1 <?php

     2 

     3 /**

     4  * @file

     5  * Database interface code for MySQL database servers.

     6  */

     7 

     8 /**

     9  * @addtogroup database

    10  * @{

    11  */

    12 

    13 class DatabaseConnection_mysql extends DatabaseConnection {

    14 

    15   /**

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

    17    *

    18    * @var boolean

    19    */

    20   protected $needsCleanup = FALSE;

    21 

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

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

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

    25 

    26     // MySQL never supports transactional DDL.

    27     $this->transactionalDDLSupport = FALSE;

    28 

    29     $this->connectionOptions = $connection_options;

    30 

    31     $charset = 'utf8';

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

    33     if ($this->utf8mb4IsActive()) {

    34       $charset = 'utf8mb4';

    35     }

    36 

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

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

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

    40     }

    41     else {

    42       // Default to TCP connection on port 3306.

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

    44     }

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

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

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

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

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

    50     // Allow PDO options to be overridden.

    51     $connection_options += array(

    52       'pdo' => array(),

    53     );

    54     $connection_options['pdo'] += array(

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

    56       PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => TRUE,

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

    58       PDO::ATTR_EMULATE_PREPARES => TRUE,

    59     );

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

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

    62       // single statement like mysqli.

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

    64     }

    65 

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

    67 

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

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

    70     // for UTF-8.

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

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

    73     }

    74     else {

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

    76     }

    77 

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

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

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

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

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

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

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

    85     // one.

    86     $connection_options += array(

    87       'init_commands' => array(),

    88     );

    89     $connection_options['init_commands'] += array(

    90       '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'",

    91     );

    92     // Execute initial commands.

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

    94       $this->exec($sql);

    95     }

    96   }

    97 

    98   public function __destruct() {

    99     if ($this->needsCleanup) {

   100       $this->nextIdDelete();

   101     }

   102   }

   103 

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

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

   106   }

   107 

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

   109     $tablename = $this->generateTemporaryTableName();

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

   111     return $tablename;

   112   }

   113 

   114   public function driver() {

   115     return 'mysql';

   116   }

   117 

   118   public function databaseType() {

   119     return 'mysql';

   120   }

   121 

   122   public function mapConditionOperator($operator) {

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

   124     return NULL;

   125   }

   126 

   127   public function nextId($existing_id = 0) {

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

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

   130     if ($existing_id >= $new_id) {

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

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

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

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

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

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

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

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

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

   140     }

   141     $this->needsCleanup = TRUE;

   142     return $new_id;

   143   }

   144 

   145   public function nextIdDelete() {

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

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

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

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

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

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

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

   153     // counter.

   154     try {

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

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

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

   158     }

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

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

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

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

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

   164     // more database storage and memory.

   165     catch (PDOException $e) {

   166     }

   167   }

   168 

   169   /**

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

   171    */

   172   protected function popCommittableTransactions() {

   173     // Commit all the committable layers.

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

   175       // Stop once we found an active transaction.

   176       if ($active) {

   177         break;

   178       }

   179 

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

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

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

   183         if (!PDO::commit()) {

   184           throw new DatabaseTransactionCommitFailedException();

   185         }

   186       }

   187       else {

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

   189         try {

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

   191         }

   192         catch (PDOException $e) {

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

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

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

   196           // savepoints which no longer exist.

   197           //

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

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

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

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

   202             // Therefore, clean the transaction stack.

   203             $this->transactionLayers = array();

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

   205             // been cleaned-up.

   206             PDO::commit();

   207           }

   208           else {

   209             throw $e;

   210           }

   211         }

   212       }

   213     }

   214   }

   215 

   216   public function utf8mb4IsConfigurable() {

   217     return TRUE;

   218   }

   219 

   220   public function utf8mb4IsActive() {

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

   222   }

   223 

   224   public function utf8mb4IsSupported() {

   225     // Ensure that the MySQL driver supports utf8mb4 encoding.

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

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

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

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

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

   231         return FALSE;

   232       }

   233     }

   234     else {

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

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

   237         return FALSE;

   238       }

   239     }

   240 

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

   242     try {

   243       $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");

   244     }

   245     catch (Exception $e) {

   246       return FALSE;

   247     }

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

   249     return TRUE;

   250   }

   251 }

   252 

   253 

   254 /**

   255  * @} End of "addtogroup database".

   256  */