, const char *from, uint length)
  {
    for (const char *end=from+length ; from != end ; from++)
      *to++= to_map[(uchar) *from];
    return to;
  }
  bool store(String *, const char *,uint);
  inline uint number() { return numb; }
};

typedef struct st_copy_info {
  ha_rows records;
  ha_rows deleted;
  ha_rows copied;
  ha_rows error_count;
  enum enum_duplicates handle_duplicates;
  int escape_char, last_errno;
/* for INSERT ... UPDATE */
  List<Item> *update_fields;
  List<Item> *update_values;
} COPY_INFO;


class key_part_spec :public Sql_alloc {
public:
  const char *field_name;
  uint length;
  key_part_spec(const char *name,uint len=0) :field_name(name), length(len) {}
};


class Alter_drop :public Sql_alloc {
public:
  enum drop_type {KEY, COLUMN };
  const char *name;
  enum drop_type type;
  Alter_drop(enum drop_type par_type,const char *par_name)
    :name(par_name), type(par_type) {}
};


class Alter_column :public Sql_alloc {
public:
  const char *name;
  Item *def;
  Alter_column(const char *par_name,Item *literal)
    :name(par_name), def(literal) {}
};


class Key :public Sql_alloc {
public:
  enum Keytype { PRIMARY, UNIQUE, MULTIPLE, FULLTEXT, SPATIAL, FOREIGN_KEY};
  enum Keytype type;
  enum ha_key_alg algorithm;
  List<key_part_spec> columns;
  const char *name;

  Key(enum Keytype type_par, const char *name_arg, enum ha_key_alg alg_par,
      List<key_part_spec> &cols)
    :type(type_par), algorithm(alg_par), columns(cols), name(name_arg)
  {}
  ~Key() {}
};

class Table_ident;

class foreign_key: public Key {
public:
  enum fk_match_opt { FK_MATCH_UNDEF, FK_MATCH_FULL,
		      FK_MATCH_PARTIAL, FK_MATCH_SIMPLE};
  enum fk_option { FK_OPTION_UNDEF, FK_OPTION_RESTRICT, FK_OPTION_CASCADE,
		   FK_OPTION_SET_NULL, FK_OPTION_NO_ACTION, FK_OPTION_DEFAULT};

  Table_ident *ref_table;
  List<key_part_spec> ref_columns;
  uint delete_opt, update_opt, match_opt;
  foreign_key(const char *name_arg, List<key_part_spec> &cols,
	      Table_ident *table,   List<key_part_spec> &ref_cols,
	      uint delete_opt_arg, uint update_opt_arg, uint match_opt_arg)
    :Key(FOREIGN_KEY, name_arg, HA_KEY_ALG_UNDEF, cols),
    ref_table(table), ref_columns(cols),
    delete_opt(delete_opt_arg), update_opt(update_opt_arg),
    match_opt(match_opt_arg)
  {}
};

typedef struct st_mysql_lock
{
  TABLE **table;
  uint table_count,lock_count;
  THR_LOCK_DATA **locks;
} MYSQL_LOCK;


class LEX_COLUMN : public Sql_alloc
{
public:
  String column;
  uint rights;
  LEX_COLUMN (const String& x,const  uint& y ): column (x),rights (y) {}
};

#include "sql_lex.h"				/* Must be here */

/* Needed to be able to have an I_List of char* strings in mysqld.cc. */

class i_string: public ilink
{
public:
  char* ptr;
  i_string():ptr(0) { }
  i_string(char* s) : ptr(s) {}
};

/* needed for linked list of two strings for replicate-rewrite-db */
class i_string_pair: public ilink
{
public:
  char* key;
  char* val;
  i_string_pair():key(0),val(0) { }
  i_string_pair(char* key_arg, char* val_arg) : key(key_arg),val(val_arg) {}
};


class MYSQL_ERROR: public Sql_alloc
{
public:
  enum enum_warning_level
  { WARN_LEVEL_NOTE, WARN_LEVEL_WARN, WARN_LEVEL_ERROR, WARN_LEVEL_END};

  uint code;
  enum_warning_level level;
  char *msg;
  
  MYSQL_ERROR(uint code_arg, enum_warning_level level_arg,
	      const char *msg_arg)
    :code(code_arg), level(level_arg)
  {
    msg=sql_strdup(msg_arg);
  }
};


/* This is a struct as it's allocated in tree_insert */

typedef struct st_prep_stmt
{
  THD *thd;
  LEX  lex; 
  Item_param **param;
  Item *free_list;
  MEM_ROOT mem_root;
  ulong stmt_id;
  uint param_count;
  uint last_errno;
  char last_error[MYSQL_ERRMSG_SIZE];
  bool error_in_prepare, long_data_used;
} PREP_STMT;


class delayed_insert;
class select_result;

#define THD_SENTRY_MAGIC 0xfeedd1ff
#define THD_SENTRY_GONE  0xdeadbeef

#define THD_CHECK_SENTRY(thd) DBUG_ASSERT(thd->dbug_sentry == THD_SENTRY_MAGIC)

struct system_variables
{
  ulonglong myisam_max_extra_sort_file_size;
  ulonglong myisam_max_sort_file_size;
  ha_rows select_limit;
  ha_rows max_join_size;
  ulong bulk_insert_buff_size;
  ulong join_buff_size;
  ulong long_query_time;
  ulong max_allowed_packet;
  ulong max_error_count;
  ulong max_heap_table_size;
  ulong max_prep_stmt_count;
  ulong max_sort_length;
  ulong max_tmp_tables;
  ulong myisam_sort_buff_size;
  ulong net_buffer_length;
  ulong net_interactive_timeout;
  ulong net_read_timeout;
  ulong net_retry_count;
  ulong net_wait_timeout;
  ulong net_write_timeout;
  ulong query_cache_type;
  ulong read_buff_size;
  ulong read_rnd_buff_size;
  ulong sortbuff_size;
  ulong table_type;
  ulong tmp_table_size;
  ulong tx_isolation;
  ulong sql_mode;
  ulong default_week_format;

  /*
    In slave thread we need to know in behalf of which
    thread the query is being run to replicate temp tables properly
  */
  ulong pseudo_thread_id;

  my_bool log_warnings;
  my_bool low_priority_updates; 

  CONVERT	*convert_set;
  CHARSET_INFO 	*thd_charset;
};

void free_tmp_table(THD *thd, TABLE *entry);
/*
  For each client connection we create a separate thread with THD serving as
  a thread/connection descriptor
*/

class THD :public ilink
{
public:
#ifdef EMBEDDED_LIBRARY
  struct st_mysql  *mysql;
#endif
  NET	  net;				// client connection descriptor
  LEX	  lex;				// parse tree descriptor
  MEM_ROOT mem_root;			// 1 command-life memory pool
  MEM_ROOT con_root;                    // connection-life memory
  MEM_ROOT warn_root;			// For warnings and errors
  Protocol *protocol;			// Current protocol
  Protocol_simple protocol_simple;	// Normal protocol
  Protocol_prep protocol_prep;		// Binary protocol
  HASH    user_vars;			// hash for user variables
  TREE	  prepared_statements;
  String  packet;			// dynamic buffer for network I/O
  struct  sockaddr_in remote;		// client socket address
  struct  rand_struct rand;		// used for authentication
  struct  system_variables variables;	// Changeable local variables
  pthread_mutex_t LOCK_delete;		// Locked before thd is deleted

  char	  *query;			// Points to the current query,
  /*
    A pointer to the stack frame of handle_one_connection(),
    which is called first in the thread for handling a client
  */
  char	  *thread_stack;

  /*
    host - host of the client
    user - user of the client, set to NULL until the user has been read from
     the connection
    priv_user - The user privilege we are using. May be '' for anonymous user.
    db - currently selected database
    ip - client IP
   */
  
  char	  *host,*user,*priv_user,*db,*ip;
  /* Points to info-string that will show in SHOW PROCESSLIST */
  const char *proc_info;
  /* points to host if host is available, otherwise points to ip */
  const char *host_or_ip;
 
  ulong client_capabilities;		/* What the client supports */
  /* Determines if which non-standard SQL behaviour should be enabled */
  ulong max_client_packet_length;
  ulong master_access;			/* Global privileges from mysql.user */
  ulong db_access;			/* Privileges for current db */

  /*
    open_tables - list of regular tables in use by this thread
    temporary_tables - list of temp tables in use by this thread
    handler_tables - list of tables that were opened with HANDLER OPEN
     and are still in use by this thread
  */
  TABLE   *open_tables,*temporary_tables, *handler_tables, *derived_tables;
  // TODO: document the variables below
  MYSQL_LOCK	*lock;				/* Current locks */
  MYSQL_LOCK	*locked_tables;			/* Tables locked with LOCK */
  ULL		*ull;
  PREP_STMT	*last_prepared_stmt;
#ifndef DBUG_OFF
  uint dbug_sentry; // watch out for memory corruption
#endif  
  struct st_my_thread_var *mysys_var;
  enum enum_server_command command;
  uint32     server_id;
  uint32     file_id;			// for LOAD DATA INFILE
  const char *where;
  time_t     start_time,time_after_lock,user_time;
  time_t     connect_time,thr_create_time; // track down slow pthread_create
  thr_lock_type update_lock_default;
  delayed_insert *di;
  struct st_transactions {
    IO_CACHE trans_log;
    THD_TRANS all;			// Trans since BEGIN WORK
    THD_TRANS stmt;			// Trans for current statement
    uint bdb_lock_count;

    /* 
       Tables changed in transaction (that must be invalidated in query cache).
       List contain only transactional tables, that not invalidated in query 
       cache (instead of full list of changed in transaction tables).
    */
    CHANGED_TABLE_LIST* changed_tables;
    MEM_ROOT mem_root; // Transaction-life memory allocation pool
    void cleanup()
    {
      changed_tables = 0;
      free_root(&mem_root,MYF(MY_KEEP_PREALLOC));
    }
  } transaction;
  Item	     *free_list, *handler_items;
  Field      *dupp_field;
#ifndef __WIN__
  sigset_t signals,block_signals;
#endif
#ifdef SIGNAL_WITH_VIO_CLOSE
  Vio* active_vio;
#endif  
  ulonglong  next_insert_id,last_insert_id,current_insert_id,
             limit_found_rows;
  ha_rows    select_limit, offset_limit, cuted_fields,
             sent_row_count, examined_row_count;
  table_map  used_tables;
  USER_CONN *user_connect;
  CHARSET_INFO *db_charset;   
  List<TABLE> temporary_tables_should_be_free; // list of temporary tables
  List	     <MYSQL_ERROR> warn_list;  
  uint	     warn_count[(uint) MYSQL_ERROR::WARN_LEVEL_END];
  uint	     total_warn_count, old_total_warn_count;
  ulong	     query_id, warn_id, version, options, thread_id, col_access;
  ulong      current_stmt_id;
  ulong	     rand_saved_seed1, rand_saved_seed2;
  long	     dbug_thread_id;
  pthread_t  real_id;
  uint	     current_tablenr,tmp_table,cond_count;
  uint	     server_status,open_options;
  uint32     query_length;
  uint32     db_length;
  uint       select_number;             //number of select (used for EXPLAIN)
  /* variables.transaction_isolation is reset to this after each commit */
  enum_tx_isolation session_tx_isolation;
  /* for user variables replication*/
  DYNAMIC_ARRAY user_var_events;
             // extend scramble to handle new auth
  char	     scramble[SCRAMBLE41_LENGTH+1];
             // old scramble is needed to handle old clients
  char       old_scramble[SCRAMBLE_LENGTH+1];
  uint8	     query_cache_type;		// type of query cache processing
  bool       slave_thread;
  bool	     set_query_id,locked,count_cuted_fields,some_tables_deleted;
  bool	     no_errors, allow_sum_func, password, is_fatal_error;
  bool	     query_start_used,last_insert_id_used,insert_id_used,rand_used;
  bool	     system_thread,in_lock_tables,global_read_lock;
  bool       query_error, bootstrap, cleanup_done;

  enum killed_state { NOT_KILLED=0, KILL_CONNECTION=ER_SERVER_SHUTDOWN, KILL_QUERY=ER_QUERY_INTERRUPTED };
  killed_state volatile killed;

  bool       prepare_command;
  bool	     tmp_table_used;
  sp_rcontext *spcont;		// SP runtime context
  List<sp_head> spfuns;		// SP FUNCTIONs

  /*
    If we do a purge of binary logs, log index info of the threads
    that are currently reading it needs to be adjusted. To do that
    each thread that is using LOG_INFO needs to adjust the pointer to it
  */
  LOG_INFO*  current_linfo;
  NET*       slave_net;			// network connection from slave -> m.
  my_off_t   log_pos;
  /* Used by the sys_var class to store temporary values */
  union
  {
    my_bool my_bool_value;
    long    long_value;
  } sys_var_tmp;

  THD();
  ~THD();

  void init(void);
  void change_user(void);
  void cleanup(void);
  bool store_globals();
#ifdef SIGNAL_WITH_VIO_CLOSE
  inline void set_active_vio(Vio* vio)
  {
    pthread_mutex_lock(&LOCK_delete);
    active_vio = vio;
    pthread_mutex_unlock(&LOCK_delete);
  }
  inline void clear_active_vio()
  {
    pthread_mutex_lock(&LOCK_delete);
    active_vio = 0;
    pthread_mutex_unlock(&LOCK_delete);
  }
  void close_active_vio();
#endif  
  void awake(THD::killed_state state_to_set);
  inline const char* enter_cond(pthread_cond_t *cond, pthread_mutex_t* mutex,
			  const char* msg)
  {
    const char* old_msg = proc_info;
    mysys_var->current_mutex = mutex;
    mysys_var->current_cond = cond;
    proc_info = msg;
    return old_msg;
  }
  inline void exit_cond(const char* old_msg)
  {
    pthread_mutex_lock(&mysys_var->mutex);
    mysys_var->current_mutex = 0;
    mysys_var->current_cond = 0;
    proc_info = old_msg;
    pthread_mutex_unlock(&mysys_var->mutex);
  }
  inline time_t query_start() { query_start_used=1; return start_time; }
  inline void	set_time()    { if (user_time) start_time=time_after_lock=user_time; else time_after_lock=time(&start_time); }
  inline void	end_time()    { time(&start_time); }
  inline void	set_time(time_t t) { time_after_lock=start_time=user_time=t; }
  inline void	lock_time()   { time(&time_after_lock); }
  inline void	insert_id(ulonglong id)
  { last_insert_id=id; insert_id_used=1; }
  inline ulonglong insert_id(void)
  {
    if (!last_insert_id_used)
    {      
      last_insert_id_used=1;
      current_insert_id=last_insert_id;
    }
    return last_insert_id;
  }
  inline ulonglong found_rows(void)
  {
    return limit_found_rows;
  }                                                                         
  inline bool active_transaction()
  {
#ifdef USING_TRANSACTIONS    
    return (transaction.all.bdb_tid != 0 ||
	    transaction.all.innodb_active_trans != 0);
#else
    return 0;
#endif
  }
  inline gptr alloc(unsigned int size) { return alloc_root(&mem_root,size); }
  inline gptr calloc(unsigned int size)
  {
    gptr ptr;
    if ((ptr=alloc_root(&mem_root,size)))
      bzero((char*) ptr,size);
    return ptr;
  }
  inline char *strdup(const char *str)
  { return strdup_root(&mem_root,str); }
  inline char *strmake(const char *str, uint size)
  { return strmake_root(&mem_root,str,size); }
  inline char *memdup(const char *str, uint size)
  { return memdup_root(&mem_root,str,size); }
  inline char *memdup_w_gap(const char *str, uint size, uint gap)
  {
    gptr ptr;
    if ((ptr=alloc_root(&mem_root,size+gap)))
      memcpy(ptr,str,size);
    return ptr;
  }
  inline gptr trans_alloc(unsigned int size) 
  { 
    return alloc_root(&transaction.mem_root,size);
  }
  void add_changed_table(TABLE *table);
  void add_changed_table(const char *key, long key_length);
  CHANGED_TABLE_LIST * changed_table_dup(const char *key, long key_length);
  int send_explain_fields(select_result *result);
#ifndef EMBEDDED_LIBRARY
  inline void clear_error()
  {
    net.last_error[0]= 0;
    net.last_errno= 0;
    net.report_error= 0;
  }
#else
  void clear_error();
#endif
  inline void fatal_error()
  {
    is_fatal_error= 1;
    net.report_error= 1; 
  }
  inline CHARSET_INFO *charset() { return variables.thd_charset; }
};

/*
  Used to hold information about file and file structure in exchainge 
  via non-DB file (...INTO OUTFILE..., ...LOAD DATA...)
*/
class sql_exchange :public Sql_alloc
{
public:
  char *file_name;
  String *field_term,*enclosed,*line_term,*line_start,*escaped;
  bool opt_enclosed;
  bool dumpfile;
  uint skip_lines;
  sql_exchange(char *name,bool dumpfile_flag);
  ~sql_exchange() {}
};

#include "log_event.h"

/*
  This is used to get result from a select
*/

class JOIN;

void send_error(THD *thd, uint sql_errno=0, const char *err=0);

class select_result :public Sql_alloc {
protected:
  THD *thd;
  SELECT_LEX_UNIT *unit;
public:
  select_result();
  virtual ~select_result() {};
  virtual int prepare(List<Item> &list, SELECT_LEX_UNIT *u)
  {
    unit= u;
    return 0;
  }
  virtual bool send_fields(List<Item> &list,uint flag)=0;
  virtual bool send_data(List<Item> &items)=0;
  virtual bool initialize_tables (JOIN *join=0) { return 0; }
  virtual void send_error(uint errcode,const char *err)
  {
    my_message(errcode, err, MYF(0));
  }
  virtual bool send_eof()=0;
  virtual void abort() {}
};


class select_send :public select_result {
public:
  select_send() {}
  bool send_fields(List<Item> &list,uint flag);
  bool send_data(List<Item> &items);
  bool send_eof();
};


class select_export :public select_result {
  sql_exchange *exchange;
  File file;
  IO_CACHE cache;
  ha_rows row_count;
  uint field_term_length;
  int field_sep_char,escape_char,line_sep_char;
  bool fixed_row_size;
public:
  select_export(sql_exchange *ex) :exchange(ex),file(-1),row_count(0L) {}
  ~select_export();
  int prepare(List<Item> &list, SELECT_LEX_UNIT *u);
  bool send_fields(List<Item> &list,
		   uint flag) { return 0; }
  bool send_data(List<Item> &items);
  void send_error(uint errcode,const char *err);
  bool send_eof();
};


class select_dump :public select_result {
  sql_exchange *exchange;
  File file;
  IO_CACHE cache;
  ha_rows row_count;
  char path[FN_REFLEN];
public:
  select_dump(sql_exchange *ex) :exchange(ex),file(-1),row_count(0L)
  { path[0]=0; }
  ~select_dump();
  int prepare(List<Item> &list, SELECT_LEX_UNIT *u);
  bool send_fields(List<Item> &list,
		   uint flag) { return 0; }
  bool send_data(List<Item> &items);
  void send_error(uint errcode,const char *err);
  bool send_eof();
};


class select_insert :public select_result {
 public:
  TABLE *table;
  List<Item> *fields;
  ulonglong last_insert_id;
  COPY_INFO info;

  select_insert(TABLE *table_par,List<Item> *fields_par,enum_duplicates duplic)
    :table(table_par),fields(fields_par), last_insert_id(0)
  {
    bzero((char*) &info,sizeof(info));
    info.handle_duplicates=duplic;
  }
  ~select_insert();
  int prepare(List<Item> &list, SELECT_LEX_UNIT *u);
  bool send_fields(List<Item> &list, uint flag)
  { return 0; }
  bool send_data(List<Item> &items);
  void send_error(uint errcode,const char *err);
  bool send_eof();
};


class select_create: public select_insert {
  ORDER *group;
  const char *db;
  const char *name;
  List<create_field> *extra_fields;
  List<Key> *keys;
  HA_CREATE_INFO *create_info;
  MYSQL_LOCK *lock;
  Field **field;
public:
  select_create (const char *db_name, const char *table_name,
		 HA_CREATE_INFO *create_info_par,
		 List<create_field> &fields_par,
		 List<Key> &keys_par,
		 List<Item> &select_fields,enum_duplicates duplic)
    :select_insert (NULL, &select_fields, duplic), db(db_name),
    name(table_name), extra_fields(&fields_par),keys(&keys_par),
    create_info(create_info_par),
    lock(0)
    {}
  int prepare(List<Item> &list, SELECT_LEX_UNIT *u);
  bool send_data(List<Item> &values);
  bool send_eof();
  void abort();
};

class select_union :public select_result {
 public:
  TABLE *table;
  COPY_INFO info;
  TMP_TABLE_PARAM *tmp_table_param;
  bool not_describe;

  select_union(TABLE *table_par);
  ~select_union();
  int prepare(List<Item> &list, SELECT_LEX_UNIT *u);
  bool send_fields(List<Item> &list, uint flag)
  { return 0; }
  bool send_data(List<Item> &items);
  bool send_eof();
  bool flush();
};

/* Base subselect interface class */
class select_subselect :public select_result
{
protected:
  Item_subselect *item;
public:
  select_subselect(Item_subselect *item);
  bool send_fields(List<Item> &list, uint flag) { return 0; };
  bool send_data(List<Item> &items)=0;
  bool send_eof() { return 0; };

  friend class Ttem_subselect;
};

/* Single value subselect interface class */
class select_singlerow_subselect :public select_subselect
{
public:
  select_singlerow_subselect(Item_subselect *item):select_subselect(item){}
  bool send_data(List<Item> &items);
};

/* EXISTS subselect interface class */
class select_exists_subselect :public select_subselect
{
public:
  select_exists_subselect(Item_subselect *item):select_subselect(item){}
  bool send_data(List<Item> &items);
};

/* Structs used when sorting */

typedef struct st_sort_field {
  Field *field;				/* Field to sort */
  Item	*item;				/* Item if not sorting fields */
  uint	 length;			/* Length of sort field */
  Item_result result_type;		/* Type of item */
  bool reverse;				/* if descending sort */
  bool need_strxnfrm;			/* If we have to use strxnfrm() */
} SORT_FIELD;


typedef struct st_sort_buffer {
  uint index;					/* 0 or 1 */
  uint sort_orders;
  uint change_pos;				/* If sort-fields changed */
  char **buff;
  SORT_FIELD *sortorder;
} SORT_BUFFER;


/* Structure for db & table in sql_yacc */

class Table_ident :public Sql_alloc
{
 public:
  LEX_STRING db;
  LEX_STRING table;
  SELECT_LEX_UNIT *sel;
  inline Table_ident(LEX_STRING db_arg, LEX_STRING table_arg, bool force)
    :table(table_arg), sel((SELECT_LEX_UNIT *)0)
  {
    if (!force && (current_thd->client_capabilities & CLIENT_NO_SCHEMA))
      db.str=0;
    else
      db= db_arg;
  }
  inline Table_ident(LEX_STRING table_arg) 
    :table(table_arg), sel((SELECT_LEX_UNIT *)0)
  {
    db.str=0;
  }
  inline Table_ident(SELECT_LEX_UNIT *s) : sel(s) 
  {
    db.str=0; table.str=(char *)""; table.length=0;
  }
  inline void change_db(char *db_name)
  {
    db.str= db_name; db.length= (uint) strlen(db_name);
  }
};

// this is needed for user_vars hash
class user_var_entry
{
 public:
  LEX_STRING name;
  char *value;
  ulong length, update_query_id, used_query_id;
  Item_result type;
  CHARSET_INFO *var_charset;
  enum Item::coercion var_coercibility;
};

/* Class for unique (removing of duplicates) */

class Unique :public Sql_alloc
{
  DYNAMIC_ARRAY file_ptrs;
  ulong max_elements, max_in_memory_size;
  IO_CACHE file;
  TREE tree;
  byte *record_pointers;
  bool flush();

public:
  ulong elements;
  Unique(qsort_cmp2 comp_func, void * comp_func_fixed_arg,
	 uint size, ulong max_in_memory_size_arg);
  ~Unique();
  inline bool unique_add(gptr ptr)
  {
    if (tree.elements_in_tree > max_elements && flush())
      return 1;
    return !tree_insert(&tree, ptr, 0, tree.custom_arg);
  }

  bool get(TABLE *table);

  friend int unique_write_to_file(gptr key, element_count count, Unique *unique);
  friend int unique_write_to_ptrs(gptr key, element_count count, Unique *unique);
};

class multi_delete : public select_result
{
  TABLE_LIST *delete_tables, *table_being_deleted;
  Unique  **tempfiles;
  THD *thd;
  ha_rows deleted;
  uint num_of_tables;
  int error;
  bool do_delete, transactional_tables, log_delayed, normal_tables;
public:
  multi_delete(THD *thd, TABLE_LIST *dt, uint num_of_tables);
  ~multi_delete();
  int prepare(List<Item> &list, SELECT_LEX_UNIT *u);
  bool send_fields(List<Item> &list,
 		   uint flag) { return 0; }
  bool send_data(List<Item> &items);
  bool initialize_tables (JOIN *join);
  void send_error(uint errcode,const char *err);
  int  do_deletes (bool from_send_error);
  bool send_eof();
};


class multi_update : public select_result
{
  TABLE_LIST *all_tables, *update_tables, *table_being_updated;
  THD *thd;
  TABLE **tmp_tables, *main_table;
  TMP_TABLE_PARAM *tmp_table_param;
  ha_rows updated, found;
  List <Item> *fields, *values;
  List <Item> **fields_for_table, **values_for_table;
  uint table_count;
  Copy_field *copy_field;
  enum enum_duplicates handle_duplicates;
  bool do_update, trans_safe, transactional_tables, log_delayed;

public:
  multi_update(THD *thd_arg, TABLE_LIST *ut, List<Item> *fields,
	       List<Item> *values, enum_duplicates handle_duplicates);
  ~multi_update();
  int prepare(List<Item> &list, SELECT_LEX_UNIT *u);
  bool send_fields(List<Item> &list, uint flag) { return 0; }
  bool send_data(List<Item> &items);
  bool initialize_tables (JOIN *join);
  void send_error(uint errcode,const char *err);
  int  do_updates (bool from_send_error);
  bool send_eof();
};

class my_var : public Sql_alloc  {
public:
  LEX_STRING s;
  bool local;
  uint offset;
  my_var (LEX_STRING& j, bool i, uint o) : s(j), local(i), offset(o) {}
  ~my_var() {}
};

class select_dumpvar :public select_result {
  ha_rows row_count;
public:
  List<my_var> var_list;
  List<Item_func_set_user_var> vars;
  List<Item_splocal> local_vars;
  select_dumpvar(void)  { var_list.empty(); local_vars.empty(); vars.empty(); row_count=0;}
  ~select_dumpvar() {}
  int prepare(List<Item> &list, SELECT_LEX_UNIT *u);
  bool send_fields(List<Item> &list, uint flag) {return 0;}
  bool send_data(List<Item> &items);
  bool send_eof();
};