xmlsitemap.module

<?php

/**
 * @defgroup xmlsitemap XML sitemap
 */

/**
 * @file
 * Main file for the xmlsitemap module.
 */
use Symfony\Component\HttpFoundation\Request;
use Drupal\Component\Utility\Crypt;
use Drupal\Core\Session\UserSession;
use Drupal\Core\Language\LanguageInterface;
use Drupal\xmlsitemap\XmlSitemapInterface;
use Drupal\user\Entity\User;
use Drupal\user\UserInterface;
use Drupal\Component\Utility\String;
use Drupal\Core\Render\Element;
use Drupal\Core\Entity\EntityFormBuilderInterface;
use Drupal\Core\Entity\EntityForm;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Entity\Entity;
use Drupal\Core\Session\AnonymousUserSession;
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Database\Query\AlterableInterface;

/**
 * The maximum number of links in one sitemap chunk file.
 */
define('XMLSITEMAP_MAX_SITEMAP_LINKS', 50000);

/**
 * The maximum filesize of a sitemap chunk file.
 */
define('XMLSITEMAP_MAX_SITEMAP_FILESIZE', 10485760);

define('XMLSITEMAP_FREQUENCY_YEARLY', 31449600); // 60 * 60 * 24 * 7 * 52
define('XMLSITEMAP_FREQUENCY_MONTHLY', 2419200); // 60 * 60 * 24 * 7 * 4
define('XMLSITEMAP_FREQUENCY_WEEKLY', 604800); // 60 * 60 * 24 * 7
define('XMLSITEMAP_FREQUENCY_DAILY', 86400); // 60 * 60 * 24
define('XMLSITEMAP_FREQUENCY_HOURLY', 3600); // 60 * 60
define('XMLSITEMAP_FREQUENCY_ALWAYS', 60);

/**
 * Short lastmod timestamp format.
 */
define('XMLSITEMAP_LASTMOD_SHORT', 'Y-m-d');

/**
 * Medium lastmod timestamp format.
 */
define('XMLSITEMAP_LASTMOD_MEDIUM', 'Y-m-d\TH:i\Z');

/**
 * Long lastmod timestamp format.
 */
define('XMLSITEMAP_LASTMOD_LONG', 'c');

/**
 * The default inclusion status for link types in the sitemaps.
 */
define('XMLSITEMAP_STATUS_DEFAULT', 0);

/**
 * The default priority for link types in the sitemaps.
 */
define('XMLSITEMAP_PRIORITY_DEFAULT', 0.5);

/**
 * Implements hook_hook_info().
 */
function xmlsitemap_hook_info() {
  $hooks = array(
    'xmlsitemap_link_info',
    'xmlsitemap_link_info_alter',
    'xmlsitemap_link_alter',
    'xmlsitemap_index_links',
    'xmlsitemap_context_info',
    'xmlsitemap_context_info_alter',
    'xmlsitemap_context_url_options',
    'xmlsitemap_context',
    'xmlsitemap_sitemap_insert',
    'xmlsitemap_sitemap_update',
    'xmlsitemap_sitemap_operations',
    'xmlsitemap_sitemap_delete',
    'xmlsitemap_sitemap_link_url_options_alter',
    'query_xmlsitemap_generate_alter',
    'query_xmlsitemap_link_bundle_access_alter',
    'form_xmlsitemap_sitemap_edit_form_alter',
  );

  $hooks = array_combine($hooks, $hooks);
  foreach ($hooks as $hook => $info) {
    $hooks[$hook] = array('group' => 'xmlsitemap');
  }

  return $hooks;
}

/**
 * Implements hook_help().
 */
function xmlsitemap_help($route_name, RouteMatchInterface $route_match) {
  $output = '';

  switch ($route_name) {
    case 'help.page.xmlsitemap':
    case 'xmlsitemap.admin_settings':
    case 'xmlsitemap.entities_settings':
    case 'xmlsitemap.admin_edit':
    case 'xmlsitemap.admin_delete':
      return;
    case 'xmlsitemap.admin_search':
      break;
    case 'xmlsitemap.admin_search_list':
      break;
    case 'xmlsitemap.admin_rebuild':
      $output .= '<p>' . t("This action rebuilds your site's XML sitemap and regenerates the cached files, and may be a lengthy process. If you just installed XML sitemap, this can be helpful to import all your site's content into the sitemap. Otherwise, this should only be used in emergencies.") . '</p>';
  }

  $currentUser = \Drupal::currentUser();
  if (strpos($route_name, 'xmlsitemap') !== FALSE && $currentUser->hasPermission('administer xmlsitemap')) {
    module_load_include('inc', 'xmlsitemap');
    // Alert the user to any potential problems detected by hook_requirements.
    xmlsitemap_check_status();
    $output .= _xmlsitemap_get_blurb();
  }

  return $output;
}

/**
 * Implements hook_perm().
 */
function xmlsitemap_permission() {
  $permissions['administer xmlsitemap'] = array(
    'title' => t('Administer XML sitemap settings.'),
  );
  return $permissions;
}

/**
 * Implements hook_menu().
 */
function xmlsitemap_menu() {
  $items['admin/config/search/xmlsitemap'] = array(
    'title' => 'XML sitemap',
    'description' => "Configure your site's XML sitemaps to help search engines find and index pages on your site.",
    'page callback' => 'drupal_get_form',
    'page arguments' => array('xmlsitemap_sitemap_list_form'),
    'access arguments' => array('administer xmlsitemap'),
    'file' => 'xmlsitemap.admin.inc',
  );
  $items['admin/config/search/xmlsitemap/list'] = array(
    'title' => 'List',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => -10,
  );
  $items['admin/config/search/xmlsitemap/add'] = array(
    'title' => 'Add new XML sitemap',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('xmlsitemap_sitemap_edit_form'),
    'access arguments' => array('administer xmlsitemap'),
    'type' => MENU_LOCAL_ACTION,
    'file' => 'xmlsitemap.admin.inc',
    'modal' => TRUE,
    'options' => array('modal' => TRUE),
  );
  $items['admin/config/search/xmlsitemap/edit/%xmlsitemap_sitemap'] = array(
    'title' => 'Edit XML sitemap',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('xmlsitemap_sitemap_edit_form', 5),
    'access arguments' => array('administer xmlsitemap'),
    'file' => 'xmlsitemap.admin.inc',
    'modal' => TRUE,
  );
  $items['admin/config/search/xmlsitemap/delete/%xmlsitemap_sitemap'] = array(
    'title' => 'Delete XML sitemap',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('xmlsitemap_sitemap_delete_form', 5),
    'access arguments' => array('administer xmlsitemap'),
    'file' => 'xmlsitemap.admin.inc',
    'modal' => TRUE,
  );

  $items['admin/config/search/xmlsitemap/settings'] = array(
    'title' => 'Settings',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('xmlsitemap_settings_form'),
    'access arguments' => array('administer xmlsitemap'),
    'type' => MENU_LOCAL_TASK,
    'file' => 'xmlsitemap.admin.inc',
    'weight' => 10,
  );
  $items['admin/config/search/xmlsitemap/settings/%xmlsitemap_link_bundle/%'] = array(
    'load arguments' => array(6),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('xmlsitemap_link_bundle_settings_form', 5),
    'access callback' => 'xmlsitemap_link_bundle_access',
    'access arguments' => array(5),
    'file' => 'xmlsitemap.admin.inc',
    'modal' => TRUE,
  );

  $items['admin/config/search/xmlsitemap/rebuild'] = array(
    'title' => 'Rebuild links',
    'description' => 'Rebuild the site map.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('xmlsitemap_rebuild_form'),
    'access callback' => '_xmlsitemap_rebuild_form_access',
    'type' => MENU_LOCAL_TASK,
    'file' => 'xmlsitemap.admin.inc',
    'weight' => 20,
  );

  $items['sitemap.xml'] = array(
    'page callback' => 'xmlsitemap_output_chunk',
    'access callback' => TRUE,
    'type' => MENU_CALLBACK,
    'file' => 'xmlsitemap.pages.inc',
  );
  $items['sitemap.xsl'] = array(
    'page callback' => 'xmlsitemap_output_xsl',
    'access callback' => TRUE,
    'type' => MENU_CALLBACK,
    'file' => 'xmlsitemap.pages.inc',
  );

  return $items;
}

/**
 * Implements hook_theme().
 */
function xmlsitemap_theme() {
  return array(
    'xmlsitemap_content_settings_table' => array(
      'render element' => 'element',
      'file' => 'xmlsitemap.module',
    ),
  );
}

/**
 * Menu access callback; determines if the user can use the rebuild links page.
 */
function _xmlsitemap_rebuild_form_access() {
  module_load_include('generate.inc', 'xmlsitemap');
  $rebuild_types = xmlsitemap_get_rebuildable_link_types();
  return !empty($rebuild_types) && user_access('administer xmlsitemap');
}

/**
 * Implements hook_cron().
 *
 * @todo Use new Queue system. Need to add {sitemap}.queued.
 * @todo Regenerate one at a time?
 */
function xmlsitemap_cron() {
  // If there were no new or changed links, skip.
  if (!\Drupal::config('xmlsitemap.settings')->get('regenerate_needed')) {
    return;
  }

  // If the minimum sitemap lifetime hasn't been passed, skip.
  $lifetime = REQUEST_TIME - \Drupal::config('xmlsitemap.settings')->get('generated_last');
  if ($lifetime < \Drupal::config('xmlsitemap.settings')->get('minimum_lifetine')) {
    return;
  }
  xmlsitemap_xmlsitemap_index_links(100);
  // Regenerate the sitemap XML files.
  module_load_include('generate.inc', 'xmlsitemap');
  xmlsitemap_run_unprogressive_batch('xmlsitemap_regenerate_batch');
}

/**
 * Implements hook_modules_enabled().
 */
function xmlsitemap_modules_enabled(array $modules) {
  cache_clear_all('xmlsitemap:', 'cache', TRUE);
}

/**
 * Implements hook_modules_disabled().
 */
function xmlsitemap_modules_disabled(array $modules) {
  cache_clear_all('xmlsitemap:', 'cache', TRUE);
}

/**
 * Implements hook_robotstxt().
 */
function xmlsitemap_robotstxt() {
  if ($sitemap = xmlsitemap_sitemap_load_by_context()) {
    $robotstxt[] = 'Sitemap: ' . url($sitemap->uri['path'], $sitemap->uri['options']);
    return $robotstxt;
  }
}

/**
 * Internal default variables for xmlsitemap_var().
 */
function xmlsitemap_variables() {
  return array(
    'rebuild_needed' => FALSE,
    'regenerate_needed' => FALSE,
    'minimum_lifetine' => 0,
    'generated_last' => 0,
    'xsl' => 1,
    'prefetch_aliases' => 1,
    'chunk_size' => 'auto',
    'batch_limit' => 100,
    'path' => 'xmlsitemap',
    'base_url' => $GLOBALS['base_url'],
    'developer_mode' => 0,
    'frontpage_priority' => 1.0,
    'frontpage_changefreq' => XMLSITEMAP_FREQUENCY_DAILY,
    'lastmod_format' => XMLSITEMAP_LASTMOD_MEDIUM,
    'gz' => FALSE,
    // Removed variables are set to NULL so they can still be deleted.
    'regenerate_last' => NULL,
    'custom_links' => NULL,
    'priority_default' => NULL,
    'languages' => NULL,
    'max_chunks' => NULL,
    'max_filesize' => NULL,
  );
}

/**
 * Internal implementation of variable_get().
 */
function xmlsitemap_var($name, $default = NULL) {
  $defaults = &drupal_static(__FUNCTION__);
  if (!isset($defaults)) {
    $defaults = xmlsitemap_variables();
  }

  // @todo Remove when stable.
  if (!isset($defaults[$name])) {
    trigger_error(strtr('Default variable for %variable not found.', array('%variable' => drupal_placeholder($name))));
  }

  return \Drupal::config('xmlsitemap.settings')->get($name);
  return variable_get($name, isset($default) || !isset($defaults[$name]) ? $default : $defaults[$name]);
}

/**
 * @defgroup xmlsitemap_api XML sitemap API.
 * @{
 * This is the XML sitemap API to be used by modules wishing to work with
 * XML sitemap and/or link data.
 */

/**
 * Load an XML sitemap array from the database.
 *
 * @param $smid
 *   An XML sitemap ID.
 *
 * @return
 *   The XML sitemap object.
 */
function xmlsitemap_sitemap_load($smid) {
  $sitemap = xmlsitemap_sitemap_load_multiple(array($smid));
  return $sitemap ? reset($sitemap) : FALSE;
}

/**
 * Load multiple XML sitemaps from the database.
 *
 * @param $smids
 *   An array of XML sitemap IDs, or FALSE to load all XML sitemaps.
 * @param $conditions
 *   An array of conditions in the form 'field' => $value.
 *
 * @return
 *   An array of XML sitemap objects.
 */
function xmlsitemap_sitemap_load_multiple($smids = array(), array $conditions = array()) {
  if ($smids !== FALSE) {
    $conditions['smid'] = $smids;
  }
  else {
    $conditions['smid'] = NULL;
  }
  $storage = Drupal::entityManager()->getStorage('xmlsitemap');

  $sitemaps = $storage->loadMultiple($conditions['smid']);
  /* $query = db_select('xmlsitemap_sitemap');
    $query->fields('xmlsitemap_sitemap');
    foreach ($conditions as $field => $value) {
    $query->condition($field, $value);
    }
    $sitemaps = $query->execute()->fetchAllAssoc('smid');
   */
  if (count($sitemaps) <= 0) {
    return array();
  }
  foreach ($sitemaps as &$sitemap) {
    $uri = xmlsitemap_sitemap_uri($sitemap);
    $sitemap->uri = $uri;
  }

  return $sitemaps;
}

/**
 * Load an XML sitemap array from the database based on its context.
 *
 * @param $context
 *   An optional XML sitemap context array to use to find the correct XML
 *   sitemap. If not provided, the current site's context will be used.
 *
 * @see xmlsitemap_get_current_context()
 */
function xmlsitemap_sitemap_load_by_context(array $context = NULL) {
  if (!isset($context)) {
    $context = xmlsitemap_get_current_context();
  }
  $sitemaps = \Drupal::entityManager()->getStorage('xmlsitemap')->loadMultiple();
  foreach ($sitemaps as $sitemap) {
    if ($sitemap->context == $context) {
      return $sitemap;
    }
  }
  return NULL;
}

/**
 * Save changes to an XML sitemap or add a new XML sitemap.
 *
 * @param $sitemap
 *   The XML sitemap array to be saved. If $sitemap->smid is omitted, a new
 *   XML sitemap will be added.
 *
 * @todo Save the sitemap's URL as a column?
 */
function xmlsitemap_sitemap_save(XmlSitemapInterface $sitemap) {
  $context = $sitemap->getContext();
  if (!isset($context) || !$context) {
    $sitemap->setContext(array());
  }

  // Make sure context is sorted before saving the hash.
  //$sitemap->is_new = empty($sitemap->getId());
  //$sitemap->old_smid = $sitemap->is_new ? NULL : $sitemap->smid;
  $sitemap->setOriginalId($sitemap->isNew() ? NULL : $sitemap->getId());
  $context = $sitemap->getContext();
  $sitemap->setId(xmlsitemap_sitemap_get_context_hash($context));
  // If the context was changed, we need to perform additional actions.
  if (!$sitemap->isNew() && $sitemap->getId() != $sitemap->getOriginalId()) {
    // Rename the files directory so the sitemap does not break.
    $old_sitemap = (object) array('smid' => $sitemap->old_smid);
    $old_dir = xmlsitemap_get_directory($old_sitemap);
    $new_dir = xmlsitemap_get_directory($sitemap);
    xmlsitemap_directory_move($old_dir, $new_dir);

    // Mark the sitemaps as needing regeneration.
    \Drupal::config('xmlsitemap.settings')->set('regenerate_needed', TRUE);
  }
  $sitemap->save();

  return $sitemap;
}

/**
 * Delete an XML sitemap.
 *
 * @param $smid
 *   An XML sitemap ID.
 */
function xmlsitemap_sitemap_delete($smid) {
  xmlsitemap_sitemap_delete_multiple(array($smid));
}

/**
 * Delete multiple XML sitemaps.
 *
 * @param $smids
 *   An array of XML sitemap IDs.
 */
function xmlsitemap_sitemap_delete_multiple(array $smids) {
  if (!empty($smids)) {
    $sitemaps = xmlsitemap_sitemap_load_multiple($smids);
    /*
      db_delete('xmlsitemap_sitemap')
      ->condition('smid', $smids)
      ->execute();
     */
    foreach ($sitemaps as $sitemap) {
      xmlsitemap_clear_directory($sitemap, TRUE);
      $sitemap->delete();
      \Drupal::moduleHandler()->invokeAll('xmlsitemap_sitemap_delete', array($sitemap));
    }
  }
}

/**
 * Return the expected file path for a specific sitemap chunk.
 *
 * @param $sitemap
 *   An XmlSitemapInterface sitemap object.
 * @param $chunk
 *   An optional specific chunk in the sitemap. Defaults to the index page.
 */
function xmlsitemap_sitemap_get_file(XmlSitemapInterface $sitemap, $chunk = 'index') {
  return xmlsitemap_get_directory($sitemap) . "/{$chunk}.xml";
}

/**
 * Find the maximum file size of all a sitemap's XML files.
 *
 * @param $sitemap
 *   The XML sitemap array.
 */
function xmlsitemap_sitemap_get_max_filesize(XmlSitemapInterface $sitemap) {
  $dir = xmlsitemap_get_directory($sitemap);
  $sitemap->setMaxFileSize(0);
  foreach (file_scan_directory($dir, '/\.xml$/') as $file) {
    $sitemap->setMaxFileSize(max($sitemap->getMaxFileSize(), filesize($file->uri)));
  }
  return $sitemap->getMaxFileSize();
}

function xmlsitemap_sitemap_get_context_hash(array &$context) {
  asort($context);
  return Crypt::hashBase64(serialize($context));
}

/**
 * Returns the uri elements of an XML sitemap.
 *
 * @param \Drupal\xmlsitemap\XmlSitemapInterface $sitemap
 *   The sitemap represented by and XmlSitemapInterface object.
 * @return
 *   An array containing the 'path' and 'options' keys used to build the uri of
 *   the XML sitemap, and matching the signature of url().
 */
function xmlsitemap_sitemap_uri(XmlSitemapInterface $sitemap) {
  $uri['path'] = 'sitemap.xml';
  $uri['options'] = \Drupal::moduleHandler()->invokeAll('xmlsitemap_context_url_options', array($sitemap->context));
  $context = $sitemap->context;
  \Drupal::moduleHandler()->alter('xmlsitemap_context_url_options', $uri['options'], $context);
  $uri['options'] += array(
    'absolute' => TRUE,
    'base_url' => \Drupal::state()->get('base_url')
  );
  return $uri;
}

/**
 * Load a specific sitemap link from the database.
 *
 * @param $entity_type
 *   A string with the entity type.
 * @param $entity_id
 *   An integer with the entity ID.
 * @return
 *   A sitemap link (array) or FALSE if the conditions were not found.
 */
function xmlsitemap_link_load($entity_type, $entity_id) {
  $link = xmlsitemap_link_load_multiple(array('type' => $entity_type, 'id' => $entity_id));
  return $link ? reset($link) : FALSE;
}

/**
 * Load sitemap links from the database.
 *
 * @param $conditions
 *   An array of conditions on the {xmlsitemap} table in the form
 *   'field' => $value.
 * @return
 *   An array of sitemap link arrays.
 */
function xmlsitemap_link_load_multiple(array $conditions = array()) {
  $query = db_select('xmlsitemap');
  $query->fields('xmlsitemap');

  foreach ($conditions as $field => $value) {
    $query->condition($field, $value);
  }

  $links = $query->execute()->fetchAll(PDO::FETCH_ASSOC);

  return $links;
}

/**
 * Saves or updates a sitemap link.
 *
 * @param $link
 *   An array with a sitemap link.
 */
function xmlsitemap_link_save(array $link) {
  $link += array(
    'access' => 1,
    'status' => 1,
    'status_override' => 0,
    'lastmod' => 0,
    'priority' => XMLSITEMAP_PRIORITY_DEFAULT,
    'priority_override' => 0,
    'changefreq' => 0,
    'changecount' => 0,
    'language' => LanguageInterface::LANGCODE_NOT_SPECIFIED,
  );

  // Allow other modules to alter the link before saving.
  drupal_alter('xmlsitemap_link', $link);

  // Temporary validation checks.
  // @todo Remove in final?
  if ($link['priority'] < 0 || $link['priority'] > 1) {
    trigger_error(t('Invalid sitemap link priority %priority.<br />@link', array('%priority' => $link['priority'], '@link' => var_export($link, TRUE))), E_USER_ERROR);
  }
  if ($link['changecount'] < 0) {
    trigger_error(t('Negative changecount value. Please report this to <a href="@516928">@516928</a>.<br />@link', array('@516928' => 'http://drupal.org/node/516928', '@link' => var_export($link, TRUE))), E_USER_ERROR);
    $link['changecount'] = 0;
  }

  $existing = db_query_range("SELECT loc, access, status, lastmod, priority, changefreq, changecount, language FROM {xmlsitemap} WHERE type = :type AND id = :id", 0, 1, array(':type' => $link['type'], ':id' => $link['id']))->fetchAssoc();

  // Check if this is a changed link and set the regenerate flag if necessary.
  if (!\Drupal::config('xmlsitemap.settings')->get('regenerate_needed')) {
    _xmlsitemap_check_changed_link($link, $existing, TRUE);
  }

  // Save the link and allow other modules to respond to the link being saved.
  if ($existing) {
    drupal_write_record('xmlsitemap', $link, array('type', 'id'));
    \Drupal::moduleHandler()->invokeAll('xmlsitemap_link_update', array($link));
  }
  else {
    $result = drupal_write_record('xmlsitemap', $link);
    \Drupal::moduleHandler()->invokeAll('xmlsitemap_link_insert', array($link));
  }

  return $link;
}

/**
 * Perform a mass update of sitemap data.
 *
 * If visible links are updated, this will automatically set the regenerate
 * needed flag to TRUE.
 *
 * @param $updates
 *   An array of values to update fields to, keyed by field name.
 * @param $conditions
 *   An array of values to match keyed by field.
 * @return
 *   The number of links that were updated.
 */
function xmlsitemap_link_update_multiple($updates = array(), $conditions = array(), $check_flag = TRUE) {
  // If we are going to modify a visible sitemap link, we will need to set
  // the regenerate needed flag.
  if ($check_flag && !\Drupal::config('xmlsitemap.settings')->get('regenerate_needed')) {
    _xmlsitemap_check_changed_links($conditions, $updates, TRUE);
  }

  // Process updates.
  $query = db_update('xmlsitemap');
  $query->fields($updates);
  foreach ($conditions as $field => $value) {
    $query->condition($field, $value);
  }

  return $query->execute();
}

/**
 * Delete a specific sitemap link from the database.
 *
 * If a visible sitemap link was deleted, this will automatically set the
 * regenerate needed flag.
 *
 * @param $entity_type
 *   A string with the entity type.
 * @param $entity_id
 *   An integer with the entity ID.
 * @return
 *   The number of links that were deleted.
 */
function xmlsitemap_link_delete($entity_type, $entity_id) {
  $conditions = array('type' => $entity_type, 'id' => $entity_id);
  return xmlsitemap_link_delete_multiple($conditions);
}

/**
 * Delete multiple sitemap links from the database.
 *
 * If visible sitemap links were deleted, this will automatically set the
 * regenerate needed flag.
 *
 * @param $conditions
 *   An array of conditions on the {xmlsitemap} table in the form
 *   'field' => $value.
 * @return
 *   The number of links that were deleted.
 */
function xmlsitemap_link_delete_multiple(array $conditions) {
  // Because this function is called from sub-module uninstall hooks, we have
  // to manually check if the table exists since it could have been removed
  // in xmlsitemap_uninstall().
  // @todo Remove this check when http://drupal.org/node/151452 is fixed.
  if (!db_table_exists('xmlsitemap')) {
    return FALSE;
  }

  if (!\Drupal::config('xmlsitemap.settings')->get('regenerate_needed')) {
    _xmlsitemap_check_changed_links($conditions, array(), TRUE);
  }

  // @todo Add a hook_xmlsitemap_link_delete() hook invoked here.

  $query = db_delete('xmlsitemap');
  foreach ($conditions as $field => $value) {
    $query->condition($field, $value);
  }

  return $query->execute();
}

/**
 * Check if there is a visible sitemap link given a certain set of conditions.
 *
 * @param $conditions
 *   An array of values to match keyed by field.
 * @param $flag
 *   An optional boolean that if TRUE, will set the regenerate needed flag if
 *   there is a match. Defaults to FALSE.
 * @return
 *   TRUE if there is a visible link, or FALSE otherwise.
 */
function _xmlsitemap_check_changed_links(array $conditions = array(), array $updates = array(), $flag = FALSE) {
  // If we are changing status or access, check for negative current values.
  $conditions['status'] = (!empty($updates['status']) && empty($conditions['status'])) ? 0 : 1;
  $conditions['access'] = (!empty($updates['access']) && empty($conditions['access'])) ? 0 : 1;

  $query = db_select('xmlsitemap');
  $query->addExpression('1');
  foreach ($conditions as $field => $value) {
    $query->condition($field, $value);
  }
  $query->range(0, 1);
  $changed = $query->execute()->fetchField();

  if ($changed && $flag) {
    \Drupal::config('xmlsitemap.settings')->set('regenerate_needed', TRUE);
  }

  return $changed;
}

/**
 * Check if there is sitemap link is changed from the existing data.
 *
 * @param $link
 *   An array of the sitemap link.
 * @param $original_link
 *   An optional array of the existing data. This should only contain the
 *   fields necessary for comparison. If not provided the existing data will be
 *   loaded from the database.
 * @param $flag
 *   An optional boolean that if TRUE, will set the regenerate needed flag if
 *   there is a match. Defaults to FALSE.
 * @return
 *   TRUE if the link is changed, or FALSE otherwise.
 */
function _xmlsitemap_check_changed_link(array $link, $original_link = NULL, $flag = FALSE) {
  $changed = FALSE;

  if ($original_link === NULL) {
    // Load only the fields necessary for data to be changed in the sitemap.
    $original_link = db_query_range("SELECT loc, access, status, lastmod, priority, changefreq, changecount, language FROM {xmlsitemap} WHERE type = :type AND id = :id", 0, 1, array(':type' => $link['type'], ':id' => $link['id']))->fetchAssoc();
  }

  if (!$original_link) {
    if ($link['access'] && $link['status']) {
      // Adding a new visible link.
      $changed = TRUE;
    }
  }
  else {
    if (!($original_link['access'] && $original_link['status']) && $link['access'] && $link['status']) {
      // Changing a non-visible link to a visible link.
      $changed = TRUE;
    }
    elseif ($original_link['access'] && $original_link['status'] && array_diff_assoc($original_link, $link)) {
      // Changing a visible link
      $changed = TRUE;
    }
  }

  if ($changed && $flag) {
    \Drupal::config('xmlsitemap.settings')->set('regenerate_needed', TRUE);
  }

  return $changed;
}

/**
 * @} End of "defgroup xmlsitemap_api"
 */
function xmlsitemap_get_directory(XmlSitemapInterface $sitemap = NULL) {
  $directory = &drupal_static(__FUNCTION__);
  if (!isset($directory)) {
    $directory = \Drupal::config('xmlsitemap.settings')->get('path');
  }

  if ($sitemap != NULL && !empty($sitemap->id)) {
    return file_build_uri($directory . '/' . $sitemap->id);
  }
  else {
    return file_build_uri($directory);
  }
}

/**
 * Check that the sitemap files directory exists and is writable.
 */
function xmlsitemap_check_directory(XmlSitemapInterface $sitemap = NULL) {
  $directory = xmlsitemap_get_directory($sitemap);
  $result = file_prepare_directory($directory, FILE_CREATE_DIRECTORY | FILE_MODIFY_PERMISSIONS);
  if (!$result) {
    watchdog('file system', 'The directory %directory does not exist or is not writable.', array('%directory' => $directory), WATCHDOG_ERROR);
  }
  return $result;
}

function xmlsitemap_check_all_directories() {
  $directories = array();

  $sitemaps = xmlsitemap_sitemap_load_multiple(FALSE);
  foreach ($sitemaps as $smid => $sitemap) {
    $directory = xmlsitemap_get_directory($sitemap);
    $directories[$directory] = $directory;
  }

  foreach ($directories as $directory) {
    $result = file_prepare_directory($directory, FILE_CREATE_DIRECTORY | FILE_MODIFY_PERMISSIONS);
    if ($result) {
      $directories[$directory] = TRUE;
    }
    else {
      $directories[$directory] = FALSE;
    }
  }

  return $directories;
}

function xmlsitemap_clear_directory(XmlSitemapInterface $sitemap = NULL, $delete = FALSE) {
  $directory = xmlsitemap_get_directory($sitemap);
  return _xmlsitemap_delete_recursive($directory, $delete);
}

/**
 * Move a directory to a new location.
 *
 * @param $old_dir
 *   A string specifying the filepath or URI of the original directory.
 * @param $new_dir
 *   A string specifying the filepath or URI of the new directory.
 * @param $replace
 *   Replace behavior when the destination file already exists.
 *
 * @return
 *   TRUE if the directory was moved successfully. FALSE otherwise.
 */
function xmlsitemap_directory_move($old_dir, $new_dir, $replace = FILE_EXISTS_REPLACE) {
  $success = file_prepare_directory($new_dir, FILE_CREATE_DIRECTORY | FILE_MODIFY_PERMISSIONS);

  $old_path = drupal_realpath($old_dir);
  $new_path = drupal_realpath($new_dir);
  if (!is_dir($old_path) || !is_dir($new_path) || !$success) {
    return FALSE;
  }

  $files = file_scan_directory($old_dir, '/.*/');
  foreach ($files as $file) {
    $file->uri_new = $new_dir . '/' . basename($file->filename);
    $success &= (bool) file_unmanaged_move($file->uri, $file->uri_new, $replace);
  }

  // The remove the directory.
  $success &= drupal_rmdir($old_dir);
  return $success;
}

/**
 * Recursively delete all files and folders in the specified filepath.
 *
 * This is a backport of Drupal 7's file_unmanaged_delete_recursive().
 *
 * Note that this only deletes visible files with write permission.
 *
 * @param $path
 *   A filepath relative to the Drupal root directory.
 * @param $delete_root
 *   A boolean if TRUE will delete the $path directory afterwards.
 */
function _xmlsitemap_delete_recursive($path, $delete_root = FALSE) {
  // Resolve streamwrapper URI to local path.
  $path = drupal_realpath($path);
  if (is_dir($path)) {
    $dir = dir($path);
    while (($entry = $dir->read()) !== FALSE) {
      if ($entry == '.' || $entry == '..') {
        continue;
      }
      $entry_path = $path . '/' . $entry;
      file_unmanaged_delete_recursive($entry_path, NULL);
    }
    $dir->close();
    return $delete_root ? drupal_rmdir($path) : TRUE;
  }
  return file_unmanaged_delete($path);
}

/**
 * Returns information about supported sitemap link types.
 *
 * @param $type
 *   (optional) The link type to return information for. If omitted,
 *   information for all link types is returned.
 * @param $reset
 *   (optional) Boolean whether to reset the static cache and do nothing. Only
 *   used for tests.
 *
 * @see hook_xmlsitemap_link_info()
 * @see hook_xmlsitemap_link_info_alter()
 */
function xmlsitemap_get_link_info($type = NULL, $reset = FALSE) {
  $language = \Drupal::languageManager()->getCurrentLanguage();
  $link_info = &drupal_static(__FUNCTION__);

  if ($reset) {
    $link_info = NULL;
    foreach (\Drupal::languageManager()->getLanguages() as $lang) {
      \Drupal::cache()->delete('xmlsitemap:link_info:' . $lang->getId());
    }
  }

  if (!isset($link_info)) {
    $cid = 'xmlsitemap:link_info:' . $language->getId();
    if ($cache = \Drupal::cache()->get($cid)) {
      $link_info = $cache->data;
    }
    else {
      \Drupal::entityManager()->clearCachedDefinitions();
      $link_info = array();
      $entity_types = \Drupal::entityManager()->getDefinitions();
      foreach ($entity_types as $key => $entity_type) {
        $link_info[$key] = array(
          'label' => $entity_type->getLabel(),
          'type' => $entity_type->id(),
          'base table' => $entity_type->getBaseTable(),
          'bundles' => \Drupal::entityManager()->getBundleInfo($entity_type->id())
        );
        $uri_callback = $entity_type->getUriCallback();
        if (empty($uri_callback) || !isset($entity_type->xmlsitemap)) {
          // Remove any non URL-able or XML sitemap un-supported entites.
          //unset($entity_types[$key]);
          //unset($link_info[$key]);
        }
        foreach (\Drupal::entityManager()->getBundleInfo($entity_type->id()) as $bundle_key => $bundle) {
          if (!isset($bundle['xmlsitemap'])) {
            // Remove any un-supported entity bundles.
            //unset($link_info[$key]['bundles'][$bundle_key]);
          }
        }