path: root/sql/sp_instr.cc

#include "sp_instr.h"

#include "opt_trace.h"    // class Opt_trace_start
#include "sql_array.h"    // class Dynamic_array
#include "sql_audit.h"    // mysql_audit_general
#include "sql_base.h"     // open_and_lock_tables
#include "sql_derived.h"  // mysql_handle_derived
#include "sp_head.h"      // class sp_head
#include "sql_parse.h"    // check_table_access
#include "sp_rcontext.h"  // class sp_rcontext
#include "sql_prepare.h"  // reinit_stmt_before_use
#include "transaction.h"  // trans_commit_stmt, trans_rollback_stmt, ...

/*
  Sufficient max length of printed destinations and frame offsets (all uints).
*/
static const int SP_STMT_PRINT_MAXLEN= 40;


static int cmp_rqp_locations(Rewritable_query_parameter * const *a,
                             Rewritable_query_parameter * const *b)
{
  return (int)((*a)->pos_in_query - (*b)->pos_in_query);
}

/**
  Prepare LEX and thread for execution of instruction, if requested open
  and lock LEX's tables, execute instruction's core function, perform
  cleanup afterwards.

  @param thd           thread context
  @param nextp         out - next instruction
  @param open_tables   if true then check read access to tables in LEX's table
                       list and open and lock them (used in instructions which
                       need to calculate some expression and don't execute
                       complete statement).
  @param sp_instr      instruction for which we prepare context, and which core
                       function execute by calling its exec_core() method.

  @note
    We are not saving/restoring some parts of THD which may need this because
    we do this once for whole routine execution in sp_head::execute().

  @return
    0/non-0 - Success/Failure
*/

int
sp_lex_keeper::reset_lex_and_exec_core(THD *thd, uint *nextp,
                                       bool open_tables, sp_instr* instr)
{
  int res= 0;
  DBUG_ENTER("reset_lex_and_exec_core");

  /*
    The flag is saved at the entry to the following substatement.
    It's reset further in the common code part.
    It's merged with the saved parent's value at the exit of this func.
  */
  bool parent_modified_non_trans_table=
    thd->transaction->stmt.modified_non_trans_table;
  unsigned int parent_unsafe_rollback_flags=
    thd->transaction->stmt.m_unsafe_rollback_flags;
  thd->transaction->stmt.modified_non_trans_table= false;
  thd->transaction->stmt.m_unsafe_rollback_flags= 0;

  DBUG_ASSERT(!thd->derived_tables);
  DBUG_ASSERT(thd->Item_change_list::is_empty());
  /*
    Use our own lex.
    We should not save old value since it is saved/restored in
    sp_head::execute() when we are entering/leaving routine.
  */
  thd->lex= m_lex;

  thd->set_query_id(next_query_id());

  if (thd->locked_tables_mode <= LTM_LOCK_TABLES)
  {
    /*
      This statement will enter/leave prelocked mode on its own.
      Entering prelocked mode changes table list and related members
      of LEX, so we'll need to restore them.
    */
    if (lex_query_tables_own_last)
    {
      /*
        We've already entered/left prelocked mode with this statement.
        Attach the list of tables that need to be prelocked and mark m_lex
        as having such list attached.
      */
      *lex_query_tables_own_last= prelocking_tables;
      m_lex->mark_as_requiring_prelocking(lex_query_tables_own_last);
    }
  }

  reinit_stmt_before_use(thd, m_lex);

#ifndef EMBEDDED_LIBRARY
  /*
    If there was instruction which changed tracking state,
    the result of changed tracking state send to client in OK packed.
    So it changes result sent to client and probably can be different
    independent on query text. So we can't cache such results.
  */
  if ((thd->client_capabilities & CLIENT_SESSION_TRACK) &&
      (thd->server_status & SERVER_SESSION_STATE_CHANGED))
    thd->lex->safe_to_cache_query= 0;
#endif

  Opt_trace_start ots(thd);
  ots.init(thd, m_lex->query_tables, SQLCOM_SELECT, &m_lex->var_list,
           nullptr, 0, thd->variables.character_set_client);

  Json_writer_object trace_command(thd);
  Json_writer_array trace_command_steps(thd, "steps");
  if (open_tables)
    res= instr->exec_open_and_lock_tables(thd, m_lex->query_tables);

  if (likely(!res))
  {
    res= instr->exec_core(thd, nextp);
    DBUG_PRINT("info",("exec_core returned: %d", res));
  }

  /*
    Call after unit->cleanup() to close open table
    key read.
  */
  if (open_tables)
  {
    m_lex->unit.cleanup();
    /* Here we also commit or rollback the current statement. */
    if (! thd->in_sub_stmt)
    {
      thd->get_stmt_da()->set_overwrite_status(true);
      thd->is_error() ? trans_rollback_stmt(thd) : trans_commit_stmt(thd);
      thd->get_stmt_da()->set_overwrite_status(false);
    }
    close_thread_tables(thd);
    thd_proc_info(thd, 0);

    if (! thd->in_sub_stmt)
    {
      if (thd->transaction_rollback_request)
      {
        trans_rollback_implicit(thd);
        thd->release_transactional_locks();
      }
      else if (! thd->in_multi_stmt_transaction_mode())
        thd->release_transactional_locks();
      else
        thd->mdl_context.release_statement_locks();
    }
  }
  //TODO: why is this here if log_slow_query is in sp_instr_stmt::execute?
  delete_explain_query(m_lex);

  if (m_lex->query_tables_own_last)
  {
    /*
      We've entered and left prelocking mode when executing statement
      stored in m_lex.
      m_lex->query_tables(->next_global)* list now has a 'tail' - a list
      of tables that are added for prelocking. (If this is the first
      execution, the 'tail' was added by open_tables(), otherwise we've
      attached it above in this function).
      Now we'll save the 'tail', and detach it.
    */
    lex_query_tables_own_last= m_lex->query_tables_own_last;
    prelocking_tables= *lex_query_tables_own_last;
    *lex_query_tables_own_last= nullptr;
    m_lex->query_tables_last= m_lex->query_tables_own_last;
    m_lex->mark_as_requiring_prelocking(nullptr);
  }
  thd->rollback_item_tree_changes();
  /*
    Update the state of the active arena if no errors on
    open_tables stage.
  */
  if (likely(!res) || likely(!thd->is_error()))
    thd->stmt_arena->state= Query_arena::STMT_EXECUTED;

  /*
    Merge here with the saved parent's values
    what is needed from the substatement gained
  */
  thd->transaction->stmt.modified_non_trans_table|=
    parent_modified_non_trans_table;
  thd->transaction->stmt.m_unsafe_rollback_flags|=
    parent_unsafe_rollback_flags;

  TRANSACT_TRACKER(add_trx_state_from_thd(thd));

  /*
    Unlike for PS we should not call Item's destructors for newly created
    items after execution of each instruction in stored routine. This is
    because SP often create Item (like Item_int, Item_string etc...) when
    they want to store some value in local variable, pass return value and
    etc... So their life time should be longer than one instruction.

    cleanup_items() is called in sp_head::execute()
  */
  thd->lex->restore_set_statement_var();
  DBUG_RETURN(res || thd->is_error());
}


int sp_lex_keeper::cursor_reset_lex_and_exec_core(THD *thd, uint *nextp,
                                                  bool open_tables,
                                                  sp_instr *instr)
{
  Query_arena *old_arena= thd->stmt_arena;
  /*
    Get the Query_arena from the cursor statement LEX, which contains
    the free_list of the query, so new items (if any) are stored in
    the right free_list, and we can cleanup after each cursor operation,
    e.g. open or cursor_copy_struct (for cursor%ROWTYPE variables).
  */
  thd->stmt_arena= m_lex->query_arena();
  int res= reset_lex_and_exec_core(thd, nextp, open_tables, instr);
  cleanup_items(thd->stmt_arena->free_list);
  thd->stmt_arena= old_arena;
  return res;
}


/*
  sp_instr class functions
*/

int sp_instr::exec_open_and_lock_tables(THD *thd, TABLE_LIST *tables)
{
  int result;

  /*
    Check whenever we have access to tables for this statement
    and open and lock them before executing instructions core function.
  */
  if (thd->open_temporary_tables(tables) ||
      check_table_access(thd, SELECT_ACL, tables, false, UINT_MAX, false)
      || open_and_lock_tables(thd, tables, true, 0))
    result= -1;
  else
    result= 0;
  /* Prepare all derived tables/views to catch possible errors. */
  if (!result)
    result= mysql_handle_derived(thd->lex, DT_PREPARE) ? -1 : 0;

  return result;
}


uint sp_instr::get_cont_dest() const
{
  return m_ip + 1;
}


int sp_instr::exec_core(THD *thd, uint *nextp)
{
  DBUG_ASSERT(0);
  return 0;
}


/*
  StoredRoutinesBinlogging
  This paragraph applies only to statement-based binlogging. Row-based
  binlogging does not need anything special like this.

  Top-down overview:

  1. Statements

  Statements that have is_update_query(stmt) == true are written into the
  binary log verbatim.
  Examples:
    UPDATE tbl SET tbl.x = spfunc_w_side_effects()
    UPDATE tbl SET tbl.x=1 WHERE spfunc_w_side_effect_that_returns_false(tbl.y)

  Statements that have is_update_query(stmt) == false (e.g. SELECTs) are not
  written into binary log. Instead we catch function calls the statement
  makes and write it into binary log separately (see #3).

  2. PROCEDURE calls

  CALL statements are not written into binary log. Instead
  * Any FUNCTION invocation (in SET, IF, WHILE, OPEN CURSOR and other SP
    instructions) is written into binlog separately.

  * Each statement executed in SP is binlogged separately, according to rules
    in #1, with the exception that we modify query string: we replace uses
    of SP local variables with NAME_CONST('spvar_name', <spvar-value>) calls.
    This substitution is done in subst_spvars().

  3. FUNCTION calls

  In sp_head::execute_function(), we check
   * If this function invocation is done from a statement that is written
     into the binary log.
   * If there were any attempts to write events to the binary log during
     function execution (grep for start_union_events and stop_union_events)

   If the answers are No and Yes, we write the function call into the binary
   log as "SELECT spfunc(<param1value>, <param2value>, ...)"


  4. Miscellaneous issues.

  4.1 User variables.

  When we call mysql_bin_log.write() for an SP statement, thd->user_var_events
  must hold set<{var_name, value}> pairs for all user variables used during
  the statement execution.
  This set is produced by tracking user variable reads during statement
  execution.

  For SPs, this has the following implications:
  1) thd->user_var_events may contain events from several SP statements and
     needs to be valid after exection of these statements was finished. In
     order to achieve that, we
     * Allocate user_var_events array elements on appropriate mem_root (grep
       for user_var_events_alloc).
     * Use is_query_in_union() to determine if user_var_event is created.

  2) We need to empty thd->user_var_events after we have wrote a function
     call. This is currently done by making
     reset_dynamic(&thd->user_var_events);
     calls in several different places. (TODO cosider moving this into
     mysql_bin_log.write() function)

  4.2 Auto_increment storage in binlog

  As we may write two statements to binlog from one single logical statement
  (case of "SELECT func1(),func2()": it is binlogged as "SELECT func1()" and
  then "SELECT func2()"), we need to reset auto_increment binlog variables
  after each binlogged SELECT. Otherwise, the auto_increment value of the
  first SELECT would be used for the second too.
*/


/**
  Replace thd->query{_length} with a string that one can write to
  the binlog.

  The binlog-suitable string is produced by replacing references to SP local
  variables with NAME_CONST('sp_var_name', value) calls.

  @param thd        Current thread.
  @param instr      Instruction (we look for Item_splocal instances in
                    instr->free_list)
  @param query_str  Original query string

  @return
    - false  on success.
    thd->query{_length} either has been appropriately replaced or there
    is no need for replacements.
    - true   out of memory error.
*/

static bool
subst_spvars(THD *thd, sp_instr *instr, LEX_STRING *query_str)
{
  DBUG_ENTER("subst_spvars");

  Dynamic_array<Rewritable_query_parameter*> rewritables(PSI_INSTRUMENT_MEM);
  char *pbuf;
  StringBuffer<512> qbuf;
  Copy_query_with_rewrite acc(thd, query_str->str, query_str->length, &qbuf);

  /* Find rewritable Items used in this statement */
  for (Item *item= instr->free_list; item; item= item->next)
  {
    Rewritable_query_parameter *rqp= item->get_rewritable_query_parameter();
    if (rqp && rqp->pos_in_query)
      rewritables.append(rqp);
  }
  if (!rewritables.elements())
    DBUG_RETURN(false);

  rewritables.sort(cmp_rqp_locations);

  thd->query_name_consts= (uint)rewritables.elements();

  for (Rewritable_query_parameter **rqp= rewritables.front();
       rqp <= rewritables.back(); rqp++)
  {
    if (acc.append(*rqp))
      DBUG_RETURN(true);
  }
  if (acc.finalize())
    DBUG_RETURN(true);

  /*
    Allocate additional space at the end of the new query string for the
    query_cache_send_result_to_client function.

    The query buffer layout is:
       buffer :==
            <statement>   The input statement(s)
            '\0'          Terminating null char
            <length>      Length of following current database name 2
            <db_name>     Name of current database
            <flags>       Flags struct
  */
  size_t buf_len= (qbuf.length() + 1 + QUERY_CACHE_DB_LENGTH_SIZE +
                thd->db.length + QUERY_CACHE_FLAGS_SIZE + 1);
  if ((pbuf= (char *) alloc_root(thd->mem_root, buf_len)))
  {
    char *ptr= pbuf + qbuf.length();
    memcpy(pbuf, qbuf.ptr(), qbuf.length());
    *ptr= 0;
    int2store(ptr+1, thd->db.length);
  }
  else
    DBUG_RETURN(true);

  thd->set_query(pbuf, qbuf.length());

  DBUG_RETURN(false);
}


/*
  sp_instr_stmt class functions
*/

PSI_statement_info sp_instr_stmt::psi_info=
{ 0, "stmt", 0};

int
sp_instr_stmt::execute(THD *thd, uint *nextp)
{
  int res;
  bool save_enable_slow_log;
  const CSET_STRING query_backup= thd->query_string;
  Sub_statement_state backup_state;
  DBUG_ENTER("sp_instr_stmt::execute");
  DBUG_PRINT("info", ("command: %d", m_lex_keeper.sql_command()));

  MYSQL_SET_STATEMENT_TEXT(thd->m_statement_psi, m_query.str,
                           static_cast<uint>(m_query.length));

#if defined(ENABLED_PROFILING)
  /* This s-p instr is profilable and will be captured. */
  thd->profiling.set_query_source(m_query.str, m_query.length);
#endif

  save_enable_slow_log= thd->enable_slow_log;
  thd->store_slow_query_state(&backup_state);

  if (!(res= alloc_query(thd, m_query.str, m_query.length)) &&
      !(res=subst_spvars(thd, this, &m_query)))
  {
    /*
      (the order of query cache and subst_spvars calls is irrelevant because
      queries with SP vars can't be cached)
    */
    general_log_write(thd, COM_QUERY, thd->query(), thd->query_length());

    if (query_cache_send_result_to_client(thd, thd->query(),
                                          thd->query_length()) <= 0)
    {
      thd->reset_slow_query_state();
      res= m_lex_keeper.reset_lex_and_exec_core(thd, nextp, false, this);
      bool log_slow= !res && thd->enable_slow_log;

      /* Finalize server status flags after executing a statement. */
      if (log_slow || thd->get_stmt_da()->is_eof())
        thd->update_server_status();

      if (thd->get_stmt_da()->is_eof())
        thd->protocol->end_statement();

      query_cache_end_of_result(thd);

      mysql_audit_general(thd, MYSQL_AUDIT_GENERAL_STATUS,
                          thd->get_stmt_da()->is_error() ?
                                 thd->get_stmt_da()->sql_errno() : 0,
                          command_name[COM_QUERY].str);

      if (log_slow)
        log_slow_statement(thd);

      /*
        Restore enable_slow_log, that can be changed by a admin or call
        command
      */
      thd->enable_slow_log= save_enable_slow_log;

      /* Add the number of rows to thd for the 'call' statistics */
      thd->add_slow_query_state(&backup_state);
    }
    else
    {
      /* change statistics */
      enum_sql_command save_sql_command= thd->lex->sql_command;
      thd->lex->sql_command= SQLCOM_SELECT;
      status_var_increment(thd->status_var.com_stat[SQLCOM_SELECT]);
      thd->update_stats();
      thd->lex->sql_command= save_sql_command;
      *nextp= m_ip+1;
    }
    thd->set_query(query_backup);
    thd->query_name_consts= 0;

    if (likely(!thd->is_error()))
    {
      res= 0;
      thd->get_stmt_da()->reset_diagnostics_area();
    }
  }

  DBUG_RETURN(res || thd->is_error());
}


void
sp_instr_stmt::print(String *str)
{
  size_t i, len;

  /* stmt CMD "..." */
  if (str->reserve(SP_STMT_PRINT_MAXLEN+SP_INSTR_UINT_MAXLEN+8))
    return;
  str->qs_append(STRING_WITH_LEN("stmt "));
  str->qs_append((uint)m_lex_keeper.sql_command());
  str->qs_append(STRING_WITH_LEN(" \""));
  len= m_query.length;
  /*
    Print the query string (but not too much of it), just to indicate which
    statement it is.
  */
  if (len > SP_STMT_PRINT_MAXLEN)
    len= SP_STMT_PRINT_MAXLEN-3;
  /* Copy the query string and replace '\n' with ' ' in the process */
  for (i= 0 ; i < len ; i++)
  {
    char c= m_query.str[i];
    if (c == '\n')
      c= ' ';
    str->qs_append(c);
  }
  if (m_query.length > SP_STMT_PRINT_MAXLEN)
    str->qs_append(STRING_WITH_LEN("...")); /* Indicate truncated string */
  str->qs_append('"');
}


int
sp_instr_stmt::exec_core(THD *thd, uint *nextp)
{
  MYSQL_QUERY_EXEC_START(thd->query(),
                         thd->thread_id,
                         thd->get_db(),
                         &thd->security_ctx->priv_user[0],
                         (char *)thd->security_ctx->host_or_ip,
                         3);
  int res= mysql_execute_command(thd);
  MYSQL_QUERY_EXEC_DONE(res);
  *nextp= m_ip + 1;
  return res;
}


/*
  sp_instr_set class functions
*/

PSI_statement_info sp_instr_set::psi_info=
{ 0, "set", 0};

int
sp_instr_set::execute(THD *thd, uint *nextp)
{
  DBUG_ENTER("sp_instr_set::execute");
  DBUG_PRINT("info", ("offset: %u", m_offset));

  DBUG_RETURN(m_lex_keeper.reset_lex_and_exec_core(thd, nextp, true, this));
}


sp_rcontext *sp_instr_set::get_rcontext(THD *thd) const
{
  return m_rcontext_handler->get_rcontext(thd->spcont);
}


int
sp_instr_set::exec_core(THD *thd, uint *nextp)
{
  int res= get_rcontext(thd)->set_variable(thd, m_offset, &m_value);
  delete_explain_query(thd->lex);
  *nextp= m_ip + 1;
  return res;
}


void
sp_instr_set::print(String *str)
{
  /* set name@offset ... */
  size_t rsrv= SP_INSTR_UINT_MAXLEN+6;
  sp_variable *var= m_ctx->find_variable(m_offset);
  const LEX_CSTRING *prefix= m_rcontext_handler->get_name_prefix();

  /* 'var' should always be non-null, but just in case... */
  if (var)
    rsrv+= var->name.length + prefix->length;
  if (str->reserve(rsrv))
    return;
  str->qs_append(STRING_WITH_LEN("set "));
  str->qs_append(prefix->str, prefix->length);
  if (var)
  {
    str->qs_append(&var->name);
    str->qs_append('@');
  }
  str->qs_append(m_offset);
  str->qs_append(' ');
  m_value->print(str, enum_query_type(QT_ORDINARY |
                                      QT_ITEM_ORIGINAL_FUNC_NULLIF));
}


/*
  sp_instr_set_field class functions
*/

int
sp_instr_set_row_field::exec_core(THD *thd, uint *nextp)
{
  int res= get_rcontext(thd)->set_variable_row_field(thd, m_offset,
                                                     m_field_offset,
                                                     &m_value);
  delete_explain_query(thd->lex);
  *nextp= m_ip + 1;
  return res;
}


void
sp_instr_set_row_field::print(String *str)
{
  /* set name@offset[field_offset] ... */
  size_t rsrv= SP_INSTR_UINT_MAXLEN + 6 + 6 + 3;
  sp_variable *var= m_ctx->find_variable(m_offset);
  const LEX_CSTRING *prefix= m_rcontext_handler->get_name_prefix();
  DBUG_ASSERT(var);
  DBUG_ASSERT(var->field_def.is_row());
  const Column_definition *def=
    var->field_def.row_field_definitions()->elem(m_field_offset);
  DBUG_ASSERT(def);

  rsrv+= var->name.length + def->field_name.length + prefix->length;
  if (str->reserve(rsrv))
    return;
  str->qs_append(STRING_WITH_LEN("set "));
  str->qs_append(prefix);
  str->qs_append(&var->name);
  str->qs_append('.');
  str->qs_append(&def->field_name);
  str->qs_append('@');
  str->qs_append(m_offset);
  str->qs_append('[');
  str->qs_append(m_field_offset);
  str->qs_append(']');
  str->qs_append(' ');
  m_value->print(str, enum_query_type(QT_ORDINARY |
                                      QT_ITEM_ORIGINAL_FUNC_NULLIF));
}


/*
  sp_instr_set_field_by_name class functions
*/

int
sp_instr_set_row_field_by_name::exec_core(THD *thd, uint *nextp)
{
  int res= get_rcontext(thd)->set_variable_row_field_by_name(thd, m_offset,
                                                             m_field_name,
                                                             &m_value);
  delete_explain_query(thd->lex);
  *nextp= m_ip + 1;
  return res;
}


void
sp_instr_set_row_field_by_name::print(String *str)
{
  /* set name.field@offset["field"] ... */
  size_t rsrv= SP_INSTR_UINT_MAXLEN + 6 + 6 + 3 + 2;
  sp_variable *var= m_ctx->find_variable(m_offset);
  const LEX_CSTRING *prefix= m_rcontext_handler->get_name_prefix();
  DBUG_ASSERT(var);
  DBUG_ASSERT(var->field_def.is_table_rowtype_ref() ||
              var->field_def.is_cursor_rowtype_ref());

  rsrv+= var->name.length + 2 * m_field_name.length + prefix->length;
  if (str->reserve(rsrv))
    return;
  str->qs_append(STRING_WITH_LEN("set "));
  str->qs_append(prefix);
  str->qs_append(&var->name);
  str->qs_append('.');
  str->qs_append(&m_field_name);
  str->qs_append('@');
  str->qs_append(m_offset);
  str->qs_append("[\"",2);
  str->qs_append(&m_field_name);
  str->qs_append("\"]",2);
  str->qs_append(' ');
  m_value->print(str, enum_query_type(QT_ORDINARY |
                                      QT_ITEM_ORIGINAL_FUNC_NULLIF));
}


/*
  sp_instr_set_trigger_field class functions
*/

PSI_statement_info sp_instr_set_trigger_field::psi_info=
{ 0, "set_trigger_field", 0};

int
sp_instr_set_trigger_field::execute(THD *thd, uint *nextp)
{
  DBUG_ENTER("sp_instr_set_trigger_field::execute");
  thd->count_cuted_fields= CHECK_FIELD_ERROR_FOR_NULL;
  DBUG_RETURN(m_lex_keeper.reset_lex_and_exec_core(thd, nextp, true, this));
}


int
sp_instr_set_trigger_field::exec_core(THD *thd, uint *nextp)
{
  Abort_on_warning_instant_set aws(thd, thd->is_strict_mode() &&
                                        !thd->lex->ignore);
  const int res= (trigger_field->set_value(thd, &value) ? -1 : 0);
  *nextp= m_ip+1;
  return res;
}


void
sp_instr_set_trigger_field::print(String *str)
{
  str->append(STRING_WITH_LEN("set_trigger_field "));
  trigger_field->print(str, enum_query_type(QT_ORDINARY |
                                            QT_ITEM_ORIGINAL_FUNC_NULLIF));
  str->append(STRING_WITH_LEN(":="));
  value->print(str, enum_query_type(QT_ORDINARY |
                                    QT_ITEM_ORIGINAL_FUNC_NULLIF));
}



/*
 sp_instr_jump class functions
*/

PSI_statement_info sp_instr_jump::psi_info=
{ 0, "jump", 0};


int
sp_instr_jump::execute(THD *thd, uint *nextp)
{
  DBUG_ENTER("sp_instr_jump::execute");
  DBUG_PRINT("info", ("destination: %u", m_dest));

  *nextp= m_dest;
  DBUG_RETURN(0);
}


void
sp_instr_jump::print(String *str)
{
  /* jump dest */
  if (str->reserve(SP_INSTR_UINT_MAXLEN+5))
    return;
  str->qs_append(STRING_WITH_LEN("jump "));
  str->qs_append(m_dest);
}


uint
sp_instr_jump::opt_mark(sp_head *sp, List<sp_instr> *leads)
{
  m_dest= opt_shortcut_jump(sp, this);
  if (m_dest != m_ip+1)   /* Jumping to following instruction? */
    marked= 1;
  m_optdest= sp->get_instr(m_dest);
  return m_dest;
}


uint
sp_instr_jump::opt_shortcut_jump(sp_head *sp, sp_instr *start)
{
  uint dest= m_dest;
  sp_instr *i;

  while ((i= sp->get_instr(dest)))
  {
    uint ndest;

    if (start == i || this == i)
      break;
    ndest= i->opt_shortcut_jump(sp, start);
    if (ndest == dest)
      break;
    dest= ndest;
  }
  return dest;
}


void
sp_instr_jump::opt_move(uint dst, List<sp_instr_opt_meta> *bp)
{
  if (m_dest > m_ip)
    bp->push_back(this);      // Forward
  else if (m_optdest)
    m_dest= m_optdest->m_ip;  // Backward
  m_ip= dst;
}


/*
  sp_instr_jump_if_not class functions
*/

PSI_statement_info sp_instr_jump_if_not::psi_info=
{ 0, "jump_if_not", 0};

int
sp_instr_jump_if_not::execute(THD *thd, uint *nextp)
{
  DBUG_ENTER("sp_instr_jump_if_not::execute");
  DBUG_PRINT("info", ("destination: %u", m_dest));
  DBUG_RETURN(m_lex_keeper.reset_lex_and_exec_core(thd, nextp, true, this));
}


int
sp_instr_jump_if_not::exec_core(THD *thd, uint *nextp)
{
  Item *it;
  int res;

  it= thd->sp_prepare_func_item(&m_expr, 1);
  if (! it)
  {
    res= -1;
  }
  else
  {
    res= 0;
    if (! it->val_bool())
      *nextp= m_dest;
    else
      *nextp= m_ip + 1;
  }

  return res;
}


void
sp_instr_jump_if_not::print(String *str)
{
  /* jump_if_not dest(cont) ... */
  if (str->reserve(2*SP_INSTR_UINT_MAXLEN+14+32)) // Add some for the expr. too
    return;
  str->qs_append(STRING_WITH_LEN("jump_if_not "));
  str->qs_append(m_dest);
  str->qs_append('(');
  str->qs_append(m_cont_dest);
  str->qs_append(STRING_WITH_LEN(") "));
  m_expr->print(str, enum_query_type(QT_ORDINARY |
                                     QT_ITEM_ORIGINAL_FUNC_NULLIF));
}


uint
sp_instr_jump_if_not::opt_mark(sp_head *sp, List<sp_instr> *leads)
{
  sp_instr *i;

  marked= 1;
  if ((i= sp->get_instr(m_dest)))
  {
    m_dest= i->opt_shortcut_jump(sp, this);
    m_optdest= sp->get_instr(m_dest);
  }
  sp->add_mark_lead(m_dest, leads);
  if ((i= sp->get_instr(m_cont_dest)))
  {
    m_cont_dest= i->opt_shortcut_jump(sp, this);
    m_cont_optdest= sp->get_instr(m_cont_dest);
  }
  sp->add_mark_lead(m_cont_dest, leads);
  return m_ip + 1;
}


void
sp_instr_jump_if_not::opt_move(uint dst, List<sp_instr_opt_meta> *bp)
{
  /*
    cont. destinations may point backwards after shortcutting jumps
    during the mark phase. If it's still pointing forwards, only
    push this for backpatching if sp_instr_jump::opt_move() will not
    do it (i.e. if the m_dest points backwards).
   */
  if (m_cont_dest > m_ip)
  {                             // Forward
    if (m_dest < m_ip)
      bp->push_back(this);
  }
  else if (m_cont_optdest)
    m_cont_dest= m_cont_optdest->m_ip; // Backward

  /*
    Take care about m_dest and m_ip
  */
  if (m_dest > m_ip)
    bp->push_back(this);      // Forward
  else if (m_optdest)
    m_dest= m_optdest->m_ip;  // Backward
  m_ip= dst;
}


/*
  sp_instr_freturn class functions
*/

PSI_statement_info sp_instr_freturn::psi_info=
{ 0, "freturn", 0};

int
sp_instr_freturn::execute(THD *thd, uint *nextp)
{
  DBUG_ENTER("sp_instr_freturn::execute");
  DBUG_RETURN(m_lex_keeper.reset_lex_and_exec_core(thd, nextp, true, this));
}


int
sp_instr_freturn::exec_core(THD *thd, uint *nextp)
{
  /*
    RETURN is a "procedure statement" (in terms of the SQL standard).
    That means, Diagnostics Area should be clean before its execution.
  */

  if (!(thd->variables.sql_mode & MODE_ORACLE))
  {
    /*
      Don't clean warnings in ORACLE mode,
      as they are needed for SQLCODE and SQLERRM:
        BEGIN
          SELECT a INTO a FROM t1;
          RETURN 'No exception ' || SQLCODE || ' ' || SQLERRM;
        EXCEPTION WHEN NO_DATA_FOUND THEN
          RETURN 'Exception ' || SQLCODE || ' ' || SQLERRM;
        END;
    */
    Diagnostics_area *da= thd->get_stmt_da();
    da->clear_warning_info(da->warning_info_id());
  }

  /*
    Change <next instruction pointer>, so that this will be the last
    instruction in the stored function.
  */

  *nextp= UINT_MAX;

  /*
    Evaluate the value of return expression and store it in current runtime
    context.

    NOTE: It's necessary to evaluate result item right here, because we must
    do it in scope of execution the current context/block.
  */

  return thd->spcont->set_return_value(thd, &m_value);
}


void
sp_instr_freturn::print(String *str)
{
  /* freturn type expr... */
  if (str->reserve(1024+8+32)) // Add some for the expr. too
    return;
  str->qs_append(STRING_WITH_LEN("freturn "));
  LEX_CSTRING name= m_type_handler->name().lex_cstring();
  str->qs_append(&name);
  str->qs_append(' ');
  m_value->print(str, enum_query_type(QT_ORDINARY |
                                      QT_ITEM_ORIGINAL_FUNC_NULLIF));
}

/*
  sp_instr_preturn class functions
*/

PSI_statement_info sp_instr_preturn::psi_info=
{ 0, "preturn", 0};


int
sp_instr_preturn::execute(THD *thd, uint *nextp)
{
  DBUG_ENTER("sp_instr_preturn::execute");
  *nextp= UINT_MAX;
  DBUG_RETURN(0);
}


void
sp_instr_preturn::print(String *str)
{
  str->append(STRING_WITH_LEN("preturn"));
}

/*
  sp_instr_hpush_jump class functions
*/

PSI_statement_info sp_instr_hpush_jump::psi_info=
{ 0, "hpush_jump", 0};

int
sp_instr_hpush_jump::execute(THD *thd, uint *nextp)
{
  DBUG_ENTER("sp_instr_hpush_jump::execute");

  int ret= thd->spcont->push_handler(this);

  *nextp= m_dest;

  DBUG_RETURN(ret);
}


void
sp_instr_hpush_jump::print(String *str)
{
  /* hpush_jump dest fsize type */
  if (str->reserve(SP_INSTR_UINT_MAXLEN*2 + 21))
    return;

  str->qs_append(STRING_WITH_LEN("hpush_jump "));
  str->qs_append(m_dest);
  str->qs_append(' ');
  str->qs_append(m_frame);

  switch (m_handler->type) {
  case sp_handler::EXIT:
    str->qs_append(STRING_WITH_LEN(" EXIT"));
    break;
  case sp_handler::CONTINUE:
    str->qs_append(STRING_WITH_LEN(" CONTINUE"));
    break;
  default:
    // The handler type must be either CONTINUE or EXIT.
    DBUG_ASSERT(0);
  }
}


uint
sp_instr_hpush_jump::opt_mark(sp_head *sp, List<sp_instr> *leads)
{
  sp_instr *i;

  marked= 1;
  if ((i= sp->get_instr(m_dest)))
  {
    m_dest= i->opt_shortcut_jump(sp, this);
    m_optdest= sp->get_instr(m_dest);
  }
  sp->add_mark_lead(m_dest, leads);

  /*
    For continue handlers, all instructions in the scope of the handler
    are possible leads. For example, the instruction after freturn might
    be executed if the freturn triggers the condition handled by the
    continue handler.

    m_dest marks the start of the handler scope. It's added as a lead
    above, so we start on m_dest+1 here.
    m_opt_hpop is the hpop marking the end of the handler scope.
  */
  if (m_handler->type == sp_handler::CONTINUE)
  {
    for (uint scope_ip= m_dest+1; scope_ip <= m_opt_hpop; scope_ip++)
      sp->add_mark_lead(scope_ip, leads);
  }

  return m_ip + 1;
}


/*
  sp_instr_hpop class functions
*/

PSI_statement_info sp_instr_hpop::psi_info=
{ 0, "hpop", 0};

int
sp_instr_hpop::execute(THD *thd, uint *nextp)
{
  DBUG_ENTER("sp_instr_hpop::execute");
  thd->spcont->pop_handlers(m_count);
  *nextp= m_ip + 1;
  DBUG_RETURN(0);
}


void
sp_instr_hpop::print(String *str)
{
  /* hpop count */
  if (str->reserve(SP_INSTR_UINT_MAXLEN+5))
    return;
  str->qs_append(STRING_WITH_LEN("hpop "));
  str->qs_append(m_count);
}


/*
  sp_instr_hreturn class functions
*/

PSI_statement_info sp_instr_hreturn::psi_info=
{ 0, "hreturn", 0};

int
sp_instr_hreturn::execute(THD *thd, uint *nextp)
{
  DBUG_ENTER("sp_instr_hreturn::execute");

  uint continue_ip= thd->spcont->exit_handler(thd->get_stmt_da());

  *nextp= m_dest ? m_dest : continue_ip;

  DBUG_RETURN(0);
}


void
sp_instr_hreturn::print(String *str)
{
  /* hreturn framesize dest */
  if (str->reserve(SP_INSTR_UINT_MAXLEN*2 + 9))
    return;
  str->qs_append(STRING_WITH_LEN("hreturn "));
  if (m_dest)
  {
    // NOTE: this is legacy: hreturn instruction for EXIT handler
    // should print out 0 as frame index.
    str->qs_append(STRING_WITH_LEN("0 "));
    str->qs_append(m_dest);
  }
  else
  {
    str->qs_append(m_frame);
  }
}


uint
sp_instr_hreturn::opt_mark(sp_head *sp, List<sp_instr> *leads)
{
  marked= 1;

  if (m_dest)
  {
    /*
      This is an EXIT handler; next instruction step is in m_dest.
     */
    return m_dest;
  }

  /*
    This is a CONTINUE handler; next instruction step will come from
    the handler stack and not from opt_mark.
   */
  return UINT_MAX;
}


/*
  sp_instr_cpush class functions
*/

PSI_statement_info sp_instr_cpush::psi_info=
{ 0, "cpush", 0};

int
sp_instr_cpush::execute(THD *thd, uint *nextp)
{
  DBUG_ENTER("sp_instr_cpush::execute");

  sp_cursor::reset(thd);
  m_lex_keeper.disable_query_cache();
  thd->spcont->push_cursor(this);

  *nextp= m_ip + 1;

  DBUG_RETURN(false);
}


void
sp_instr_cpush::print(String *str)
{
  const LEX_CSTRING *cursor_name= m_ctx->find_cursor(m_cursor);

  /* cpush name@offset */
  size_t rsrv= SP_INSTR_UINT_MAXLEN+7;

  if (cursor_name)
    rsrv+= cursor_name->length;
  if (str->reserve(rsrv))
    return;
  str->qs_append(STRING_WITH_LEN("cpush "));
  if (cursor_name)
  {
    str->qs_append(cursor_name->str, cursor_name->length);
    str->qs_append('@');
  }
  str->qs_append(m_cursor);
}


/*
  sp_instr_cpop class functions
*/

PSI_statement_info sp_instr_cpop::psi_info=
{ 0, "cpop", 0};

int
sp_instr_cpop::execute(THD *thd, uint *nextp)
{
  DBUG_ENTER("sp_instr_cpop::execute");
  thd->spcont->pop_cursors(thd, m_count);
  *nextp= m_ip + 1;
  DBUG_RETURN(0);
}


void
sp_instr_cpop::print(String *str)
{
  /* cpop count */
  if (str->reserve(SP_INSTR_UINT_MAXLEN+5))
    return;
  str->qs_append(STRING_WITH_LEN("cpop "));
  str->qs_append(m_count);
}


/*
  sp_instr_copen class functions
*/

/**
  @todo
    Assert that we either have an error or a cursor
*/

PSI_statement_info sp_instr_copen::psi_info=
{ 0, "copen", 0};

int
sp_instr_copen::execute(THD *thd, uint *nextp)
{
  /*
    We don't store a pointer to the cursor in the instruction to be
    able to reuse the same instruction among different threads in future.
  */
  sp_cursor *c= thd->spcont->get_cursor(m_cursor);
  int res;
  DBUG_ENTER("sp_instr_copen::execute");

  if (! c)
    res= -1;
  else
  {
    sp_lex_keeper *lex_keeper= c->get_lex_keeper();
    res= lex_keeper->cursor_reset_lex_and_exec_core(thd, nextp, false, this);
    /* TODO: Assert here that we either have an error or a cursor */
  }
  DBUG_RETURN(res);
}


int
sp_instr_copen::exec_core(THD *thd, uint *nextp)
{
  sp_cursor *c= thd->spcont->get_cursor(m_cursor);
  int res= c->open(thd);
  *nextp= m_ip + 1;
  return res;
}

void
sp_instr_copen::print(String *str)
{
  const LEX_CSTRING *cursor_name= m_ctx->find_cursor(m_cursor);

  /* copen name@offset */
  size_t rsrv= SP_INSTR_UINT_MAXLEN+7;

  if (cursor_name)
    rsrv+= cursor_name->length;
  if (str->reserve(rsrv))
    return;
  str->qs_append(STRING_WITH_LEN("copen "));
  if (cursor_name)
  {
    str->qs_append(cursor_name->str, cursor_name->length);
    str->qs_append('@');
  }
  str->qs_append(m_cursor);
}


/*
  sp_instr_cclose class functions
*/

PSI_statement_info sp_instr_cclose::psi_info=
{ 0, "cclose", 0};

int
sp_instr_cclose::execute(THD *thd, uint *nextp)
{
  sp_cursor *c= thd->spcont->get_cursor(m_cursor);
  int res;
  DBUG_ENTER("sp_instr_cclose::execute");

  if (! c)
    res= -1;
  else
    res= c->close(thd);
  *nextp= m_ip + 1;
  DBUG_RETURN(res);
}


void
sp_instr_cclose::print(String *str)
{
  const LEX_CSTRING *cursor_name= m_ctx->find_cursor(m_cursor);

  /* cclose name@offset */
  size_t rsrv= SP_INSTR_UINT_MAXLEN+8;

  if (cursor_name)
    rsrv+= cursor_name->length;
  if (str->reserve(rsrv))
    return;
  str->qs_append(STRING_WITH_LEN("cclose "));
  if (cursor_name)
  {
    str->qs_append(cursor_name->str, cursor_name->length);
    str->qs_append('@');
  }
  str->qs_append(m_cursor);
}


/*
  sp_instr_cfetch class functions
*/

PSI_statement_info sp_instr_cfetch::psi_info=
{ 0, "cfetch", 0};

int
sp_instr_cfetch::execute(THD *thd, uint *nextp)
{
  sp_cursor *c= thd->spcont->get_cursor(m_cursor);
  int res;
  Query_arena backup_arena;
  DBUG_ENTER("sp_instr_cfetch::execute");

  res= c ? c->fetch(thd, &m_varlist, m_error_on_no_data) : -1;

  *nextp= m_ip + 1;
  DBUG_RETURN(res);
}


void
sp_instr_cfetch::print(String *str)
{
  List_iterator_fast<sp_variable> li(m_varlist);
  sp_variable *pv;
  const LEX_CSTRING *cursor_name= m_ctx->find_cursor(m_cursor);

  /* cfetch name@offset vars... */
  size_t rsrv= SP_INSTR_UINT_MAXLEN+8;

  if (cursor_name)
    rsrv+= cursor_name->length;
  if (str->reserve(rsrv))
    return;
  str->qs_append(STRING_WITH_LEN("cfetch "));
  if (cursor_name)
  {
    str->qs_append(cursor_name->str, cursor_name->length);
    str->qs_append('@');
  }
  str->qs_append(m_cursor);
  while ((pv= li++))
  {
    if (str->reserve(pv->name.length+SP_INSTR_UINT_MAXLEN+2))
      return;
    str->qs_append(' ');
    str->qs_append(&pv->name);
    str->qs_append('@');
    str->qs_append(pv->offset);
  }
}


/*
  sp_instr_agg_cfetch class functions
*/

PSI_statement_info sp_instr_agg_cfetch::psi_info=
{ 0, "agg_cfetch", 0};

int
sp_instr_agg_cfetch::execute(THD *thd, uint *nextp)
{
  DBUG_ENTER("sp_instr_agg_cfetch::execute");
  int res= 0;
  if (!thd->spcont->instr_ptr)
  {
    *nextp= m_ip + 1;
    thd->spcont->instr_ptr= m_ip + 1;
  }
  else if (!thd->spcont->pause_state)
    thd->spcont->pause_state= true;
  else
  {
    thd->spcont->pause_state= false;
    if (thd->server_status & SERVER_STATUS_LAST_ROW_SENT)
    {
      my_message(ER_SP_FETCH_NO_DATA,
                 ER_THD(thd, ER_SP_FETCH_NO_DATA), MYF(0));
      res= -1;
      thd->spcont->quit_func= true;
    }
    else
      *nextp= m_ip + 1;
  }
  DBUG_RETURN(res);
}


void
sp_instr_agg_cfetch::print(String *str)
{

  uint rsrv= SP_INSTR_UINT_MAXLEN+11;

  if (str->reserve(rsrv))
    return;
  str->qs_append(STRING_WITH_LEN("agg_cfetch"));
}

/*
  sp_instr_cursor_copy_struct class functions
*/

/**
  This methods processes cursor %ROWTYPE declarations, e.g.:
    CURSOR cur IS SELECT * FROM t1;
    rec cur%ROWTYPE;
  and does the following:
  - opens the cursor without copying data (materialization).
  - copies the cursor structure to the associated %ROWTYPE variable.
*/

PSI_statement_info sp_instr_cursor_copy_struct::psi_info=
{ 0, "cursor_copy_struct", 0};

int
sp_instr_cursor_copy_struct::exec_core(THD *thd, uint *nextp)
{
  DBUG_ENTER("sp_instr_cursor_copy_struct::exec_core");
  int ret= 0;
  Item_field_row *row= (Item_field_row*) thd->spcont->get_variable(m_var);
  DBUG_ASSERT(row->type_handler() == &type_handler_row);

  /*
    Copy structure only once. If the cursor%ROWTYPE variable is declared
    inside a LOOP block, it gets its structure on the first loop iteration
    and remembers the structure for all consequent loop iterations.
    It we recreated the structure on every iteration, we would get
    potential memory leaks, and it would be less efficient.
  */
  if (!row->arguments())
  {
    sp_cursor tmp(thd, true);
    // Open the cursor without copying data
    if (!(ret= tmp.open(thd)))
    {
      Row_definition_list defs;
      /*
        Create row elements on the caller arena.
        It's the same arena that was used during sp_rcontext::create().
        This puts cursor%ROWTYPE elements on the same mem_root
        where explicit ROW elements and table%ROWTYPE reside:
        - tmp.export_structure() allocates new Spvar_definition instances
          and their components (such as TYPELIBs).
        - row->row_create_items() creates new Item_field instances.
        They all are created on the same mem_root.
      */
      Query_arena current_arena;
      thd->set_n_backup_active_arena(thd->spcont->callers_arena,
                                     &current_arena);
      if (!(ret= tmp.export_structure(thd, &defs)))
        row->row_create_items(thd, &defs);
      thd->restore_active_arena(thd->spcont->callers_arena, &current_arena);
      tmp.close(thd);
    }
  }
  *nextp= m_ip + 1;
  DBUG_RETURN(ret);
}


int
sp_instr_cursor_copy_struct::execute(THD *thd, uint *nextp)
{
  DBUG_ENTER("sp_instr_cursor_copy_struct::execute");
  int ret= m_lex_keeper.cursor_reset_lex_and_exec_core(thd, nextp, false, this);
  DBUG_RETURN(ret);
}


void
sp_instr_cursor_copy_struct::print(String *str)
{
  sp_variable *var= m_ctx->find_variable(m_var);
  const LEX_CSTRING *name= m_ctx->find_cursor(m_cursor);
  str->append(STRING_WITH_LEN("cursor_copy_struct "));
  str->append(name);
  str->append(' ');
  str->append(&var->name);
  str->append('@');
  str->append_ulonglong(m_var);
}


/*
  sp_instr_error class functions
*/

PSI_statement_info sp_instr_error::psi_info=
{ 0, "error", 0};

int
sp_instr_error::execute(THD *thd, uint *nextp)
{
  DBUG_ENTER("sp_instr_error::execute");
  my_message(m_errcode, ER_THD(thd, m_errcode), MYF(0));
  WSREP_DEBUG("sp_instr_error: %s %d", ER_THD(thd, m_errcode), thd->is_error());
  *nextp= m_ip + 1;
  DBUG_RETURN(-1);
}


void
sp_instr_error::print(String *str)
{
  /* error code */
  if (str->reserve(SP_INSTR_UINT_MAXLEN+6))
    return;
  str->qs_append(STRING_WITH_LEN("error "));
  str->qs_append(m_errcode);
}


/**************************************************************************
  sp_instr_set_case_expr class implementation
**************************************************************************/

PSI_statement_info sp_instr_set_case_expr::psi_info=
{ 0, "set_case_expr", 0};

int
sp_instr_set_case_expr::execute(THD *thd, uint *nextp)
{
  DBUG_ENTER("sp_instr_set_case_expr::execute");

  DBUG_RETURN(m_lex_keeper.reset_lex_and_exec_core(thd, nextp, true, this));
}


int
sp_instr_set_case_expr::exec_core(THD *thd, uint *nextp)
{
  int res= thd->spcont->set_case_expr(thd, m_case_expr_id, &m_case_expr);

  if (res && !thd->spcont->get_case_expr(m_case_expr_id))
  {
    /*
      Failed to evaluate the value, the case expression is still not
      initialized. Set to NULL so we can continue.
    */

    Item *null_item= new (thd->mem_root) Item_null(thd);

    if (!null_item ||
        thd->spcont->set_case_expr(thd, m_case_expr_id, &null_item))
    {
      /* If this also failed, we have to abort. */
      my_error(ER_OUT_OF_RESOURCES, MYF(ME_FATAL));
    }
  }
  else
    *nextp= m_ip + 1;

  return res;
}


void
sp_instr_set_case_expr::print(String *str)
{
  /* set_case_expr (cont) id ... */
  str->reserve(2*SP_INSTR_UINT_MAXLEN+18+32); // Add some extra for expr too
  str->qs_append(STRING_WITH_LEN("set_case_expr ("));
  str->qs_append(m_cont_dest);
  str->qs_append(STRING_WITH_LEN(") "));
  str->qs_append(m_case_expr_id);
  str->qs_append(' ');
  m_case_expr->print(str, enum_query_type(QT_ORDINARY |
                                          QT_ITEM_ORIGINAL_FUNC_NULLIF));
}


uint
sp_instr_set_case_expr::opt_mark(sp_head *sp, List<sp_instr> *leads)
{
  sp_instr *i;

  marked= 1;
  if ((i= sp->get_instr(m_cont_dest)))
  {
    m_cont_dest= i->opt_shortcut_jump(sp, this);
    m_cont_optdest= sp->get_instr(m_cont_dest);
  }
  sp->add_mark_lead(m_cont_dest, leads);
  return m_ip + 1;
}


void
sp_instr_set_case_expr::opt_move(uint dst, List<sp_instr_opt_meta> *bp)
{
  if (m_cont_dest > m_ip)
    bp->push_back(this);        // Forward
  else if (m_cont_optdest)
    m_cont_dest= m_cont_optdest->m_ip; // Backward
  m_ip= dst;
}