character_sets.cc

/* Copyright (c) 2014, 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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   as designated in a particular file or component or in included license
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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
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   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

#include "sql/dd/impl/tables/character_sets.h"

#include <assert.h>
#include <stddef.h>
#include <new>
#include <set>
#include <vector>

#include "my_sys.h"
#include "mysql/strings/m_ctype.h"
#include "sql/dd/cache/dictionary_client.h"     // dd::cache::Dictionary_...
#include "sql/dd/dd.h"                          // dd::create_object
#include "sql/dd/impl/cache/storage_adapter.h"  // Storage_adapter
#include "sql/dd/impl/raw/object_keys.h"        // Global_name_key
#include "sql/dd/impl/raw/raw_record.h"
#include "sql/dd/impl/tables/dd_properties.h"  // TARGET_DD_VERSION
#include "sql/dd/impl/types/charset_impl.h"    // dd::Charset_impl
#include "sql/dd/impl/types/object_table_definition_impl.h"
#include "sql/dd/object_id.h"
#include "sql/dd/types/charset.h"
#include "sql/item_create.h"
#include "sql/sql_class.h"  // THD

namespace dd {
namespace tables {

const Character_sets &Character_sets::instance() {
  static Character_sets *s_instance = new Character_sets();
  return *s_instance;
}

///////////////////////////////////////////////////////////////////////////

const CHARSET_INFO *Character_sets::name_collation() {
  return &my_charset_utf8mb3_general_ci;
}

///////////////////////////////////////////////////////////////////////////

Character_sets::Character_sets() {
  m_target_def.set_table_name("character_sets");

  m_target_def.add_field(FIELD_ID, "FIELD_ID",
                         "id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT");
  m_target_def.add_field(FIELD_NAME, "FIELD_NAME",
                         "name VARCHAR(64) NOT NULL COLLATE " +
                             String_type(name_collation()->m_coll_name));
  m_target_def.add_field(FIELD_DEFAULT_COLLATION_ID,
                         "FIELD_DEFAULT_COLLATION_ID",
                         "default_collation_id BIGINT UNSIGNED NOT NULL");
  m_target_def.add_field(FIELD_COMMENT, "FIELD_COMMENT",
                         "comment VARCHAR(2048)"
                         " COLLATE utf8mb3_general_ci NOT NULL");
  m_target_def.add_field(FIELD_MB_MAX_LENGTH, "FIELD_MB_MAX_LENGTH",
                         "mb_max_length INT UNSIGNED NOT NULL");
  m_target_def.add_field(FIELD_OPTIONS, "FIELD_OPTIONS", "options MEDIUMTEXT");

  m_target_def.add_index(INDEX_PK_ID, "INDEX_PK_ID", "PRIMARY KEY(id)");
  m_target_def.add_index(INDEX_UK_NAME, "INDEX_UK_NAME", "UNIQUE KEY(name)");
  m_target_def.add_index(INDEX_UK_DEFAULT_COLLATION_ID,
                         "INDEX_UK_DEFAULT_COLLATION_ID",
                         "UNIQUE KEY(default_collation_id)");

  m_target_def.add_foreign_key(FK_DEFAULT_COLLATION_ID,
                               "FK_DEFAULT_COLLATION_ID",
                               "FOREIGN KEY (default_collation_id) "
                               "REFERENCES collations(id)");
}

///////////////////////////////////////////////////////////////////////////

// The table is populated when the server is started, unless it is
// started in read only mode.

bool Character_sets::populate(THD *thd) const {
  // Obtain a list of the previously stored charsets.
  cache::Dictionary_client::Auto_releaser releaser(thd->dd_client());
  std::vector<const Charset *> prev_cset;
  if (thd->dd_client()->fetch_global_components(&prev_cset)) return true;

  std::set<Object_id> prev_cset_ids;
  for (const Charset *cset : prev_cset) prev_cset_ids.insert(cset->id());

  // We have an outer loop identifying the primary collations, i.e.,
  // the collations which are default for some character set. Then,
  // the character set of each primary collation is stored in an entry
  // in the dd.character_sets table. This means that if there are
  // collations referring to a character set which has no default
  // collation, we will not have an entry for this character set in
  // the dd.character_sets table. This also means that a given character
  // set can have only one primary collation, since character set identity
  // is given by the character set name, and we have a unique key on the
  // character set name in the dd.character_sets table. Populating the
  // dd.collations table follows a similar pattern, but has an additional
  // inner loop adding the actual collations referring to the character
  // sets. Each character set is stored with the id (primary key) of its
  // corresponding primary collation as the id (primary key).

  Charset_impl *new_charset = create_object<Charset_impl>();
  bool error = false;
  for (int internal_charset_id = 0;
       internal_charset_id < MY_ALL_CHARSETS_SIZE && !error;
       internal_charset_id++) {
    const CHARSET_INFO *cs = all_charsets[internal_charset_id];
    if (cs && (cs->state & MY_CS_PRIMARY) && (cs->state & MY_CS_AVAILABLE) &&
        !(cs->state & MY_CS_HIDDEN)) {
      // Remove the id from the set of non-updated old ids.
      prev_cset_ids.erase(cs->number);

      // The character set is stored on the same id as its primary collation
      new_charset->set_id(cs->number);
      new_charset->set_name(cs->csname);
      new_charset->set_default_collation_id(cs->number);
      new_charset->set_mb_max_length(cs->mbmaxlen);
      new_charset->set_comment(cs->comment ? cs->comment : "");

      // If the charset exists, it will be updated; otherwise,
      // it will be inserted.
      error = cache::Storage_adapter::instance()->store(
          thd, static_cast<Charset *>(new_charset));
    }
  }
  delete new_charset;

  // The remaining ids in the prev_cset_ids set were not updated, and must
  // therefore be deleted from the DD since they are not supported anymore.
  for (std::set<Object_id>::const_iterator del_it = prev_cset_ids.begin();
       del_it != prev_cset_ids.end(); ++del_it) {
    const Charset *del_cset = nullptr;
    if (thd->dd_client()->acquire(*del_it, &del_cset)) return true;

    assert(del_cset);
    if (thd->dd_client()->drop(del_cset)) return true;
  }

  return error;
}

///////////////////////////////////////////////////////////////////////////

/* purecov: begin deadcode */
Charset *Character_sets::create_entity_object(const Raw_record &) const {
  return new (std::nothrow) Charset_impl();
}
/* purecov: end */

///////////////////////////////////////////////////////////////////////////

bool Character_sets::update_object_key(Global_name_key *key,
                                       const String_type &charset_name) {
  key->update(FIELD_NAME, charset_name, name_collation());
  return false;
}

///////////////////////////////////////////////////////////////////////////

}  // namespace tables
}  // namespace dd