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root / drupal7 / includes / database / mysql / database.inc @ b0dc3a2e

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<?php
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/**
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 * @file
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 * Database interface code for MySQL database servers.
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 */
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/**
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 * @addtogroup database
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 * @{
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 */
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class DatabaseConnection_mysql extends DatabaseConnection {
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  /**
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   * Flag to indicate if the cleanup function in __destruct() should run.
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   *
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   * @var boolean
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   */
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  protected $needsCleanup = FALSE;
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  public function __construct(array $connection_options = array()) {
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    // This driver defaults to transaction support, except if explicitly passed FALSE.
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    $this->transactionSupport = !isset($connection_options['transactions']) || ($connection_options['transactions'] !== FALSE);
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    // MySQL never supports transactional DDL.
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    $this->transactionalDDLSupport = FALSE;
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    $this->connectionOptions = $connection_options;
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    $charset = 'utf8';
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    // Check if the charset is overridden to utf8mb4 in settings.php.
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    if ($this->utf8mb4IsActive()) {
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      $charset = 'utf8mb4';
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    }
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    // The DSN should use either a socket or a host/port.
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    if (isset($connection_options['unix_socket'])) {
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      $dsn = 'mysql:unix_socket=' . $connection_options['unix_socket'];
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    }
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    else {
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      // Default to TCP connection on port 3306.
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      $dsn = 'mysql:host=' . $connection_options['host'] . ';port=' . (empty($connection_options['port']) ? 3306 : $connection_options['port']);
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    }
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    // Character set is added to dsn to ensure PDO uses the proper character
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    // set when escaping. This has security implications. See
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    // https://www.drupal.org/node/1201452 for further discussion.
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    $dsn .= ';charset=' . $charset;
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    $dsn .= ';dbname=' . $connection_options['database'];
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    // Allow PDO options to be overridden.
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    $connection_options += array(
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      'pdo' => array(),
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    );
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    $connection_options['pdo'] += array(
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      // So we don't have to mess around with cursors and unbuffered queries by default.
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      PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => TRUE,
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      // Because MySQL's prepared statements skip the query cache, because it's dumb.
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      PDO::ATTR_EMULATE_PREPARES => TRUE,
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    );
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    if (defined('PDO::MYSQL_ATTR_MULTI_STATEMENTS')) {
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      // An added connection option in PHP 5.5.21+ to optionally limit SQL to a
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      // single statement like mysqli.
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      $connection_options['pdo'] += array(PDO::MYSQL_ATTR_MULTI_STATEMENTS => FALSE);
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    }
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    parent::__construct($dsn, $connection_options['username'], $connection_options['password'], $connection_options['pdo']);
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    // Force MySQL to use the UTF-8 character set. Also set the collation, if a
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    // certain one has been set; otherwise, MySQL defaults to 'utf8_general_ci'
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    // for UTF-8.
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    if (!empty($connection_options['collation'])) {
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      $this->exec('SET NAMES ' . $charset . ' COLLATE ' . $connection_options['collation']);
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    }
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    else {
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      $this->exec('SET NAMES ' . $charset);
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    }
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    // Set MySQL init_commands if not already defined.  Default Drupal's MySQL
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    // behavior to conform more closely to SQL standards.  This allows Drupal
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    // to run almost seamlessly on many different kinds of database systems.
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    // These settings force MySQL to behave the same as postgresql, or sqlite
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    // in regards to syntax interpretation and invalid data handling.  See
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    // http://drupal.org/node/344575 for further discussion. Also, as MySQL 5.5
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    // changed the meaning of TRADITIONAL we need to spell out the modes one by
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    // one.
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    $connection_options += array(
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      'init_commands' => array(),
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    );
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    $connection_options['init_commands'] += array(
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      'sql_mode' => "SET sql_mode = 'REAL_AS_FLOAT,PIPES_AS_CONCAT,ANSI_QUOTES,IGNORE_SPACE,STRICT_TRANS_TABLES,STRICT_ALL_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER'",
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    );
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    // Execute initial commands.
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    foreach ($connection_options['init_commands'] as $sql) {
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      $this->exec($sql);
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    }
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  }
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  public function __destruct() {
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    if ($this->needsCleanup) {
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      $this->nextIdDelete();
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    }
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  }
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  public function queryRange($query, $from, $count, array $args = array(), array $options = array()) {
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    return $this->query($query . ' LIMIT ' . (int) $from . ', ' . (int) $count, $args, $options);
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  }
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  public function queryTemporary($query, array $args = array(), array $options = array()) {
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    $tablename = $this->generateTemporaryTableName();
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    $this->query('CREATE TEMPORARY TABLE {' . $tablename . '} Engine=MEMORY ' . $query, $args, $options);
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    return $tablename;
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  }
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  public function driver() {
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    return 'mysql';
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  }
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  public function databaseType() {
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    return 'mysql';
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  }
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  public function mapConditionOperator($operator) {
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    // We don't want to override any of the defaults.
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    return NULL;
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  }
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  public function nextId($existing_id = 0) {
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    $new_id = $this->query('INSERT INTO {sequences} () VALUES ()', array(), array('return' => Database::RETURN_INSERT_ID));
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    // This should only happen after an import or similar event.
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    if ($existing_id >= $new_id) {
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      // If we INSERT a value manually into the sequences table, on the next
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      // INSERT, MySQL will generate a larger value. However, there is no way
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      // of knowing whether this value already exists in the table. MySQL
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      // provides an INSERT IGNORE which would work, but that can mask problems
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      // other than duplicate keys. Instead, we use INSERT ... ON DUPLICATE KEY
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      // UPDATE in such a way that the UPDATE does not do anything. This way,
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      // duplicate keys do not generate errors but everything else does.
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      $this->query('INSERT INTO {sequences} (value) VALUES (:value) ON DUPLICATE KEY UPDATE value = value', array(':value' => $existing_id));
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      $new_id = $this->query('INSERT INTO {sequences} () VALUES ()', array(), array('return' => Database::RETURN_INSERT_ID));
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    }
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    $this->needsCleanup = TRUE;
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    return $new_id;
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  }
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  public function nextIdDelete() {
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    // While we want to clean up the table to keep it up from occupying too
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    // much storage and memory, we must keep the highest value in the table
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    // because InnoDB  uses an in-memory auto-increment counter as long as the
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    // server runs. When the server is stopped and restarted, InnoDB
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    // reinitializes the counter for each table for the first INSERT to the
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    // table based solely on values from the table so deleting all values would
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    // be a problem in this case. Also, TRUNCATE resets the auto increment
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    // counter.
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    try {
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      $max_id = $this->query('SELECT MAX(value) FROM {sequences}')->fetchField();
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      // We know we are using MySQL here, no need for the slower db_delete().
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      $this->query('DELETE FROM {sequences} WHERE value < :value', array(':value' => $max_id));
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    }
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    // During testing, this function is called from shutdown with the
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    // simpletest prefix stored in $this->connection, and those tables are gone
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    // by the time shutdown is called so we need to ignore the database
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    // errors. There is no problem with completely ignoring errors here: if
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    // these queries fail, the sequence will work just fine, just use a bit
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    // more database storage and memory.
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    catch (PDOException $e) {
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    }
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  }
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  /**
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   * Overridden to work around issues to MySQL not supporting transactional DDL.
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   */
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  protected function popCommittableTransactions() {
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    // Commit all the committable layers.
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    foreach (array_reverse($this->transactionLayers) as $name => $active) {
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      // Stop once we found an active transaction.
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      if ($active) {
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        break;
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      }
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      // If there are no more layers left then we should commit.
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      unset($this->transactionLayers[$name]);
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      if (empty($this->transactionLayers)) {
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        if (!PDO::commit()) {
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          throw new DatabaseTransactionCommitFailedException();
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        }
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      }
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      else {
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        // Attempt to release this savepoint in the standard way.
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        try {
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          $this->query('RELEASE SAVEPOINT ' . $name);
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        }
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        catch (PDOException $e) {
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          // However, in MySQL (InnoDB), savepoints are automatically committed
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          // when tables are altered or created (DDL transactions are not
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          // supported). This can cause exceptions due to trying to release
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          // savepoints which no longer exist.
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          //
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          // To avoid exceptions when no actual error has occurred, we silently
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          // succeed for MySQL error code 1305 ("SAVEPOINT does not exist").
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          if ($e->errorInfo[1] == '1305') {
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            // If one SAVEPOINT was released automatically, then all were.
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            // Therefore, clean the transaction stack.
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            $this->transactionLayers = array();
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            // We also have to explain to PDO that the transaction stack has
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            // been cleaned-up.
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            PDO::commit();
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          }
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          else {
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            throw $e;
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          }
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        }
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      }
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    }
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  }
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  public function utf8mb4IsConfigurable() {
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    return TRUE;
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  }
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  public function utf8mb4IsActive() {
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    return isset($this->connectionOptions['charset']) && $this->connectionOptions['charset'] === 'utf8mb4';
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  }
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  public function utf8mb4IsSupported() {
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    // Ensure that the MySQL driver supports utf8mb4 encoding.
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    $version = $this->getAttribute(PDO::ATTR_CLIENT_VERSION);
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    if (strpos($version, 'mysqlnd') !== FALSE) {
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      // The mysqlnd driver supports utf8mb4 starting at version 5.0.9.
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      $version = preg_replace('/^\D+([\d.]+).*/', '$1', $version);
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      if (version_compare($version, '5.0.9', '<')) {
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        return FALSE;
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      }
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    }
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    else {
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      // The libmysqlclient driver supports utf8mb4 starting at version 5.5.3.
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      if (version_compare($version, '5.5.3', '<')) {
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        return FALSE;
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      }
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    }
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    // Ensure that the MySQL server supports large prefixes and utf8mb4.
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    try {
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      $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");
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    }
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    catch (Exception $e) {
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      return FALSE;
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    }
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    $this->query("DROP TABLE {drupal_utf8mb4_test}");
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    return TRUE;
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  }
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}
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/**
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 * @} End of "addtogroup database".
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 */