/* Copyright (c) 2023, 2024, 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 designed to work 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 either included with
the program or referenced in the documentation.

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 "sql/statement/statement_runnable.h"

#include "mysql/psi/mysql_ps.h"  // MYSQL_EXECUTE_PS
#include "sql/sp_head.h"
#include "sql/sp_rcontext.h"
#include "sql/sql_class.h"
#include "sql/sql_digest_stream.h"
#include "sql/sql_lex.h"
#include "sql/sql_parse.h"  // sql_command_flags
#include "sql/statement/utils.h"

Server_runnable::~Server_runnable() = default;

Statement_runnable::Statement_runnable(LEX_STRING sql_text)
    : m_sql_text(sql_text) {}

/**
  Parse and execute a statement. Does not prepare the query.

  Allows to execute a statement from within another statement.
  Supports even executing a statement from within stored program.
  The main property of the implementation is that it does not
  affect the environment -- i.e. you  can run many
  executions without having to cleanup/reset THD in between.
*/

bool Statement_runnable::execute_server_code(THD *thd) {
  sql_digest_state *parent_digest;
  PSI_statement_locker *parent_locker;

  if (alloc_query(thd, m_sql_text.str, m_sql_text.length)) return true;

  Parser_state parser_state;
  if (parser_state.init(thd, thd->query().str, thd->query().length)) {
    // OOM
    return true; /* purecov: inspected */
  }

  parser_state.m_lip.multi_statements = false;
  lex_start(thd);

  const bool executing_statement_under_stored_program =
      (thd->sp_runtime_ctx != nullptr);

  if (executing_statement_under_stored_program) {
    thd->lex->sphead = thd->sp_runtime_ctx->sp;

    /*
      Make sure that we are not here while parsing a statement under stored
      program. In other words, Execute_regular_statement::execute() and
      Ed_connection::execute_direct() should not be invoked while parsing
      another SP statement.
    */
    assert(thd->lex->get_sp_current_parsing_ctx() == nullptr);
  }

  parent_digest = thd->m_digest;
  parent_locker = thd->m_statement_psi;
  thd->m_digest = nullptr;
  thd->m_statement_psi = nullptr;
  bool error = parse_sql(thd, &parser_state, nullptr) || thd->is_error();
  thd->m_digest = parent_digest;
  thd->m_statement_psi = parent_locker;

  if (error) goto end;

  /*
    Make sure that no new stored program is created while executed statement
    under stored program. CREATE/ALTER/DROP SP under stored program are
    restricted.
  */
  assert(!executing_statement_under_stored_program ||
         thd->lex->sphead == thd->sp_runtime_ctx->sp);

  // Set multi-result state if statement belongs to SP.
  if (executing_statement_under_stored_program) {
    error = set_sp_multi_result_state(thd, thd->lex);
    if (error) goto end;
  }

  thd->lex->set_trg_event_type_for_tables();

  parent_locker = thd->m_statement_psi;
  thd->m_statement_psi = nullptr;

  /*
    Rewrite first (if needed); execution might replace passwords
    with hashes in situ without flagging it, and then we'd make
    a hash of that hash.
  */
  rewrite_query_if_needed(thd);
  log_execute_line(thd);

  set_query_for_display(thd);

  error = mysql_execute_command(thd);
  thd->m_statement_psi = parent_locker;

end:
  /*
    lex_end() would free sphead. Don't free sphead which invoked this
    statement.
  */
  if (executing_statement_under_stored_program) {
    assert(thd->lex->sphead == thd->sp_runtime_ctx->sp);
    thd->lex->sphead = nullptr;
  }

  lex_end(thd->lex);

  return error;
}