Club Drupal

<?php

/**

 * @file

 * Database interface code for MySQL database servers.

 */

/**

 * The default character for quoting identifiers in MySQL.

 */

define('MYSQL_IDENTIFIER_QUOTE_CHARACTER_DEFAULT', '`');

/**

 * @addtogroup database

 * @{

 */

class DatabaseConnection_mysql extends DatabaseConnection {

  /**

   * Flag to indicate if the cleanup function in __destruct() should run.

   *

   * @var boolean

   */

  protected $needsCleanup = FALSE;

  /**

   * The list of MySQL reserved key words.

   *

   * @link https://dev.mysql.com/doc/refman/8.0/en/keywords.html

   */

  private $reservedKeyWords = array(

    'accessible',

    'add',

    'admin',

    'all',

    'alter',

    'analyze',

    'and',

    'as',

    'asc',

    'asensitive',

    'before',

    'between',

    'bigint',

    'binary',

    'blob',

    'both',

    'by',

    'call',

    'cascade',

    'case',

    'change',

    'char',

    'character',

    'check',

    'collate',

    'column',

    'condition',

    'constraint',

    'continue',

    'convert',

    'create',

    'cross',

    'cube',

    'cume_dist',

    'current_date',

    'current_time',

    'current_timestamp',

    'current_user',

    'cursor',

    'database',

    'databases',

    'day_hour',

    'day_microsecond',

    'day_minute',

    'day_second',

    'dec',

    'decimal',

    'declare',

    'default',

    'delayed',

    'delete',

    'dense_rank',

    'desc',

    'describe',

    'deterministic',

    'distinct',

    'distinctrow',

    'div',

    'double',

    'drop',

    'dual',

    'each',

    'else',

    'elseif',

    'empty',

    'enclosed',

    'escaped',

    'except',

    'exists',

    'exit',

    'explain',

    'false',

    'fetch',

    'first_value',

    'float',

    'float4',

    'float8',

    'for',

    'force',

    'foreign',

    'from',

    'fulltext',

    'function',

    'generated',

    'get',

    'grant',

    'group',

    'grouping',

    'groups',

    'having',

    'high_priority',

    'hour_microsecond',

    'hour_minute',

    'hour_second',

    'if',

    'ignore',

    'in',

    'index',

    'infile',

    'inner',

    'inout',

    'insensitive',

    'insert',

    'int',

    'int1',

    'int2',

    'int3',

    'int4',

    'int8',

    'integer',

    'interval',

    'into',

    'io_after_gtids',

    'io_before_gtids',

    'is',

    'iterate',

    'join',

    'json_table',

    'key',

    'keys',

    'kill',

    'lag',

    'last_value',

    'lead',

    'leading',

    'leave',

    'left',

    'like',

    'limit',

    'linear',

    'lines',

    'load',

    'localtime',

    'localtimestamp',

    'lock',

    'long',

    'longblob',

    'longtext',

    'loop',

    'low_priority',

    'master_bind',

    'master_ssl_verify_server_cert',

    'match',

    'maxvalue',

    'mediumblob',

    'mediumint',

    'mediumtext',

    'middleint',

    'minute_microsecond',

    'minute_second',

    'mod',

    'modifies',

    'natural',

    'not',

    'no_write_to_binlog',

    'nth_value',

    'ntile',

    'null',

    'numeric',

    'of',

    'on',

    'optimize',

    'optimizer_costs',

    'option',

    'optionally',

    'or',

    'order',

    'out',

    'outer',

    'outfile',

    'over',

    'partition',

    'percent_rank',

    'persist',

    'persist_only',

    'precision',

    'primary',

    'procedure',

    'purge',

    'range',

    'rank',

    'read',

    'reads',

    'read_write',

    'real',

    'recursive',

    'references',

    'regexp',

    'release',

    'rename',

    'repeat',

    'replace',

    'require',

    'resignal',

    'restrict',

    'return',

    'revoke',

    'right',

    'rlike',

    'row',

    'rows',

    'row_number',

    'schema',

    'schemas',

    'second_microsecond',

    'select',

    'sensitive',

    'separator',

    'set',

    'show',

    'signal',

    'smallint',

    'spatial',

    'specific',

    'sql',

    'sqlexception',

    'sqlstate',

    'sqlwarning',

    'sql_big_result',

    'sql_calc_found_rows',

    'sql_small_result',

    'ssl',

    'starting',

    'stored',

    'straight_join',

    'system',

    'table',

    'terminated',

    'then',

    'tinyblob',

    'tinyint',

    'tinytext',

    'to',

    'trailing',

    'trigger',

    'true',

    'undo',

    'union',

    'unique',

    'unlock',

    'unsigned',

    'update',

    'usage',

    'use',

    'using',

    'utc_date',

    'utc_time',

    'utc_timestamp',

    'values',

    'varbinary',

    'varchar',

    'varcharacter',

    'varying',

    'virtual',

    'when',

    'where',

    'while',

    'window',

    'with',

    'write',

    'xor',

    'year_month',

    'zerofill',

  );

  public function __construct(array $connection_options = array()) {

    // This driver defaults to transaction support, except if explicitly passed FALSE.

    $this->transactionSupport = !isset($connection_options['transactions']) || ($connection_options['transactions'] !== FALSE);

    // MySQL never supports transactional DDL.

    $this->transactionalDDLSupport = FALSE;

    $this->connectionOptions = $connection_options;

    $charset = 'utf8';

    // Check if the charset is overridden to utf8mb4 in settings.php.

    if ($this->utf8mb4IsActive()) {

      $charset = 'utf8mb4';

    }

    // The DSN should use either a socket or a host/port.

    if (isset($connection_options['unix_socket'])) {

      $dsn = 'mysql:unix_socket=' . $connection_options['unix_socket'];

    }

    else {

      // Default to TCP connection on port 3306.

      $dsn = 'mysql:host=' . $connection_options['host'] . ';port=' . (empty($connection_options['port']) ? 3306 : $connection_options['port']);

    }

    // Character set is added to dsn to ensure PDO uses the proper character

    // set when escaping. This has security implications. See

    // https://www.drupal.org/node/1201452 for further discussion.

    $dsn .= ';charset=' . $charset;

    $dsn .= ';dbname=' . $connection_options['database'];

    // Allow PDO options to be overridden.

    $connection_options += array(

      'pdo' => array(),

    );

    $connection_options['pdo'] += array(

      // So we don't have to mess around with cursors and unbuffered queries by default.

      PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => TRUE,

      // Because MySQL's prepared statements skip the query cache, because it's dumb.

      PDO::ATTR_EMULATE_PREPARES => TRUE,

    );

    if (defined('PDO::MYSQL_ATTR_MULTI_STATEMENTS')) {

      // An added connection option in PHP 5.5.21+ to optionally limit SQL to a

      // single statement like mysqli.

      $connection_options['pdo'] += array(PDO::MYSQL_ATTR_MULTI_STATEMENTS => FALSE);

    }

    parent::__construct($dsn, $connection_options['username'], $connection_options['password'], $connection_options['pdo']);

    // Force MySQL to use the UTF-8 character set. Also set the collation, if a

    // certain one has been set; otherwise, MySQL defaults to 'utf8_general_ci'

    // for UTF-8.

    if (!empty($connection_options['collation'])) {

      $this->exec('SET NAMES ' . $charset . ' COLLATE ' . $connection_options['collation']);

    }

    else {

      $this->exec('SET NAMES ' . $charset);

    }

    // Set MySQL init_commands if not already defined.  Default Drupal's MySQL

    // behavior to conform more closely to SQL standards.  This allows Drupal

    // to run almost seamlessly on many different kinds of database systems.

    // These settings force MySQL to behave the same as postgresql, or sqlite

    // in regards to syntax interpretation and invalid data handling.  See

    // http://drupal.org/node/344575 for further discussion. Also, as MySQL 5.5

    // changed the meaning of TRADITIONAL we need to spell out the modes one by

    // one.

    $connection_options += array(

      'init_commands' => array(),

    );

    $sql_mode = 'REAL_AS_FLOAT,PIPES_AS_CONCAT,ANSI_QUOTES,IGNORE_SPACE,STRICT_TRANS_TABLES,STRICT_ALL_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO';

    // NO_AUTO_CREATE_USER was removed in MySQL 8.0.11

    // https://dev.mysql.com/doc/relnotes/mysql/8.0/en/news-8-0-11.html#mysqld-8-0-11-deprecation-removal

    if (version_compare($this->getAttribute(PDO::ATTR_SERVER_VERSION), '8.0.11', '<')) {

      $sql_mode .= ',NO_AUTO_CREATE_USER';

    }

    $connection_options['init_commands'] += array(

      'sql_mode' => "SET sql_mode = '$sql_mode'",

    );

    // Execute initial commands.

    foreach ($connection_options['init_commands'] as $sql) {

      $this->exec($sql);

    }

  }

  /**

   * {@inheritdoc}}

   */

  protected function setPrefix($prefix) {

    parent::setPrefix($prefix);

    // Successive versions of MySQL have become increasingly strict about the

    // use of reserved keywords as table names. Drupal 7 uses at least one such

    // table (system). Therefore we surround all table names with quotes.

    $quote_char = variable_get('mysql_identifier_quote_character', MYSQL_IDENTIFIER_QUOTE_CHARACTER_DEFAULT);

    foreach ($this->prefixSearch as $i => $prefixSearch) {

      if (substr($prefixSearch, 0, 1) === '{') {

        // If the prefix already contains one or more quotes remove them.

        // This can happen when - for example - DrupalUnitTestCase sets up a

        // "temporary prefixed database". Also if there's a dot in the prefix,

        // wrap it in quotes to cater for schema names in prefixes.

        $search = array($quote_char, '.');

        $replace = array('', $quote_char . '.' . $quote_char);

        $this->prefixReplace[$i] = $quote_char . str_replace($search, $replace, $this->prefixReplace[$i]);

      }

      if (substr($prefixSearch, -1) === '}') {

        $this->prefixReplace[$i] .= $quote_char;

      }

    }

  }

  /**

   * {@inheritdoc}

   */

  public function escapeField($field) {

    $field = parent::escapeField($field);

    return $this->quoteIdentifier($field);

  }

  public function escapeFields(array $fields) {

    foreach ($fields as &$field) {

      $field = $this->escapeField($field);

    }

    return $fields;

  }

  /**

   * {@inheritdoc}

   */

  public function escapeAlias($field) {

    $field = parent::escapeAlias($field);

    return $this->quoteIdentifier($field);

  }

  /**

   * Quotes an identifier if it matches a MySQL reserved keyword.

   *

   * @param string $identifier

   *   The field to check.

   *

   * @return string

   *   The identifier, quoted if it matches a MySQL reserved keyword.

   */

  private function quoteIdentifier($identifier) {

    // Quote identifiers so that MySQL reserved words like 'function' can be

    // used as column names. Sometimes the 'table.column_name' format is passed

    // in. For example, menu_load_links() adds a condition on "ml.menu_name".

    if (strpos($identifier, '.') !== FALSE) {

      list($table, $identifier) = explode('.', $identifier, 2);

    }

    if (in_array(strtolower($identifier), $this->reservedKeyWords, TRUE)) {

      // Quote the string for MySQL reserved keywords.

      $quote_char = variable_get('mysql_identifier_quote_character', MYSQL_IDENTIFIER_QUOTE_CHARACTER_DEFAULT);

      $identifier = $quote_char . $identifier . $quote_char;

    }

    return isset($table) ? $table . '.' . $identifier : $identifier;

  }

  public function __destruct() {

    if ($this->needsCleanup) {

      $this->nextIdDelete();

    }

  }

  public function queryRange($query, $from, $count, array $args = array(), array $options = array()) {

    return $this->query($query . ' LIMIT ' . (int) $from . ', ' . (int) $count, $args, $options);

  }

  public function queryTemporary($query, array $args = array(), array $options = array()) {

    $tablename = $this->generateTemporaryTableName();

    $this->query('CREATE TEMPORARY TABLE {' . $tablename . '} Engine=MEMORY ' . $query, $args, $options);

    return $tablename;

  }

  public function driver() {

    return 'mysql';

  }

  public function databaseType() {

    return 'mysql';

  }

  public function mapConditionOperator($operator) {

    // We don't want to override any of the defaults.

    return NULL;

  }

  public function nextId($existing_id = 0) {

    $new_id = $this->query('INSERT INTO {sequences} () VALUES ()', array(), array('return' => Database::RETURN_INSERT_ID));

    // This should only happen after an import or similar event.

    if ($existing_id >= $new_id) {

      // If we INSERT a value manually into the sequences table, on the next

      // INSERT, MySQL will generate a larger value. However, there is no way

      // of knowing whether this value already exists in the table. MySQL

      // provides an INSERT IGNORE which would work, but that can mask problems

      // other than duplicate keys. Instead, we use INSERT ... ON DUPLICATE KEY

      // UPDATE in such a way that the UPDATE does not do anything. This way,

      // duplicate keys do not generate errors but everything else does.

      $this->query('INSERT INTO {sequences} (value) VALUES (:value) ON DUPLICATE KEY UPDATE value = value', array(':value' => $existing_id));

      $new_id = $this->query('INSERT INTO {sequences} () VALUES ()', array(), array('return' => Database::RETURN_INSERT_ID));

    }

    $this->needsCleanup = TRUE;

    return $new_id;

  }

  public function nextIdDelete() {

    // While we want to clean up the table to keep it up from occupying too

    // much storage and memory, we must keep the highest value in the table

    // because InnoDB  uses an in-memory auto-increment counter as long as the

    // server runs. When the server is stopped and restarted, InnoDB

    // reinitializes the counter for each table for the first INSERT to the

    // table based solely on values from the table so deleting all values would

    // be a problem in this case. Also, TRUNCATE resets the auto increment

    // counter.

    try {

      $max_id = $this->query('SELECT MAX(value) FROM {sequences}')->fetchField();

      // We know we are using MySQL here, no need for the slower db_delete().

      $this->query('DELETE FROM {sequences} WHERE value < :value', array(':value' => $max_id));

    }

    // During testing, this function is called from shutdown with the

    // simpletest prefix stored in $this->connection, and those tables are gone

    // by the time shutdown is called so we need to ignore the database

    // errors. There is no problem with completely ignoring errors here: if

    // these queries fail, the sequence will work just fine, just use a bit

    // more database storage and memory.

    catch (PDOException $e) {

    }

  }

  /**

   * Overridden to work around issues to MySQL not supporting transactional DDL.

   */

  protected function popCommittableTransactions() {

    // Commit all the committable layers.

    foreach (array_reverse($this->transactionLayers) as $name => $active) {

      // Stop once we found an active transaction.

      if ($active) {

        break;

      }

      // If there are no more layers left then we should commit.

      unset($this->transactionLayers[$name]);

      if (empty($this->transactionLayers)) {

        if (!PDO::commit()) {

          throw new DatabaseTransactionCommitFailedException();

        }

      }

      else {

        // Attempt to release this savepoint in the standard way.

        try {

          $this->query('RELEASE SAVEPOINT ' . $name);

        }

        catch (PDOException $e) {

          // However, in MySQL (InnoDB), savepoints are automatically committed

          // when tables are altered or created (DDL transactions are not

          // supported). This can cause exceptions due to trying to release

          // savepoints which no longer exist.

          //

          // To avoid exceptions when no actual error has occurred, we silently

          // succeed for MySQL error code 1305 ("SAVEPOINT does not exist").

          if ($e->errorInfo[1] == '1305') {

            // If one SAVEPOINT was released automatically, then all were.

            // Therefore, clean the transaction stack.

            $this->transactionLayers = array();

            // We also have to explain to PDO that the transaction stack has

            // been cleaned-up.

            PDO::commit();

          }

          else {

            throw $e;

          }

        }

      }

    }

  }

  public function utf8mb4IsConfigurable() {

    return TRUE;

  }

  public function utf8mb4IsActive() {

    return isset($this->connectionOptions['charset']) && $this->connectionOptions['charset'] === 'utf8mb4';

  }

  public function utf8mb4IsSupported() {

    // Ensure that the MySQL driver supports utf8mb4 encoding.

    $version = $this->getAttribute(PDO::ATTR_CLIENT_VERSION);

    if (strpos($version, 'mysqlnd') !== FALSE) {

      // The mysqlnd driver supports utf8mb4 starting at version 5.0.9.

      $version = preg_replace('/^\D+([\d.]+).*/', '$1', $version);

      if (version_compare($version, '5.0.9', '<')) {

        return FALSE;

      }

    }

    else {

      // The libmysqlclient driver supports utf8mb4 starting at version 5.5.3.

      if (version_compare($version, '5.5.3', '<')) {

        return FALSE;

      }

    }

    // Ensure that the MySQL server supports large prefixes and utf8mb4.

    try {

      $this->query("CREATE TABLE {drupal_utf8mb4_test} (id VARCHAR(255), PRIMARY KEY(id(255))) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci ROW_FORMAT=DYNAMIC ENGINE=INNODB");

    }

    catch (Exception $e) {

      return FALSE;

    }

    $this->query("DROP TABLE {drupal_utf8mb4_test}");

    return TRUE;

  }

}

/**

 * @} End of "addtogroup database".

 */