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<?php

/**

 * @file

 * Database schema code for MySQL database servers.

 */

/**

 * @addtogroup schemaapi

 * @{

 */

class DatabaseSchema_mysql extends DatabaseSchema {

  /**

   * Maximum length of a table comment in MySQL.

   */

  const COMMENT_MAX_TABLE = 60;

  /**

   * Maximum length of a column comment in MySQL.

   */

  const COMMENT_MAX_COLUMN = 255;

  /**

   * Get information about the table and database name from the prefix.

   *

   * @return

   *   A keyed array with information about the database, table name and prefix.

   */

  protected function getPrefixInfo($table = 'default', $add_prefix = TRUE) {

    $info = array('prefix' => $this->connection->tablePrefix($table));

    if ($add_prefix) {

      $table = $info['prefix'] . $table;

    }

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

      $info['database'] = substr($table, 0, $pos);

      $info['table'] = substr($table, ++$pos);

    }

    else {

      $db_info = $this->connection->getConnectionOptions();

      $info['database'] = $db_info['database'];

      $info['table'] = $table;

    }

    return $info;

  }

  /**

   * Build a condition to match a table name against a standard information_schema.

   *

   * MySQL uses databases like schemas rather than catalogs so when we build

   * a condition to query the information_schema.tables, we set the default

   * database as the schema unless specified otherwise, and exclude table_catalog

   * from the condition criteria.

   */

  protected function buildTableNameCondition($table_name, $operator = '=', $add_prefix = TRUE) {

    $info = $this->connection->getConnectionOptions();

    $table_info = $this->getPrefixInfo($table_name, $add_prefix);

    $condition = new DatabaseCondition('AND');

    $condition->condition('table_schema', $table_info['database']);

    $condition->condition('table_name', $table_info['table'], $operator);

    return $condition;

  }

  /**

   * Generate SQL to create a new table from a Drupal schema definition.

   *

   * @param $name

   *   The name of the table to create.

   * @param $table

   *   A Schema API table definition array.

   * @return

   *   An array of SQL statements to create the table.

   */

  protected function createTableSql($name, $table) {

    $info = $this->connection->getConnectionOptions();

    // Provide defaults if needed.

    $table += array(

      'mysql_engine' => 'InnoDB',

      // Allow the default charset to be overridden in settings.php.

      'mysql_character_set' => $this->connection->utf8mb4IsActive() ? 'utf8mb4' : 'utf8',

    );

    $sql = "CREATE TABLE {" . $name . "} (\n";

    // Add the SQL statement for each field.

    foreach ($table['fields'] as $field_name => $field) {

      $sql .= $this->createFieldSql($field_name, $this->processField($field)) . ", \n";

    }

    // Process keys & indexes.

    $keys = $this->createKeysSql($table);

    if (count($keys)) {

      $sql .= implode(", \n", $keys) . ", \n";

    }

    // Remove the last comma and space.

    $sql = substr($sql, 0, -3) . "\n) ";

    $sql .= 'ENGINE = ' . $table['mysql_engine'] . ' DEFAULT CHARACTER SET ' . $table['mysql_character_set'];

    // By default, MySQL uses the default collation for new tables, which is

    // 'utf8_general_ci' for utf8. If an alternate collation has been set, it

    // needs to be explicitly specified.

    // @see DatabaseConnection_mysql

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

      $sql .= ' COLLATE ' . $info['collation'];

    }

    // The row format needs to be either DYNAMIC or COMPRESSED in order to allow

    // for the innodb_large_prefix setting to take effect, see

    // https://dev.mysql.com/doc/refman/5.6/en/create-table.html

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

      $sql .= ' ROW_FORMAT=DYNAMIC';

    }

    // Add table comment.

    if (!empty($table['description'])) {

      $sql .= ' COMMENT ' . $this->prepareComment($table['description'], self::COMMENT_MAX_TABLE);

    }

    return array($sql);

  }

  /**

   * Create an SQL string for a field to be used in table creation or alteration.

   *

   * Before passing a field out of a schema definition into this function it has

   * to be processed by _db_process_field().

   *

   * @param $name

   *   Name of the field.

   * @param $spec

   *   The field specification, as per the schema data structure format.

   */

  protected function createFieldSql($name, $spec) {

    $sql = "`" . $name . "` " . $spec['mysql_type'];

    if (in_array($spec['mysql_type'], array('VARCHAR', 'CHAR', 'TINYTEXT', 'MEDIUMTEXT', 'LONGTEXT', 'TEXT'))) {

      if (isset($spec['length'])) {

        $sql .= '(' . $spec['length'] . ')';

      }

      if (!empty($spec['binary'])) {

        $sql .= ' BINARY';

      }

    }

    elseif (isset($spec['precision']) && isset($spec['scale'])) {

      $sql .= '(' . $spec['precision'] . ', ' . $spec['scale'] . ')';

    }

    if (!empty($spec['unsigned'])) {

      $sql .= ' unsigned';

    }

    if (isset($spec['not null'])) {

      if ($spec['not null']) {

        $sql .= ' NOT NULL';

      }

      else {

        $sql .= ' NULL';

      }

    }

    if (!empty($spec['auto_increment'])) {

      $sql .= ' auto_increment';

    }

    // $spec['default'] can be NULL, so we explicitly check for the key here.

    if (array_key_exists('default', $spec)) {

      if (is_string($spec['default'])) {

        $spec['default'] = "'" . $spec['default'] . "'";

      }

      elseif (!isset($spec['default'])) {

        $spec['default'] = 'NULL';

      }

      $sql .= ' DEFAULT ' . $spec['default'];

    }

    if (empty($spec['not null']) && !isset($spec['default'])) {

      $sql .= ' DEFAULT NULL';

    }

    // Add column comment.

    if (!empty($spec['description'])) {

      $sql .= ' COMMENT ' . $this->prepareComment($spec['description'], self::COMMENT_MAX_COLUMN);

    }

    return $sql;

  }

  /**

   * Set database-engine specific properties for a field.

   *

   * @param $field

   *   A field description array, as specified in the schema documentation.

   */

  protected function processField($field) {

    if (!isset($field['size'])) {

      $field['size'] = 'normal';

    }

    // Set the correct database-engine specific datatype.

    // In case one is already provided, force it to uppercase.

    if (isset($field['mysql_type'])) {

      $field['mysql_type'] = drupal_strtoupper($field['mysql_type']);

    }

    else {

      $map = $this->getFieldTypeMap();

      $field['mysql_type'] = $map[$field['type'] . ':' . $field['size']];

    }

    if (isset($field['type']) && $field['type'] == 'serial') {

      $field['auto_increment'] = TRUE;

    }

    return $field;

  }

  public function getFieldTypeMap() {

    // Put :normal last so it gets preserved by array_flip. This makes

    // it much easier for modules (such as schema.module) to map

    // database types back into schema types.

    // $map does not use drupal_static as its value never changes.

    static $map = array(

      'varchar:normal'  => 'VARCHAR',

      'char:normal'     => 'CHAR',

      'text:tiny'       => 'TINYTEXT',

      'text:small'      => 'TINYTEXT',

      'text:medium'     => 'MEDIUMTEXT',

      'text:big'        => 'LONGTEXT',

      'text:normal'     => 'TEXT',

      'serial:tiny'     => 'TINYINT',

      'serial:small'    => 'SMALLINT',

      'serial:medium'   => 'MEDIUMINT',

      'serial:big'      => 'BIGINT',

      'serial:normal'   => 'INT',

      'int:tiny'        => 'TINYINT',

      'int:small'       => 'SMALLINT',

      'int:medium'      => 'MEDIUMINT',

      'int:big'         => 'BIGINT',

      'int:normal'      => 'INT',

      'float:tiny'      => 'FLOAT',

      'float:small'     => 'FLOAT',

      'float:medium'    => 'FLOAT',

      'float:big'       => 'DOUBLE',

      'float:normal'    => 'FLOAT',

      'numeric:normal'  => 'DECIMAL',

      'blob:big'        => 'LONGBLOB',

      'blob:normal'     => 'BLOB',

    );

    return $map;

  }

  protected function createKeysSql($spec) {

    $keys = array();

    if (!empty($spec['primary key'])) {

      $keys[] = 'PRIMARY KEY (' . $this->createKeysSqlHelper($spec['primary key']) . ')';

    }

    if (!empty($spec['unique keys'])) {

      foreach ($spec['unique keys'] as $key => $fields) {

        $keys[] = 'UNIQUE KEY `' . $key . '` (' . $this->createKeysSqlHelper($fields) . ')';

      }

    }

    if (!empty($spec['indexes'])) {

      foreach ($spec['indexes'] as $index => $fields) {

        $keys[] = 'INDEX `' . $index . '` (' . $this->createKeysSqlHelper($fields) . ')';

      }

    }

    return $keys;

  }

  protected function createKeySql($fields) {

    $return = array();

    foreach ($fields as $field) {

      if (is_array($field)) {

        $return[] = '`' . $field[0] . '`(' . $field[1] . ')';

      }

      else {

        $return[] = '`' . $field . '`';

      }

    }

    return implode(', ', $return);

  }

  protected function createKeysSqlHelper($fields) {

    $return = array();

    foreach ($fields as $field) {

      if (is_array($field)) {

        $return[] = '`' . $field[0] . '`(' . $field[1] . ')';

      }

      else {

        $return[] = '`' . $field . '`';

      }

    }

    return implode(', ', $return);

  }

  public function renameTable($table, $new_name) {

    if (!$this->tableExists($table)) {

      throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot rename @table to @table_new: table @table doesn't exist.", array('@table' => $table, '@table_new' => $new_name)));

    }

    if ($this->tableExists($new_name)) {

      throw new DatabaseSchemaObjectExistsException(t("Cannot rename @table to @table_new: table @table_new already exists.", array('@table' => $table, '@table_new' => $new_name)));

    }

    $info = $this->getPrefixInfo($new_name);

    return $this->connection->query('ALTER TABLE {' . $table . '} RENAME TO `' . $info['table'] . '`');

  }

  public function dropTable($table) {

    if (!$this->tableExists($table)) {

      return FALSE;

    }

    $this->connection->query('DROP TABLE {' . $table . '}');

    return TRUE;

  }

  public function addField($table, $field, $spec, $keys_new = array()) {

    if (!$this->tableExists($table)) {

      throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot add field @table.@field: table doesn't exist.", array('@field' => $field, '@table' => $table)));

    }

    if ($this->fieldExists($table, $field)) {

      throw new DatabaseSchemaObjectExistsException(t("Cannot add field @table.@field: field already exists.", array('@field' => $field, '@table' => $table)));

    }

    $fixnull = FALSE;

    if (!empty($spec['not null']) && !isset($spec['default'])) {

      $fixnull = TRUE;

      $spec['not null'] = FALSE;

    }

    $query = 'ALTER TABLE {' . $table . '} ADD ';

    $query .= $this->createFieldSql($field, $this->processField($spec));

    if ($keys_sql = $this->createKeysSql($keys_new)) {

      $query .= ', ADD ' . implode(', ADD ', $keys_sql);

    }

    $this->connection->query($query);

    if (isset($spec['initial'])) {

      $this->connection->update($table)

        ->fields(array($field => $spec['initial']))

        ->execute();

    }

    if ($fixnull) {

      $spec['not null'] = TRUE;

      $this->changeField($table, $field, $field, $spec);

    }

  }

  public function dropField($table, $field) {

    if (!$this->fieldExists($table, $field)) {

      return FALSE;

    }

    $this->connection->query('ALTER TABLE {' . $table . '} DROP `' . $field . '`');

    return TRUE;

  }

  public function fieldSetDefault($table, $field, $default) {

    if (!$this->fieldExists($table, $field)) {

      throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot set default value of field @table.@field: field doesn't exist.", array('@table' => $table, '@field' => $field)));

    }

    if (!isset($default)) {

      $default = 'NULL';

    }

    else {

      $default = is_string($default) ? "'$default'" : $default;

    }

    $this->connection->query('ALTER TABLE {' . $table . '} ALTER COLUMN `' . $field . '` SET DEFAULT ' . $default);

  }

  public function fieldSetNoDefault($table, $field) {

    if (!$this->fieldExists($table, $field)) {

      throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot remove default value of field @table.@field: field doesn't exist.", array('@table' => $table, '@field' => $field)));

    }

    $this->connection->query('ALTER TABLE {' . $table . '} ALTER COLUMN `' . $field . '` DROP DEFAULT');

  }

  public function indexExists($table, $name) {

    // Returns one row for each column in the index. Result is string or FALSE.

    // Details at http://dev.mysql.com/doc/refman/5.0/en/show-index.html

    $row = $this->connection->query('SHOW INDEX FROM {' . $table . "} WHERE key_name = '$name'")->fetchAssoc();

    return isset($row['Key_name']);

  }

  public function addPrimaryKey($table, $fields) {

    if (!$this->tableExists($table)) {

      throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot add primary key to table @table: table doesn't exist.", array('@table' => $table)));

    }

    if ($this->indexExists($table, 'PRIMARY')) {

      throw new DatabaseSchemaObjectExistsException(t("Cannot add primary key to table @table: primary key already exists.", array('@table' => $table)));

    }

    $this->connection->query('ALTER TABLE {' . $table . '} ADD PRIMARY KEY (' . $this->createKeySql($fields) . ')');

  }

  public function dropPrimaryKey($table) {

    if (!$this->indexExists($table, 'PRIMARY')) {

      return FALSE;

    }

    $this->connection->query('ALTER TABLE {' . $table . '} DROP PRIMARY KEY');

    return TRUE;

  }

  public function addUniqueKey($table, $name, $fields) {

    if (!$this->tableExists($table)) {

      throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot add unique key @name to table @table: table doesn't exist.", array('@table' => $table, '@name' => $name)));

    }

    if ($this->indexExists($table, $name)) {

      throw new DatabaseSchemaObjectExistsException(t("Cannot add unique key @name to table @table: unique key already exists.", array('@table' => $table, '@name' => $name)));

    }

    $this->connection->query('ALTER TABLE {' . $table . '} ADD UNIQUE KEY `' . $name . '` (' . $this->createKeySql($fields) . ')');

  }

  public function dropUniqueKey($table, $name) {

    if (!$this->indexExists($table, $name)) {

      return FALSE;

    }

    $this->connection->query('ALTER TABLE {' . $table . '} DROP KEY `' . $name . '`');

    return TRUE;

  }

  public function addIndex($table, $name, $fields) {

    if (!$this->tableExists($table)) {

      throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot add index @name to table @table: table doesn't exist.", array('@table' => $table, '@name' => $name)));

    }

    if ($this->indexExists($table, $name)) {

      throw new DatabaseSchemaObjectExistsException(t("Cannot add index @name to table @table: index already exists.", array('@table' => $table, '@name' => $name)));

    }

    $this->connection->query('ALTER TABLE {' . $table . '} ADD INDEX `' . $name . '` (' . $this->createKeySql($fields) . ')');

  }

  public function dropIndex($table, $name) {

    if (!$this->indexExists($table, $name)) {

      return FALSE;

    }

    $this->connection->query('ALTER TABLE {' . $table . '} DROP INDEX `' . $name . '`');

    return TRUE;

  }

  public function changeField($table, $field, $field_new, $spec, $keys_new = array()) {

    if (!$this->fieldExists($table, $field)) {

      throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot change the definition of field @table.@name: field doesn't exist.", array('@table' => $table, '@name' => $field)));

    }

    if (($field != $field_new) && $this->fieldExists($table, $field_new)) {

      throw new DatabaseSchemaObjectExistsException(t("Cannot rename field @table.@name to @name_new: target field already exists.", array('@table' => $table, '@name' => $field, '@name_new' => $field_new)));

    }

    $sql = 'ALTER TABLE {' . $table . '} CHANGE `' . $field . '` ' . $this->createFieldSql($field_new, $this->processField($spec));

    if ($keys_sql = $this->createKeysSql($keys_new)) {

      $sql .= ', ADD ' . implode(', ADD ', $keys_sql);

    }

    $this->connection->query($sql);

  }

  public function prepareComment($comment, $length = NULL) {

    // Work around a bug in some versions of PDO, see http://bugs.php.net/bug.php?id=41125

    $comment = str_replace("'", '’', $comment);

    // Truncate comment to maximum comment length.

    if (isset($length)) {

      // Add table prefixes before truncating.

      $comment = truncate_utf8($this->connection->prefixTables($comment), $length, TRUE, TRUE);

    }

    return $this->connection->quote($comment);

  }

  /**

   * Retrieve a table or column comment.

   */

  public function getComment($table, $column = NULL) {

    $condition = $this->buildTableNameCondition($table);

    if (isset($column)) {

      $condition->condition('column_name', $column);

      $condition->compile($this->connection, $this);

      // Don't use {} around information_schema.columns table.

      return $this->connection->query("SELECT column_comment FROM information_schema.columns WHERE " . (string) $condition, $condition->arguments())->fetchField();

    }

    $condition->compile($this->connection, $this);

    // Don't use {} around information_schema.tables table.

    $comment = $this->connection->query("SELECT table_comment FROM information_schema.tables WHERE " . (string) $condition, $condition->arguments())->fetchField();

    // Work-around for MySQL 5.0 bug http://bugs.mysql.com/bug.php?id=11379

    return preg_replace('/; InnoDB free:.*$/', '', $comment);

  }

  public function tableExists($table) {

    // The information_schema table is very slow to query under MySQL 5.0.

    // Instead, we try to select from the table in question.  If it fails,

    // the most likely reason is that it does not exist. That is dramatically

    // faster than using information_schema.

    // @link http://bugs.mysql.com/bug.php?id=19588

    // @todo: This override should be removed once we require a version of MySQL

    // that has that bug fixed.

    try {

      $this->connection->queryRange("SELECT 1 FROM {" . $table . "}", 0, 1);

      return TRUE;

    }

    catch (Exception $e) {

      return FALSE;

    }

  }

  public function fieldExists($table, $column) {

    // The information_schema table is very slow to query under MySQL 5.0.

    // Instead, we try to select from the table and field in question. If it

    // fails, the most likely reason is that it does not exist. That is

    // dramatically faster than using information_schema.

    // @link http://bugs.mysql.com/bug.php?id=19588

    // @todo: This override should be removed once we require a version of MySQL

    // that has that bug fixed.

    try {

      $this->connection->queryRange("SELECT $column FROM {" . $table . "}", 0, 1);

      return TRUE;

    }

    catch (Exception $e) {

      return FALSE;

    }

  }

}

/**

 * @} End of "addtogroup schemaapi".

 */