<?php

/**
 * @file
 * Definition of Drupal\Core\Database\Query\Truncate
 */

namespace Drupal\Core\Database\Query;

use Drupal\Core\Database\Database;
use Drupal\Core\Database\Connection;


/**
 * General class for an abstracted TRUNCATE operation.
 */
class Truncate extends Query {

  /**
   * The table to truncate.
   *
   * @var string
   */
  protected $table;

  /**
   * Constructs a Truncate query object.
   *
   * @param DatabaseConnection $connection
   *   A DatabaseConnection object.
   * @param string $table
   *   Name of the table to associate with this query.
   * @param array $options
   *   Array of database options.
   */
  public function __construct(Connection $connection, $table, array $options = array()) {
    $options['return'] = Database::RETURN_AFFECTED;
    parent::__construct($connection, $options);
    $this->table = $table;
  }

  /**
   * Implements Drupal\Core\Database\Query\ConditionInterface::compile().
   */
  public function compile(Connection $connection, PlaceholderInterface $queryPlaceholder) {
    return $this->condition->compile($connection, $queryPlaceholder);
  }

  /**
   * Implements Drupal\Core\Database\Query\ConditionInterface::compiled().
   */
  public function compiled() {
    return $this->condition->compiled();
  }

  /**
   * Executes the TRUNCATE query.
   *
   * @return
   *   Return value is dependent on the database type.
   */
  public function execute() {
    return $this->connection->query((string) $this, array(), $this->queryOptions);
  }

  /**
   * Implements PHP magic __toString method to convert the query to a string.
   *
   * @return string
   *   The prepared statement.
   */
  public function __toString() {
    // Create a sanitized comment string to prepend to the query.
    $comments = $this->connection->makeComment($this->comments);

    return $comments . 'TRUNCATE {' . $this->connection->escapeTable($this->table) . '} ';
  }
}
