/*
   Copyright (c) 2011, 2021, 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.

   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 "ndb_local_schema.h"

#include "sql_class.h"
#include "sql_table.h"
#include "mdl.h"
#include "log.h"
#include "table_trigger_dispatcher.h"
#include "sql_trigger.h"
#include "auth_common.h"              // check_readonly()

static const char *ndb_ext=".ndb";


bool Ndb_local_schema::Base::mdl_try_lock(void) const
{
  MDL_request_list mdl_requests;
  MDL_request global_request;
  MDL_request schema_request;
  MDL_request mdl_request;

  MDL_REQUEST_INIT(&global_request,
                   MDL_key::GLOBAL, "", "", MDL_INTENTION_EXCLUSIVE,
                   MDL_STATEMENT);
  MDL_REQUEST_INIT(&schema_request,
                   MDL_key::SCHEMA, m_db, "", MDL_INTENTION_EXCLUSIVE,
                   MDL_TRANSACTION);
  MDL_REQUEST_INIT(&mdl_request,
                   MDL_key::TABLE, m_db, m_name, MDL_EXCLUSIVE,
                   MDL_TRANSACTION);

  mdl_requests.push_front(&mdl_request);
  mdl_requests.push_front(&schema_request);
  mdl_requests.push_front(&global_request);

  if (m_thd->mdl_context.acquire_locks(&mdl_requests,
                                       0 /* don't wait for lock */))
  {
    // Check that an error has been pushed to thd and then
    // clear it since this is just a _try lock_
    assert(m_thd->is_error());
    m_thd->clear_error();

    log_warning("Failed to acquire metadata lock");

    return false;
  }

  /*
    Now when we have protection against concurrent change of read_only
    option we can safely re-check its value.
  */
  if (check_readonly(m_thd, true))
    return false;

  DBUG_PRINT("info", ("acquired metadata lock"));
  return true;
}


void Ndb_local_schema::Base::mdl_unlock(void)
{
  m_thd->mdl_context.release_transactional_locks();
}


void Ndb_local_schema::Base::log_warning(const char* fmt, ...) const
{
  char buf[1024];
  va_list args;
  va_start(args, fmt);
  my_vsnprintf(buf, sizeof(buf), fmt, args);
  va_end(args);

  if (m_push_warnings)
  {
    // Append the error which caused the error to thd's warning list
    push_warning_printf(m_thd, Sql_condition::SL_NOTE,
                        ER_GET_ERRMSG, "Ndb schema[%s.%s]: %s",
                        m_db, m_name, buf);
  }
  else
  {
    // Print the warning to log file
    sql_print_warning("Ndb schema[%s.%s]: %s",
                      m_db, m_name, buf);
  }
}


Ndb_local_schema::Base::Base(THD* thd, const char* db, const char* name) :
  m_thd(thd),
  m_db(db), m_name(name)
{
  /*
    System(or daemon) threads report error to log file
    all other threads use push_warning
  */
  m_push_warnings = (thd->get_command() != COM_DAEMON);

  m_have_mdl_lock= mdl_try_lock();
}


Ndb_local_schema::Base::~Base()
{
  // Release MDL locks
  if (m_have_mdl_lock)
  {
   DBUG_PRINT("info", ("releasing mdl lock"));
    mdl_unlock();
  }
}


bool
Ndb_local_schema::Table::file_exists(const char* ext) const
{
  char buf[FN_REFLEN + 1];
  build_table_filename(buf, sizeof(buf)-1,
                       m_db, m_name, ext, 0);

  if (my_access(buf, F_OK))
  {
    DBUG_PRINT("info", ("File '%s' does not exist", buf));
    return false;
  }

  DBUG_PRINT("info", ("File '%s' exist", buf));
  return true;
}


bool
Ndb_local_schema::Table::remove_file(const char* ext) const
{
  char buf[FN_REFLEN + 1];
  build_table_filename(buf, sizeof(buf)-1,
                       m_db, m_name, ext, 0);

  int error = my_delete(buf, 0);
  if (!error || errno == ENOENT)
    return true;

  log_warning("Failed to remove file '%s', errno: %d", buf, errno);
  return false;
}


bool
Ndb_local_schema::Table::rename_file(const char* new_db, const char* new_name,
                             const char* ext) const
{
  char from[FN_REFLEN + 1];
  build_table_filename(from, sizeof(from)-1,
                       m_db, m_name, ext, 0);

  char to[FN_REFLEN + 1];
  build_table_filename(to, sizeof(to) - 1, new_db, new_name, ext, 0);

  int error = my_rename(from, to, 0);
  if (!error)
    return true;

  log_warning("Failed to rename file '%s' to '%s', errno: %d",
            from, to, errno);
  return false;
}


// Read the engine type from .frm and return true if it says NDB
bool
Ndb_local_schema::Table::frm_engine_is_ndb(void) const
{
  char buf[FN_REFLEN + 1];
  build_table_filename(buf, sizeof(buf)-1,
                       m_db, m_name, reg_ext, 0);

  legacy_db_type engine_type;
  (void)dd_frm_type(m_thd, buf, &engine_type);
  DBUG_PRINT("info", ("engine_type: %d", engine_type));

  return (engine_type == DB_TYPE_NDBCLUSTER);
}


Ndb_local_schema::Table::Table(THD* thd,
                               const char* db, const char* name) :
  Ndb_local_schema::Base(thd, db, name),
  m_ndb_file_exist(false),
  m_has_triggers(false)
{
  DBUG_ENTER("Ndb_local_table");
  DBUG_PRINT("enter", ("name: '%s.%s'", db, name));

  // Check if .frm file exist
  m_frm_file_exist = file_exists(reg_ext);
  if (!m_frm_file_exist)
  {
    // Check for stray .ndb file
    assert(!file_exists(ndb_ext));
    DBUG_VOID_RETURN;
  }

  // Check if .ndb file exist
  m_ndb_file_exist = file_exists(ndb_ext);

  // Check if there are trigger files
  m_has_triggers = file_exists(TRG_EXT);

  DBUG_VOID_RETURN;
}


bool
Ndb_local_schema::Table::is_local_table(void) const
{
  if (m_frm_file_exist && !m_ndb_file_exist)
  {
    // The .frm exist but no .ndb file , this is a "local" table

    // Double check that the engine type in .frm doesn't say NDB
    assert(!frm_engine_is_ndb());

    return true;
  }
  return false;
}


void
Ndb_local_schema::Table::remove_table(void) const
{
  (void)remove_file(reg_ext);
  (void)remove_file(ndb_ext);

  if (m_has_triggers)
  {
    // Copy to buffers since 'drop_all_triggers' want char*
    char db_name_buf[FN_REFLEN + 1], table_name_buf[FN_REFLEN + 1];
    my_stpcpy(db_name_buf, m_db);
    my_stpcpy(table_name_buf, m_name);

    if (drop_all_triggers(m_thd, db_name_buf, table_name_buf))
    {
      log_warning("Failed to drop all triggers");
    }
  }
}


void
Ndb_local_schema::Table::rename_table(const char* new_db,
                                      const char* new_name) const
{
  (void)rename_file(new_db, new_name, reg_ext);
  (void)rename_file(new_db, new_name, ndb_ext);

  if (m_has_triggers)
  {
    if (!have_mdl_lock())
    {
      // change_trigger_table_name() requires an EXLUSIVE mdl lock
      // so if the mdl lock was not aquired, skip this part
      log_warning("Can't rename triggers, no mdl lock");
    }
    else
    {
      if (change_trigger_table_name(m_thd,
                                    m_db, m_name, m_name,
                                    new_db, new_name))
      {
        log_warning("Failed to rename all triggers");
      }
    }
  }
}
