text: /* Copyright (c) 2000, 2020, 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 also distributed 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 included with MySQL.
  
     Without limiting anything contained in the foregoing, this file,
     which is part of C Driver for MySQL (Connector/C), is also subject to the
     Universal FOSS Exception, version 1.0, a copy of which can be found at
     http://oss.oracle.com/licenses/universal-foss-exception.
  
     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 */
  
  #include "my_config.h"
  
  #include <fcntl.h>
  #include <limits.h>
  #include <math.h>
  #include <sys/types.h>
  
  #include "m_ctype.h"
  #include "m_string.h"
  #include "my_alloc.h"
  #include "my_sys.h"
  #include "my_time.h"
  #include "mysys_err.h"
  #ifndef _WIN32
  #include <netdb.h>
  #endif
  #include <signal.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <sys/stat.h>
  #include <time.h>
  
  #include <algorithm>
  
  #include "errmsg.h"
  #include "my_byteorder.h"
  #include "my_compiler.h"
  #include "my_dbug.h"
  #include "my_double2ulonglong.h"
  #include "my_inttypes.h"
  #include "my_io.h"
  #include "my_macros.h"
  #include "my_pointer_arithmetic.h"
  #include "my_thread_local.h"
  #include "mysql.h"
  #include "mysql/service_mysql_alloc.h"
  #include "mysql_com.h"
  #include "mysql_version.h"
  #include "mysqld_error.h"
  #include "template_utils.h"
  #include "violite.h"
  
  #ifdef HAVE_PWD_H
  #include <pwd.h>
  #endif
  #ifdef HAVE_SYS_SELECT_H
  #include <sys/select.h>
  #endif
  #ifdef HAVE_POLL
  #include <poll.h>
  #endif
  #ifdef HAVE_SYS_UN_H
  #include <sys/un.h>
  #endif
  #if !defined(_WIN32)
  #include "my_thread.h" /* because of signal()	*/
  #endif
  #ifndef INADDR_NONE
  #define INADDR_NONE -1
  #endif
  
  #include <memory>
  
  #include "../sql-common/client_extensions_macros.h"
  #include "client_settings.h"
  #include "mysql_trace.h"
  #include "sql_common.h"
  
  /*
    Temporary replacement for COM_SHUTDOWN. This will be removed once
    mysql_shutdown C API is removed.
  */
  #define COM_SHUTDOWN_DEPRECATED 8
  static void append_wild(char *to, char *end, const char *wild);
  
  static bool mysql_client_init = false;
  static bool org_my_init_done = false;
  
  struct MYSQL_STMT_EXT {
    MEM_ROOT fields_mem_root;
  };
  
  /*
    Initialize the MySQL client library
  
    SYNOPSIS
      mysql_server_init()
  
    NOTES
      Should be called before doing any other calls to the MySQL
      client library to initialize thread specific variables etc.
      It's called by mysql_init() to ensure that things will work for
      old not threaded applications that doesn't call mysql_server_init()
      directly.
  
    RETURN
      0  ok
      1  could not initialize environment (out of memory or thread keys)
  */
  
  int STDCALL mysql_server_init(int argc MY_ATTRIBUTE((unused)),
                                char **argv MY_ATTRIBUTE((unused)),
                                char **groups MY_ATTRIBUTE((unused))) {
    int result = 0;
    if (!mysql_client_init) {
      mysql_client_init = true;
      org_my_init_done = my_init_done;
      if (my_init()) /* Will init threads */
        return 1;
      init_client_errs();
      if (mysql_client_plugin_init()) return 1;
      ssl_start();
  
      if (!mysql_port) {
        char *env;
        struct servent *serv_ptr MY_ATTRIBUTE((unused));
  
        mysql_port = MYSQL_PORT;
  
        /*
          if builder specifically requested a default port, use that
          (even if it coincides with our factory default).
          only if they didn't do we check /etc/services (and, failing
          on that, fall back to the factory default of 3306).
          either default can be overridden by the environment variable
          MYSQL_TCP_PORT, which in turn can be overridden with command
          line options.
        */
  
  #if MYSQL_PORT_DEFAULT == 0
        if ((serv_ptr = getservbyname("mysql", "tcp")))
          mysql_port = (uint)ntohs((ushort)serv_ptr->s_port);
  #endif
        if ((env = getenv("MYSQL_TCP_PORT"))) mysql_port = (uint)atoi(env);
      }
  
      if (!mysql_unix_port) {
        char *env;
  #ifdef _WIN32
        mysql_unix_port = const_cast<char *>(MYSQL_NAMEDPIPE);
  #else
        mysql_unix_port = const_cast<char *>(MYSQL_UNIX_ADDR);
  #endif
        if ((env = getenv("MYSQL_UNIX_PORT"))) mysql_unix_port = env;
      }
      mysql_debug(NullS);
  #if defined(SIGPIPE) && !defined(_WIN32)
      (void)signal(SIGPIPE, SIG_IGN);
  #endif
    } else
      result = (int)my_thread_init(); /* Init if new thread */
    return result;
  }
  
  /*
    Free all memory and resources used by the client library
  
    NOTES
      When calling this there should not be any other threads using
      the library.
  
      To make things simpler when used with windows dll's (which calls this
      function automaticly), it's safe to call this function multiple times.
  */
  
  void STDCALL mysql_server_end() {
    if (!mysql_client_init) return;
  
    mysql_client_plugin_deinit();
  
    finish_client_errs();
    vio_end();
  
    /* If library called my_init(), free memory allocated by it */
    if (!org_my_init_done) {
      my_end(0);
    } else {
      mysql_thread_end();
    }
  
    mysql_client_init = org_my_init_done = false;
  }
  
  bool STDCALL mysql_thread_init() { return my_thread_init(); }
  
  void STDCALL mysql_thread_end() { my_thread_end(); }
  
  /*
    Expand wildcard to a sql string
  */
  
  static void append_wild(char *to, char *end, const char *wild) {
    end -= 5; /* Some extra */
    if (wild && wild[0]) {
      to = my_stpcpy(to, " like '");
      while (*wild && to < end) {
        if (*wild == '\\' || *wild == '\'') *to++ = '\\';
        *to++ = *wild++;
      }
      if (*wild)     /* Too small buffer */
        *to++ = '%'; /* Nicer this way */
      to[0] = '\'';
      to[1] = 0;
    }
  }
  
  /**************************************************************************
    Init debugging if MYSQL_DEBUG environment variable is found
  **************************************************************************/
  
  void STDCALL mysql_debug(const char *debug MY_ATTRIBUTE((unused))) {
  #ifndef DBUG_OFF
    char *env;
    if (debug) {
      DBUG_PUSH(debug);
    } else if ((env = getenv("MYSQL_DEBUG"))) {
      DBUG_PUSH(env);
  #if !defined(_WINVER) && !defined(WINVER)
      puts("\n-------------------------------------------------------");
      puts("MYSQL_DEBUG found. libmysql started with the following:");
      puts(env);
      puts("-------------------------------------------------------\n");
  #else
      {
        char buff[80];
        buff[sizeof(buff) - 1] = 0;
        strxnmov(buff, sizeof(buff) - 1, "libmysql: ", env, NullS);
        MessageBox((HWND)0, "Debugging variable MYSQL_DEBUG used", buff, MB_OK);
      }
  #endif
    }
  #endif
  }
  
  /**************************************************************************
    Change user and database
  **************************************************************************/
  
  bool STDCALL mysql_change_user(MYSQL *mysql, const char *user,
                                 const char *passwd, const char *db) {
    int rc;
    CHARSET_INFO *saved_cs = mysql->charset;
    char *saved_user = mysql->user;
    char *saved_passwd = mysql->passwd;
    char *saved_db = mysql->db;
  
    DBUG_TRACE;
  
    /* Get the connection-default character set. */
  
    if (mysql_init_character_set(mysql)) {
      mysql->charset = saved_cs;
      return true;
    }
  
    /*
      Use an empty string instead of NULL.
      Alloc user and password on heap because mysql_reconnect()
      calls mysql_close() on success.
    */
    mysql->user = my_strdup(PSI_NOT_INSTRUMENTED, user ? user : "", MYF(MY_WME));
    mysql->passwd =
        my_strdup(PSI_NOT_INSTRUMENTED, passwd ? passwd : "", MYF(MY_WME));
    mysql->db = nullptr;
  
    rc = run_plugin_auth(mysql, nullptr, 0, nullptr, db);
  
    MYSQL_TRACE_STAGE(mysql, READY_FOR_COMMAND);
  
    /*
      The server will close all statements no matter was the attempt
      to change user successful or not.
    */
    mysql_detach_stmt_list(&mysql->stmts, "mysql_change_user");
    if (rc == 0) {
      /* Free old connect information */
      my_free(saved_user);
      my_free(saved_passwd);
      my_free(saved_db);
  
      /* alloc new connect information */
      mysql->db = db ? my_strdup(PSI_NOT_INSTRUMENTED, db, MYF(MY_WME)) : nullptr;
    } else {
      /* Free temporary connect information */
      my_free(mysql->user);
      my_free(mysql->passwd);
      my_free(mysql->db);
  
      /* Restore saved state */
      mysql->charset = saved_cs;
      mysql->user = saved_user;
      mysql->passwd = saved_passwd;
      mysql->db = saved_db;
    }
  
    return rc;
  }
  
  #if defined(HAVE_GETPWUID) && defined(NO_GETPWUID_DECL)
  struct passwd *getpwuid(uid_t);
  char *getlogin(void);
  #endif
  
  #if !defined(_WIN32)
  
  void read_user_name(char *name) {
    DBUG_TRACE;
    if (geteuid() == 0)
      (void)my_stpcpy(name, "root"); /* allow use of surun */
    else {
  #ifdef HAVE_GETPWUID
      struct passwd *skr;
      const char *str;
      if ((str = getlogin()) == nullptr) {
        if ((skr = getpwuid(geteuid())) != nullptr)
          str = skr->pw_name;
        else if (!(str = getenv("USER")) && !(str = getenv("LOGNAME")) &&
                 !(str = getenv("LOGIN")))
          str = "UNKNOWN_USER";
      }
      (void)strmake(name, str, USERNAME_LENGTH);
  #elif HAVE_CUSERID
      (void)cuserid(name);
  #else
      my_stpcpy(name, "UNKNOWN_USER");
  #endif
    }
  }
  
  #else /* If Windows */
  
  void read_user_name(char *name) {
    char *str = getenv("USER"); /* ODBC will send user variable */
    strmake(name, str ? str : "ODBC", USERNAME_LENGTH);
  }
  
  #endif
  
  /**
    Checks if the file name supplied by the server is a valid name.
  
    Name is valid if it's either equal to or starts with the value stored
    in the mysql options.
    If the value in the options is NULL then no name is valid.
  
    Note that we rely that the options name, if supplied, is normalized before
    being stored.
  
    @note Will allocate the extension if not already allocated
  
    @param options the options to read the load_data_file_from.
    @param net_filename the path to check
    @retval true the name is valid
    @retval false the name is invalid
  */
  static bool is_valid_local_infile_name(st_mysql_options *options,
                                         const char *net_filename) {
    char buff1[FN_REFLEN], buff2[FN_REFLEN];
  
    ENSURE_EXTENSIONS_PRESENT(options);
  
    // null load_data_dir means no exceptions (compatibility)
    if (options->extension->load_data_dir == nullptr) return false;
  
    // make fully qualified name
    if (my_realpath(buff1, net_filename, 0)) return false;
  
    // with uniform directory separators
    convert_dirname(buff2, buff1, NullS);
  
    /* if the name supplied starts with load_data_dir accept it */
    int ret = strncmp(options->extension->load_data_dir, buff2,
                      strlen(options->extension->load_data_dir));
    return ret == 0;
  }
  
  bool handle_local_infile(MYSQL *mysql, const char *net_filename) {
    bool result = true;
    uint packet_length = MY_ALIGN(mysql->net.max_packet - 16, IO_SIZE);
    NET *net = &mysql->net;
    int readcount;
    void *li_ptr; /* pass state to local_infile functions */
    char *buf;    /* buffer to be filled by local_infile_read */
    struct st_mysql_options *options = &mysql->options;
    DBUG_TRACE;
  
    /*
      Throw an error if --local-infile is not specified and the
      file requested is not "safe" (i.e. within the supplied directory
      to MYSQL_OPT_LOAD_DATA_LOCAL_DIR.
      If --local-infile is specified then no need to check the file name.
    */
    if (!(mysql->options.client_flag & CLIENT_LOCAL_FILES) &&
        !is_valid_local_infile_name(&(mysql->options), net_filename)) {
      MYSQL_TRACE(SEND_FILE, mysql, (0, nullptr));
      (void)my_net_write(net, (const uchar *)"", 0); /* Server needs one packet */
      net_flush(net);
      MYSQL_TRACE(PACKET_SENT, mysql, (0));
      set_mysql_error(mysql, CR_LOAD_DATA_LOCAL_INFILE_REJECTED,
                      unknown_sqlstate);
      return true;
    }
  
    /* check that we've got valid callback functions */
    if (!(options->local_infile_init && options->local_infile_read &&
          options->local_infile_end && options->local_infile_error)) {
      /* if any of the functions is invalid, set the default */
      mysql_set_local_infile_default(mysql);
    }
  
    /* copy filename into local memory and allocate read buffer */
    if (!(buf = pointer_cast<char *>(
              my_malloc(PSI_NOT_INSTRUMENTED, packet_length, MYF(0))))) {
      set_mysql_error(mysql, CR_OUT_OF_MEMORY, unknown_sqlstate);
      return true;
    }
  
    /* initialize local infile (open file, usually) */
    if ((*options->local_infile_init)(&li_ptr, net_filename,
                                      options->local_infile_userdata)) {
      MYSQL_TRACE(SEND_FILE, mysql, (0, nullptr));
      (void)my_net_write(net, (const uchar *)"", 0); /* Server needs one packet */
      net_flush(net);
      MYSQL_TRACE(PACKET_SENT, mysql, (0));
      my_stpcpy(net->sqlstate, unknown_sqlstate);
      net->last_errno = (*options->local_infile_error)(
          li_ptr, net->last_error, sizeof(net->last_error) - 1);
      MYSQL_TRACE(ERROR, mysql, ());
      goto err;
    }
  
    /* read blocks of data from local infile callback */
    while ((readcount =
                (*options->local_infile_read)(li_ptr, buf, packet_length)) > 0) {
      MYSQL_TRACE(SEND_FILE, mysql,
                  ((size_t)readcount, (const unsigned char *)buf));
      if (my_net_write(net, (uchar *)buf, readcount)) {
        DBUG_PRINT(
            "error",
            ("Lost connection to MySQL server during LOAD DATA of local file"));
        set_mysql_error(mysql, CR_SERVER_LOST, unknown_sqlstate);
        goto err;
      }
      MYSQL_TRACE(PACKET_SENT, mysql, (static_cast<size_t>(readcount)));
    }
  
    /* Send empty packet to mark end of file */
    MYSQL_TRACE(SEND_FILE, mysql, (0, nullptr));
    if (my_net_write(net, (const uchar *)"", 0) || net_flush(net)) {
      set_mysql_error(mysql, CR_SERVER_LOST, unknown_sqlstate);
      goto err;
    }
    MYSQL_TRACE(PACKET_SENT, mysql, (0));
  
    if (readcount < 0) {
      net->last_errno = (*options->local_infile_error)(
          li_ptr, net->last_error, sizeof(net->last_error) - 1);
      MYSQL_TRACE(ERROR, mysql, ());
      goto err;
    }
  
    result = false; /* Ok */
  
  err:
    /* free up memory allocated with _init, usually */
    (*options->local_infile_end)(li_ptr);
    my_free(buf);
    return result;
  }
  
  /****************************************************************************
    Default handlers for LOAD LOCAL INFILE
  ****************************************************************************/
  
  struct default_local_infile_data {
    int fd;
    int error_num;
    const char *filename;
    char error_msg[LOCAL_INFILE_ERROR_LEN];
  };
  
  /*
    Open file for LOAD LOCAL INFILE
  
    SYNOPSIS
      default_local_infile_init()
      ptr			Store pointer to internal data here
      filename		File name to open. This may be in unix format !
  
  
    NOTES
      Even if this function returns an error, the load data interface
      guarantees that default_local_infile_end() is called.
  
    RETURN
      0	ok
      1	error
  */
  
  static int default_local_infile_init(void **ptr, const char *filename,
                                       void *userdata MY_ATTRIBUTE((unused))) {
    default_local_infile_data *data;
    char tmp_name[FN_REFLEN];
  
    if (!(*ptr = data = ((default_local_infile_data *)my_malloc(
              PSI_NOT_INSTRUMENTED, sizeof(default_local_infile_data), MYF(0)))))
      return 1; /* out of memory */
  
    data->error_msg[0] = 0;
    data->error_num = 0;
    data->filename = filename;
  
    fn_format(tmp_name, filename, "", "", MY_UNPACK_FILENAME);
    if ((data->fd = my_open(tmp_name, O_RDONLY, MYF(0))) < 0) {
      char errbuf[MYSYS_STRERROR_SIZE];
      data->error_num = my_errno();
      snprintf(data->error_msg, sizeof(data->error_msg) - 1, EE(EE_FILENOTFOUND),
               tmp_name, data->error_num,
               my_strerror(errbuf, sizeof(errbuf), data->error_num));
      return 1;
    }
    return 0; /* ok */
  }
  
  /*
    Read data for LOAD LOCAL INFILE
  
    SYNOPSIS
      default_local_infile_read()
      ptr			Points to handle allocated by _init
      buf			Read data here
      buf_len		Ammount of data to read
  
    RETURN
      > 0		number of bytes read
      == 0	End of data
      < 0		Error
  */
  
  static int default_local_infile_read(void *ptr, char *buf, uint buf_len) {
    int count;
    default_local_infile_data *data = (default_local_infile_data *)ptr;
  
    if ((count = (int)my_read(data->fd, (uchar *)buf, buf_len, MYF(0))) < 0) {
      char errbuf[MYSYS_STRERROR_SIZE];
      data->error_num = EE_READ; /* the errmsg for not entire file read */
      snprintf(data->error_msg, sizeof(data->error_msg) - 1, EE(EE_READ),
               data->filename, my_errno(),
               my_strerror(errbuf, sizeof(errbuf), my_errno()));
    }
    return count;
  }
  
  /*
    Read data for LOAD LOCAL INFILE
  
    SYNOPSIS
      default_local_infile_end()
      ptr			Points to handle allocated by _init
                          May be NULL if _init failed!
  
    RETURN
  */
  
  static void default_local_infile_end(void *ptr) {
    default_local_infile_data *data = (default_local_infile_data *)ptr;
    if (data) /* If not error on open */
    {
      if (data->fd >= 0) my_close(data->fd, MYF(MY_WME));
      my_free(ptr);
    }
  }
  
  /*
    Return error from LOAD LOCAL INFILE
  
    SYNOPSIS
      default_local_infile_end()
      ptr			Points to handle allocated by _init
                          May be NULL if _init failed!
      error_msg		Store error text here
      error_msg_len	Max lenght of error_msg
  
    RETURN
      error message number
  */
  
  static int default_local_infile_error(void *ptr, char *error_msg,
                                        uint error_msg_len) {
    default_local_infile_data *data = (default_local_infile_data *)ptr;
    if (data) /* If not error on open */
    {
      strmake(error_msg, data->error_msg, error_msg_len);
      return data->error_num;
    }
    /* This can only happen if we got error on malloc of handle */
    my_stpcpy(error_msg, ER_CLIENT(CR_OUT_OF_MEMORY));
    return CR_OUT_OF_MEMORY;
  }
  
  /*
    Explicit extern "C" because otherwise solaris studio thinks
    that the function pointer arguments have C++ linkage,
    and then it overloads the declaration in include/mysql.h
   */
  extern "C" void mysql_set_local_infile_handler(
      MYSQL *mysql, int (*local_infile_init)(void **, const char *, void *),
      int (*local_infile_read)(void *, char *, uint),
      void (*local_infile_end)(void *),
      int (*local_infile_error)(void *, char *, uint), void *userdata) {
    mysql->options.local_infile_init = local_infile_init;
    mysql->options.local_infile_read = local_infile_read;
    mysql->options.local_infile_end = local_infile_end;
    mysql->options.local_infile_error = local_infile_error;
    mysql->options.local_infile_userdata = userdata;
  }
  
  void mysql_set_local_infile_default(MYSQL *mysql) {
    mysql->options.local_infile_init = default_local_infile_init;
    mysql->options.local_infile_read = default_local_infile_read;
    mysql->options.local_infile_end = default_local_infile_end;
    mysql->options.local_infile_error = default_local_infile_error;
  }
  
  /**************************************************************************
    Do a query. If query returned rows, free old rows.
    Read data by mysql_store_result or by repeat call of mysql_fetch_row
  **************************************************************************/
  
  int STDCALL mysql_query(MYSQL *mysql, const char *query) {
    return mysql_real_query(mysql, query, (ulong)strlen(query));
  }
  
  /**************************************************************************
    Return next field of the query results
  **************************************************************************/
  
  MYSQL_FIELD *STDCALL mysql_fetch_field(MYSQL_RES *result) {
    if (result->current_field >= result->field_count || !result->fields)
      return (nullptr);
    return &result->fields[result->current_field++];
  }
  
  /**************************************************************************
    Move to a specific row and column
  **************************************************************************/
  
  void STDCALL mysql_data_seek(MYSQL_RES *result, uint64_t row) {
    MYSQL_ROWS *tmp = nullptr;
    DBUG_PRINT("info", ("mysql_data_seek(%ld)", (long)row));
    if (result->data)
      for (tmp = result->data->data; row-- && tmp; tmp = tmp->next)
        ;
    result->current_row = nullptr;
    result->data_cursor = tmp;
  }
  
  /*************************************************************************
    put the row or field cursor one a position one got from mysql_row_tell()
    This doesn't restore any data. The next mysql_fetch_row or
    mysql_fetch_field will return the next row or field after the last used
  *************************************************************************/
  
  MYSQL_ROW_OFFSET STDCALL mysql_row_seek(MYSQL_RES *result,
                                          MYSQL_ROW_OFFSET row) {
    MYSQL_ROW_OFFSET return_value = result->data_cursor;
    result->current_row = nullptr;
    result->data_cursor = row;
    return return_value;
  }
  
  MYSQL_FIELD_OFFSET STDCALL mysql_field_seek(MYSQL_RES *result,
                                              MYSQL_FIELD_OFFSET field_offset) {
    MYSQL_FIELD_OFFSET return_value = result->current_field;
    result->current_field = field_offset;
    return return_value;
  }
  
  /*****************************************************************************
    List all databases
  *****************************************************************************/
  
  MYSQL_RES *STDCALL mysql_list_dbs(MYSQL *mysql, const char *wild) {
    char buff[255];
    DBUG_TRACE;
  
    append_wild(my_stpcpy(buff, "show databases"), buff + sizeof(buff), wild);
    if (mysql_query(mysql, buff)) return nullptr;
    return mysql_store_result(mysql);
  }
  
  /*****************************************************************************
    List all tables in a database
    If wild is given then only the tables matching wild is returned
  *****************************************************************************/
  
  MYSQL_RES *STDCALL mysql_list_tables(MYSQL *mysql, const char *wild) {
    char buff[255];
    DBUG_TRACE;
  
    append_wild(my_stpcpy(buff, "show tables"), buff + sizeof(buff), wild);
    if (mysql_query(mysql, buff)) return nullptr;
    return mysql_store_result(mysql);
  }
  
  MYSQL_FIELD *cli_list_fields(MYSQL *mysql) {
    MYSQL_DATA *query;
    MYSQL_FIELD *result;
  
    MYSQL_TRACE_STAGE(mysql, WAIT_FOR_FIELD_DEF);
    query =
        cli_read_rows(mysql, (MYSQL_FIELD *)nullptr, protocol_41(mysql) ? 8 : 6);
    MYSQL_TRACE_STAGE(mysql, READY_FOR_COMMAND);
  
    if (!query) return nullptr;
  
    mysql->field_count = (uint)query->rows;
    result = unpack_fields(mysql, query->data, mysql->field_alloc,
                           mysql->field_count, true, mysql->server_capabilities);
    free_rows(query);
    return result;
  }
  
  /**************************************************************************
    List all fields in a table
    If wild is given then only the fields matching wild is returned
    Instead of this use query:
    show fields in 'table' like "wild"
  **************************************************************************/
  
  MYSQL_RES *STDCALL mysql_list_fields(MYSQL *mysql, const char *table,
                                       const char *wild) {
    MYSQL_RES *result;
    MYSQL_FIELD *fields;
    MEM_ROOT *new_root;
    char buff[258], *end;
    DBUG_TRACE;
    DBUG_PRINT("enter", ("table: '%s'  wild: '%s'", table, wild ? wild : ""));
  
    end = strmake(strmake(buff, table, 128) + 1, wild ? wild : "", 128);
    free_old_query(mysql);
    if (simple_command(mysql, COM_FIELD_LIST, (uchar *)buff, (ulong)(end - buff),
                       1) ||
        !(fields = (*mysql->methods->list_fields)(mysql)))
      return nullptr;
  
    if (!(new_root = (MEM_ROOT *)my_malloc(PSI_NOT_INSTRUMENTED, sizeof(MEM_ROOT),
                                           MYF(MY_WME | MY_ZEROFILL))))
      return nullptr;
    if (!(result = (MYSQL_RES *)my_malloc(PSI_NOT_INSTRUMENTED, sizeof(MYSQL_RES),
                                          MYF(MY_WME | MY_ZEROFILL)))) {
      my_free(new_root);
      return nullptr;
    }
  
    result->methods = mysql->methods;
    result->field_alloc = mysql->field_alloc;
    mysql->fields = nullptr;
    mysql->field_alloc = new_root;
    result->field_count = mysql->field_count;
    result->fields = fields;
    result->eof = true;
    return result;
  }
  
  /* List all running processes (threads) in server */
  
  MYSQL_RES *STDCALL mysql_list_processes(MYSQL *mysql) {
    uint field_count;
    uchar *pos;
    DBUG_TRACE;
  
    if (simple_command(mysql, COM_PROCESS_INFO, nullptr, 0, 0)) return nullptr;
    free_old_query(mysql);
    pos = (uchar *)mysql->net.read_pos;
    field_count = (uint)net_field_length(&pos);
    if (!(mysql->fields =
              cli_read_metadata(mysql, field_count, protocol_41(mysql) ? 7 : 5)))
      return nullptr;
    mysql->status = MYSQL_STATUS_GET_RESULT;
    mysql->field_count = field_count;
    return mysql_store_result(mysql);
  }
  
  int STDCALL mysql_shutdown(MYSQL *mysql,
                             enum mysql_enum_shutdown_level shutdown_level
                                 MY_ATTRIBUTE((unused))) {
    if (mysql_get_server_version(mysql) < 50709)
      return simple_command(mysql, COM_DEPRECATED_1, nullptr, 0, 0);
    else
      return mysql_real_query(mysql, STRING_WITH_LEN("shutdown"));
  }
  
  int STDCALL mysql_refresh(MYSQL *mysql, uint options) {
    uchar bits[1];
    DBUG_TRACE;
    bits[0] = (uchar)options;
    return simple_command(mysql, COM_REFRESH, bits, 1, 0);
  }
  
  int STDCALL mysql_kill(MYSQL *mysql, ulong pid) {
    uchar buff[4];
    DBUG_TRACE;
    /*
      Sanity check: if ulong is 64-bits, user can submit a PID here that
      overflows our 32-bit parameter to the somewhat obsolete COM_PROCESS_KILL.
      If this is the case, we'll flag an error here.
      The SQL statement KILL CONNECTION is the safer option here.
      There is an analog of this failsafe in the server as we might see old
      libmysql connection to a new server as well as the other way around.
    */
    if (pid & (~0xfffffffful)) return CR_INVALID_CONN_HANDLE;
    int4store(buff, pid);
    return simple_command(mysql, COM_PROCESS_KILL, buff, sizeof(buff), 0);
  }
  
  int STDCALL mysql_set_server_option(MYSQL *mysql,
                                      enum enum_mysql_set_option option) {
    uchar buff[2];
    DBUG_TRACE;
    int2store(buff, (uint)option);
    return simple_command(mysql, COM_SET_OPTION, buff, sizeof(buff), 0);
  }
  
  int STDCALL mysql_dump_debug_info(MYSQL *mysql) {
    DBUG_TRACE;
    return simple_command(mysql, COM_DEBUG, nullptr, 0, 0);
  }
  
  const char *cli_read_statistics(MYSQL *mysql) {
    mysql->net.read_pos[mysql->packet_length] = 0; /* End of stat string */
    if (!mysql->net.read_pos[0]) {
      set_mysql_error(mysql, CR_WRONG_HOST_INFO, unknown_sqlstate);
      return mysql->net.last_error;
    }
    /*
      After reading the single packet with reply to COM_STATISTICS
      we are ready for new commands.
    */
    MYSQL_TRACE_STAGE(mysql, READY_FOR_COMMAND);
    return (char *)mysql->net.read_pos;
  }
  
  const char *STDCALL mysql_stat(MYSQL *mysql) {
    DBUG_TRACE;
    if (simple_command(mysql, COM_STATISTICS, nullptr, 0, 0))
      return mysql->net.last_error;
    return (*mysql->methods->read_statistics)(mysql);
  }
  
  int STDCALL mysql_ping(MYSQL *mysql) {
    int res;
    DBUG_TRACE;
    res = simple_command(mysql, COM_PING, nullptr, 0, 0);
    if (res == CR_SERVER_LOST && mysql->reconnect)
      res = simple_command(mysql, COM_PING, nullptr, 0, 0);
    return res;
  }
  
  const char *STDCALL mysql_get_server_info(MYSQL *mysql) {
    return ((char *)mysql->server_version);
  }
  
  const char *STDCALL mysql_get_host_info(MYSQL *mysql) {
    return (mysql->host_info);
  }
  
  uint STDCALL mysql_get_proto_info(MYSQL *mysql) {
    return (mysql->protocol_version);
  }
  
  const char *STDCALL mysql_get_client_info(void) { return MYSQL_SERVER_VERSION; }
  
  ulong STDCALL mysql_get_client_version(void) { return MYSQL_VERSION_ID; }
  
  bool STDCALL mysql_eof(MYSQL_RES *res) { return res->eof; }
  
  MYSQL_FIELD *STDCALL mysql_fetch_field_direct(MYSQL_RES *res, uint fieldnr) {
    if (fieldnr >= res->field_count || !res->fields) return (nullptr);
    return &(res)->fields[fieldnr];
  }
  
  MYSQL_FIELD *STDCALL mysql_fetch_fields(MYSQL_RES *res) {
    return (res)->fields;
  }
  
  MYSQL_ROW_OFFSET STDCALL mysql_row_tell(MYSQL_RES *res) {
    return res->data_cursor;
  }
  
  MYSQL_FIELD_OFFSET STDCALL mysql_field_tell(MYSQL_RES *res) {
    return (res)->current_field;
  }
  
  enum_resultset_metadata STDCALL mysql_result_metadata(MYSQL_RES *result) {
    return result->metadata;
  }
  
  /* MYSQL */
  
  unsigned int STDCALL mysql_field_count(MYSQL *mysql) {
    return mysql->field_count;
  }
  
  uint64_t STDCALL mysql_affected_rows(MYSQL *mysql) {
    return mysql->affected_rows;
  }
  
  uint64_t STDCALL mysql_insert_id(MYSQL *mysql) { return mysql->insert_id; }
  
  const char *STDCALL mysql_sqlstate(MYSQL *mysql) {
    return mysql ? mysql->net.sqlstate : cant_connect_sqlstate;
  }
  
  uint STDCALL mysql_warning_count(MYSQL *mysql) { return mysql->warning_count; }
  
  const char *STDCALL mysql_info(MYSQL *mysql) {
    if (!mysql) {
  #if defined(CLIENT_PROTOCOL_TRACING)
      return "protocol tracing enabled";
  #else
      return NULL;
  #endif
    }
    return mysql->info;
  }
  
  ulong STDCALL mysql_thread_id(MYSQL *mysql) {
    /*
      ulong may be 64-bit, but we currently only transmit 32-bit.
      mysql_thread_id() is usually used in conjunction with mysql_kill()
      which is similarly limited (and obsolete).
      SELECTION CONNECTION_ID() / KILL CONNECTION avoid this issue.
    */
    return (mysql)->thread_id;
  }
  
  const char *STDCALL mysql_character_set_name(MYSQL *mysql) {
    return mysql->charset->csname;
  }
  
  void STDCALL mysql_get_character_set_info(MYSQL *mysql,
                                            MY_CHARSET_INFO *csinfo) {
    csinfo->number = mysql->charset->number;
    csinfo->state = mysql->charset->state;
    csinfo->csname = mysql->charset->csname;
    csinfo->name = mysql->charset->name;
    csinfo->comment = mysql->charset->comment;
    csinfo->mbminlen = mysql->charset->mbminlen;
    csinfo->mbmaxlen = mysql->charset->mbmaxlen;
  
    if (mysql->options.charset_dir)
      csinfo->dir = mysql->options.charset_dir;
    else
      csinfo->dir = charsets_dir;
  }
  
  uint STDCALL mysql_thread_safe(void) { return 1; }
  
  /****************************************************************************
    Some support functions
  ****************************************************************************/
  
  /*
    Functions called my my_net_init() to set some application specific variables
  */
  
  void my_net_local_init(NET *net) {
    ulong local_net_buffer_length = 0;
    ulong local_max_allowed_packet = 0;
  
    (void)mysql_get_option(nullptr, MYSQL_OPT_MAX_ALLOWED_PACKET,
                           &local_max_allowed_packet);
    (void)mysql_get_option(nullptr, MYSQL_OPT_NET_BUFFER_LENGTH,
                           &local_net_buffer_length);
  
    net->max_packet = (uint)local_net_buffer_length;
    my_net_set_read_timeout(net, CLIENT_NET_READ_TIMEOUT);
    my_net_set_write_timeout(net, CLIENT_NET_WRITE_TIMEOUT);
    my_net_set_retry_count(net, CLIENT_NET_RETRY_COUNT);
    net->max_packet_size =
        std::max(local_net_buffer_length, local_max_allowed_packet);
  }
  
  /*
    This function is used to create HEX string that you
    can use in a SQL statement in of the either ways:
      INSERT INTO blob_column VALUES (0xAABBCC);  (any MySQL version)
      INSERT INTO blob_column VALUES (X'AABBCC'); (4.1 and higher)
  
    The string in "from" is encoded to a HEX string.
    The result is placed in "to" and a terminating null byte is appended.
  
    The string pointed to by "from" must be "length" bytes long.
    You must allocate the "to" buffer to be at least length*2+1 bytes long.
    Each character needs two bytes, and you need room for the terminating
    null byte. When mysql_hex_string() returns, the contents of "to" will
    be a null-terminated string. The return value is the length of the
    encoded string, not including the terminating null character.
  
    The return value does not contain any leading 0x or a leading X' and
    trailing '. The caller must supply whichever of those is desired.
  */
  
  ulong STDCALL mysql_hex_string(char *to, const char *from, ulong length) {
    char *to0 = to;
    const char *end;
  
    for (end = from + length; from < end; from++) {
      *to++ = _dig_vec_upper[((unsigned char)*from) >> 4];
      *to++ = _dig_vec_upper[((unsigned char)*from) & 0x0F];
    }
    *to = '\0';
    return (ulong)(to - to0);
  }
  
  /*
    Add escape characters to a string (blob?) to make it suitable for a insert
    to should at least have place for length*2+1 chars
    Returns the length of the to string
  */
  
  ulong STDCALL mysql_escape_string(char *to, const char *from, ulong length) {
    return (uint)escape_string_for_mysql(default_charset_info, to, 0, from,
                                         length);
  }
  
  /**
    Escapes special characters in a string for use in an SQL statement.
  
    Escapes special characters in the unescaped string, taking into account
    the current character set and sql mode of the connection so that is safe
    to place the string in a mysql_query(). This function must be used for
    binary data.
  
    This function does not work correctly when NO_BACKSLASH_ESCAPES sql mode
    is used and string quote in the SQL statement is different than '\''.
  
    @deprecated This function should not be used.
                Use mysql_real_escape_string_quote instead.
  
    @see mysql_real_escape_string_quote
  
    @param [in] mysql   MySQL connection structure.
    @param [out] to     Escaped string output buffer.
    @param [in] from    String to escape.
    @param [in] length  String to escape length.
  
    @return Result value.
      @retval != (ulong)-1 Succeeded. Number of bytes written to the output
                           buffer without the '\0' character.
      @retval (ulong)-1    Failed. Use mysql_error() to get error message.
  */
  
  ulong STDCALL mysql_real_escape_string(MYSQL *mysql, char *to, const char *from,
                                         ulong length) {
    if (mysql->server_status & SERVER_STATUS_NO_BACKSLASH_ESCAPES) {
      DBUG_PRINT("error", ("NO_BACKSLASH_ESCAPES sql mode requires usage of the "
                           "mysql_real_escape_string_quote function"));
      set_mysql_extended_error(mysql, CR_INSECURE_API_ERR, unknown_sqlstate,
                               ER_CLIENT(CR_INSECURE_API_ERR),
                               "mysql_real_escape_string",
                               "mysql_real_escape_string_quote");
      return (ulong)-1;
    }
  
    return (uint)mysql_real_escape_string_quote(mysql, to, from, length, '\'');
  }
  
  /**
    Escapes special characters in a string for use in an SQL statement.
  
    Escapes special characters in the unescaped string, taking into account
    the current character set and sql mode of the connection so that is safe
    to place the string in a mysql_query(). This function must be used for
    binary data.
  
    This function should be used for escaping identifiers and string parameters.
  
    @param [in] mysql   MySQL connection structure.
    @param [out] to     Escaped string output buffer.
    @param [in] from    String to escape.
    @param [in] length  String to escape length.
    @param [in] quote   String quoting character used in an SQL statement. This
                        should be one of '\'', '"' or '`' depending on the
                        parameter quoting applied in the SQL statement.
  
    @return Result value.
      @retval != (ulong)-1 Succeeded. Number of bytes written to the output
                           buffer without the '\0' character.
      @retval (ulong)-1    Failed.
  */
  
  ulong STDCALL mysql_real_escape_string_quote(MYSQL *mysql, char *to,
                                               const char *from, ulong length,
                                               char quote) {
    if (quote == '`' || mysql->server_status & SERVER_STATUS_NO_BACKSLASH_ESCAPES)
      return (uint)escape_quotes_for_mysql(mysql->charset, to, 0, from, length,
                                           quote);
    return (uint)escape_string_for_mysql(mysql->charset, to, 0, from, length);
  }
  
  void STDCALL myodbc_remove_escape(MYSQL *mysql, char *name) {
    char *to;
    bool use_mb_flag = use_mb(mysql->charset);
    char *end = nullptr;
    if (use_mb_flag)
      for (end = name; *end; end++)
        ;
  
    for (to = name; *name; name++) {
      int l;
      if (use_mb_flag && (l = my_ismbchar(mysql->charset, name, end))) {
        while (l--) *to++ = *name++;
        name--;
        continue;
      }
      if (*name == '\\' && name[1]) name++;
      *to++ = *name;
    }
    *to = 0;
  }
  
  /********************************************************************
   Implementation of new client API for 4.1 version.
  
   mysql_stmt_* are real prototypes used by applications.
  
   All functions performing
   real I/O are prefixed with 'cli_' (abbreviated from 'Call Level
   Interface'). This functions are invoked via pointers set in
   MYSQL::methods structure.
  *********************************************************************/
  
  /******************* Declarations ***********************************/
  
  /* Default number of rows fetched per one COM_STMT_FETCH command. */
  
  #define DEFAULT_PREFETCH_ROWS (ulong)1
  
  /*
    These functions are called by function pointer MYSQL_STMT::read_row_func.
    Each function corresponds to one of the read methods:
    - mysql_stmt_fetch without prior mysql_stmt_store_result,
    - mysql_stmt_fetch when result is stored,
    - mysql_stmt_fetch when there are no rows (always returns MYSQL_NO_DATA)
  */
  
  static int stmt_read_row_unbuffered(MYSQL_STMT *stmt, unsigned char **row);
  static int stmt_read_row_buffered(MYSQL_STMT *stmt, unsigned char **row);
  static int stmt_read_row_from_cursor(MYSQL_STMT *stmt, unsigned char **row);
  static int stmt_read_row_no_data(MYSQL_STMT *stmt, unsigned char **row);
  static int stmt_read_row_no_result_set(MYSQL_STMT *stmt, unsigned char **row);
  
  /*
    This function is used in mysql_stmt_store_result if
    STMT_ATTR_UPDATE_MAX_LENGTH attribute is set.
  */
  static void stmt_update_metadata(MYSQL_STMT *stmt, MYSQL_ROWS *data);
  static bool setup_one_fetch_function(MYSQL_BIND *, MYSQL_FIELD *field);
  
  /* Auxilary function used to reset statement handle. */
  
  #define RESET_SERVER_SIDE 1
  #define RESET_LONG_DATA 2
  #define RESET_STORE_RESULT 4
  #define RESET_CLEAR_ERROR 8
  
  static bool reset_stmt_handle(MYSQL_STMT *stmt, uint flags);
  
  #define MAX_DOUBLE_STRING_REP_LENGTH 331
  
  /* A macro to check truncation errors */
  
  #define IS_TRUNCATED(value, is_unsigned, min, max, umax)       \
    ((is_unsigned) ? (((value) > (umax) || (value) < 0) ? 1 : 0) \
                   : (((value) > (max) || (value) < (min)) ? 1 : 0))
  
  #define BIND_RESULT_DONE 1
  /*
    We report truncations only if at least one of MYSQL_BIND::error
    pointers is set. In this case stmt->bind_result_done |-ed with
    this flag.
  */
  #define REPORT_DATA_TRUNCATION 2
  
  /**************** Misc utility functions ****************************/
  
  static void stmt_clear_error(MYSQL_STMT *stmt) {
    if (stmt->last_errno) {
      stmt->last_errno = 0;
      stmt->last_error[0] = '\0';
      my_stpcpy(stmt->sqlstate, not_error_sqlstate);
    }
  }
  
  /**
    Set statement error code, sqlstate, and error message
    from given errcode and sqlstate.
  */
  
  void set_stmt_error(MYSQL_STMT *stmt, int errcode, const char *sqlstate,
                      const char *err) {
    DBUG_TRACE;
    DBUG_PRINT("enter", ("error: %d '%s'", errcode, ER_CLIENT(errcode)));
    DBUG_ASSERT(stmt != nullptr);
  
    if (err == nullptr) err = ER_CLIENT(errcode);
  
    stmt->last_errno = errcode;
    my_stpcpy(stmt->last_error, ER_CLIENT(errcode));
    my_stpcpy(stmt->sqlstate, sqlstate);
  }
  
  /**
    Set statement error code, sqlstate, and error message from NET.
  
    @param stmt  a statement handle. Copy the error here.
    @param net   mysql->net. Source of the error.
  */
  
  void set_stmt_errmsg(MYSQL_STMT *stmt, NET *net) {
    DBUG_TRACE;
    DBUG_PRINT("enter", ("error: %d/%s '%s'", net->last_errno, net->sqlstate,
                         net->last_error));
    DBUG_ASSERT(stmt != nullptr);
  
    stmt->last_errno = net->last_errno;
    if (net->last_error[0] != '\0') my_stpcpy(stmt->last_error, net->last_error);
    my_stpcpy(stmt->sqlstate, net->sqlstate);
  }
  
  /*
    Read and unpack server reply to COM_STMT_PREPARE command (sent from
    mysql_stmt_prepare).
  
    SYNOPSIS
      cli_read_prepare_result()
      mysql   connection handle
      stmt    statement handle
  
    RETURN VALUES
      0	ok
      1	error
  */
  
  bool cli_read_prepare_result(MYSQL *mysql, MYSQL_STMT *stmt) {
    uchar *pos;
    uint field_count, param_count;
    ulong packet_length;
    DBUG_TRACE;
  
    /* free old result and initialize mysql->field_alloc */
    free_old_query(mysql);
  
    if ((packet_length = cli_safe_read(mysql, nullptr)) == packet_error)
      return true;
    mysql->warning_count = 0;
  
    pos = (uchar *)mysql->net.read_pos;
    stmt->stmt_id = uint4korr(pos + 1);
    pos += 5;
    /* Number of columns in result set */
    field_count = uint2korr(pos);
    pos += 2;
    /* Number of placeholders in the statement */
    param_count = uint2korr(pos);
    pos += 2;
  
    mysql->resultset_metadata = RESULTSET_METADATA_FULL;
    if (packet_length >= 12) {
      mysql->warning_count = uint2korr(pos + 1);
      if (mysql->client_flag & CLIENT_OPTIONAL_RESULTSET_METADATA) {
        mysql->resultset_metadata =
            static_cast<enum enum_resultset_metadata>(*(pos + 3));
      }
    }
  
    if (param_count != 0 &&
        mysql->resultset_metadata == RESULTSET_METADATA_FULL) {
      MYSQL_TRACE_STAGE(mysql, WAIT_FOR_PARAM_DEF);
      /* skip parameters data: we don't support it yet */
      if (!(cli_read_metadata(mysql, param_count, 7))) return true;
      /* free memory allocated by cli_read_metadata() for parameters data */
      free_root(mysql->field_alloc, MYF(0));
    }
  
    if (field_count != 0) {
      if (!(mysql->server_status & SERVER_STATUS_AUTOCOMMIT))
        mysql->server_status |= SERVER_STATUS_IN_TRANS;
  
      if (mysql->resultset_metadata == RESULTSET_METADATA_FULL) {
        MYSQL_TRACE_STAGE(mysql, WAIT_FOR_FIELD_DEF);
        if (!(stmt->fields =
                  cli_read_metadata_ex(mysql, stmt->mem_root, field_count, 7)))
          return true;
      }
    }
  
    MYSQL_TRACE_STAGE(mysql, READY_FOR_COMMAND);
  
    stmt->field_count = field_count;
    stmt->param_count = (ulong)param_count;
    DBUG_PRINT("exit", ("field_count: %u  param_count: %u  warning_count: %u",
                        field_count, param_count, (uint)mysql->warning_count));
  
    return false;
  }
  
  /*
    Allocate memory and init prepared statement structure.
  
    SYNOPSIS
      mysql_stmt_init()
      mysql   connection handle
  
    DESCRIPTION
      This is an entry point of the new API. Returned handle stands for
      a server-side prepared statement. Memory for this structure (~700
      bytes) is allocated using 'malloc'. Once created, the handle can be
      reused many times. Created statement handle is bound to connection
      handle provided to this call: its lifetime is limited by lifetime
      of connection.
      'mysql_stmt_init()' is a pure local call, server side structure is
      created only in mysql_stmt_prepare.
      Next steps you may want to make:
      - set a statement attribute (mysql_stmt_attr_set()),
      - prepare statement handle with a query (mysql_stmt_prepare()),
      - close statement handle and free its memory (mysql_stmt_close()),
      - reset statement with mysql_stmt_reset() (a no-op which will
        just return).
      Behaviour of the rest of API calls on this statement is not defined yet
      (though we're working on making each wrong call sequence return
      error).
  
    RETURN VALUE
      statement structure upon success and NULL if out of
      memory
  */
  
  MYSQL_STMT *STDCALL mysql_stmt_init(MYSQL *mysql) {
    MYSQL_STMT *stmt;
    DBUG_TRACE;
  
    if (!(stmt = (MYSQL_STMT *)my_malloc(PSI_NOT_INSTRUMENTED, sizeof(MYSQL_STMT),
                                         MYF(MY_WME | MY_ZEROFILL))) ||
        !(stmt->extension = (MYSQL_STMT_EXT *)my_malloc(
              PSI_NOT_INSTRUMENTED, sizeof(MYSQL_STMT_EXT),
              MYF(MY_WME | MY_ZEROFILL))) ||
        !(stmt->mem_root =
              (MEM_ROOT *)my_malloc(PSI_NOT_INSTRUMENTED, sizeof(MEM_ROOT),
                                    MYF(MY_WME | MY_ZEROFILL))) ||
        !(stmt->result.alloc =
              (MEM_ROOT *)my_malloc(PSI_NOT_INSTRUMENTED, sizeof(MEM_ROOT),
                                    MYF(MY_WME | MY_ZEROFILL)))) {
      set_mysql_error(mysql, CR_OUT_OF_MEMORY, unknown_sqlstate);
      my_free(stmt);
      return nullptr;
    }
  
    init_alloc_root(PSI_NOT_INSTRUMENTED, stmt->mem_root, 2048, 2048);
    init_alloc_root(PSI_NOT_INSTRUMENTED, stmt->result.alloc, 4096, 4096);
    mysql->stmts = list_add(mysql->stmts, &stmt->list);
    stmt->list.data = stmt;
    stmt->state = MYSQL_STMT_INIT_DONE;
    stmt->mysql = mysql;
    stmt->read_row_func = stmt_read_row_no_result_set;
    stmt->prefetch_rows = DEFAULT_PREFETCH_ROWS;
    my_stpcpy(stmt->sqlstate, not_error_sqlstate);
    /* The rest of statement members was zeroed inside malloc */
  
    init_alloc_root(PSI_NOT_INSTRUMENTED, &stmt->extension->fields_mem_root, 2048,
                    0);
  
    return stmt;
  }
  
  /*
    Prepare server side statement with query.
  
    SYNOPSIS
      mysql_stmt_prepare()
      stmt    statement handle
      query   statement to prepare
      length  statement length
  
    DESCRIPTION
      Associate statement with statement handle. This is done both on
      client and server sides. At this point the server parses given query
      and creates an internal structure to represent it.
      Next steps you may want to make:
      - find out if this statement returns a result set by
        calling mysql_stmt_field_count(), and get result set metadata
        with mysql_stmt_result_metadata(),
      - if query contains placeholders, bind input parameters to placeholders
        using mysql_stmt_bind_param(),
      - otherwise proceed directly to mysql_stmt_execute().
  
    IMPLEMENTATION NOTES
    - if this is a re-prepare of the statement, first close previous data
      structure on the server and free old statement data
    - then send the query to server and get back number of placeholders,
      number of columns in result set (if any), and result set metadata.
      At the same time allocate memory for input and output parameters
      to have less checks in mysql_stmt_bind_{param, result}.
  
    RETURN VALUES
      0  success
     !0  error
  */
  
  int STDCALL mysql_stmt_prepare(MYSQL_STMT *stmt, const char *query,
                                 ulong length) {
    MYSQL *mysql = stmt->mysql;
    DBUG_TRACE;
  
    if (!mysql) {
      /* mysql can be reset in mysql_close called from mysql_reconnect */
      set_stmt_error(stmt, CR_SERVER_LOST, unknown_sqlstate, nullptr);
      return 1;
    }
  
    /*
      Reset the last error in any case: that would clear the statement
      if the previous prepare failed.
    */
    stmt->last_errno = 0;
    stmt->last_error[0] = '\0';
  
    if ((int)stmt->state > (int)MYSQL_STMT_INIT_DONE) {
      /* This is second prepare with another statement */
      uchar buff[MYSQL_STMT_HEADER]; /* 4 bytes - stmt id */
  
      if (reset_stmt_handle(stmt, RESET_LONG_DATA | RESET_STORE_RESULT)) return 1;
      /*
        These members must be reset for API to
        function in case of error or misuse.
      */
      stmt->bind_param_done = false;
      stmt->bind_result_done = false;
      stmt->param_count = stmt->field_count = 0;
      free_root(stmt->mem_root, MYF(MY_KEEP_PREALLOC));
      free_root(&stmt->extension->fields_mem_root, MYF(0));
  
      int4store(buff, stmt->stmt_id);
  
      /*
        Close statement in server
  
        If there was a 'use' result from another statement, or from
        mysql_use_result it won't be freed in mysql_stmt_free_result and
        we should get 'Commands out of sync' here.
      */
      stmt->state = MYSQL_STMT_INIT_DONE;
      if (stmt_command(mysql, COM_STMT_CLOSE, buff, 4, stmt)) {
        set_stmt_errmsg(stmt, &mysql->net);
        return 1;
      }
    }
  
    if (stmt_command(mysql, COM_STMT_PREPARE, (const uchar *)query, length,
                     stmt)) {
      set_stmt_errmsg(stmt, &mysql->net);
      return 1;
    }
  
    if ((*mysql->methods->read_prepare_result)(mysql, stmt)) {
      set_stmt_errmsg(stmt, &mysql->net);
      return 1;
    }
  
    /*
      alloc_root will return valid address even in case when param_count
      and field_count are zero. Thus we should never rely on stmt->bind
      or stmt->params when checking for existence of placeholders or
      result set.
    */
    if (!(stmt->params = (MYSQL_BIND *)stmt->mem_root->Alloc(
              sizeof(MYSQL_BIND) * (stmt->param_count + stmt->field_count)))) {
      set_stmt_error(stmt, CR_OUT_OF_MEMORY, unknown_sqlstate, nullptr);
      return 1;
    }
    stmt->bind = stmt->params + stmt->param_count;
    stmt->state = MYSQL_STMT_PREPARE_DONE;
    DBUG_PRINT("info", ("Parameter count: %u", stmt->param_count));
    return 0;
  }
  
  /*
    Get result set metadata from reply to mysql_stmt_execute.
    This is used mainly for SHOW commands, as metadata for these
    commands is sent only with result set.
    To be removed when all commands will fully support prepared mode.
  */
  
  static void alloc_stmt_fields(MYSQL_STMT *stmt) {
    MYSQL_FIELD *fields, *field, *end;
    MEM_ROOT *fields_mem_root = &stmt->extension->fields_mem_root;
    MYSQL *mysql = stmt->mysql;
  
    DBUG_ASSERT(stmt->field_count);
  
    free_root(fields_mem_root, MYF(0));
  
    /*
      mysql->fields is NULL when the client set CLIENT_OPTIONAL_RESULTSET_METADATA
      flag and server @@session.resultset_metadata is "NONE". That means that the
      client received a resultset without metadata.
    */
    if (!mysql->fields) return;
  
    /*
      Get the field information for non-select statements
      like SHOW and DESCRIBE commands
    */
    if (!(stmt->fields = (MYSQL_FIELD *)fields_mem_root->Alloc(
              sizeof(MYSQL_FIELD) * stmt->field_count)) ||
        !(stmt->bind = (MYSQL_BIND *)fields_mem_root->Alloc(sizeof(MYSQL_BIND) *
                                                            stmt->field_count))) {
      set_stmt_error(stmt, CR_OUT_OF_MEMORY, unknown_sqlstate, nullptr);
      return;
    }
  
    for (fields = mysql->fields, end = fields + stmt->field_count,
        field = stmt->fields;
         field && fields < end; fields++, field++) {
      *field = *fields; /* To copy all numeric parts. */
      field->catalog =
          strmake_root(fields_mem_root, fields->catalog, fields->catalog_length);
      field->db = strmake_root(fields_mem_root, fields->db, fields->db_length);
      field->table =
          strmake_root(fields_mem_root, fields->table, fields->table_length);
      field->org_table = strmake_root(fields_mem_root, fields->org_table,
                                      fields->org_table_length);
      field->name =
          strmake_root(fields_mem_root, fields->name, fields->name_length);
      field->org_name = strmake_root(fields_mem_root, fields->org_name,
                                     fields->org_name_length);
      if (fields->def) {
        field->def =
            strmake_root(fields_mem_root, fields->def, fields->def_length);
        field->def_length = fields->def_length;
      } else {
        field->def = nullptr;
        field->def_length = 0;
      }
      field->extension = nullptr; /* Avoid dangling links. */
      field->max_length = 0; /* max_length is set in mysql_stmt_store_result() */
    }
  }
  
  /**
    Update result set columns metadata if it was sent again in
    reply to COM_STMT_EXECUTE.
  
    @note If the new field count is different from the original one,
          an error is set and no update is performed.
  */
  
  static void update_stmt_fields(MYSQL_STMT *stmt) {
    MYSQL_FIELD *field = stmt->mysql->fields;
    MYSQL_FIELD *field_end =
        field != nullptr ? field + stmt->field_count : nullptr;
    MYSQL_FIELD *stmt_field = stmt->fields;
    MYSQL_BIND *my_bind = stmt->bind_result_done ? stmt->bind : nullptr;
  
    if (stmt->field_count != stmt->mysql->field_count) {
      /*
        The tables used in the statement were altered,
        and the query now returns a different number of columns.
        There is no way to continue without reallocating the bind
        array:
        - if the number of columns increased, mysql_stmt_fetch()
        will write beyond allocated memory
        - if the number of columns decreased, some user-bound
        buffers will be left unassigned without user knowing
        that.
      */
      set_stmt_error(stmt, CR_NEW_STMT_METADATA, unknown_sqlstate, nullptr);
      return;
    }
  
    /*
      mysql->fields is NULL when the client set CLIENT_OPTIONAL_RESULTSET_METADATA
      flag and server @@session.resultset_metadata is "NONE". That means that the
      client received a resultset without metadata.
    */
    if (!field) return;
  
    for (; field < field_end; ++field, ++stmt_field) {
      stmt_field->charsetnr = field->charsetnr;
      stmt_field->length = field->length;
      stmt_field->type = field->type;
      stmt_field->flags = field->flags;
      stmt_field->decimals = field->decimals;
      if (my_bind) {
        /* Ignore return value: it should be 0 if bind_result succeeded. */
        (void)setup_one_fetch_function(my_bind++, stmt_field);
      }
    }
  }
  
  /*
    Returns prepared statement metadata in the form of a result set.
  
    SYNOPSIS
      mysql_stmt_result_metadata()
      stmt  statement handle
  
    DESCRIPTION
      This function should be used after mysql_stmt_execute().
      You can safely check that prepared statement has a result set by calling
      mysql_stmt_field_count(): if number of fields is not zero, you can call
      this function to get fields metadata.
      Next steps you may want to make:
      - find out number of columns in result set by calling
        mysql_num_fields(res) (the same value is returned by
        mysql_stmt_field_count())
      - fetch metadata for any column with mysql_fetch_field,
        mysql_fetch_field_direct, mysql_fetch_fields, mysql_field_seek.
      - free returned MYSQL_RES structure with mysql_free_result.
      - proceed to binding of output parameters.
  
    RETURN
      NULL  statement contains no result set or out of memory.
            In the latter case you can retreive error message
            with mysql_stmt_error.
      MYSQL_RES  a result set with no rows
  */
  
  MYSQL_RES *STDCALL mysql_stmt_result_metadata(MYSQL_STMT *stmt) {
    MYSQL_RES *result;
    DBUG_TRACE;
  
    /*
      stmt->fields is only defined if stmt->field_count is not null;
      stmt->field_count is initialized in prepare.
    */
    if (!stmt->field_count) return nullptr;
  
    if (!(result = (MYSQL_RES *)my_malloc(PSI_NOT_INSTRUMENTED, sizeof(*result),
                                          MYF(MY_WME | MY_ZEROFILL)))) {
      set_stmt_error(stmt, CR_OUT_OF_MEMORY, unknown_sqlstate, nullptr);
      return nullptr;
    }
  
    result->methods = stmt->mysql->methods;
    result->eof = true; /* Marker for buffered */
    result->fields = stmt->fields;
    result->field_count = stmt->field_count;
    /* The rest of members of 'result' was zeroed inside malloc */
    return result;
  }
  
  /*
    Returns parameter columns meta information in the form of
    result set.
  
    SYNOPSYS
      mysql_stmt_param_metadata()
      stmt    statement handle
  
    DESCRIPTION
      This function can be called after you prepared the statement handle
      with mysql_stmt_prepare().
      XXX: not implemented yet.
  
    RETURN
      MYSQL_RES on success, 0 if there is no metadata.
      Currently this function always returns 0.
  */
  
  MYSQL_RES *STDCALL mysql_stmt_param_metadata(MYSQL_STMT *stmt) {
    DBUG_TRACE;
  
    if (!stmt->param_count) return nullptr;
  
    /*
      TODO: Fix this when server sends the information.
      Till then keep a dummy prototype.
    */
    return nullptr;
  }
  
  static inline int add_binary_row(NET *net, MYSQL_STMT *stmt, ulong pkt_len,
                                   MYSQL_ROWS ***prev_ptr) {
    MYSQL_ROWS *row;
    uchar *cp = net->read_pos;
    MYSQL_DATA *result = &stmt->result;
    if (!(row = (MYSQL_ROWS *)result->alloc->Alloc(sizeof(MYSQL_ROWS) + pkt_len -
                                                   1))) {
      set_stmt_error(stmt, CR_OUT_OF_MEMORY, unknown_sqlstate, nullptr);
      return 1;
    }
    row->data = (MYSQL_ROW)(row + 1);
    **prev_ptr = row;
    *prev_ptr = &row->next;
    memcpy((char *)row->data, (char *)cp + 1, pkt_len - 1);
    row->length = pkt_len; /* To allow us to do sanity checks */
    result->rows++;
    return 0;
  }
  
  /*
    Auxilary function to send COM_STMT_EXECUTE packet to server and read reply.
    Used from cli_stmt_execute, which is in turn used by mysql_stmt_execute.
  */
  
  static bool execute(MYSQL_STMT *stmt, char *packet, ulong length) {
    MYSQL *mysql = stmt->mysql;
    NET *net = &mysql->net;
    uchar buff[4 /* size of stmt id */ + 5 /* execution flags */];
    bool res;
    bool is_data_packet = false;
    ulong pkt_len;
    MYSQL_ROWS **prev_ptr = nullptr;
    DBUG_TRACE;
    DBUG_DUMP("packet", (uchar *)packet, length);
  
    int4store(buff, stmt->stmt_id); /* Send stmt id to server */
    buff[4] = (char)stmt->flags;
    int4store(buff + 5, 1); /* iteration count */
  
    res = (cli_advanced_command(mysql, COM_STMT_EXECUTE, buff, sizeof(buff),
                                (uchar *)packet, length, true, stmt) ||
           (*mysql->methods->read_query_result)(mysql));
  
    if ((mysql->server_capabilities & CLIENT_DEPRECATE_EOF)) {
      if (mysql->server_status & SERVER_STATUS_CURSOR_EXISTS)
        mysql->server_status &= ~SERVER_STATUS_CURSOR_EXISTS;
  
      /*
        After having read the query result, we need to make sure that the client
        does not end up into a hang waiting for the server to send a packet.
        If the CURSOR_TYPE_READ_ONLY flag is set, we would want to perform the
        additional packet read mainly for prepared statements involving SELECT
        queries. For SELECT queries, the result format would either be
        <Metadata><OK> or <Metadata><rows><OK>. We would have read the metadata
        by now and have the field_count populated. The check for field_count will
        help determine if we can expect an additional packet from the server.
      */
  
      if (!res && (stmt->flags & CURSOR_TYPE_READ_ONLY) &&
          mysql->field_count != 0) {
        /*
          server can now respond with a cursor - then the respond will be
          <Metadata><OK> or with binary rows result set <Metadata><row(s)><OK>.
          The former can be the case when the prepared statement is a procedure
          invocation, ie. call(). There also other cases. When server responds
          with <OK> (cursor) packet we read it and get the server status. In case
          it responds with binary row we add it to the binary rows result set
          (the reset of the result set will be read in prepare_to_fetch_result).
        */
  
        if ((pkt_len = cli_safe_read(mysql, &is_data_packet)) == packet_error)
          return true;
  
        if (is_data_packet) {
          DBUG_ASSERT(stmt->result.rows == 0);
          prev_ptr = &stmt->result.data;
          if (add_binary_row(net, stmt, pkt_len, &prev_ptr)) return true;
        } else {
          read_ok_ex(mysql, pkt_len);
          /*
            If the result set was empty and the server did not open a cursor,
            then the response from the server would have been <metadata><OK>.
            This means the OK packet read above was the last OK packet of the
            sequence. Hence, we set the status to indicate that the client is
            now ready for next command. The stmt->read_row_func is set so as
            to ensure that the next call to C API mysql_stmt_fetch() will not
            read on the network. Instead, it will return NO_MORE_DATA.
          */
          if (!(mysql->server_status & SERVER_STATUS_CURSOR_EXISTS)) {
            mysql->status = MYSQL_STATUS_READY;
            stmt->read_row_func = stmt_read_row_no_data;
          }
        }
      }
    }
  
    stmt->affected_rows = mysql->affected_rows;
    stmt->server_status = mysql->server_status;
    stmt->insert_id = mysql->insert_id;
    if (res) {
      /*
        Don't set stmt error if stmt->mysql is NULL, as the error in this case
        has already been set by mysql_prune_stmt_list().
      */
      if (stmt->mysql) set_stmt_errmsg(stmt, net);
      return true;
    } else if (mysql->status == MYSQL_STATUS_GET_RESULT)
      stmt->mysql->status = MYSQL_STATUS_STATEMENT_GET_RESULT;
    return false;
  }
  
  int cli_stmt_execute(MYSQL_STMT *stmt) {
    DBUG_TRACE;
  
    if (stmt->param_count) {
      MYSQL *mysql = stmt->mysql;
      uchar *param_data = nullptr;
      bool result;
      unsigned long param_length = 0;
      bool send_named_params =
          (mysql->server_capabilities & CLIENT_QUERY_ATTRIBUTES) != 0;
  
      if (!stmt->bind_param_done) {
        set_stmt_error(stmt, CR_PARAMS_NOT_BOUND, unknown_sqlstate, nullptr);
        return 1;
      }
      if (mysql->status != MYSQL_STATUS_READY ||
          mysql->server_status & SERVER_MORE_RESULTS_EXISTS) {
        set_stmt_error(stmt, CR_COMMANDS_OUT_OF_SYNC, unknown_sqlstate, nullptr);
        return 1;
      }
  
      if (mysql->net.vio)
        net_clear(&mysql->net, true); /* Sets net->write_pos */
      else {
        set_stmt_errmsg(stmt, &mysql->net);
        return 1;
      }
  
      if (mysql_int_serialize_param_data(
              &mysql->net, stmt->param_count, stmt->params, NULL, 1, &param_data,
              &param_length, stmt->send_types_to_server, send_named_params,
              false)) {
        set_stmt_errmsg(stmt, &mysql->net);
        return 1;
      }
  
      result = execute(stmt, pointer_cast<char *>(param_data), param_length);
      stmt->send_types_to_server = false;
      my_free(param_data);
      return result;
    }
    return (int)execute(stmt, nullptr, 0);
  }
  
  /*
    Read one row from buffered result set.  Result set is created by prior
    call to mysql_stmt_store_result().
    SYNOPSIS
      stmt_read_row_buffered()
  
    RETURN VALUE
      0             - success; *row is set to valid row pointer (row data
                      is stored in result set buffer)
      MYSQL_NO_DATA - end of result set. *row is set to NULL
  */
  
  static int stmt_read_row_buffered(MYSQL_STMT *stmt, unsigned char **row) {
    if (stmt->data_cursor) {
      *row = (uchar *)stmt->data_cursor->data;
      stmt->data_cursor = stmt->data_cursor->next;
      return 0;
    }
    *row = nullptr;
    return MYSQL_NO_DATA;
  }
  
  /*
    Read one row from network: unbuffered non-cursor fetch.
    If last row was read, or error occurred, erase this statement
    from record pointing to object unbuffered fetch is performed from.
  
    SYNOPSIS
      stmt_read_row_unbuffered()
      stmt  statement handle
      row   pointer to write pointer to row data;
  
    RETURN VALUE
      0           - success; *row contains valid address of a row;
                    row data is stored in network buffer
      1           - error; error code is written to
                    stmt->last_{errno,error}; *row is not changed
    MYSQL_NO_DATA - end of file was read from network;
                    *row is set to NULL
  */
  
  static int stmt_read_row_unbuffered(MYSQL_STMT *stmt, unsigned char **row) {
    int rc = 1;
    MYSQL *mysql = stmt->mysql;
    /*
      This function won't be called if stmt->field_count is zero
      or execution wasn't done: this is ensured by mysql_stmt_execute.
    */
    if (!mysql) {
      set_stmt_error(stmt, CR_SERVER_LOST, unknown_sqlstate, nullptr);
      return 1;
    }
    if (mysql->status != MYSQL_STATUS_STATEMENT_GET_RESULT) {
      set_stmt_error(stmt,
                     stmt->unbuffered_fetch_cancelled ? CR_FETCH_CANCELED
                                                      : CR_COMMANDS_OUT_OF_SYNC,
                     unknown_sqlstate, nullptr);
      goto error;
    }
    if ((*mysql->methods->unbuffered_fetch)(mysql, (char **)row)) {
      set_stmt_errmsg(stmt, &mysql->net);
      /*
        If there was an error, there are no more pending rows:
        reset statement status to not hang up in following
        mysql_stmt_close (it will try to flush result set before
        closing the statement).
      */
      mysql->status = MYSQL_STATUS_READY;
      goto error;
    }
    if (!*row) {
      mysql->status = MYSQL_STATUS_READY;
      rc = MYSQL_NO_DATA;
      goto error;
    }
    return 0;
  error:
    if (mysql->unbuffered_fetch_owner == &stmt->unbuffered_fetch_cancelled)
      mysql->unbuffered_fetch_owner = nullptr;
    return rc;
  }
  
  /*
    Fetch statement row using server side cursor.
  
    SYNOPSIS
      stmt_read_row_from_cursor()
  
    RETURN VALUE
      0            success
      1            error
    MYSQL_NO_DATA  end of data
  */
  
  static int stmt_read_row_from_cursor(MYSQL_STMT *stmt, unsigned char **row) {
    if (stmt->data_cursor) return stmt_read_row_buffered(stmt, row);
    if (stmt->server_status & SERVER_STATUS_LAST_ROW_SENT)
      stmt->server_status &= ~SERVER_STATUS_LAST_ROW_SENT;
    else {
      MYSQL *mysql = stmt->mysql;
      NET *net = &mysql->net;
      MYSQL_DATA *result = &stmt->result;
      uchar buff[4 /* statement id */ + 4 /* number of rows to fetch */];
  
      free_root(result->alloc, MYF(MY_KEEP_PREALLOC));
      result->data = nullptr;
      result->rows = 0;
      /* Send row request to the server */
      int4store(buff, stmt->stmt_id);
      int4store(buff + 4, stmt->prefetch_rows); /* number of rows to fetch */
      if ((*mysql->methods->advanced_command)(mysql, COM_STMT_FETCH, buff,
                                              sizeof(buff), (uchar *)nullptr, 0,
                                              true, stmt)) {
        /*
          Don't set stmt error if stmt->mysql is NULL, as the error in this case
          has already been set by mysql_prune_stmt_list().
        */
        if (stmt->mysql) set_stmt_errmsg(stmt, net);
        return 1;
      }
      if ((*mysql->methods->read_rows_from_cursor)(stmt)) return 1;
      stmt->server_status = mysql->server_status;
  
      stmt->data_cursor = result->data;
      return stmt_read_row_buffered(stmt, row);
    }
    *row = nullptr;
    return MYSQL_NO_DATA;
  }
  
  /*
    Default read row function to not SIGSEGV in client in
    case of wrong sequence of API calls.
  */
  
  static int stmt_read_row_no_data(MYSQL_STMT *stmt MY_ATTRIBUTE((unused)),
                                   unsigned char **row MY_ATTRIBUTE((unused))) {
    return MYSQL_NO_DATA;
  }
  
  static int stmt_read_row_no_result_set(MYSQL_STMT *stmt MY_ATTRIBUTE((unused)),
                                         unsigned char **row
                                             MY_ATTRIBUTE((unused))) {
    set_stmt_error(stmt, CR_NO_RESULT_SET, unknown_sqlstate, nullptr);
    return 1;
  }
  
  /*
    Get/set statement attributes
  
    SYNOPSIS
      mysql_stmt_attr_get()
      mysql_stmt_attr_set()
  
      attr_type  statement attribute
      value      casted to const void * pointer to value.
  
    RETURN VALUE
      0 success
     !0 wrong attribute type
  */
  
  bool STDCALL mysql_stmt_attr_set(MYSQL_STMT *stmt,
                                   enum enum_stmt_attr_type attr_type,
                                   const void *value) {
    switch (attr_type) {
      case STMT_ATTR_UPDATE_MAX_LENGTH:
        stmt->update_max_length = value ? *(const bool *)value : false;
        break;
      case STMT_ATTR_CURSOR_TYPE: {
        ulong cursor_type;
        cursor_type = value ? *static_cast<const ulong *>(value) : 0UL;
        if (cursor_type > (ulong)CURSOR_TYPE_READ_ONLY) goto err_not_implemented;
        stmt->flags = cursor_type;
        break;
      }
      case STMT_ATTR_PREFETCH_ROWS: {
        ulong prefetch_rows =
            value ? *static_cast<const ulong *>(value) : DEFAULT_PREFETCH_ROWS;
        if (value == nullptr) return true;
        stmt->prefetch_rows = prefetch_rows;
        break;
      }
      default:
        goto err_not_implemented;
    }
    return false;
  err_not_implemented:
    set_stmt_error(stmt, CR_NOT_IMPLEMENTED, unknown_sqlstate, nullptr);
    return true;
  }
  
  bool STDCALL mysql_stmt_attr_get(MYSQL_STMT *stmt,
                                   enum enum_stmt_attr_type attr_type,
                                   void *value) {
    switch (attr_type) {
      case STMT_ATTR_UPDATE_MAX_LENGTH:
        *(bool *)value = stmt->update_max_length;
        break;
      case STMT_ATTR_CURSOR_TYPE:
        *(ulong *)value = stmt->flags;
        break;
      case STMT_ATTR_PREFETCH_ROWS:
        *(ulong *)value = stmt->prefetch_rows;
        break;
      default:
        return true;
    }
    return false;
  }
  
  /**
    Update statement result set metadata from with the new field
    information sent during statement execute.
  
    @pre mysql->field_count is not zero
  */
  
  static void reinit_result_set_metadata(MYSQL_STMT *stmt) {
    /* Server has sent result set metadata */
    if (stmt->field_count == 0) {
      /*
        This is 'SHOW'/'EXPLAIN'-like query. Current implementation of
        prepared statements can't send result set metadata for these queries
        on prepare stage. Read it now.
      */
  
      stmt->field_count = stmt->mysql->field_count;
  
      alloc_stmt_fields(stmt);
    } else {
      /*
        Update result set metadata if it for some reason changed between
        prepare and execute, i.e.:
        - in case of 'SELECT ?' we don't know column type unless data was
        supplied to mysql_stmt_execute, so updated column type is sent
        now.
        - if data dictionary changed between prepare and execute, for
        example a table used in the query was altered.
        Note, that now (4.1.3) we always send metadata in reply to
        COM_STMT_EXECUTE (even if it is not necessary), so either this or
        previous branch always works.
        TODO: send metadata only when it's really necessary and add a warning
        'Metadata changed' when it's sent twice.
      */
      update_stmt_fields(stmt);
    }
  }
  
  static void prepare_to_fetch_result(MYSQL_STMT *stmt) {
    if (stmt->server_status & SERVER_STATUS_CURSOR_EXISTS) {
      stmt->mysql->status = MYSQL_STATUS_READY;
      stmt->read_row_func = stmt_read_row_from_cursor;
    } else if (stmt->flags & CURSOR_TYPE_READ_ONLY) {
      /*
        This is a single-row result set, a result set with no rows, EXPLAIN,
        SHOW VARIABLES, or some other command which either a) bypasses the
        cursors framework in the server and writes rows directly to the
        network or b) is more efficient if all (few) result set rows are
        precached on client and server's resources are freed.
        The below check for mysql->status is required because we could
        have already read the last packet sent by the server in execute()
        and set the status to MYSQL_STATUS_READY. In such cases, we need
        not call mysql_stmt_store_result().
      */
      if (stmt->mysql->status != MYSQL_STATUS_READY)
        mysql_stmt_store_result(stmt);
    } else {
      stmt->mysql->unbuffered_fetch_owner = &stmt->unbuffered_fetch_cancelled;
      stmt->unbuffered_fetch_cancelled = false;
      stmt->read_row_func = stmt_read_row_unbuffered;
    }
  }
  
  /*
    Send placeholders data to server (if there are placeholders)
    and execute prepared statement.
  
    SYNOPSIS
      mysql_stmt_execute()
      stmt  statement handle. The handle must be created
            with mysql_stmt_init() and prepared with
            mysql_stmt_prepare(). If there are placeholders
            in the statement they must be bound to local
            variables with mysql_stmt_bind_param().
  
    DESCRIPTION
      This function will automatically flush pending result
      set (if there is one), send parameters data to the server
      and read result of statement execution.
      If previous result set was cached with mysql_stmt_store_result()
      it will also be freed in the beginning of this call.
      The server can return 3 types of responses to this command:
      - error, can be retrieved with mysql_stmt_error()
      - ok, no result set pending. In this case we just update
        stmt->insert_id and stmt->affected_rows.
      - the query returns a result set: there could be 0 .. N
      rows in it. In this case the server can also send updated
      result set metadata.
  
      Next steps you may want to make:
      - find out if there is result set with mysql_stmt_field_count().
      If there is one:
      - optionally, cache entire result set on client to unblock
      connection with mysql_stmt_store_result()
      - bind client variables to result set columns and start read rows
      with mysql_stmt_fetch().
      - reset statement with mysql_stmt_reset() or close it with
      mysql_stmt_close()
      Otherwise:
      - find out last insert id and number of affected rows with
      mysql_stmt_insert_id(), mysql_stmt_affected_rows()
  
    RETURN
      0   success
      1   error, message can be retrieved with mysql_stmt_error().
  */
  
  int STDCALL mysql_stmt_execute(MYSQL_STMT *stmt) {
    MYSQL *mysql = stmt->mysql;
    DBUG_TRACE;
  
    if (!mysql) {
      /* Error is already set in mysql_detatch_stmt_list */
      return 1;
    }
  
    if (reset_stmt_handle(stmt, RESET_STORE_RESULT | RESET_CLEAR_ERROR)) return 1;
    /*
      No need to check for stmt->state: if the statement wasn't
      prepared we'll get 'unknown statement handler' error from server.
    */
    if (mysql->methods->stmt_execute(stmt)) return 1;
    stmt->state = MYSQL_STMT_EXECUTE_DONE;
    if (mysql->field_count) {
      reinit_result_set_metadata(stmt);
      prepare_to_fetch_result(stmt);
    }
    return stmt->last_errno != 0;
  }
  
  /*
    Return total parameters count in the statement
  */
  
  ulong STDCALL mysql_stmt_param_count(MYSQL_STMT *stmt) {
    DBUG_TRACE;
    return stmt->param_count;
  }
  
  /*
    Return total affected rows from the last statement
  */
  
  uint64_t STDCALL mysql_stmt_affected_rows(MYSQL_STMT *stmt) {
    return stmt->affected_rows;
  }
  
  /*
    Returns the number of result columns for the most recent query
    run on this statement.
  */
  
  unsigned int STDCALL mysql_stmt_field_count(MYSQL_STMT *stmt) {
    return stmt->field_count;
  }
  
  /*
    Return last inserted id for auto_increment columns.
  
    SYNOPSIS
      mysql_stmt_insert_id()
      stmt    statement handle
  
    DESCRIPTION
      Current implementation of this call has a caveat: stmt->insert_id is
      unconditionally updated from mysql->insert_id in the end of each
      mysql_stmt_execute(). This works OK if mysql->insert_id contains new
      value (sent in reply to mysql_stmt_execute()), otherwise stmt->insert_id
      value gets undefined, as it's updated from some arbitrary value saved in
      connection structure during some other call.
  */
  
  uint64_t STDCALL mysql_stmt_insert_id(MYSQL_STMT *stmt) {
    return stmt->insert_id;
  }
  
  /*
    Set up input data buffers for a statement.
  
    SYNOPSIS
      mysql_stmt_bind_param()
      stmt    statement handle
              The statement must be prepared with mysql_stmt_prepare().
      my_bind Array of mysql_stmt_param_count() bind parameters.
              This function doesn't check that size of this argument
              is >= mysql_stmt_field_count(): it's user's responsibility.
  
    DESCRIPTION
      Use this call after mysql_stmt_prepare() to bind user variables to
      placeholders.
      Each element of bind array stands for a placeholder. Placeholders
      are counted from 0.  For example statement
      'INSERT INTO t (a, b) VALUES (?, ?)'
      contains two placeholders, and for such statement you should supply
      bind array of two elements (MYSQL_BIND bind[2]).
  
      By properly initializing bind array you can bind virtually any
      C language type to statement's placeholders:
      First, it's strongly recommended to always zero-initialize entire
      bind structure before setting its members. This will both shorten
      your application code and make it robust to future extensions of
      MYSQL_BIND structure.
      Then you need to assign typecode of your application buffer to
      MYSQL_BIND::buffer_type. The following typecodes with their
      correspondence to C language types are supported:
      MYSQL_TYPE_TINY       for 8-bit integer variables. Normally it's
                            'signed char' and 'unsigned char';
      MYSQL_TYPE_SHORT      for 16-bit signed and unsigned variables. This
                            is usually 'short' and 'unsigned short';
      MYSQL_TYPE_LONG       for 32-bit signed and unsigned variables. It
                            corresponds to 'int' and 'unsigned int' on
                            vast majority of platforms. On IA-32 and some
                            other 32-bit systems you can also use 'long'
                            here;
      MYSQL_TYPE_LONGLONG   64-bit signed or unsigned integer.  Stands for
                            '[unsigned] long long' on most platforms;
      MYSQL_TYPE_FLOAT      32-bit floating point type, 'float' on most
                            systems;
      MYSQL_TYPE_DOUBLE     64-bit floating point type, 'double' on most
                            systems;
      MYSQL_TYPE_TIME       broken-down time stored in MYSQL_TIME
                            structure
      MYSQL_TYPE_DATE       date stored in MYSQL_TIME structure
      MYSQL_TYPE_DATETIME   datetime stored in MYSQL_TIME structure See
                            more on how to use these types for sending
                            dates and times below;
      MYSQL_TYPE_STRING     character string, assumed to be in
                            character-set-client. If character set of
                            client is not equal to character set of
                            column, value for this placeholder will be
                            converted to destination character set before
                            insert.
      MYSQL_TYPE_BLOB       sequence of bytes. This sequence is assumed to
                            be in binary character set (which is the same
                            as no particular character set), and is never
                            converted to any other character set. See also
                            notes about supplying string/blob length
                            below.
      MYSQL_TYPE_NULL       special typecode for binding nulls.
      These C/C++ types are not supported yet by the API: long double,
      bool.
  
      As you can see from the list above, it's responsibility of
      application programmer to ensure that chosen typecode properly
      corresponds to host language type. For example on all platforms
      where we build MySQL packages (as of MySQL 4.1.4) int is a 32-bit
      type. So for int you can always assume that proper typecode is
      MYSQL_TYPE_LONG (however queer it sounds, the name is legacy of the
      old MySQL API). In contrary sizeof(long) can be 4 or 8 8-bit bytes,
      depending on platform.
  
      TODO: provide client typedefs for each integer and floating point
      typecode, i. e. int8, uint8, float32, etc.
  
      Once typecode was set, it's necessary to assign MYSQL_BIND::buffer
      to point to the buffer of given type. Finally, additional actions
      may be taken for some types or use cases:
  
      Binding integer types.
        For integer types you might also need to set MYSQL_BIND::is_unsigned
        member. Set it to true when binding unsigned char, unsigned short,
        unsigned int, unsigned long, unsigned long long.
  
      Binding floating point types.
        For floating point types you just need to set
        MYSQL_BIND::buffer_type and MYSQL_BIND::buffer. The rest of the
        members should be zero-initialized.
  
      Binding NULLs.
        You might have a column always NULL, never NULL, or sometimes
        NULL.  For an always NULL column set MYSQL_BIND::buffer_type to
        MYSQL_TYPE_NULL.  The rest of the members just need to be
        zero-initialized.  For never NULL columns set
        MYSQL_BIND::is_null to 0, or this has already been done if you
        zero-initialized the entire structure.  If you set
        MYSQL_TYPE::is_null to point to an application buffer of type
        'bool', then this buffer will be checked on each execution:
        this way you can set the buffer to true, or any non-0 value for
        NULLs, and to false or 0 for not NULL data.
  
      Binding text strings and sequences of bytes.
        For strings, in addition to MYSQL_BIND::buffer_type and
        MYSQL_BIND::buffer you need to set MYSQL_BIND::length or
        MYSQL_BIND::buffer_length.  If 'length' is set, 'buffer_length'
        is ignored. 'buffer_length' member should be used when size of
        string doesn't change between executions. If you want to vary
        buffer length for each value, set 'length' to point to an
        application buffer of type 'unsigned long' and set this long to
        length of the string before each mysql_stmt_execute().
  
      Binding dates and times.
        For binding dates and times prepared statements API provides
        clients with MYSQL_TIME structure. A pointer to instance of this
        structure should be assigned to MYSQL_BIND::buffer whenever
        MYSQL_TYPE_TIME, MYSQL_TYPE_DATE, MYSQL_TYPE_DATETIME typecodes
        are used.  When typecode is MYSQL_TYPE_TIME, only members
        'hour', 'minute', 'second' and 'neg' (is time offset negative)
        are used. These members only will be sent to the server.
        MYSQL_TYPE_DATE implies use of 'year', 'month', 'day', 'neg'.
        MYSQL_TYPE_DATETIME utilizes both parts of MYSQL_TIME structure.
        You don't have to set MYSQL_TIME::time_type member: it's not
        used when sending data to the server, typecode information is
        enough.  'second_part' member can hold microsecond precision of
        time value, but now it's only supported on protocol level: you
        can't store microsecond in a column, or use in temporal
        calculations. However, if you send a time value with microsecond
        part for 'SELECT ?', statement, you'll get it back unchanged
        from the server.
  
      Data conversion.
        If conversion from host language type to data representation,
        corresponding to SQL type, is required it's done on the server.
        Data truncation is possible when conversion is lossy. For
        example, if you supply MYSQL_TYPE_DATETIME value out of valid
        SQL type TIMESTAMP range, the same conversion will be applied as
        if this value would have been sent as string in the old
        protocol.  TODO: document how the server will behave in case of
        truncation/data loss.
  
      After variables were bound, you can repeatedly set/change their
      values and mysql_stmt_execute() the statement.
  
      See also: mysql_stmt_send_long_data() for sending long text/blob
      data in pieces, examples in tests/mysql_client_test.c.
      Next steps you might want to make:
      - execute statement with mysql_stmt_execute(),
      - reset statement using mysql_stmt_reset() or reprepare it with
        another query using mysql_stmt_prepare()
      - close statement with mysql_stmt_close().
  
    IMPLEMENTATION
      The function copies given bind array to internal storage of the
      statement, and sets up typecode-specific handlers to perform
      serialization of bound data. This means that although you don't need
      to call this routine after each assignment to bind buffers, you
      need to call it each time you change parameter typecodes, or other
      members of MYSQL_BIND array.
      This is a pure local call. Data types of client buffers are sent
      along with buffers' data at first execution of the statement.
  
    RETURN
      0  success
      1  error, can be retrieved with mysql_stmt_error.
  */
  
  bool STDCALL mysql_stmt_bind_param(MYSQL_STMT *stmt, MYSQL_BIND *my_bind) {
    uint count = 0;
    MYSQL_BIND *param, *end;
    DBUG_TRACE;
  
    if (!stmt->param_count) {
      if ((int)stmt->state < (int)MYSQL_STMT_PREPARE_DONE) {
        set_stmt_error(stmt, CR_NO_PREPARE_STMT, unknown_sqlstate, nullptr);
        return true;
      }
      return false;
    }
  
    /* Allocated on prepare */
    memcpy((char *)stmt->params, (char *)my_bind,
           sizeof(MYSQL_BIND) * stmt->param_count);
  
    for (param = stmt->params, end = param + stmt->param_count; param < end;
         param++) {
      if (fix_param_bind(param, count++)) {
        my_stpcpy(stmt->sqlstate, unknown_sqlstate);
        sprintf(stmt->last_error,
                ER_CLIENT(stmt->last_errno = CR_UNSUPPORTED_PARAM_TYPE),
                param->buffer_type, count);
        return true;
      }
    }
    /* We have to send/resend type information to MySQL */
    stmt->send_types_to_server = true;
    stmt->bind_param_done = true;
    return false;
  }
  
  bool STDCALL mysql_bind_param(MYSQL *mysql, unsigned n_params,
                                MYSQL_BIND *binds, const char **names) {
    MYSQL_EXTENSION *ext = MYSQL_EXTENSION_PTR(mysql);
  
    mysql_extension_bind_free(ext);
  
    /* if any of the above is empty our work here is done */
    if (!n_params || !binds || !names) return false;
  
    ext->bind_info.n_params = n_params;
    ext->bind_info.bind = (MYSQL_BIND *)my_malloc(
        PSI_NOT_INSTRUMENTED, sizeof(MYSQL_BIND) * n_params, MYF(0));
    ext->bind_info.names = (char **)my_malloc(PSI_NOT_INSTRUMENTED,
                                              sizeof(char *) * n_params, MYF(0));
  
    memcpy(ext->bind_info.bind, binds, sizeof(MYSQL_BIND) * n_params);
  
    MYSQL_BIND *param = ext->bind_info.bind;
    for (uint idx = 0; idx < n_params; idx++, param++) {
      ext->bind_info.names[idx] =
          names[idx] ? my_strdup(PSI_NOT_INSTRUMENTED, names[idx], MYF(0))
                     : nullptr;
      if (fix_param_bind(param, idx)) {
        my_stpcpy(mysql->net.sqlstate, unknown_sqlstate);
        sprintf(mysql->net.last_error,
                ER_CLIENT(mysql->net.last_errno = CR_UNSUPPORTED_PARAM_TYPE),
                param->buffer_type, idx);
        for (uint idx2 = 0; idx2 <= idx; idx2++)
          my_free(ext->bind_info.names[idx]);
        my_free(ext->bind_info.names);
        my_free(ext->bind_info.bind);
        memset(&ext->bind_info, 0, sizeof(ext->bind_info));
        return true;
      }
    }
    return false;
  }
  
  /********************************************************************
   Long data implementation
  *********************************************************************/
  
  /*
    Send long data in pieces to the server
  
    SYNOPSIS
      mysql_stmt_send_long_data()
      stmt			Statement handler
      param_number		Parameter number (0 - N-1)
      data			Data to send to server
      length			Length of data to send (may be 0)
  
    DESCRIPTION
      This call can be used repeatedly to send long data in pieces
      for any string/binary placeholder. Data supplied for
      a placeholder is saved at server side till execute, and then
      used instead of value from MYSQL_BIND object. More precisely,
      if long data for a parameter was supplied, MYSQL_BIND object
      corresponding to this parameter is not sent to server. In the
      end of execution long data states of placeholders are reset,
      so next time values of such placeholders will be taken again
      from MYSQL_BIND array.
      The server does not reply to this call: if there was an error
      in data handling (which now only can happen if server run out
      of memory) it would be returned in reply to
      mysql_stmt_execute().
      You should choose type of long data carefully if you care
      about character set conversions performed by server when the
      statement is executed.  No conversion is performed at all for
      MYSQL_TYPE_BLOB and other binary typecodes. For
      MYSQL_TYPE_STRING and the rest of text placeholders data is
      converted from client character set to character set of
      connection. If these character sets are different, this
      conversion may require additional memory at server, equal to
      total size of supplied pieces.
  
    RETURN VALUES
      0	ok
      1	error
  */
  
  bool STDCALL mysql_stmt_send_long_data(MYSQL_STMT *stmt, uint param_number,
                                         const char *data, ulong length) {
    MYSQL_BIND *param;
    DBUG_TRACE;
    DBUG_ASSERT(stmt != nullptr);
    DBUG_PRINT("enter", ("param no: %d  data: %p, length : %ld", param_number,
                         data, length));
  
    /*
      We only need to check for stmt->param_count, if it's not null
      prepare was done.
    */
    if (param_number >= stmt->param_count) {
      set_stmt_error(stmt, CR_INVALID_PARAMETER_NO, unknown_sqlstate, nullptr);
      return true;
    }
  
    param = stmt->params + param_number;
    if (!IS_LONGDATA(param->buffer_type)) {
      /* Long data handling should be used only for string/binary types */
      my_stpcpy(stmt->sqlstate, unknown_sqlstate);
      sprintf(stmt->last_error,
              ER_CLIENT(stmt->last_errno = CR_INVALID_BUFFER_USE),
              param->param_number);
      return true;
    }
  
    /*
      Send long data packet if there is data or we're sending long data
      for the first time.
    */
    if (length || param->long_data_used == 0) {
      MYSQL *mysql = stmt->mysql;
      /* Packet header: stmt id (4 bytes), param no (2 bytes) */
      uchar buff[MYSQL_LONG_DATA_HEADER];
  
      int4store(buff, stmt->stmt_id);
      int2store(buff + 4, param_number);
      param->long_data_used = true;
  
      /*
        Note that we don't get any ok packet from the server in this case
        This is intentional to save bandwidth.
      */
      if ((*mysql->methods->advanced_command)(
              mysql, COM_STMT_SEND_LONG_DATA, buff, sizeof(buff),
              pointer_cast<const uchar *>(data), length, true, stmt)) {
        /*
          Don't set stmt error if stmt->mysql is NULL, as the error in this case
          has already been set by mysql_prune_stmt_list().
        */
        if (stmt->mysql) set_stmt_errmsg(stmt, &mysql->net);
        return true;
      }
    }
    return false;
  }
  
  /********************************************************************
   Fetch and conversion of result set rows (binary protocol).
  *********************************************************************/
  
  /*
    Read date, (time, datetime) value from network buffer and store it
    in MYSQL_TIME structure.
  
    SYNOPSIS
      read_binary_{date,time,datetime}()
      tm    MYSQL_TIME structure to fill
      pos   pointer to current position in network buffer.
            These functions increase pos to point to the beginning of the
            next column.
  
    Auxiliary functions to read time (date, datetime) values from network
    buffer and store in MYSQL_TIME structure. Jointly used by conversion
    and no-conversion fetching.
  */
  
  static void read_binary_time(MYSQL_TIME *tm, uchar **pos) {
    /* net_field_length will set pos to the first byte of data */
    uint length = net_field_length(pos);
  
    if (length) {
      uchar *to = *pos;
      tm->neg = to[0];
  
      tm->day = (ulong)sint4korr(to + 1);
      tm->hour = (uint)to[5];
      tm->minute = (uint)to[6];
      tm->second = (uint)to[7];
      tm->second_part = (length > 8) ? (ulong)sint4korr(to + 8) : 0;
      tm->year = tm->month = 0;
      if (tm->day) {
        /* Convert days to hours at once */
        tm->hour += tm->day * 24;
        tm->day = 0;
      }
      tm->time_type = MYSQL_TIMESTAMP_TIME;
  
      *pos += length;
    } else
      set_zero_time(tm, MYSQL_TIMESTAMP_TIME);
  }
  
  static void read_binary_datetime(MYSQL_TIME *tm, uchar **pos) {
    uint length = net_field_length(pos);
  
    if (length) {
      uchar *to = *pos;
  
      tm->neg = false;
      tm->year = (uint)sint2korr(to);
      tm->month = (uint)to[2];
      tm->day = (uint)to[3];
  
      if (length > 4) {
        tm->hour = (uint)to[4];
        tm->minute = (uint)to[5];
        tm->second = (uint)to[6];
      } else
        tm->hour = tm->minute = tm->second = 0;
      tm->second_part = (length > 7) ? (ulong)sint4korr(to + 7) : 0;
      tm->time_type = MYSQL_TIMESTAMP_DATETIME;
  
      *pos += length;
    } else
      set_zero_time(tm, MYSQL_TIMESTAMP_DATETIME);
  }
  
  static void read_binary_date(MYSQL_TIME *tm, uchar **pos) {
    uint length = net_field_length(pos);
  
    if (length) {
      uchar *to = *pos;
      tm->year = (uint)sint2korr(to);
      tm->month = (uint)to[2];
      tm->day = (uint)to[3];
  
      tm->hour = tm->minute = tm->second = 0;
      tm->second_part = 0;
      tm->neg = false;
      tm->time_type = MYSQL_TIMESTAMP_DATE;
  
      *pos += length;
    } else
      set_zero_time(tm, MYSQL_TIMESTAMP_DATE);
  }
  
  /*
    Convert string to supplied buffer of any type.
  
    SYNOPSIS
      fetch_string_with_conversion()
      param   output buffer descriptor
      value   column data
      length  data length
  */
  
  static void fetch_string_with_conversion(MYSQL_BIND *param, char *value,
                                           size_t length) {
    uchar *buffer = pointer_cast<uchar *>(param->buffer);
    const char *endptr = value + length;
  
    /*
      This function should support all target buffer types: the rest
      of conversion functions can delegate conversion to it.
    */
    switch (param->buffer_type) {
      case MYSQL_TYPE_NULL: /* do nothing */
        break;
      case MYSQL_TYPE_TINY: {
        int err;
        longlong data = my_strtoll10(value, &endptr, &err);
        *param->error = (IS_TRUNCATED(data, param->is_unsigned, INT_MIN8,
                                      INT_MAX8, UINT_MAX8) ||
                         err > 0);
        *buffer = (uchar)data;
        break;
      }
      case MYSQL_TYPE_SHORT: {
        int err;
        longlong data = my_strtoll10(value, &endptr, &err);
        *param->error = (IS_TRUNCATED(data, param->is_unsigned, INT_MIN16,
                                      INT_MAX16, UINT_MAX16) ||
                         err > 0);
        shortstore(buffer, (short)data);
        break;
      }
      case MYSQL_TYPE_LONG: {
        int err;
        longlong data = my_strtoll10(value, &endptr, &err);
        *param->error = (IS_TRUNCATED(data, param->is_unsigned, INT_MIN32,
                                      INT_MAX32, UINT_MAX32) ||
                         err > 0);
        longstore(buffer, (int32)data);
        break;
      }
      case MYSQL_TYPE_LONGLONG: {
        int err;
        longlong data = my_strtoll10(value, &endptr, &err);
        *param->error =
            param->is_unsigned ? err != 0 : (err > 0 || (err == 0 && data < 0));
        longlongstore(buffer, data);
        break;
      }
      case MYSQL_TYPE_FLOAT: {
        int err;
        double data =
            my_strntod(&my_charset_latin1, value, length, &endptr, &err);
        float fdata = (float)data;
        *param->error = (fdata != data) | (err != 0);
        floatstore(buffer, fdata);
        break;
      }
      case MYSQL_TYPE_DOUBLE: {
        int err;
        double data =
            my_strntod(&my_charset_latin1, value, length, &endptr, &err);
        *param->error = (err != 0);
        doublestore(buffer, data);
        break;
      }
      case MYSQL_TYPE_TIME: {
        MYSQL_TIME_STATUS status;
        MYSQL_TIME *tm = (MYSQL_TIME *)buffer;
        str_to_time(value, length, tm, &status);
        *param->error = (status.warnings != 0);
        break;
      }
      case MYSQL_TYPE_DATE:
      case MYSQL_TYPE_DATETIME:
      case MYSQL_TYPE_TIMESTAMP: {
        MYSQL_TIME_STATUS status;
        MYSQL_TIME *tm = (MYSQL_TIME *)buffer;
        (void)str_to_datetime(value, length, tm, TIME_FUZZY_DATE, &status);
        *param->error =
            (status.warnings != 0) && (param->buffer_type == MYSQL_TYPE_DATE &&
                                       tm->time_type != MYSQL_TIMESTAMP_DATE);
        break;
      }
      case MYSQL_TYPE_TINY_BLOB:
      case MYSQL_TYPE_MEDIUM_BLOB:
      case MYSQL_TYPE_LONG_BLOB:
      case MYSQL_TYPE_BLOB:
      case MYSQL_TYPE_DECIMAL:
      case MYSQL_TYPE_NEWDECIMAL:
      default: {
        /*
          Copy column data to the buffer taking into account offset,
          data length and buffer length.
        */
        char *start = value + param->offset;
        char *end = value + length;
        size_t copy_length;
        if (start < end) {
          copy_length = end - start;
          /* We've got some data beyond offset: copy up to buffer_length bytes */
          if (param->buffer_length)
            memcpy(buffer, start,
                   std::min<size_t>(copy_length, param->buffer_length));
        } else
          copy_length = 0;
        if (copy_length < param->buffer_length) buffer[copy_length] = '\0';
        *param->error = copy_length > param->buffer_length;
        /*
          param->length will always contain length of entire column;
          number of copied bytes may be way different:
        */
        *param->length = (unsigned long)length;
        break;
      }
    }
  }
  
  // Convert an integer (signed or unsigned) to float/double, with checking
  // for loss of precision in the conversion. (double can represent all integers
  // up to 2^53 exactly, but only certain integers above this limit. For instance,
  // 2^53 + 1 is rounded off, while 2^53 + 2 is exact.)
  template <class Int, class Float>
  static inline Float convert_with_inexact_check(Int i, bool *is_inexact) {
    /*
      We need to mark the local variable volatile to
      workaround Intel FPU executive precision feature.
      (See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=323 for details)
     */
    volatile Float f = static_cast<Float>(i);
  
    // If i is positive, it is possible for it to have been rounded outside
    // Int's range. If so, converting back to check is undefined behavior,
    // and UBSan will complain. Thus, we need to check before we convert.
    // Rounding of 2^64 - 1 (and similarly for int64_t) to float/double is
    // platform-dependent, so we need a bit of trickery to get the right
    // value in a safe manner.
    //
    // For both int64_t and uint64_t, the minimum possible value is a
    // (negative) power of two, which is exact, so the test is applicable
    // for max() only.
    constexpr Float out_of_range =
        static_cast<Float>(1ULL << (std::numeric_limits<Int>::digits - 1)) *
        (std::numeric_limits<Int>::is_signed ? 1.0 : 2.0);
    if (f >= out_of_range) {
      // Obviously inexact.
      *is_inexact = true;
    } else {
      *is_inexact = static_cast<Int>(f) != i;
    }
    return f;
  }
  
  /*
    Convert integer value to client buffer of any type.
  
    SYNOPSIS
      fetch_long_with_conversion()
      param   output buffer descriptor
      field   column metadata
      value   column data
  */
  
  static void fetch_long_with_conversion(MYSQL_BIND *param, MYSQL_FIELD *field,
                                         longlong value, bool is_unsigned) {
    uchar *buffer = pointer_cast<uchar *>(param->buffer);
  
    switch (param->buffer_type) {
      case MYSQL_TYPE_NULL: /* do nothing */
        break;
      case MYSQL_TYPE_TINY:
        *param->error = IS_TRUNCATED(value, param->is_unsigned, INT_MIN8,
                                     INT_MAX8, UINT_MAX8);
        *(uchar *)param->buffer = (uchar)value;
        break;
      case MYSQL_TYPE_SHORT:
        *param->error = IS_TRUNCATED(value, param->is_unsigned, INT_MIN16,
                                     INT_MAX16, UINT_MAX16);
        shortstore(buffer, (short)value);
        break;
      case MYSQL_TYPE_LONG:
        *param->error = IS_TRUNCATED(value, param->is_unsigned, INT_MIN32,
                                     INT_MAX32, UINT_MAX32);
        longstore(buffer, (int32)value);
        break;
      case MYSQL_TYPE_LONGLONG:
        longlongstore(buffer, value);
        *param->error = param->is_unsigned != is_unsigned && value < 0;
        break;
      case MYSQL_TYPE_FLOAT: {
        float data;
        if (is_unsigned) {
          data =
              convert_with_inexact_check<ulonglong, float>(value, param->error);
        } else {
          data = convert_with_inexact_check<longlong, float>(value, param->error);
        }
        floatstore(buffer, data);
        break;
      }
      case MYSQL_TYPE_DOUBLE: {
        double data;
        if (is_unsigned) {
          data =
              convert_with_inexact_check<ulonglong, double>(value, param->error);
        } else {
          data =
              convert_with_inexact_check<longlong, double>(value, param->error);
        }
        doublestore(buffer, data);
        break;
      }
      case MYSQL_TYPE_TIME:
      case MYSQL_TYPE_DATE:
      case MYSQL_TYPE_TIMESTAMP:
      case MYSQL_TYPE_DATETIME: {
        int error;
        value = number_to_datetime(value, (MYSQL_TIME *)buffer, TIME_FUZZY_DATE,
                                   &error);
        *param->error = (error != 0);
        break;
      }
      default: {
        uchar buff[22]; /* Enough for longlong */
        uchar *end = (uchar *)longlong10_to_str(value, (char *)buff,
                                                is_unsigned ? 10 : -10);
        /* Resort to string conversion which supports all typecodes */
        uint length = (uint)(end - buff);
  
        if (field->flags & ZEROFILL_FLAG && length < field->length &&
            field->length < 21) {
          memmove(buff + field->length - length, buff, length);
          memset(buff, '0', field->length - length);
          length = field->length;
        }
        fetch_string_with_conversion(param, (char *)buff, length);
        break;
      }
    }
  }
  
  /*
    Convert double/float column to supplied buffer of any type.
  
    SYNOPSIS
      fetch_float_with_conversion()
      param   output buffer descriptor
      field   column metadata
      value   column data
      type    either MY_GCVT_ARG_FLOAT or MY_GCVT_ARG_DOUBLE.
              Affects the maximum number of significant digits
              returned by my_gcvt().
  */
  
  static void fetch_float_with_conversion(MYSQL_BIND *param, MYSQL_FIELD *field,
                                          double value, my_gcvt_arg_type type) {
    uchar *buffer = pointer_cast<uchar *>(param->buffer);
    double val64 = (value < 0 ? -floor(-value) : floor(value));
  
    switch (param->buffer_type) {
      case MYSQL_TYPE_NULL: /* do nothing */
        break;
      case MYSQL_TYPE_TINY:
        /*
          We need to _store_ data in the buffer before the truncation check to
          workaround Intel FPU executive precision feature.
          (See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=323 for details)
          Sic: AFAIU it does not guarantee to work.
        */
        if (param->is_unsigned) {
          if (value < 0.0) {
            *param->error = true;
            break;
          }
          *buffer = (uint8)value;
        } else {
          *buffer = (int8)value;
        }
        *param->error = val64 != (param->is_unsigned ? (double)((uint8)*buffer)
                                                     : (double)((int8)*buffer));
        break;
      case MYSQL_TYPE_SHORT:
        if (param->is_unsigned) {
          if (value < 0.0) {
            *param->error = true;
            break;
          }
          ushort data = (ushort)value;
          shortstore(buffer, data);
        } else {
          short data = (short)value;
          shortstore(buffer, data);
        }
        *param->error =
            val64 != (param->is_unsigned ? (double)(*(ushort *)buffer)
                                         : (double)(*(short *)buffer));
        break;
      case MYSQL_TYPE_LONG:
        if (param->is_unsigned) {
          if (value < 0.0) {
            *param->error = true;
            break;
          }
          uint32 data = (uint32)value;
          longstore(buffer, data);
        } else {
          int32 data = (int32)value;
          longstore(buffer, data);
        }
        *param->error =
            val64 != (param->is_unsigned ? (double)(*(uint32 *)buffer)
                                         : (double)(*(int32 *)buffer));
        break;
      case MYSQL_TYPE_LONGLONG:
        if (param->is_unsigned) {
          if (value < 0.0) {
            *param->error = true;
            break;
          }
          ulonglong data = (ulonglong)value;
          longlongstore(buffer, data);
        } else {
          longlong data = (longlong)value;
          longlongstore(buffer, data);
        }
        *param->error =
            val64 != (param->is_unsigned ? ulonglong2double(*(ulonglong *)buffer)
                                         : (double)(*(longlong *)buffer));
        break;
      case MYSQL_TYPE_FLOAT: {
        float data = (float)value;
        floatstore(buffer, data);
        *param->error = (*(float *)buffer) != value;
        break;
      }
      case MYSQL_TYPE_DOUBLE: {
        doublestore(buffer, value);
        break;
      }
      default: {
        /*
          Resort to fetch_string_with_conversion: this should handle
          floating point -> string conversion nicely, honor all typecodes
          and param->offset possibly set in mysql_stmt_fetch_column
        */
        char buff[FLOATING_POINT_BUFFER];
        size_t len;
        if (field->decimals >= DECIMAL_NOT_SPECIFIED)
          len = my_gcvt(
              value, type,
              std::min<unsigned long>(sizeof(buff) - 1, param->buffer_length),
              buff, nullptr);
        else
          len = my_fcvt(value, (int)field->decimals, buff, nullptr);
  
        if (field->flags & ZEROFILL_FLAG && len < field->length &&
            field->length < MAX_DOUBLE_STRING_REP_LENGTH - 1) {
          memmove(buff + field->length - len, buff, len);
          memset(buff, '0', field->length - len);
          len = field->length;
        }
        fetch_string_with_conversion(param, buff, len);
  
        break;
      }
    }
  }
  
  /*
    Fetch time/date/datetime to supplied buffer of any type
  
    SYNOPSIS
      param   output buffer descriptor
      time    column data
  */
  
  static void fetch_datetime_with_conversion(MYSQL_BIND *param,
                                             MYSQL_FIELD *field,
                                             MYSQL_TIME *my_time) {
    switch (param->buffer_type) {
      case MYSQL_TYPE_NULL: /* do nothing */
        break;
      case MYSQL_TYPE_DATE:
        *(MYSQL_TIME *)(param->buffer) = *my_time;
        *param->error = my_time->time_type != MYSQL_TIMESTAMP_DATE;
        break;
      case MYSQL_TYPE_TIME:
        *(MYSQL_TIME *)(param->buffer) = *my_time;
        *param->error = my_time->time_type != MYSQL_TIMESTAMP_TIME;
        break;
      case MYSQL_TYPE_DATETIME:
      case MYSQL_TYPE_TIMESTAMP:
        *(MYSQL_TIME *)(param->buffer) = *my_time;
        /* No error: time and date are compatible with datetime */
        break;
      case MYSQL_TYPE_YEAR:
        shortstore(pointer_cast<uchar *>(param->buffer), my_time->year);
        *param->error = true;
        break;
      case MYSQL_TYPE_FLOAT:
      case MYSQL_TYPE_DOUBLE: {
        ulonglong value = TIME_to_ulonglong(*my_time);
        fetch_float_with_conversion(param, field, ulonglong2double(value),
                                    MY_GCVT_ARG_DOUBLE);
        break;
      }
      case MYSQL_TYPE_TINY:
      case MYSQL_TYPE_SHORT:
      case MYSQL_TYPE_INT24:
      case MYSQL_TYPE_LONG:
      case MYSQL_TYPE_LONGLONG: {
        longlong value = (longlong)TIME_to_ulonglong(*my_time);
        fetch_long_with_conversion(param, field, value, true);
        break;
      }
      default: {
        /*
          Convert time value  to string and delegate the rest to
          fetch_string_with_conversion:
        */
        char buff[MAX_DATE_STRING_REP_LENGTH];
        uint length = my_TIME_to_str(*my_time, buff, field->decimals);
        /* Resort to string conversion */
        fetch_string_with_conversion(param, (char *)buff, length);
        break;
      }
    }
  }
  
  /*
    Fetch and convert result set column to output buffer.
  
    SYNOPSIS
      fetch_result_with_conversion()
      param   output buffer descriptor
      field   column metadata
      row     points to a column of result set tuple in binary format
  
    DESCRIPTION
      This is a fallback implementation of column fetch used
      if column and output buffer types do not match.
      Increases tuple pointer to point at the next column within the
      tuple.
  */
  
  static void fetch_result_with_conversion(MYSQL_BIND *param, MYSQL_FIELD *field,
                                           uchar **row) {
    enum enum_field_types field_type = field->type;
    uint field_is_unsigned = field->flags & UNSIGNED_FLAG;
  
    switch (field_type) {
      case MYSQL_TYPE_BOOL:
      case MYSQL_TYPE_TINY: {
        uchar value = **row;
        /* sic: we need to cast to 'signed char' as 'char' may be unsigned */
        longlong data =
            field_is_unsigned ? (longlong)value : (longlong)(signed char)value;
        fetch_long_with_conversion(param, field, data, false);
        *row += 1;
        break;
      }
      case MYSQL_TYPE_SHORT:
      case MYSQL_TYPE_YEAR: {
        short value = sint2korr(*row);
        longlong data =
            field_is_unsigned ? (longlong)(unsigned short)value : (longlong)value;
        fetch_long_with_conversion(param, field, data, false);
        *row += 2;
        break;
      }
      case MYSQL_TYPE_INT24: /* mediumint is sent as 4 bytes int */
      case MYSQL_TYPE_LONG: {
        int32 value = sint4korr(*row);
        longlong data =
            field_is_unsigned ? (longlong)(uint32)value : (longlong)value;
        fetch_long_with_conversion(param, field, data, false);
        *row += 4;
        break;
      }
      case MYSQL_TYPE_LONGLONG: {
        longlong value = (longlong)sint8korr(*row);
        fetch_long_with_conversion(param, field, value,
                                   field->flags & UNSIGNED_FLAG);
        *row += 8;
        break;
      }
      case MYSQL_TYPE_FLOAT: {
        float value = float4get(*row);
        fetch_float_with_conversion(param, field, value, MY_GCVT_ARG_FLOAT);
        *row += 4;
        break;
      }
      case MYSQL_TYPE_DOUBLE: {
        double value = float8get(*row);
        fetch_float_with_conversion(param, field, value, MY_GCVT_ARG_DOUBLE);
        *row += 8;
        break;
      }
      case MYSQL_TYPE_DATE: {
        MYSQL_TIME tm;
  
        read_binary_date(&tm, row);
        fetch_datetime_with_conversion(param, field, &tm);
        break;
      }
      case MYSQL_TYPE_TIME: {
        MYSQL_TIME tm;
  
        read_binary_time(&tm, row);
        fetch_datetime_with_conversion(param, field, &tm);
        break;
      }
      case MYSQL_TYPE_DATETIME:
      case MYSQL_TYPE_TIMESTAMP: {
        MYSQL_TIME tm;
  
        read_binary_datetime(&tm, row);
        fetch_datetime_with_conversion(param, field, &tm);
        break;
      }
      default: {
        ulong length = net_field_length(row);
        fetch_string_with_conversion(param, (char *)*row, length);
        *row += length;
        break;
      }
    }
  }
  
  /*
    Functions to fetch data to application buffers without conversion.
  
    All functions have the following characteristics:
  
    SYNOPSIS
      fetch_result_xxx()
      param   MySQL bind param
      pos     Row value
  
    DESCRIPTION
      These are no-conversion functions, used in binary protocol to store
      rows in application buffers. A function used only if type of binary data
      is compatible with type of application buffer.
  
    RETURN
      none
  */
  
  static void fetch_result_tinyint(MYSQL_BIND *param, MYSQL_FIELD *field,
                                   uchar **row) {
    bool field_is_unsigned = (field->flags & UNSIGNED_FLAG);
    uchar data = **row;
    *(uchar *)param->buffer = data;
    *param->error = param->is_unsigned != field_is_unsigned && data > INT_MAX8;
    (*row)++;
  }
  
  static void fetch_result_short(MYSQL_BIND *param, MYSQL_FIELD *field,
                                 uchar **row) {
    bool field_is_unsigned = (field->flags & UNSIGNED_FLAG);
    ushort data = (ushort)sint2korr(*row);
    shortstore(pointer_cast<uchar *>(param->buffer), data);
    *param->error = param->is_unsigned != field_is_unsigned && data > INT_MAX16;
    *row += 2;
  }
  
  static void fetch_result_int32(MYSQL_BIND *param,
                                 MYSQL_FIELD *field MY_ATTRIBUTE((unused)),
                                 uchar **row) {
    bool field_is_unsigned = (field->flags & UNSIGNED_FLAG);
    uint32 data = (uint32)sint4korr(*row);
    longstore(pointer_cast<uchar *>(param->buffer), data);
    *param->error = param->is_unsigned != field_is_unsigned && data > INT_MAX32;
    *row += 4;
  }
  
  static void fetch_result_int64(MYSQL_BIND *param,
                                 MYSQL_FIELD *field MY_ATTRIBUTE((unused)),
                                 uchar **row) {
    bool field_is_unsigned = (field->flags & UNSIGNED_FLAG);
    ulonglong data = (ulonglong)sint8korr(*row);
    *param->error = param->is_unsigned != field_is_unsigned && data > LLONG_MAX;
    longlongstore(pointer_cast<uchar *>(param->buffer), data);
    *row += 8;
  }
  
  static void fetch_result_float(MYSQL_BIND *param,
                                 MYSQL_FIELD *field MY_ATTRIBUTE((unused)),
                                 uchar **row) {
    float value = float4get(*row);
    floatstore(pointer_cast<uchar *>(param->buffer), value);
    *row += 4;
  }
  
  static void fetch_result_double(MYSQL_BIND *param,
                                  MYSQL_FIELD *field MY_ATTRIBUTE((unused)),
                                  uchar **row) {
    double value = float8get(*row);
    doublestore(pointer_cast<uchar *>(param->buffer), value);
    *row += 8;
  }
  
  static void fetch_result_time(MYSQL_BIND *param,
                                MYSQL_FIELD *field MY_ATTRIBUTE((unused)),
                                uchar **row) {
    MYSQL_TIME *tm = (MYSQL_TIME *)param->buffer;
    read_binary_time(tm, row);
  }
  
  static void fetch_result_date(MYSQL_BIND *param,
                                MYSQL_FIELD *field MY_ATTRIBUTE((unused)),
                                uchar **row) {
    MYSQL_TIME *tm = (MYSQL_TIME *)param->buffer;
    read_binary_date(tm, row);
  }
  
  static void fetch_result_datetime(MYSQL_BIND *param,
                                    MYSQL_FIELD *field MY_ATTRIBUTE((unused)),
                                    uchar **row) {
    MYSQL_TIME *tm = (MYSQL_TIME *)param->buffer;
    read_binary_datetime(tm, row);
  }
  
  static void fetch_result_bin(MYSQL_BIND *param,
                               MYSQL_FIELD *field MY_ATTRIBUTE((unused)),
                               uchar **row) {
    ulong length = net_field_length(row);
    ulong copy_length = std::min(length, param->buffer_length);
    memcpy(param->buffer, (char *)*row, copy_length);
    *param->length = length;
    *param->error = copy_length < length;
    *row += length;
  }
  
  static void fetch_result_str(MYSQL_BIND *param,
                               MYSQL_FIELD *field MY_ATTRIBUTE((unused)),
                               uchar **row) {
    ulong length = net_field_length(row);
    ulong copy_length = std::min(length, param->buffer_length);
    memcpy(param->buffer, (char *)*row, copy_length);
    /* Add an end null if there is room in the buffer */
    if (copy_length != param->buffer_length)
      ((uchar *)param->buffer)[copy_length] = '\0';
    *param->length = length; /* return total length */
    *param->error = copy_length < length;
    *row += length;
  }
  
  /*
    functions to calculate max lengths for strings during
    mysql_stmt_store_result()
  */
  
  static void skip_result_fixed(MYSQL_BIND *param,
                                MYSQL_FIELD *field MY_ATTRIBUTE((unused)),
                                uchar **row)
  
  {
    (*row) += param->pack_length;
  }
  
  static void skip_result_with_length(MYSQL_BIND *param MY_ATTRIBUTE((unused)),
                                      MYSQL_FIELD *field MY_ATTRIBUTE((unused)),
                                      uchar **row)
  
  {
    ulong length = net_field_length(row);
    (*row) += length;
  }
  
  static void skip_result_string(MYSQL_BIND *param MY_ATTRIBUTE((unused)),
                                 MYSQL_FIELD *field, uchar **row)
  
  {
    ulong length = net_field_length(row);
    (*row) += length;
    if (field->max_length < length) field->max_length = length;
  }
  
  /*
    Check that two field types are binary compatible i. e.
    have equal representation in the binary protocol and
    require client-side buffers of the same type.
  
    SYNOPSIS
      is_binary_compatible()
      type1   parameter type supplied by user
      type2   field type, obtained from result set metadata
  
    RETURN
      true or false
  */
  
  static bool is_binary_compatible(enum enum_field_types type1,
                                   enum enum_field_types type2) {
    static const enum enum_field_types
        range1[] = {MYSQL_TYPE_SHORT, MYSQL_TYPE_YEAR, MYSQL_TYPE_NULL},
        range2[] = {MYSQL_TYPE_INT24, MYSQL_TYPE_LONG, MYSQL_TYPE_NULL},
        range3[] = {MYSQL_TYPE_DATETIME, MYSQL_TYPE_TIMESTAMP, MYSQL_TYPE_NULL},
        range4[] = {
            MYSQL_TYPE_ENUM,        MYSQL_TYPE_SET,       MYSQL_TYPE_TINY_BLOB,
            MYSQL_TYPE_MEDIUM_BLOB, MYSQL_TYPE_LONG_BLOB, MYSQL_TYPE_BLOB,
            MYSQL_TYPE_VAR_STRING,  MYSQL_TYPE_STRING,    MYSQL_TYPE_GEOMETRY,
            MYSQL_TYPE_DECIMAL,     MYSQL_TYPE_NULL};
    static const enum enum_field_types *range_list[] = {range1, range2, range3,
                                                        range4},
                                       **range_list_end =
                                           range_list + sizeof(range_list) /
                                                            sizeof(*range_list);
    const enum enum_field_types **range, *type;
  
    if (type1 == type2) return true;
    for (range = range_list; range != range_list_end; ++range) {
      /* check that both type1 and type2 are in the same range */
      bool type1_found = false, type2_found = false;
      for (type = *range; *type != MYSQL_TYPE_NULL; type++) {
        type1_found |= type1 == *type;
        type2_found |= type2 == *type;
      }
      if (type1_found || type2_found) return type1_found && type2_found;
    }
    return false;
  }
  
  /*
    Setup a fetch function for one column of a result set.
  
    SYNOPSIS
      setup_one_fetch_function()
      param    output buffer descriptor
      field    column descriptor
  
    DESCRIPTION
      When user binds result set buffers or when result set
      metadata is changed, we need to setup fetch (and possibly
      conversion) functions for all columns of the result set.
      In addition to that here we set up skip_result function, used
      to update result set metadata in case when
      STMT_ATTR_UPDATE_MAX_LENGTH attribute is set.
      Notice that while fetch_result is chosen depending on both
      field->type and param->type, skip_result depends on field->type
      only.
  
    RETURN
      true   fetch function for this typecode was not found (typecode
            is not supported by the client library)
      false  success
  */
  
  static bool setup_one_fetch_function(MYSQL_BIND *param, MYSQL_FIELD *field) {
    DBUG_TRACE;
  
    /* Setup data copy functions for the different supported types */
    switch (param->buffer_type) {
      case MYSQL_TYPE_NULL: /* for dummy binds */
        /*
          It's not binary compatible with anything the server can return:
          no need to setup fetch_result, as it'll be reset anyway
        */
        *param->length = 0;
        break;
      case MYSQL_TYPE_TINY:
        param->fetch_result = fetch_result_tinyint;
        *param->length = 1;
        break;
      case MYSQL_TYPE_SHORT:
      case MYSQL_TYPE_YEAR:
        param->fetch_result = fetch_result_short;
        *param->length = 2;
        break;
      case MYSQL_TYPE_INT24:
      case MYSQL_TYPE_LONG:
        param->fetch_result = fetch_result_int32;
        *param->length = 4;
        break;
      case MYSQL_TYPE_LONGLONG:
        param->fetch_result = fetch_result_int64;
        *param->length = 8;
        break;
      case MYSQL_TYPE_FLOAT:
        param->fetch_result = fetch_result_float;
        *param->length = 4;
        break;
      case MYSQL_TYPE_DOUBLE:
        param->fetch_result = fetch_result_double;
        *param->length = 8;
        break;
      case MYSQL_TYPE_TIME:
        param->fetch_result = fetch_result_time;
        *param->length = sizeof(MYSQL_TIME);
        break;
      case MYSQL_TYPE_DATE:
        param->fetch_result = fetch_result_date;
        *param->length = sizeof(MYSQL_TIME);
        break;
      case MYSQL_TYPE_DATETIME:
      case MYSQL_TYPE_TIMESTAMP:
        param->fetch_result = fetch_result_datetime;
        *param->length = sizeof(MYSQL_TIME);
        break;
      case MYSQL_TYPE_TINY_BLOB:
      case MYSQL_TYPE_MEDIUM_BLOB:
      case MYSQL_TYPE_LONG_BLOB:
      case MYSQL_TYPE_BLOB:
      case MYSQL_TYPE_BIT:
        DBUG_ASSERT(param->buffer_length != 0);
        param->fetch_result = fetch_result_bin;
        break;
      case MYSQL_TYPE_VAR_STRING:
      case MYSQL_TYPE_STRING:
      case MYSQL_TYPE_DECIMAL:
      case MYSQL_TYPE_NEWDECIMAL:
      case MYSQL_TYPE_NEWDATE:
      case MYSQL_TYPE_JSON:
        DBUG_ASSERT(param->buffer_length != 0);
        param->fetch_result = fetch_result_str;
        break;
      default:
        DBUG_PRINT("error",
                   ("Unknown param->buffer_type: %u", (uint)param->buffer_type));
        return true;
    }
    if (!is_binary_compatible(param->buffer_type, field->type))
      param->fetch_result = fetch_result_with_conversion;
  
    /* Setup skip_result functions (to calculate max_length) */
    param->skip_result = skip_result_fixed;
    switch (field->type) {
      case MYSQL_TYPE_NULL: /* for dummy binds */
        param->pack_length = 0;
        field->max_length = 0;
        break;
      case MYSQL_TYPE_TINY:
        param->pack_length = 1;
        field->max_length = 4; /* as in '-127' */
        break;
      case MYSQL_TYPE_YEAR:
      case MYSQL_TYPE_SHORT:
        param->pack_length = 2;
        field->max_length = 6; /* as in '-32767' */
        break;
      case MYSQL_TYPE_INT24:
        field->max_length = 9; /* as in '16777216' or in '-8388607' */
        param->pack_length = 4;
        break;
      case MYSQL_TYPE_LONG:
        field->max_length = 11; /* '-2147483647' */
        param->pack_length = 4;
        break;
      case MYSQL_TYPE_LONGLONG:
        field->max_length = 21; /* '18446744073709551616' */
        param->pack_length = 8;
        break;
      case MYSQL_TYPE_FLOAT:
        param->pack_length = 4;
        field->max_length = MAX_DOUBLE_STRING_REP_LENGTH;
        break;
      case MYSQL_TYPE_DOUBLE:
        param->pack_length = 8;
        field->max_length = MAX_DOUBLE_STRING_REP_LENGTH;
        break;
      case MYSQL_TYPE_TIME:
        field->max_length = 17; /* -819:23:48.123456 */
        param->skip_result = skip_result_with_length;
        break;
      case MYSQL_TYPE_DATE:
        field->max_length = 10; /* 2003-11-11 */
        param->skip_result = skip_result_with_length;
        break;
      case MYSQL_TYPE_DATETIME:
      case MYSQL_TYPE_TIMESTAMP:
        param->skip_result = skip_result_with_length;
        field->max_length = MAX_DATE_STRING_REP_LENGTH;
        break;
      case MYSQL_TYPE_DECIMAL:
      case MYSQL_TYPE_NEWDECIMAL:
      case MYSQL_TYPE_ENUM:
      case MYSQL_TYPE_SET:
      case MYSQL_TYPE_GEOMETRY:
      case MYSQL_TYPE_TINY_BLOB:
      case MYSQL_TYPE_MEDIUM_BLOB:
      case MYSQL_TYPE_LONG_BLOB:
      case MYSQL_TYPE_BLOB:
      case MYSQL_TYPE_VAR_STRING:
      case MYSQL_TYPE_STRING:
      case MYSQL_TYPE_BIT:
      case MYSQL_TYPE_NEWDATE:
      case MYSQL_TYPE_JSON:
        param->skip_result = skip_result_string;
        break;
      default:
        DBUG_PRINT("error", ("Unknown field->type: %u", (uint)field->type));
        return true;
    }
    return false;
  }
  
  /*
    Setup the bind buffers for resultset processing
  */
  
  bool STDCALL mysql_stmt_bind_result(MYSQL_STMT *stmt, MYSQL_BIND *my_bind) {
    MYSQL_BIND *param, *end;
    MYSQL_FIELD *field;
    ulong bind_count = stmt->field_count;
    uint param_count = 0;
    DBUG_TRACE;
    DBUG_PRINT("enter", ("field_count: %lu", bind_count));
  
    if (!bind_count) {
      int errorcode = (int)stmt->state < (int)MYSQL_STMT_PREPARE_DONE
                          ? CR_NO_PREPARE_STMT
                          : CR_NO_STMT_METADATA;
      set_stmt_error(stmt, errorcode, unknown_sqlstate, nullptr);
      return true;
    }
  
    /*
      We only need to check that stmt->field_count - if it is not null
      stmt->bind was initialized in mysql_stmt_prepare
      stmt->bind overlaps with bind if mysql_stmt_bind_param
      is called from mysql_stmt_store_result.
      BEWARE of buffer overwrite ...
    */
  
    if (stmt->bind != my_bind)
      memcpy((char *)stmt->bind, (char *)my_bind,
             sizeof(MYSQL_BIND) * bind_count);
  
    for (param = stmt->bind, end = param + bind_count, field = stmt->fields;
         param < end; param++, field++) {
      DBUG_PRINT("info", ("buffer_type: %u  field_type: %u",
                          (uint)param->buffer_type, (uint)field->type));
      /*
        Set param->is_null to point to a dummy variable if it's not set.
        This is to make the execute code easier
      */
      if (!param->is_null) param->is_null = &param->is_null_value;
  
      if (!param->length) param->length = &param->length_value;
  
      if (!param->error) param->error = &param->error_value;
  
      param->param_number = param_count++;
      param->offset = 0;
  
      if (setup_one_fetch_function(param, field)) {
        my_stpcpy(stmt->sqlstate, unknown_sqlstate);
        sprintf(stmt->last_error,
                ER_CLIENT(stmt->last_errno = CR_UNSUPPORTED_PARAM_TYPE),
                field->type, param_count);
        return true;
      }
    }
    stmt->bind_result_done = BIND_RESULT_DONE;
    if (stmt->mysql->options.report_data_truncation)
      stmt->bind_result_done |= REPORT_DATA_TRUNCATION;
  
    return false;
  }
  
  /*
    Fetch row data to bind buffers
  */
  
  static int stmt_fetch_row(MYSQL_STMT *stmt, uchar *row) {
    MYSQL_BIND *my_bind, *end;
    MYSQL_FIELD *field;
    uchar *null_ptr, bit;
    int truncation_count = 0;
    /*
      Precondition: if stmt->field_count is zero or row is NULL, read_row_*
      function must return no data.
    */
    DBUG_ASSERT(stmt->field_count);
    DBUG_ASSERT(row);
  
    if (!stmt->bind_result_done) {
      /* If output parameters were not bound we should just return success */
      return 0;
    }
  
    null_ptr = row;
    row += (stmt->field_count + 9) / 8; /* skip null bits */
    bit = 4;                            /* first 2 bits are reserved */
  
    /* Copy complete row to application buffers */
    for (my_bind = stmt->bind, end = my_bind + stmt->field_count,
        field = stmt->fields;
         my_bind < end; my_bind++, field++) {
      *my_bind->error = false;
      if (*null_ptr & bit) {
        /*
          We should set both row_ptr and is_null to be able to see
          nulls in mysql_stmt_fetch_column. This is because is_null may point
          to user data which can be overwritten between mysql_stmt_fetch and
          mysql_stmt_fetch_column, and in this case nullness of column will be
          lost. See mysql_stmt_fetch_column for details.
        */
        my_bind->row_ptr = nullptr;
        *my_bind->is_null = true;
      } else {
        *my_bind->is_null = false;
        my_bind->row_ptr = row;
        (*my_bind->fetch_result)(my_bind, field, &row);
        truncation_count += *my_bind->error;
      }
      if (!((bit <<= 1) & 255)) {
        bit = 1; /* To next uchar */
        null_ptr++;
      }
    }
    if (truncation_count && (stmt->bind_result_done & REPORT_DATA_TRUNCATION))
      return MYSQL_DATA_TRUNCATED;
    return 0;
  }
  
  int cli_unbuffered_fetch(MYSQL *mysql, char **row) {
    ulong len = 0;
    bool is_data_packet;
    if (packet_error == (len = cli_safe_read(mysql, &is_data_packet))) {
      MYSQL_TRACE_STAGE(mysql, READY_FOR_COMMAND);
      return 1;
    }
  
    if (mysql->net.read_pos[0] != 0 && !is_data_packet) {
      /* in case of new client read the OK packet */
      if (mysql->server_capabilities & CLIENT_DEPRECATE_EOF)
        read_ok_ex(mysql, len);
      *row = nullptr;
      MYSQL_TRACE_STAGE(mysql, READY_FOR_COMMAND);
    } else {
      *row = (char *)(mysql->net.read_pos + 1);
    }
  
    return 0;
  }
  
  /*
    Fetch and return row data to bound buffers, if any
  */
  
  int STDCALL mysql_stmt_fetch(MYSQL_STMT *stmt) {
    int rc;
    uchar *row;
    DBUG_TRACE;
  
    if ((rc = (*stmt->read_row_func)(stmt, &row)) ||
        ((rc = stmt_fetch_row(stmt, row)) && rc != MYSQL_DATA_TRUNCATED)) {
      stmt->state = MYSQL_STMT_PREPARE_DONE; /* XXX: this is buggy */
      stmt->read_row_func = (rc == MYSQL_NO_DATA) ? stmt_read_row_no_data
                                                  : stmt_read_row_no_result_set;
    } else {
      /* This is to know in mysql_stmt_fetch_column that data was fetched */
      stmt->state = MYSQL_STMT_FETCH_DONE;
    }
    return rc;
  }
  
  /*
    Fetch data for one specified column data
  
    SYNOPSIS
      mysql_stmt_fetch_column()
      stmt		Prepared statement handler
      my_bind		Where data should be placed. Should be filled in as
                          when calling mysql_stmt_bind_result()
      column		Column to fetch (first column is 0)
      ulong offset	Offset in result data (to fetch blob in pieces)
                          This is normally 0
    RETURN
      0	ok
      1	error
  */
  
  int STDCALL mysql_stmt_fetch_column(MYSQL_STMT *stmt, MYSQL_BIND *my_bind,
                                      uint column, ulong offset) {
    MYSQL_BIND *param = stmt->bind + column;
    DBUG_TRACE;
  
    if ((int)stmt->state < (int)MYSQL_STMT_FETCH_DONE) {
      set_stmt_error(stmt, CR_NO_DATA, unknown_sqlstate, nullptr);
      return 1;
    }
    if (column >= stmt->field_count) {
      set_stmt_error(stmt, CR_INVALID_PARAMETER_NO, unknown_sqlstate, nullptr);
      return 1;
    }
  
    if (!my_bind->error) my_bind->error = &my_bind->error_value;
    *my_bind->error = false;
    if (param->row_ptr) {
      MYSQL_FIELD *field = stmt->fields + column;
      uchar *row = param->row_ptr;
      my_bind->offset = offset;
      if (my_bind->is_null) *my_bind->is_null = false;
      if (my_bind->length) /* Set the length if non char/binary types */
        *my_bind->length = *param->length;
      else
        my_bind->length = &param->length_value; /* Needed for fetch_result() */
      fetch_result_with_conversion(my_bind, field, &row);
    } else {
      if (my_bind->is_null) *my_bind->is_null = true;
    }
    return 0;
  }
  
  /*
    Read all rows of data from server  (binary format)
  */
  
  int cli_read_binary_rows(MYSQL_STMT *stmt) {
    ulong pkt_len;
    uchar *cp;
    MYSQL *mysql = stmt->mysql;
    MYSQL_DATA *result = &stmt->result;
    MYSQL_ROWS **prev_ptr = &result->data;
    NET *net;
    bool is_data_packet;
  
    DBUG_TRACE;
  
    if (!mysql) {
      set_stmt_error(stmt, CR_SERVER_LOST, unknown_sqlstate, nullptr);
      return 1;
    }
  
    net = &mysql->net;
    /*
     We could have read one row in execute() due to the lack of a cursor,
     but one at most.
    */
    DBUG_ASSERT(result->rows <= 1);
    if (result->rows == 1) prev_ptr = &result->data->next;
  
    while ((pkt_len = cli_safe_read(mysql, &is_data_packet)) != packet_error) {
      cp = net->read_pos;
      if (*cp == 0 || is_data_packet) {
        if (add_binary_row(net, stmt, pkt_len, &prev_ptr)) goto err;
      } else {
        /* end of data */
        *prev_ptr = nullptr;
        /* read warning count from OK packet or EOF packet if it is old client */
        if (mysql->server_capabilities & CLIENT_DEPRECATE_EOF && !is_data_packet)
          read_ok_ex(mysql, pkt_len);
        else
          mysql->warning_count = uint2korr(cp + 1);
        /*
          OUT parameters result sets has SERVER_PS_OUT_PARAMS and
          SERVER_MORE_RESULTS_EXISTS flags in first EOF_Packet only.
          Last EOF_Packet of OUT parameters result sets have no
          SERVER_MORE_RESULTS_EXISTS flag as described here:
          http://dev.mysql.com/doc/internals/en/stored-procedures.html#out-parameter-set
          Following code reads last EOF_Packet of result set and can clear
          those flags in server_status if we don't preserve them.
          Without SERVER_MORE_RESULTS_EXISTS flag mysql_stmt_next_result fails
          to read OK_Packet after OUT parameters result set.
          So we need to preserve SERVER_MORE_RESULTS_EXISTS flag for OUT
          parameters result set.
        */
        if (mysql->server_status & SERVER_PS_OUT_PARAMS) {
          mysql->server_status =
              uint2korr(cp + 3) | SERVER_PS_OUT_PARAMS |
              (mysql->server_status & SERVER_MORE_RESULTS_EXISTS);
        } else
          mysql->server_status = uint2korr(cp + 3);
        DBUG_PRINT("info", ("status: %u  warning_count: %u", mysql->server_status,
                            mysql->warning_count));
  #if defined(CLIENT_PROTOCOL_TRACING)
        if (mysql->server_status & SERVER_MORE_RESULTS_EXISTS)
          MYSQL_TRACE_STAGE(mysql, WAIT_FOR_RESULT);
        else
          MYSQL_TRACE_STAGE(mysql, READY_FOR_COMMAND);
  #endif
        return 0;
      }
    }
    set_stmt_errmsg(stmt, net);
  
  err:
    return 1;
  }
  
  /*
    Update meta data for statement
  
    SYNOPSIS
      stmt_update_metadata()
      stmt			Statement handler
      row				Binary data
  
    NOTES
      Only updates MYSQL_FIELD->max_length for strings
  */
  
  static void stmt_update_metadata(MYSQL_STMT *stmt, MYSQL_ROWS *data) {
    MYSQL_BIND *my_bind, *end;
    MYSQL_FIELD *field;
    uchar *null_ptr, bit;
    uchar *row = (uchar *)data->data;
  #ifndef DBUG_OFF
    uchar *row_end = row + data->length;
  #endif
  
    null_ptr = row;
    row += (stmt->field_count + 9) / 8; /* skip null bits */
    bit = 4;                            /* first 2 bits are reserved */
  
    /* Go through all fields and calculate metadata */
    for (my_bind = stmt->bind, end = my_bind + stmt->field_count,
        field = stmt->fields;
         my_bind < end; my_bind++, field++) {
      if (!(*null_ptr & bit)) (*my_bind->skip_result)(my_bind, field, &row);
      DBUG_ASSERT(row <= row_end);
      if (!((bit <<= 1) & 255)) {
        bit = 1; /* To next uchar */
        null_ptr++;
      }
    }
  }
  
  /*
    Store or buffer the binary results to stmt
  */
  
  int STDCALL mysql_stmt_store_result(MYSQL_STMT *stmt) {
    MYSQL *mysql = stmt->mysql;
    MYSQL_DATA *result = &stmt->result;
    DBUG_TRACE;
  
    if (!mysql) {
      /* mysql can be reset in mysql_close called from mysql_reconnect */
      set_stmt_error(stmt, CR_SERVER_LOST, unknown_sqlstate, nullptr);
      return 1;
    }
  
    if (!stmt->field_count) return 0;
  
    if ((int)stmt->state < (int)MYSQL_STMT_EXECUTE_DONE) {
      set_stmt_error(stmt, CR_COMMANDS_OUT_OF_SYNC, unknown_sqlstate, nullptr);
      return 1;
    }
  
    if (stmt->last_errno) {
      /* An attempt to use an invalid statement handle. */
      return 1;
    }
  
    if (mysql->status == MYSQL_STATUS_READY &&
        stmt->server_status & SERVER_STATUS_CURSOR_EXISTS) {
      /*
        Server side cursor exist, tell server to start sending the rows
      */
      NET *net = &mysql->net;
      uchar buff[4 /* statement id */ + 4 /* number of rows to fetch */];
  
      /* Send row request to the server */
      int4store(buff, stmt->stmt_id);
      int4store(buff + 4, (int)~0); /* number of rows to fetch */
      if (cli_advanced_command(mysql, COM_STMT_FETCH, buff, sizeof(buff),
                               (uchar *)nullptr, 0, true, stmt)) {
        /*
          Don't set stmt error if stmt->mysql is NULL, as the error in this case
          has already been set by mysql_prune_stmt_list().
        */
        if (stmt->mysql) set_stmt_errmsg(stmt, net);
        return 1;
      }
    } else if (mysql->status != MYSQL_STATUS_STATEMENT_GET_RESULT) {
      set_stmt_error(stmt, CR_COMMANDS_OUT_OF_SYNC, unknown_sqlstate, nullptr);
      return 1;
    }
  
    if (stmt->update_max_length && !stmt->bind_result_done) {
      /*
        We must initalize the bind structure to be able to calculate
        max_length
      */
      MYSQL_BIND *my_bind, *end;
      MYSQL_FIELD *field;
      memset(stmt->bind, 0, sizeof(*stmt->bind) * stmt->field_count);
  
      for (my_bind = stmt->bind, end = my_bind + stmt->field_count,
          field = stmt->fields;
           my_bind < end; my_bind++, field++) {
        my_bind->buffer_type = MYSQL_TYPE_NULL;
        my_bind->buffer_length = 1;
      }
  
      if (mysql_stmt_bind_result(stmt, stmt->bind)) return 1;
      stmt->bind_result_done = 0; /* No normal bind done */
    }
  
    if ((*mysql->methods->read_binary_rows)(stmt)) {
      free_root(result->alloc, MYF(MY_KEEP_PREALLOC));
      result->data = nullptr;
      result->rows = 0;
      mysql->status = MYSQL_STATUS_READY;
      return 1;
    }
  
    /* Assert that if there was a cursor, all rows have been fetched */
    DBUG_ASSERT(mysql->status != MYSQL_STATUS_READY ||
                (mysql->server_status & SERVER_STATUS_LAST_ROW_SENT));
  
    if (stmt->update_max_length) {
      MYSQL_ROWS *cur = result->data;
      for (; cur; cur = cur->next) stmt_update_metadata(stmt, cur);
    }
  
    stmt->data_cursor = result->data;
    mysql->affected_rows = stmt->affected_rows = result->rows;
    stmt->read_row_func = stmt_read_row_buffered;
    mysql->unbuffered_fetch_owner = nullptr; /* set in stmt_execute */
    mysql->status = MYSQL_STATUS_READY;      /* server is ready */
    return 0; /* Data buffered, must be fetched with mysql_stmt_fetch() */
  }
  
  /*
    Seek to desired row in the statement result set
  */
  
  MYSQL_ROW_OFFSET STDCALL mysql_stmt_row_seek(MYSQL_STMT *stmt,
                                               MYSQL_ROW_OFFSET row) {
    MYSQL_ROW_OFFSET offset = stmt->data_cursor;
    DBUG_TRACE;
  
    stmt->data_cursor = row;
    return offset;
  }
  
  /*
    Return the current statement row cursor position
  */
  
  MYSQL_ROW_OFFSET STDCALL mysql_stmt_row_tell(MYSQL_STMT *stmt) {
    DBUG_TRACE;
  
    return stmt->data_cursor;
  }
  
  /*
    Move the stmt result set data cursor to specified row
  */
  
  void STDCALL mysql_stmt_data_seek(MYSQL_STMT *stmt, uint64_t row) {
    MYSQL_ROWS *tmp = stmt->result.data;
    DBUG_TRACE;
    DBUG_PRINT("enter", ("row id to seek: %ld", (long)row));
  
    for (; tmp && row; --row, tmp = tmp->next)
      ;
    stmt->data_cursor = tmp;
    if (!row && tmp) {
      /*  Rewind the counter */
      stmt->read_row_func = stmt_read_row_buffered;
      stmt->state = MYSQL_STMT_EXECUTE_DONE;
    }
  }
  
  /*
    Return total rows the current statement result set
  */
  
  uint64_t STDCALL mysql_stmt_num_rows(MYSQL_STMT *stmt) {
    DBUG_TRACE;
  
    return stmt->result.rows;
  }
  
  /*
    Free the client side memory buffers, reset long data state
    on client if necessary, and reset the server side statement if
    this has been requested.
  */
  
  static bool reset_stmt_handle(MYSQL_STMT *stmt, uint flags) {
    /* If statement hasn't been prepared there is nothing to reset */
    if ((int)stmt->state > (int)MYSQL_STMT_INIT_DONE) {
      MYSQL *mysql = stmt->mysql;
      MYSQL_DATA *result = &stmt->result;
  
      /*
        Reset stored result set if so was requested or it's a part
        of cursor fetch.
      */
      if (flags & RESET_STORE_RESULT) {
        /* Result buffered */
        free_root(result->alloc, MYF(MY_KEEP_PREALLOC));
        result->data = nullptr;
        result->rows = 0;
        stmt->data_cursor = nullptr;
      }
      if (flags & RESET_LONG_DATA) {
        MYSQL_BIND *param = stmt->params, *param_end = param + stmt->param_count;
        /* Clear long_data_used flags */
        for (; param < param_end; param++) param->long_data_used = false;
      }
      stmt->read_row_func = stmt_read_row_no_result_set;
      if (mysql) {
        if ((int)stmt->state > (int)MYSQL_STMT_PREPARE_DONE) {
          if (mysql->unbuffered_fetch_owner == &stmt->unbuffered_fetch_cancelled)
            mysql->unbuffered_fetch_owner = nullptr;
          if (stmt->field_count && mysql->status != MYSQL_STATUS_READY) {
            /* There is a result set and it belongs to this statement */
            (*mysql->methods->flush_use_result)(mysql, false);
            if (mysql->unbuffered_fetch_owner)
              *mysql->unbuffered_fetch_owner = true;
            mysql->status = MYSQL_STATUS_READY;
          }
        }
        if (flags & RESET_SERVER_SIDE) {
          /*
            Reset the server side statement and close the server side
            cursor if it exists.
          */
          uchar buff[MYSQL_STMT_HEADER]; /* packet header: 4 bytes for stmt id */
          int4store(buff, stmt->stmt_id);
          if ((*mysql->methods->advanced_command)(mysql, COM_STMT_RESET, buff,
                                                  sizeof(buff), nullptr, 0, false,
                                                  stmt)) {
            set_stmt_errmsg(stmt, &mysql->net);
            stmt->state = MYSQL_STMT_INIT_DONE;
            return true;
          }
        }
      }
      if (flags & RESET_CLEAR_ERROR) stmt_clear_error(stmt);
      stmt->state = MYSQL_STMT_PREPARE_DONE;
    }
    return false;
  }
  
  bool STDCALL mysql_stmt_free_result(MYSQL_STMT *stmt) {
    DBUG_TRACE;
  
    /* Free the client side and close the server side cursor if there is one */
    return reset_stmt_handle(
        stmt, RESET_LONG_DATA | RESET_STORE_RESULT | RESET_CLEAR_ERROR);
  }
  
  /********************************************************************
   statement error handling and close
  *********************************************************************/
  
  /*
    Close the statement handle by freeing all alloced resources
  
    SYNOPSIS
      mysql_stmt_close()
      stmt	       Statement handle
  
    RETURN VALUES
      0	ok
      1	error
  */
  
  bool STDCALL mysql_stmt_close(MYSQL_STMT *stmt) {
    MYSQL *mysql = stmt->mysql;
    int rc = 0;
    DBUG_TRACE;
  
    free_root(stmt->result.alloc, MYF(0));
    free_root(stmt->mem_root, MYF(0));
    free_root(&stmt->extension->fields_mem_root, MYF(0));
  
    if (mysql) {
      mysql->stmts = list_delete(mysql->stmts, &stmt->list);
      /*
        Clear NET error state: if the following commands come through
        successfully, connection will still be usable for other commands.
      */
      net_clear_error(&mysql->net);
      if ((int)stmt->state > (int)MYSQL_STMT_INIT_DONE) {
        uchar buff[MYSQL_STMT_HEADER]; /* 4 bytes - stmt id */
  
        if (mysql->unbuffered_fetch_owner == &stmt->unbuffered_fetch_cancelled)
          mysql->unbuffered_fetch_owner = nullptr;
        if (mysql->status != MYSQL_STATUS_READY) {
          /*
            Flush result set of the connection. If it does not belong
            to this statement, set a warning.
          */
          (*mysql->methods->flush_use_result)(mysql, true);
          if (mysql->unbuffered_fetch_owner)
            *mysql->unbuffered_fetch_owner = true;
          mysql->status = MYSQL_STATUS_READY;
        }
        int4store(buff, stmt->stmt_id);
        /*
          If stmt_command failed, it would have already raised
          error using set_mysql_error. Caller should use
          mysql_error() or mysql_errno() to find out details.
          Memory allocated for stmt will be released regardless
          of the error.
        */
        rc = stmt_command(mysql, COM_STMT_CLOSE, buff, 4, stmt);
      }
    }
  
    my_free(stmt->result.alloc);
    my_free(stmt->mem_root);
    my_free(stmt->extension);
    my_free(stmt);
  
    return rc != 0;
  }
  
  /*
    Reset the statement buffers in server
  */
  
  bool STDCALL mysql_stmt_reset(MYSQL_STMT *stmt) {
    DBUG_TRACE;
    DBUG_ASSERT(stmt != nullptr);
    if (!stmt->mysql) {
      /* mysql can be reset in mysql_close called from mysql_reconnect */
      set_stmt_error(stmt, CR_SERVER_LOST, unknown_sqlstate, nullptr);
      return true;
    }
    /* Reset the client and server sides of the prepared statement */
    return reset_stmt_handle(
        stmt, RESET_SERVER_SIDE | RESET_LONG_DATA | RESET_CLEAR_ERROR);
  }
  
  /*
    Return statement error code
  */
  
  uint STDCALL mysql_stmt_errno(MYSQL_STMT *stmt) {
    DBUG_TRACE;
    return stmt->last_errno;
  }
  
  const char *STDCALL mysql_stmt_sqlstate(MYSQL_STMT *stmt) {
    DBUG_TRACE;
    return stmt->sqlstate;
  }
  
  /*
    Return statement error message
  */
  
  const char *STDCALL mysql_stmt_error(MYSQL_STMT *stmt) {
    DBUG_TRACE;
    return stmt->last_error;
  }
  
  /********************************************************************
   Transactional APIs
  *********************************************************************/
  
  /*
    Commit the current transaction
  */
  
  bool STDCALL mysql_commit(MYSQL *mysql) {
    DBUG_TRACE;
    return (bool)mysql_real_query(mysql, "commit", 6);
  }
  
  /*
    Rollback the current transaction
  */
  
  bool STDCALL mysql_rollback(MYSQL *mysql) {
    DBUG_TRACE;
    return (bool)mysql_real_query(mysql, "rollback", 8);
  }
  
  /*
    Set autocommit to either true or false
  */
  
  bool STDCALL mysql_autocommit(MYSQL *mysql, bool auto_mode) {
    DBUG_TRACE;
    DBUG_PRINT("enter", ("mode : %d", auto_mode));
  
    return (bool)mysql_real_query(
        mysql, auto_mode ? "set autocommit=1" : "set autocommit=0", 16);
  }
  
  /********************************************************************
   Multi query execution + SPs APIs
  *********************************************************************/
  
  /*
    Returns true/false to indicate whether any more query results exist
    to be read using mysql_next_result()
  */
  
  bool STDCALL mysql_more_results(MYSQL *mysql) {
    bool res;
    DBUG_TRACE;
  
    res = ((mysql->server_status & SERVER_MORE_RESULTS_EXISTS) ? 1 : 0);
    DBUG_PRINT("exit", ("More results exists ? %d", res));
    return res;
  }
  
  /*
    Reads and returns the next query results
  */
  int STDCALL mysql_next_result(MYSQL *mysql) {
    DBUG_TRACE;
  
    MYSQL_TRACE_STAGE(mysql, WAIT_FOR_RESULT);
  
    if (mysql->status != MYSQL_STATUS_READY) {
      set_mysql_error(mysql, CR_COMMANDS_OUT_OF_SYNC, unknown_sqlstate);
      return 1;
    }
  
    net_clear_error(&mysql->net);
    mysql->affected_rows = ~(uint64_t)0;
  
    if (mysql->server_status & SERVER_MORE_RESULTS_EXISTS)
      return (*mysql->methods->next_result)(mysql);
    else {
      MYSQL_TRACE_STAGE(mysql, READY_FOR_COMMAND);
    }
  
    return -1; /* No more results */
  }
  
  /*
    This API reads the next statement result and returns a status to indicate
    whether more results exist
  
    @param[in]    mysql                                    connection handle
  
    @retval       NET_ASYNC_ERROR                          Error
    @retval       NET_ASYNC_NOT_READY                      reading next result not
                                                           yet completed, call
                                                           this API again
    @retval       NET_ASYNC_COMPLETE                       finished reading result
    @retval       NET_ASYNC_COMPLETE_NO_MORE_RESULTS       status to indicate if
                                                           more results exist
  */
  net_async_status STDCALL mysql_next_result_nonblocking(MYSQL *mysql) {
    DBUG_TRACE;
    net_async_status status;
    if (mysql->status != MYSQL_STATUS_READY) {
      set_mysql_error(mysql, CR_COMMANDS_OUT_OF_SYNC, unknown_sqlstate);
      return NET_ASYNC_ERROR;
    }
    net_clear_error(&mysql->net);
    mysql->affected_rows = ~(uint64_t)0;
  
    if (mysql->server_status & SERVER_MORE_RESULTS_EXISTS) {
      status = (*mysql->methods->next_result_nonblocking)(mysql);
      return status;
    } else {
      MYSQL_TRACE_STAGE(mysql, READY_FOR_COMMAND);
    }
  
    return NET_ASYNC_COMPLETE_NO_MORE_RESULTS; /* No more results */
  }
  
  int STDCALL mysql_stmt_next_result(MYSQL_STMT *stmt) {
    MYSQL *mysql = stmt->mysql;
    int rc;
    DBUG_TRACE;
  
    if (!mysql) return 1;
  
    if (stmt->last_errno) return stmt->last_errno;
  
    if (mysql->server_status & SERVER_MORE_RESULTS_EXISTS) {
      if (reset_stmt_handle(stmt, RESET_STORE_RESULT)) return 1;
    }
  
    rc = mysql_next_result(mysql);
  
    if (rc) {
      set_stmt_errmsg(stmt, &mysql->net);
      return rc;
    }
  
    if (mysql->status == MYSQL_STATUS_GET_RESULT)
      mysql->status = MYSQL_STATUS_STATEMENT_GET_RESULT;
  
    stmt->state = MYSQL_STMT_EXECUTE_DONE;
    stmt->bind_result_done = false;
    stmt->field_count = mysql->field_count;
  
    if (mysql->field_count) {
      alloc_stmt_fields(stmt);
      prepare_to_fetch_result(stmt);
    }
  
    return 0;
  }
  
  MYSQL_RES *STDCALL mysql_use_result(MYSQL *mysql) {
    return (*mysql->methods->use_result)(mysql);
  }
  
  bool STDCALL mysql_read_query_result(MYSQL *mysql) {
    return (*mysql->methods->read_query_result)(mysql);
  }
  
  int STDCALL mysql_reset_connection(MYSQL *mysql) {
    DBUG_TRACE;
    if (simple_command(mysql, COM_RESET_CONNECTION, nullptr, 0, 0))
      return 1;
    else {
      mysql_detach_stmt_list(&mysql->stmts, "mysql_reset_connection");
      /* reset some of the members in mysql */
      mysql->insert_id = 0;
      mysql->affected_rows = ~(uint64_t)0;
      free_old_query(mysql);
      mysql->status = MYSQL_STATUS_READY;
      mysql_extension_bind_free(MYSQL_EXTENSION_PTR(mysql));
      return 0;
    }
  }
  