class DatabaseTasks

abstract class DatabaseTasks  {
 
 /**
 * Structure that describes each task to run.
 *
 * @var array
 *
 * Each value of the tasks array is an associative array defining the function
 * to call (optional) and any arguments to be passed to the function.
 */
 protected $tasks = array(
 array(
 'function' => 'checkEngineVersion',
 'arguments' => array(),
 ),
 array(
 'arguments' => array(
 'CREATE TABLE {drupal_install_test} (id int NULL)',
 'Drupal can use CREATE TABLE database commands.',
 'Failed to <strong>CREATE</strong> a test table on your database server with the command %query. The server reports the following message: %error.<p>Are you sure the configured username has the necessary permissions to create tables in the database?</p>',
 TRUE,
 ),
 ),
 array(
 'arguments' => array(
 'INSERT INTO {drupal_install_test} (id) VALUES (1)',
 'Drupal can use INSERT database commands.',
 'Failed to <strong>INSERT</strong> a value into a test table on your database server. We tried inserting a value with the command %query and the server reported the following error: %error.',
 ),
 ),
 array(
 'arguments' => array(
 'UPDATE {drupal_install_test} SET id = 2',
 'Drupal can use UPDATE database commands.',
 'Failed to <strong>UPDATE</strong> a value in a test table on your database server. We tried updating a value with the command %query and the server reported the following error: %error.',
 ),
 ),
 array(
 'arguments' => array(
 'DELETE FROM {drupal_install_test}',
 'Drupal can use DELETE database commands.',
 'Failed to <strong>DELETE</strong> a value from a test table on your database server. We tried deleting a value with the command %query and the server reported the following error: %error.',
 ),
 ),
 array(
 'arguments' => array(
 'DROP TABLE {drupal_install_test}',
 'Drupal can use DROP TABLE database commands.',
 'Failed to <strong>DROP</strong> a test table from your database server. We tried dropping a table with the command %query and the server reported the following error %error.',
 ),
 ),
 );
 
 /**
 * Results from tasks.
 *
 * @var array
 */
 protected $results = array();
 
 /**
 * Ensure the PDO driver is supported by the version of PHP in use.
 */
 protected function hasPdoDriver() {
 return in_array ($this->pdoDriver, PDO::getAvailableDrivers());
 }
 
 /**
 * Assert test as failed.
 */
 protected function fail($message) {
 $this->results [$message] = FALSE;
 }
 
 /**
 * Assert test as a pass.
 */
 protected function pass($message) {
 $this->results [$message] = TRUE;
 }
 
 /**
 * Check whether Drupal is installable on the database.
 */
 public function installable() {
 return $this->hasPdoDriver () && empty($this->error);
 }
 
 /**
 * Return the human-readable name of the driver.
 */
 abstract public function name();
 
 /**
 * Return the minimum required version of the engine.
 *
 * @return
 * A version string. If not NULL, it will be checked against the version
 * reported by the Database engine using version_compare().
 */
 public function minimumVersion() {
 return NULL;
 }
 
 /**
 * Run database tasks and tests to see if Drupal can run on the database.
 */
 public function runTasks() {
 // We need to establish a connection before we can run tests.
 if ($this->connect ()) {
 foreach ($this->tasks  as $task) {
 if (!isset($task['function'])) {
 $task['function'] = 'runTestQuery';
 }
 if (method_exists ($this, $task['function'])) {
 // Returning false is fatal. No other tasks can run.
 if (FALSE === call_user_func_array (array(
 $this,
 $task['function'],
 ), $task['arguments'])) {
 break;
 }
 }
 else {
 throw new DatabaseTaskException (st ("Failed to run all tasks against the database server. The task %task wasn't found.", array(
 '%task' => $task['function'],
 )));
 }
 }
 }
 // Check for failed results and compile message
 $message = '';
 foreach ($this->results  as $result => $success) {
 if (!$success) {
 $message .= '<p class="error">' . $result . '</p>';
 }
 }
 if (!empty($message)) {
 $message = 'Resolve all issues below to continue the installation. For help configuring your database server, see the <a href="http://drupal.org/getting-started/install">installation handbook</a>, or contact your hosting provider.' . $message;
 throw new DatabaseTaskException ($message);
 }
 }
 
 /**
 * Check if we can connect to the database.
 */
 protected function connect() {
 try {
 // This doesn't actually test the connection.
 db_set_active ();
 // Now actually do a check.
 Database ::getConnection ();
 $this->pass ('Drupal can CONNECT to the database ok.');
 } catch (Exception $e) {
 $this->fail (st ('Failed to connect to your database server. The server reports the following message: %error.<ul><li>Is the database server running?</li><li>Does the database exist, and have you entered the correct database name?</li><li>Have you entered the correct username and password?</li><li>Have you entered the correct database hostname?</li></ul>', array(
 '%error' => $e->getMessage(),
 )));
 return FALSE;
 }
 return TRUE;
 }
 
 /**
 * Run SQL tests to ensure the database can execute commands with the current user.
 */
 protected function runTestQuery($query, $pass, $fail, $fatal = FALSE) {
 try {
 db_query ($query);
 $this->pass (st ($pass));
 } catch (Exception $e) {
 $this->fail (st ($fail, array(
 '%query' => $query,
 '%error' => $e->getMessage(),
 '%name' => $this->name (),
 )));
 return !$fatal;
 }
 }
 
 /**
 * Check the engine version.
 */
 protected function checkEngineVersion() {
 if ($this->minimumVersion () && version_compare (Database ::getConnection ()->version (), $this->minimumVersion (), '<')) {
 $this->fail (st ("The database version %version is less than the minimum required version %minimum_version.", array(
 '%version' => Database ::getConnection ()->version (),
 '%minimum_version' => $this->minimumVersion (),
 )));
 }
 }
 
 /**
 * Return driver specific configuration options.
 *
 * @param $database
 * An array of driver specific configuration options.
 *
 * @return
 * The options form array.
 */
 public function getFormOptions($database) {
 $form['database'] = array(
 '#type' => 'textfield',
 '#title' => st ('Database name'),
 '#default_value' => empty($database['database']) ? '' : $database['database'],
 '#size' => 45,
 '#required' => TRUE,
 '#description' => st ('The name of the database your @drupal data will be stored in. It must exist on your server before @drupal can be installed.', array(
 '@drupal' => drupal_install_profile_distribution_name (),
 )),
 );
 $form['username'] = array(
 '#type' => 'textfield',
 '#title' => st ('Database username'),
 '#default_value' => empty($database['username']) ? '' : $database['username'],
 '#required' => TRUE,
 '#size' => 45,
 );
 $form['password'] = array(
 '#type' => 'password',
 '#title' => st ('Database password'),
 '#default_value' => empty($database['password']) ? '' : $database['password'],
 '#required' => FALSE,
 '#size' => 45,
 );
 $form['advanced_options'] = array(
 '#type' => 'fieldset',
 '#title' => st ('Advanced options'),
 '#collapsible' => TRUE,
 '#collapsed' => TRUE,
 '#description' => st ("These options are only necessary for some sites. If you're not sure what you should enter here, leave the default settings or check with your hosting provider."),
 '#weight' => 10,
 );
 $profile = drupal_get_profile ();
 $db_prefix = $profile == 'standard' ? 'drupal_' : $profile . '_';
 $form['advanced_options']['db_prefix'] = array(
 '#type' => 'textfield',
 '#title' => st ('Table prefix'),
 '#default_value' => '',
 '#size' => 45,
 '#description' => st ('If more than one application will be sharing this database, enter a table prefix such as %prefix for your @drupal site here.', array(
 '@drupal' => drupal_install_profile_distribution_name (),
 '%prefix' => $db_prefix,
 )),
 '#weight' => 10,
 );
 $form['advanced_options']['host'] = array(
 '#type' => 'textfield',
 '#title' => st ('Database host'),
 '#default_value' => empty($database['host']) ? 'localhost' : $database['host'],
 '#size' => 45,
 // Hostnames can be 255 characters long.
'#maxlength' => 255,
 '#required' => TRUE,
 '#description' => st ('If your database is located on a different server, change this.'),
 );
 $form['advanced_options']['port'] = array(
 '#type' => 'textfield',
 '#title' => st ('Database port'),
 '#default_value' => empty($database['port']) ? '' : $database['port'],
 '#size' => 45,
 // The maximum port number is 65536, 5 digits.
'#maxlength' => 5,
 '#description' => st ('If your database server is listening to a non-standard port, enter its number.'),
 );
 return $form;
 }
 
 /**
 * Validates driver specific configuration settings.
 *
 * Checks to ensure correct basic database settings and that a proper
 * connection to the database can be established.
 *
 * @param $database
 * An array of driver specific configuration options.
 *
 * @return
 * An array of driver configuration errors, keyed by form element name.
 */
 public function validateDatabaseSettings($database) {
 $errors = array();
 // Verify the table prefix.
 if (!empty($database['prefix']) && is_string ($database['prefix']) && !preg_match ('/^[A-Za-z0-9_.]+$/', $database['prefix'])) {
 $errors[$database['driver'] . '][advanced_options][db_prefix'] = st ('The database table prefix you have entered, %prefix, is invalid. The table prefix can only contain alphanumeric characters, periods, or underscores.', array(
 '%prefix' => $database['prefix'],
 ));
 }
 // Verify the database port.
 if (!empty($database['port']) && !is_numeric ($database['port'])) {
 $errors[$database['driver'] . '][advanced_options][port'] = st ('Database port must be a number.');
 }
 return $errors;
 }
}