sql_signal.h

/* Copyright (c) 2008, 2025, 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.

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   permission to link the program and your derivative works with the
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   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 */

#ifndef SQL_SIGNAL_H
#define SQL_SIGNAL_H

#include <string.h>

#include "my_sqlcommand.h"
#include "sql/sql_cmd.h"    // Sql_cmd
#include "sql/sql_error.h"  // Sql_condition

class Item;
class THD;
class sp_condition_value;

/**
   This enumeration list all the condition item names of a condition in the
   SQL condition area.
*/
enum enum_condition_item_name {
  /*
    Conditions that can be set by the user (SIGNAL/RESIGNAL),
    and by the server implementation.
  */

  CIN_CLASS_ORIGIN = 0,
  CIN_FIRST_PROPERTY = CIN_CLASS_ORIGIN,
  CIN_SUBCLASS_ORIGIN = 1,
  CIN_CONSTRAINT_CATALOG = 2,
  CIN_CONSTRAINT_SCHEMA = 3,
  CIN_CONSTRAINT_NAME = 4,
  CIN_CATALOG_NAME = 5,
  CIN_SCHEMA_NAME = 6,
  CIN_TABLE_NAME = 7,
  CIN_COLUMN_NAME = 8,
  CIN_CURSOR_NAME = 9,
  CIN_MESSAGE_TEXT = 10,
  CIN_MYSQL_ERRNO = 11,
  CIN_LAST_PROPERTY = CIN_MYSQL_ERRNO
};

/**
  Set_signal_information is a container used in the parsed tree to represent
  the collection of assignments to condition items in the SIGNAL and RESIGNAL
  statements.
*/
class Set_signal_information {
 public:
  Set_signal_information() { memset(m_item, 0, sizeof(m_item)); }

  ~Set_signal_information() = default;

  bool set_item(enum_condition_item_name name, Item *item);

  /**
    For each condition item assignment, m_item[] contains the parsed tree
    that represents the expression assigned, if any.
    m_item[] is an array indexed by enum_condition_item_name.
  */
  Item *m_item[CIN_LAST_PROPERTY + 1];
};

/**
  Sql_cmd_common_signal represents the common properties of the
  SIGNAL and RESIGNAL statements.
*/
class Sql_cmd_common_signal : public Sql_cmd {
 protected:
  /**
    Constructor.
    @param cond the condition signaled if any, or NULL.
    @param set collection of signal condition item assignments.
  */
  Sql_cmd_common_signal(const sp_condition_value *cond,
                        Set_signal_information *set)
      : Sql_cmd(), m_cond(cond), m_set_signal_information(set) {}

  ~Sql_cmd_common_signal() override = default;

  /**
    Assign the condition items 'MYSQL_ERRNO', 'level' and 'MESSAGE_TEXT'
    default values of a condition.
    @param thd the current thread.
    @param cond the condition to update.
    @param set_level_code true if 'level' and 'MYSQL_ERRNO' needs to be
    overwritten
    @param level the level to assign
    @param sqlcode the sql code to assign
  */
  static void assign_defaults(THD *thd, Sql_condition *cond,
                              bool set_level_code,
                              Sql_condition::enum_severity_level level,
                              int sqlcode);

  /**
    Evaluate the condition items 'SQLSTATE', 'MYSQL_ERRNO', 'level' and
    'MESSAGE_TEXT' default values for this statement.
    @param thd the current thread.
    @param cond the condition to update.
  */
  void eval_defaults(THD *thd, Sql_condition *cond);

  /**
    Evaluate each signal condition items for this statement.
    @param thd the current thread.
    @param cond the condition to update.
    @return 0 on success.
  */
  int eval_signal_informations(THD *thd, Sql_condition *cond);

  /**
    The condition to signal or resignal.
    This member is optional and can be NULL (RESIGNAL).
  */
  const sp_condition_value *m_cond;

  /**
    Collection of 'SET item = value' assignments in the
    SIGNAL/RESIGNAL statement.
  */
  Set_signal_information *m_set_signal_information;
};

/**
  Sql_cmd_signal represents a SIGNAL statement.
*/
class Sql_cmd_signal : public Sql_cmd_common_signal {
 public:
  /**
    Constructor, used to represent a SIGNAL statement.
    @param cond the SQL condition to signal (required).
    @param set the collection of signal information to signal.
  */
  Sql_cmd_signal(const sp_condition_value *cond, Set_signal_information *set)
      : Sql_cmd_common_signal(cond, set) {}

  ~Sql_cmd_signal() override = default;

  enum_sql_command sql_command_code() const override { return SQLCOM_SIGNAL; }

  bool execute(THD *thd) override;
};

/**
  Sql_cmd_resignal represents a RESIGNAL statement.
*/
class Sql_cmd_resignal : public Sql_cmd_common_signal {
 public:
  /**
    Constructor, used to represent a RESIGNAL statement.
    @param cond the SQL condition to resignal (optional, may be NULL).
    @param set the collection of signal information to resignal.
  */
  Sql_cmd_resignal(const sp_condition_value *cond, Set_signal_information *set)
      : Sql_cmd_common_signal(cond, set) {}

  ~Sql_cmd_resignal() override = default;

  enum_sql_command sql_command_code() const override { return SQLCOM_RESIGNAL; }

  bool execute(THD *thd) override;
};

#endif