node.module

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<?php
// $Id: node.module,v 1.1181 2009/12/11 16:49:40 dries Exp $

/**
 * @file
 * The core that allows content to be submitted to the site. Modules and
 * scripts may programmatically submit nodes using the usual form API pattern.
 */

/**
 * Node is not published.
 */
define('NODE_NOT_PUBLISHED', 0);

/**
 * Node is published.
 */
define('NODE_PUBLISHED', 1);

/**
 * Node is not promoted to front page.
 */
define('NODE_NOT_PROMOTED', 0);

/**
 * Node is promoted to front page.
 */
define('NODE_PROMOTED', 1);

/**
 * Node is not sticky at top of the page.
 */
define('NODE_NOT_STICKY', 0);

/**
 * Node is sticky at top of the page.
 */
define('NODE_STICKY', 1);

/**
 * Nodes changed before this time are always marked as read.
 *
 * Nodes changed after this time may be marked new, updated, or read, depending
 * on their state for the current user. Defaults to 30 days ago.
 */
define('NODE_NEW_LIMIT', REQUEST_TIME - 30 * 24 * 60 * 60);

/**
 * Modules should return this value from hook_node_access() to allow access to a node.
 */
define('NODE_ACCESS_ALLOW', 'allow');

/**
 * Modules should return this value from hook_node_access() to deny access to a node.
 */
define('NODE_ACCESS_DENY', 'deny');

/**
 * Modules should return this value from hook_node_access() to not affect node access.
 */
define('NODE_ACCESS_IGNORE', NULL);

/**
 * Implements hook_help().
 */
function node_help($path, $arg) {
  // Remind site administrators about the {node_access} table being flagged
  // for rebuild. We don't need to issue the message on the confirm form, or
  // while the rebuild is being processed.
  if ($path != 'admin/reports/status/rebuild' && $path != 'batch' && strpos($path, '#') === FALSE
      && user_access('access administration pages') && node_access_needs_rebuild()) {
    if ($path == 'admin/reports/status') {
      $message = t('The content access permissions need to be rebuilt.');
    }
    else {
      $message = t('The content access permissions need to be rebuilt. Please visit <a href="@node_access_rebuild">this page</a>.', array('@node_access_rebuild' => url('admin/reports/status/rebuild')));
    }
    drupal_set_message($message, 'error');
  }

  switch ($path) {
    case 'admin/help#node':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('The Node module manages the creation, editing, deletion, settings, and display of all site content. For more information, see the online handbook entry for <a href="@node">Node module</a>.', array('@node' => 'http://drupal.org/handbook/modules/node')) . '</p>';
      $output .= '<h3>' . t('Uses') . '</h3>';
      $output .= '<dl>';
      $output .= '<dt>' . t('Creating content') . '</dt>';
      $output .= '<dd>' . t('When new content is created, the Node module records basic information about the content, including the author, date of creation, and the <a href="@content-type">Content type</a>. It also manages the <em>publishing options</em>, which define whether or not the content is published, promoted to the front page of the site, and/or sticky at the top of content lists. Default settings can be configured for each <a href="@content-type">type of content</a> on your site.', array('@content-type' => url('admin/structure/types'))) . '</dd>';
      $output .= '<dt>' . t('Creating custom content types') . '</dt>';
      $output .= '<dd>' . t('The Node module gives users with the <em>Administer content types</em> permission the ability to <a href="@content-new">create new content types</a> in addition to the default ones already configured. Creating custom content types allows you the flexibility to add <a href="@field">fields</a> and configure default settings that suit the differing needs of various site content.', array('@content-new' => url('admin/structure/types/add'), '@field' => url('admin/help/field'))) . '</dd>';
      $output .= '<dt>' . t('Administering content') . '</dt>';
      $output .= '<dd>' . t('The <a href="@content">Content administration page</a> allows you to review and bulk manage your site content.', array('@content' => url('admin/content'))) . '</dd>';
      $output .= '<dt>' . t('Creating revisions') . '</dt>';
      $output .= '<dd>' . t('The Node module also enables you to create multiple versions of any content, and revert to older versions using the <em>Revision information</em> settings.') . '</dd>';
      $output .= '<dt>' . t('User permissions') . '</dt>';
      $output .= '<dd>' . t('The Node module makes a number of permissions available for each content type, which can be set by role on the <a href="@permissions">permissions page</a>.', array('@permissions' => url('admin/settings/permissions'))) . '</dd>';
      $output .= '</dl>';
      return $output;

    case 'admin/content':
      // Return a non-null value so that the 'more help' link is shown.
      return ' ';

    case 'admin/structure/types/add':
      return '<p>' . t('Individual content types can have different fields, behaviors, and permissions assigned to them.') . '</p>';

    case 'admin/structure/types/manage/' . $arg[3] . '/fields':
      return '<p>' . t('This form allows you to add, edit, and arrange fields within the %type content type.', array('%type' => node_type_get_name($arg[3]))) . '</p>';

    case 'admin/structure/types/manage/' . $arg[3] . '/display':
      return '<p>' . t('This form allows you to configure how fields should be displayed when %type content is rendered in the following contexts.', array('%type' => node_type_get_name($arg[3]))) . '</p>';

    case 'admin/structure/types/manage/' . $arg[3] . '/display/' . $arg[5]:
      return '<p>' . t('This form allows you to configure how fields should be displayed when %type content is rendered in the following contexts.', array('%type' => node_type_get_name($arg[3]))) . '</p>';

    case 'node/%/revisions':
      return '<p>' . t('Revisions allow you to track differences between multiple versions of your content, and revert back to older versions.') . '</p>';

    case 'node/%/edit':
      $node = node_load($arg[1]);
      $type = node_type_get_type($node);
      return (!empty($type->help) ? '<p>' . filter_xss_admin($type->help) . '</p>' : '');
  }

  if ($arg[0] == 'node' && $arg[1] == 'add' && $arg[2]) {
    $type = node_type_get_type(str_replace('-', '_', $arg[2]));
    return (!empty($type->help) ? '<p>' . filter_xss_admin($type->help) . '</p>' : '');
  }
}

/**
 * Implements hook_theme().
 */
function node_theme() {
  return array(
    'node' => array(
      'render element' => 'elements',
      'template' => 'node',
    ),
    'node_list' => array(
      'variables' => array('items' => NULL, 'title' => NULL),
    ),
    'node_search_admin' => array(
      'render element' => 'form',
    ),
    'node_filter_form' => array(
      'render element' => 'form',
      'file' => 'node.admin.inc',
    ),
    'node_filters' => array(
      'render element' => 'form',
      'file' => 'node.admin.inc',
    ),
    'node_add_list' => array(
      'variables' => array('content' => NULL),
      'file' => 'node.pages.inc',
    ),
    'node_form' => array(
      'render element' => 'form',
      'file' => 'node.pages.inc',
    ),
    'node_preview' => array(
      'variables' => array('node' => NULL),
      'file' => 'node.pages.inc',
    ),
    'node_log_message' => array(
      'variables' => array('log' => NULL),
    ),
    'node_admin_overview' => array(
      'variables' => array('name' => NULL, 'type' => NULL),
    ),
  );
}

/**
 * Implements hook_cron().
 */
function node_cron() {
  db_delete('history')
    ->condition('timestamp', NODE_NEW_LIMIT, '<')
    ->execute();
}

/**
 * Implements hook_entity_info().
 */
function node_entity_info() {
  $return = array(
    'node' => array(
      'label' => t('Node'),
      'controller class' => 'NodeController',
      'base table' => 'node',
      'revision table' => 'node_revision',
      'fieldable' => TRUE,
      'object keys' => array(
        'id' => 'nid',
        'revision' => 'vid',
        'bundle' => 'type',
      ),
      'bundle keys' => array(
        'bundle' => 'type',
      ),
      // Node.module handles its own caching.
      // 'cacheable' => FALSE,
      'bundles' => array(),
    ),
  );
  // Bundles must provide a human readable name so we can create help and error
  // messages, and the path to attach Field admin pages to.
  foreach (node_type_get_names() as $type => $name) {
    $return['node']['bundles'][$type] = array(
      'label' => $name,
      'admin' => array(
        'path' => 'admin/structure/types/manage/%node_type',
        'real path' => 'admin/structure/types/manage/' . str_replace('_', '-', $type),
        'bundle argument' => 4,
        'access arguments' => array('administer content types'),
      ),
    );
  }
  return $return;
}


/**
 * Implements hook_field_build_modes().
 */
function node_field_build_modes($obj_type) {
  $modes = array();
  if ($obj_type == 'node') {
    $modes = array(
      'teaser' => t('Teaser'),
      'full' => t('Full node'),
      'rss' => t('RSS'),
    );
    // Search integration is provided by node.module, so search-related
    // build-modes for nodes are defined here and not in search.module.
    if (module_exists('search')) {
      $modes += array(
        'search_index' => t('Search Index'),
        'search_result' => t('Search Result'),
      );
    }
  }
  return $modes;
}

/**
 * Implements hook_admin_paths().
 */
function node_admin_paths() {
  $paths = array(
    'node/*/add' => TRUE,
    'node/*/edit' => TRUE,
    'node/*/delete' => TRUE,
    'node/add' => TRUE,
    'node/add/*' => TRUE,
  );
  return $paths;
}

/**
 * Gather a listing of links to nodes.
 *
 * @param $result
 *   A DB result object from a query to fetch node entities. If your query
 *   joins the <code>node_comment_statistics</code> table so that the
 *   <code>comment_count</code> field is available, a title attribute will
 *   be added to show the number of comments.
 * @param $title
 *   A heading for the resulting list.
 *
 * @return
 *   An HTML list suitable as content for a block, or FALSE if no result can
 *   fetch from DB result object.
 */
function node_title_list($result, $title = NULL) {
  $items = array();
  $num_rows = FALSE;
  foreach ($result as $node) {
    $items[] = l($node->title, 'node/' . $node->nid, !empty($node->comment_count) ? array('attributes' => array('title' => format_plural($node->comment_count, '1 comment', '@count comments'))) : array());
    $num_rows = TRUE;
  }

  return $num_rows ? theme('node_list', array('items' => $items, 'title' => $title)) : FALSE;
}

/**
 * Format a listing of links to nodes.
 *
 * @ingroup themeable
 */
function theme_node_list($variables) {
  return theme('item_list', $variables);
}

/**
 * Update the 'last viewed' timestamp of the specified node for current user.
 */
function node_tag_new($nid) {
  global $user;

  if ($user->uid) {
    db_merge('history')
      ->key(array(
        'uid' => $user->uid,
        'nid' => $nid,
      ))
      ->fields(array('timestamp' => REQUEST_TIME))
      ->execute();
  }
}

/**
 * Retrieves the timestamp at which the current user last viewed the
 * specified node.
 */
function node_last_viewed($nid) {
  global $user;
  static $history;

  if (!isset($history[$nid])) {
    $history[$nid] = db_query("SELECT timestamp FROM {history} WHERE uid = :uid AND nid = :nid", array(':uid' => $user->uid, ':nid' => $nid))->fetchObject();
  }

  return (isset($history[$nid]->timestamp) ? $history[$nid]->timestamp : 0);
}

/**
 * Decide on the type of marker to be displayed for a given node.
 *
 * @param $nid
 *   Node ID whose history supplies the "last viewed" timestamp.
 * @param $timestamp
 *   Time which is compared against node's "last viewed" timestamp.
 * @return
 *   One of the MARK constants.
 */
function node_mark($nid, $timestamp) {
  global $user;
  static $cache;

  if (!$user->uid) {
    return MARK_READ;
  }
  if (!isset($cache[$nid])) {
    $cache[$nid] = node_last_viewed($nid);
  }
  if ($cache[$nid] == 0 && $timestamp > NODE_NEW_LIMIT) {
    return MARK_NEW;
  }
  elseif ($timestamp > $cache[$nid] && $timestamp > NODE_NEW_LIMIT) {
    return MARK_UPDATED;
  }
  return MARK_READ;
}

/**
 * Extract the type name.
 *
 * @param $node
 *   Either a string or object, containing the node type information.
 *
 * @return
 *   Node type of the passed in data.
 */
function _node_extract_type($node) {
  return is_object($node) ? $node->type : $node;
}

/**
 * Returns a list of all the available node types.
 *
 * @return
 *   An array of node types, keyed by the type.
 * @see node_type_get_type()
 */
function node_type_get_types() {
  return _node_types_build()->types;
}

/**
 * Returns the node type of the passed node or node type string.
 *
 *@param $node
 *   A node object or string that indicates the node type to return.
 * @return
 *   A single node type, as an object or FALSE if the node type is not found.
 *   The node type is an array with following content:
 *
 *   @code
 *   array(
 *     'type' => 'Machine readable type name',
 *     'name' => 'Name of the node type',
 *     'base' => 'Indicates to which module this node type belongs',
 *     'description' => 'Description of the node type',
 *     // ...
 *   )
 *   @endcode
 */
function node_type_get_type($node) {
  $type = _node_extract_type($node);
  $types = _node_types_build()->types;
  return isset($types[$type]) ? $types[$type] : FALSE;
}

/**
 * Returns the node type base of the passed node or node type string.
 *
 * The base indicates which module implement this node type and is used to
 * execute node type specific hooks.
 *
 * @see node_invoke()
 *
 * @param $node
 *   A node object or string that indicates the node type to return.
 * @return
 *   The node type base or FALSE if the node type is not found.
 */
function node_type_get_base($node) {
  $type = _node_extract_type($node);
  $types = _node_types_build()->types;
  return isset($types[$type]) && isset($types[$type]->base) ? $types[$type]->base : FALSE;
}

/**
 * Returns a list of available node names.
 *
 * @return
 *   An array of node type names, keyed by the type.
 */
function node_type_get_names() {
  return _node_types_build()->names;
}

/**
 * Returns the node type name of the passed node or node type string.
 *
 * @param $node
 *   A node object or string that indicates the node type to return.
 *
 * @return
 *   The node type name or FALSE if the node type is not found.
 */
function node_type_get_name($node) {
  $type = _node_extract_type($node);
  $types = _node_types_build()->names;
  return isset($types[$type]) ? $types[$type] : FALSE;
}

/**
 * Resets the database cache of node types.
 *
 * All new or non-modified module-defined node types are saved to the database.
 */
function node_types_rebuild() {
  // Reset and load updated node types.
  drupal_static_reset('_node_types_build');
  foreach (node_type_get_types() as $type => $info) {
    if (!empty($info->is_new)) {
      node_type_save($info);
    }
    if (!empty($info->disabled)) {
      node_type_delete($info->type);
    }
  }
}

/**
 * Menu argument loader; Load a node type by string.
 *
 * @param $name
 *   The machine-readable name of a node type to load; having '_' replaced with
 *   '-'.
 *
 * @return
 *   A node type object or FALSE if $name does not exist.
 */
function node_type_load($name) {
  return node_type_get_type(strtr($name, array('-' => '_')));
}

/**
 * Saves a node type to the database.
 *
 * @param $info
 *   The node type to save, as an object.
 *
 * @return
 *   Status flag indicating outcome of the operation.
 */
function node_type_save($info) {
  $is_existing = FALSE;
  $existing_type = !empty($info->old_type) ? $info->old_type : $info->type;
  $is_existing = (bool) db_query_range('SELECT 1 FROM {node_type} WHERE type = :type', 0, 1, array(':type' => $existing_type))->fetchField();
  $type = node_type_set_defaults($info);

  $fields = array(
    'type' => (string) $type->type,
    'name' => (string) $type->name,
    'base' => (string) $type->base,
    'has_title' => (int) $type->has_title,
    'title_label' => (string) $type->title_label,
    'has_body' => (int) $type->has_body,
    'body_label' => (string) $type->body_label,
    'description' => (string) $type->description,
    'help' => (string) $type->help,
    'custom' => (int) $type->custom,
    'modified' => (int) $type->modified,
    'locked' => (int) $type->locked,
  );

  if ($is_existing) {
    db_update('node_type')
      ->fields($fields)
      ->condition('type', $existing_type)
      ->execute();

    if (!empty($type->old_type) && $type->old_type != $type->type) {
      field_attach_rename_bundle('node', $type->old_type, $type->type);
    }
    node_configure_fields($type);
    module_invoke_all('node_type_update', $type);
    $status = SAVED_UPDATED;
  }
  else {
    $fields['orig_type'] = (string) $type->orig_type;
    db_insert('node_type')
      ->fields($fields)
      ->execute();

    field_attach_create_bundle('node', $type->type);
    node_configure_fields($type);
    module_invoke_all('node_type_insert', $type);
    $status = SAVED_NEW;
  }

  // Clear the node type cache.
  drupal_static_reset('_node_types_build');

  return $status;
}

/**
 * Manage the field(s) for a node type.
 *
 * Currently, the node module manages a single Field API field,
 * 'body'.  If $type->has_body is true, this function ensures the
 * 'body' field exists and creates an instance of it for the bundle
 * $type->type (e.g. 'page', 'story', ...).  If $type->has_body is
 * false, this function removes the instance (if it exists) for the
 * 'body' field on $type->type.
 */
function node_configure_fields($type) {
   // Add or remove the body field, as needed.
  $field = field_info_field('body');
  $instance = field_info_instance('node', 'body', $type->type);
  if ($type->has_body) {
    if (empty($field)) {
      $field = array(
        'field_name' => 'body',
        'type' => 'text_with_summary',
        'translatable' => TRUE,
      );
      $field = field_create_field($field);
    }
    if (empty($instance)) {
      $instance = array(
        'field_name' => 'body',
        'object_type' => 'node',
        'bundle' => $type->type,
        'label' => $type->body_label,
        'widget_type' => 'text_textarea_with_summary',
        'settings' => array('display_summary' => TRUE),

        // Define default formatters for the teaser and full view.
        'display' => array(
          'full' => array(
            'label' => 'hidden',
            'type' => 'text_default',
          ),
          'teaser' => array(
            'label' => 'hidden',
            'type' => 'text_summary_or_trimmed',
          ),
        ),
      );
      field_create_instance($instance);
    }
    else {
      $instance['label'] = $type->body_label;
      $instance['settings']['display_summary'] = TRUE;
      field_update_instance($instance);
    }
  }
  elseif (!empty($instance)) {
    field_delete_instance($instance);
  }

  if ($type->has_title) {
    // Add the title field if not present.
    $field = field_info_field('title');
    $instance = field_info_instance('node', 'title', $type->type);

    if (empty($field)) {
      $field = array(
        'field_name' => 'title',
        'type' => 'text',
      );
      $field = field_create_field($field);
    }
    if (empty($instance)) {
      $weight = -5;
      $instance = array(
        'field_name' => 'title',
        'object_type' => 'node',
        'bundle' => $type->type,
        'label' => $type->title_label,
        'widget_type' => 'text',
        'widget' => array(
          'weight' => $weight,
        ),
        'required' => TRUE,
        'locked' => TRUE,
        'display' => array(
          'full' => array(
            'label' => 'hidden',
            'type' => 'text_default',
            'weight' => $weight,
          ),
          'teaser' => array(
            'label' => 'hidden',
            'type' => 'text_default',
            'weight' => $weight,
          ),
        ),
      );
      field_create_instance($instance);
    }
    else {
      $instance['label'] = $type->title_label;
      field_update_instance($instance);
    }
  }
}

/**
 * Deletes a node type from the database.
 *
 * @param $type
 *   The machine-readable name of the node type to be deleted.
 */
function node_type_delete($type) {
  $info = node_type_get_type($type);
  db_delete('node_type')
    ->condition('type', $type)
    ->execute();
  module_invoke_all('node_type_delete', $info);

  // Clear the node type cache.
  drupal_static_reset('_node_types_build');
}

/**
 * Updates all nodes of one type to be of another type.
 *
 * @param $old_type
 *   The current node type of the nodes.
 * @param $type
 *   The new node type of the nodes.
 *
 * @return
 *   The number of nodes whose node type field was modified.
 */
function node_type_update_nodes($old_type, $type) {
  return db_update('node')
    ->fields(array('type' => $type))
    ->condition('type', $old_type)
    ->execute();
}

/**
 * Builds and returns the list of available node types.
 *
 * The list of types is built by querying hook_node_info() in all modules, and
 * by comparing this information with the node types in the {node_type} table.
 *
 */
function _node_types_build() {
  $_node_types = &drupal_static(__FUNCTION__);
  if (is_object($_node_types)) {
    return $_node_types;
  }
  $_node_types = (object)array('types' => array(), 'names' => array());

  $info_array = module_invoke_all('node_info');
  foreach ($info_array as $type => $info) {
    $info['type'] = $type;
    $_node_types->types[$type] = node_type_set_defaults($info);
    $_node_types->names[$type] = $info['name'];
  }
  $type_result = db_select('node_type', 'nt')
    ->addTag('translatable')
    ->addTag('node_type_access')
    ->fields('nt')
    ->orderBy('nt.type', 'ASC')
    ->execute();
  foreach ($type_result as $type_object) {
    // Check for node types from disabled modules and mark their types for removal.
    // Types defined by the node module in the database (rather than by a separate
    // module using hook_node_info) have a base value of 'node_content'. The isset()
    // check prevents errors on old (pre-Drupal 7) databases.
    if (isset($type_object->base) && $type_object->base != 'node_content' && empty($info_array[$type_object->type])) {
      $type_object->disabled = TRUE;
    }
    if (!isset($_node_types->types[$type_object->type]) || $type_object->modified) {
      $_node_types->types[$type_object->type] = $type_object;
      $_node_types->names[$type_object->type] = $type_object->name;

      if ($type_object->type != $type_object->orig_type) {
        unset($_node_types->types[$type_object->orig_type]);
        unset($_node_types->names[$type_object->orig_type]);
      }
    }
  }

  asort($_node_types->names);

  return $_node_types;
}

/**
 * Set the default values for a node type.
 *
 * The defaults are for a type defined through hook_node_info().
 * When populating a custom node type $info should have the 'custom'
 * key set to 1.
 *
 * @param $info
 *   An object or array containing values to override the defaults.
 *
 * @return
 *  A node type object.
 */
function node_type_set_defaults($info = array()) {
  static $type;

  if (!isset($type)) {
    $type = new stdClass();
    $type->type = '';
    $type->name = '';
    $type->base = '';
    $type->description = '';
    $type->help = '';
    $type->has_title = 1;
    $type->has_body = 1;
    $type->title_label = t('Title');
    $type->body_label = t('Body');
    $type->custom = 0;
    $type->modified = 0;
    $type->locked = 1;
    $type->is_new = 1;
  }

  $new_type = clone $type;
  $info = (array) $info;
  foreach ($info as $key => $data) {
    $new_type->$key = $data;
  }
  // If the type has no title or body, set an empty label.
  if (!$new_type->has_title) {
    $new_type->title_label = '';
  }
  if (!$new_type->has_body) {
    $new_type->body_label = '';
  }
  $new_type->orig_type = isset($info['type']) ? $info['type'] : '';

  return $new_type;
}

/**
 * Implements hook_rdf_mapping().
 */
function node_rdf_mapping() {
  return array(
    array(
      'type' => 'node',
      'bundle' => RDF_DEFAULT_BUNDLE,
      'mapping' => array(
        'rdftype' => array('sioc:Item', 'foaf:Document'),
        'title' => array(
          'predicates' => array('dc:title'),
        ),
        'created' => array(
          'predicates' => array('dc:date', 'dc:created'),
          'datatype' => 'xsd:dateTime',
          'callback' => 'date_iso8601',
        ),
        'changed' => array(
          'predicates' => array('dc:modified'),
        ),
        'body' => array(
          'predicates' => array('content:encoded'),
        ),
        'uid' => array(
          'predicates' => array('sioc:has_creator'),
        ),
        'name' => array(
          'predicates' => array('foaf:name'),
        ),
      ),
    ),
  );
}

/**
 * Determine whether a node hook exists.
 *
 * @param $node
 *   A node object or a string containing the node type.
 * @param $hook
 *   A string containing the name of the hook.
 * @return
 *   TRUE if the $hook exists in the node type of $node.
 */
function node_hook($node, $hook) {
  $base = node_type_get_base($node);
  return module_hook($base, $hook);
}

/**
 * Invoke a node hook.
 *
 * @param $node
 *   A node object or a string containing the node type.
 * @param $hook
 *   A string containing the name of the hook.
 * @param $a2, $a3, $a4
 *   Arguments to pass on to the hook, after the $node argument.
 * @return
 *   The returned value of the invoked hook.
 */
function node_invoke($node, $hook, $a2 = NULL, $a3 = NULL, $a4 = NULL) {
  if (node_hook($node, $hook)) {
    $base = node_type_get_base($node);
    $function = $base . '_' . $hook;
    return ($function($node, $a2, $a3, $a4));
  }
}

/**
 * Load node entities from the database.
 *
 * This function should be used whenever you need to load more than one node
 * from the database. Nodes are loaded into memory and will not require
 * database access if loaded again during the same page request.
 *
 * @see entity_load()
 *
 * @param $nids
 *   An array of node IDs.
 * @param $conditions
 *   An array of conditions on the {node} table in the form 'field' => $value.
 * @param $reset
 *   Whether to reset the internal node_load cache.
 *
 * @return
 *   An array of node objects indexed by nid.
 */
function node_load_multiple($nids = array(), $conditions = array(), $reset = FALSE) {
  return entity_load('node', $nids, $conditions, $reset);
}

/**
 * Load a node object from the database.
 *
 * @param $nid
 *   The node ID.
 * @param $vid
 *   The revision ID.
 * @param $reset
 *   Whether to reset the node_load_multiple cache.
 *
 * @return
 *   A fully-populated node object.
 */
function node_load($nid = NULL, $vid = NULL, $reset = FALSE) {
  $nids = (isset($nid) ? array($nid) : array());
  $conditions = (isset($vid) ? array('vid' => $vid) : array());
  $node = node_load_multiple($nids, $conditions, $reset);
  return $node ? reset($node) : FALSE;
}

/**
 * Perform validation checks on the given node.
 */
function node_validate($node, $form = array()) {
  $type = node_type_get_type($node);

  if (isset($node->nid) && (node_last_changed($node->nid) > $node->changed)) {
    form_set_error('changed', t('The content on this page has either been modified by another user, or you have already submitted modifications using this form. As a result, your changes cannot be saved.'));
  }

  if (user_access('administer nodes')) {
    // Validate the "authored by" field.
    if (!empty($node->name) && !($account = user_load_by_name($node->name))) {
      // The use of empty() is mandatory in the context of usernames
      // as the empty string denotes the anonymous user. In case we
      // are dealing with an anonymous user we set the user ID to 0.
      form_set_error('name', t('The username %name does not exist.', array('%name' => $node->name)));
    }

    // Validate the "authored on" field.
    if (!empty($node->date) && strtotime($node->date) === FALSE) {
      form_set_error('date', t('You have to specify a valid date.'));
    }
  }

  // Do node-type-specific validation checks.
  node_invoke($node, 'validate', $form);
  module_invoke_all('node_validate', $node, $form);
}

/**
 * Prepare node for saving by populating author and creation date.
 */
function node_submit($node) {
  global $user;

  // A user with 'administer nodes' permission might assign the node author by
  // entering a user name in the node form, which we then need to translate to a
  // user ID, unless we've already been provided a user ID by other means.
  if (user_access('administer nodes') && !isset($node->uid)) {
    if ($account = user_load_by_name($node->name)) {
      $node->uid = $account->uid;
    }
    else {
      $node->uid = 0;
    }
  }
  $node->created = !empty($node->date) ? strtotime($node->date) : REQUEST_TIME;
  $node->validated = TRUE;

  return $node;
}

/**
 * Save changes to a node or add a new node.
 *
 * @param $node
 *   The $node object to be saved. If $node->nid is
 *   omitted (or $node->is_new is TRUE), a new node will be added.
 */
function node_save($node) {
  $transaction = db_transaction();

  try {
    field_attach_presave('node', $node);
    // Let modules modify the node before it is saved to the database.
    module_invoke_all('node_presave', $node);
    global $user;

    if (!isset($node->is_new)) {
      $node->is_new = empty($node->nid);
    }

    // Apply filters to some default node fields:
    if ($node->is_new) {
      // Insert a new node.
      $node->is_new = TRUE;

      // When inserting a node, $node->log must be set because
      // {node_revision}.log does not (and cannot) have a default
      // value. If the user does not have permission to create
      // revisions, however, the form will not contain an element for
      // log so $node->log will be unset at this point.
      if (!isset($node->log)) {
        $node->log = '';
      }
    }
    elseif (!empty($node->revision)) {
      $node->old_vid = $node->vid;
      unset($node->vid);
    }
    else {
      // When updating a node, avoid clobbering an existing log entry with an empty one.
      if (empty($node->log)) {
        unset($node->log);
      }
    }

    // Set some required fields:
    if (empty($node->created)) {
      $node->created = REQUEST_TIME;
    }
    // The changed timestamp is always updated for bookkeeping purposes (revisions, searching, ...)
    $node->changed = REQUEST_TIME;

    $node->timestamp = REQUEST_TIME;
    $update_node = TRUE;

    // When converting the title property to fields we preserved the {node}.title
    // db column for performance, setting the default language value into this
    // column. After this we restore the field data structure to the previous node
    // title field.
    $title_field = $node->title;
    $langcode = LANGUAGE_NONE;
    $node->title = $title_field[$langcode][0]['value'];

    // Generate the node table query and the node_revisions table query.
    if ($node->is_new) {
      drupal_write_record('node', $node);
      _node_save_revision($node, $user->uid);
      $op = 'insert';
    }
    else {
      drupal_write_record('node', $node, 'nid');
      if (!empty($node->revision)) {
        _node_save_revision($node, $user->uid);
      }
      else {
        _node_save_revision($node, $user->uid, 'vid');
        $update_node = FALSE;
      }
      $op = 'update';
    }
    if ($update_node) {
      db_update('node')
        ->fields(array('vid' => $node->vid))
        ->condition('nid', $node->nid)
        ->execute();
    }

    // Restore the title field data structure after db storage.
    $node->title = $title_field;

    // Call the node specific callback (if any). This can be
    // node_invoke($node, 'insert') or
    // node_invoke($node, 'update').
    node_invoke($node, $op);

    // Save fields.
    $function = "field_attach_$op";
    $function('node', $node);

    module_invoke_all('node_' . $op, $node);

    // Update the node access table for this node.
    node_access_acquire_grants($node);

    // Clear internal properties.
    unset($node->is_new);

    // Clear the page and block caches.
    cache_clear_all();

    // Ignore slave server temporarily to give time for the
    // saved node to be propagated to the slave.
    db_ignore_slave();
  }
  catch (Exception $e) {
    $transaction->rollback('node', $e->getMessage(), array(), WATCHDOG_ERROR);
  }
}

/**
 * Helper function to save a revision with the uid of the current user.
 *
 * Node is taken by reference, because drupal_write_record() updates the
 * $node with the revision id, and we need to pass that back to the caller.
 */
function _node_save_revision($node, $uid, $update = NULL) {
  $temp_uid = $node->uid;
  $node->uid = $uid;
  if (isset($update)) {
    drupal_write_record('node_revision', $node, $update);
  }
  else {
    drupal_write_record('node_revision', $node);
  }
  $node->uid = $temp_uid;
}

/**
 * Delete a node.
 *
 * @param $nid
 *   A node ID.
 */
function node_delete($nid) {
  node_delete_multiple(array($nid));
}

/**
 * Delete multiple nodes.
 *
 * @param $nids
 *   An array of node IDs.
 */
function node_delete_multiple($nids) {
  if (!empty($nids)) {
    $nodes = node_load_multiple($nids, array());

    db_delete('node')
      ->condition('nid', $nids, 'IN')
      ->execute();
    db_delete('node_revision')
      ->condition('nid', $nids, 'IN')
      ->execute();
    db_delete('history')
      ->condition('nid', $nids, 'IN')
      ->execute();

    foreach ($nodes as $nid => $node) {
      // Call the node-specific callback (if any):
      node_invoke($node, 'delete');
      module_invoke_all('node_delete', $node);
      field_attach_delete('node', $node);

      // Remove this node from the search index if needed.
      // This code is implemented in node module rather than in search module,
      // because node module is implementing search module's API, not the other
      // way around.
      if (module_exists('search')) {
        search_reindex($nid, 'node');
      }
    }

    // Clear the page and block and node_load_multiple caches.
    cache_clear_all();
    entity_get_controller('node')->resetCache();
  }
}

/**
 * Delete a node revision.
 *
 * @param $revision_id
 *   The revision ID to delete.
 */
function node_revision_delete($revision_id) {
  if ($revision = node_load(NULL, $revision_id)) {
    // Prevent deleting the current revision.
    $node = node_load($revision->nid);
    if ($revision_id == $node->vid) {
      return FALSE;
    }

    db_delete('node_revision')
      ->condition('nid', $revision->nid)
      ->condition('vid', $revision->vid)
      ->execute();
    module_invoke_all('node_revision_delete', $revision);
    field_attach_delete_revision('node', $revision);
    return TRUE;
  }
  return FALSE;
}

/**
 * Generate an array for rendering the given node.
 *
 * @param $node
 *   A node object.
 * @param $build_mode
 *   Build mode, e.g. 'full', 'teaser'...
 *
 * @return
 *   An array as expected by drupal_render().
 */
function node_build($node, $build_mode = 'full') {
  // Populate $node->content with a render() array.
  node_build_content($node, $build_mode);

  $build = $node->content;
  // We don't need duplicate rendering info in node->content.
  unset($node->content);

  $build += array(
    '#theme' => 'node',
    '#node' => $node,
    '#build_mode' => $build_mode,
  );
  // Add contextual links for this node.
  // @todo Make this configurable per build mode.
  $build['#contextual_links']['node'] = array('node', array($node->nid));

  // Allow modules to modify the structured node.
  drupal_alter('node_build', $build);

  return $build;
}

/**
 * Builds a structured array representing the node's content.
 *
 * The content built for the node (field values, comments, file attachments or
 * other node components) will vary depending on the $build_mode parameter.
 *
 * Drupal core defines the following build modes for nodes, with the following
 * default use cases:
 *   - full (default): node is being displayed on its own page (node/123)
 *   - teaser: node is being displayed on the default home page listing, on
 *     taxonomy listing pages, or on blog listing pages.
 *   - rss: node displayed in an RSS feed.
 *   If search.module is enabled:
 *   - search_index: node is being indexed for search.
 *   - search_result: node is being displayed as a search result.
 *   If book.module is enabled:
 *   - print: node is being displayed in print-friendly mode.
 * Contributed modules might define additional build modes, or use existing
 * build modes in additional contexts.
 *
 * @param $node
 *   A node object.
 * @param $build_mode
 *   Build mode, e.g. 'full', 'teaser'...
 */
function node_build_content($node, $build_mode = 'full') {
  // Remove previously built content, if exists.
  $node->content = array();

  // The 'view' hook can be implemented to overwrite the default function
  // to display nodes.
  if (node_hook($node, 'view')) {
    $node = node_invoke($node, 'view', $build_mode);
  }

  // Build fields content.
  // @todo field_attach_prepare_view() is only invoked by node_build_multiple(),
  //   all other entities invoke it _here_.
  //field_attach_prepare_view('node', array($node->nid => $node), $build_mode);
  $node->content += field_attach_view('node', $node, $build_mode);

  // Always display a read more link on teasers because we have no way
  // to know when a teaser view is different than a full view.
  $links = array();
  if ($build_mode == 'teaser') {
    $links['node_readmore'] = array(
      'title' => t('Read more'),
      'href' => 'node/' . $node->nid,
      'attributes' => array('rel' => 'tag', 'title' => strip_tags($node->title[LANGUAGE_NONE][0]['value']))
    );
  }
  $node->content['links']['node'] = array(
    '#theme' => 'links',
    '#links' => $links,
    '#attributes' => array('class' => array('links', 'inline')),
  );

  // Allow modules to make their own additions to the node.
  module_invoke_all('node_view', $node, $build_mode);
}

/**
 * Implements hook_language_negotiation_info().
 */
function node_language_negotiation_info() {
  $providers = array();

  $providers['node-language'] = array(
    'types' => array(LANGUAGE_TYPE_CONTENT),
    'callbacks' => array('language' => 'node_language_provider'),
    'file' => drupal_get_path('module', 'node') . '/node.module',
    'name' => t('Node'),
    'description' => t('The current node language is used.'),
  );

  return $providers;
}

/**
 * Return the language of the current node.
 *
 * @param $languages
 *   An array of valid language objects.
 *
 * @return
 *   A valid language code on succes, FALSE otherwise.
 */
function node_language_provider($languages) {
  require_once DRUPAL_ROOT . '/' . variable_get('path_inc', 'includes/path.inc');

  $path = isset($_GET['q']) ? $_GET['q'] : '';
  list($language, $path) = language_url_split_prefix($path, $languages);
  $language = $language ? $language : language_default();
  $path = drupal_get_normal_path($path, $language->language);

  // We cannot use args now.
  $path = explode('/', $path);
  // Act only if we are in a node page.
  if (isset($path[0]) && isset($path[1]) && $path[0] == 'node' && $nid = intval($path[1])) {
    // We cannot perform a node load here.
    $result = db_query('SELECT n.language FROM {node} n WHERE n.nid = :nid', array(':nid' => $nid))->fetchAssoc();
    return $result['language'];
  }

  return FALSE;
}

/**
 * Generate an array which displays a node detail page.
 *
 * @param $node
 *   A node object.
 * @param $message
 *   A flag which sets a page title relevant to the revision being viewed.
 * @return
 *   A $page element suitable for use by drupal_page_render().
 */
function node_show($node, $message = FALSE) {
  if ($message) {
    drupal_set_title(t('Revision of %title from %date', array('%title' => $node->title[LANGUAGE_NONE][0]['value'], '%date' => format_date($node->revision_timestamp))), PASS_THROUGH);
  }

  // Update the history table, stating that this user viewed this node.
  node_tag_new($node->nid);

  // For markup consistency with other pages, use node_build_multiple() rather than node_build().
  return node_build_multiple(array($node->nid => $node), 'full');
}

/**
 * Process variables for node.tpl.php
 *
 * Most themes utilize their own copy of node.tpl.php. The default is located
 * inside "modules/node/node.tpl.php". Look in there for the full list of
 * variables.
 *
 * The $variables array contains the following arguments:
 * - $node
 * - $build_mode
 * - $page
 *
 * @see node.tpl.php
 */
function template_preprocess_node(&$variables) {
  $variables['build_mode'] = $variables['elements']['#build_mode'];
  // Provide a distinct $teaser boolean.
  $variables['teaser'] = $variables['build_mode'] == 'teaser';
  $variables['node'] = $variables['elements']['#node'];
  $node = $variables['node'];

  $variables['date']      = format_date($node->created);
  $variables['name']      = theme('username', array('account' => $node));
  $variables['node_url']  = url('node/' . $node->nid);
  $variables['node_title'] = check_plain($node->title[LANGUAGE_NONE][0]['value']);
  $variables['page']      = (bool)menu_get_object();

  if (!empty($node->in_preview)) {
    unset($node->content['links']);
  }

  // Flatten the node object's member fields.
  $variables = array_merge((array)$node, $variables);

  // Helpful $content variable for templates.
  foreach (element_children($variables['elements']) as $key) {
    $variables['content'][$key] = $variables['elements'][$key];
  }

  // Make the field variables available with the appropriate language.
  field_attach_preprocess('node', $node, $variables['content'], $variables);

  if (isset($variables['content']['title'])) {
    unset($variables['content']['title']);
  }

  // Display post information only on certain node types.
  if (variable_get('node_submitted_' . $node->type, TRUE)) {
    $variables['display_submitted'] = TRUE;
    $variables['user_picture'] = theme_get_setting('toggle_node_user_picture') ? theme('user_picture', array('account' => $node)) : '';
  }
  else {
    $variables['display_submitted'] = FALSE;
    $variables['user_picture'] = '';
  }

  // Gather node classes.
  $variables['classes_array'][] = drupal_html_class('node-' . $node->type);
  if ($variables['promote']) {
    $variables['classes_array'][] = 'node-promoted';
  }
  if ($variables['sticky']) {
    $variables['classes_array'][] = 'node-sticky';
  }
  if (!$variables['status']) {
    $variables['classes_array'][] = 'node-unpublished';
  }
  if ($variables['teaser']) {
    $variables['classes_array'][] = 'node-teaser';
  }
  if (isset($variables['preview'])) {
    $variables['classes_array'][] = 'node-preview';
  }

  // Clean up name so there are no underscores.
  $variables['template_files'][] = 'node-' . str_replace('_', '-', $node->type);
  $variables['template_files'][] = 'node-' . $node->nid;
}

/**
 * Theme a log message.
 *
 * @ingroup themeable
 */
function theme_node_log_message($variables) {
  return '<div class="log"><div class="title">' . t('Log') . ':</div>' . $variables['log'] . '</div>';
}

/**
 * Implements hook_permission().
 */
function node_permission() {
  $perms = array(
    'administer content types' => array(
      'title' => t('Administer content types'),
    ),
    'administer nodes' => array(
      'title' => t('Administer content'),
      'description' => theme('placeholder', array('text' => t('Warning: Give to trusted roles only; this permission has security implications.'))),
    ),
    'access content' => array(
      'title' => t('View published content'),
    ),
    'access content overview' => array(
      'title' => t('Access the content overview page'),
    ),
    'bypass node access' => array(
      'title' => t('Bypass content access control'),
      'description' => t('View, edit and delete all content regardless of permission restrictions. %warning', array('%warning' => t('Warning: Give to trusted roles only; this permission has security implications.'))),
    ),
    'view revisions' => array(
      'title' => t('View content revisions'),
    ),
    'revert revisions' => array(
      'title' => t('Revert content revisions'),
    ),
    'delete revisions' => array(
      'title' => t('Delete content revisions'),
    ),
    'view own unpublished content' => array(
      'title' => t('View own unpublished content'),
    ),
  );

  // Generate standard node permissions for all applicable node types.
  foreach (node_permissions_get_configured_types() as $type) {
    $perms += node_list_permissions($type);
  }

  return $perms;
}

/**
 * Gather the rankings from the the hook_ranking implementations.
 *
 * @param $query
 *   A query object that has been extended with the Search DB Extender.
 */
function _node_rankings(SelectQueryExtender $query) {
  if ($ranking = module_invoke_all('ranking')) {
    $tables = &$query->getTables();
    foreach ($ranking as $rank => $values) {
      if ($node_rank = variable_get('node_rank_' . $rank, 0)) {
        // If the table defined in the ranking isn't already joined, then add it.
        if (isset($values['join']) && !isset($tables[$values['join']['alias']])) {
          $query->addJoin($values['join']['type'], $values['join']['table'], $values['join']['alias'], $values['join']['on']);
        }
        $arguments = isset($values['arguments']) ? $values['arguments'] : array();
        $query->addScore($values['score'], $arguments, $node_rank);
      }
    }
  }
}

/**
 * Implements hook_search_info().
 */
function node_search_info() {
  return array(
    'title' => 'Content',
    'path' => 'node',
  );
}

/**
 * Implements hook_search_access().
 */
function node_search_access() {
  return user_access('access content');
}

/**
 * Implements hook_search_reset().
 */
function node_search_reset() {
  db_update('search_dataset')
    ->fields(array('reindex' => REQUEST_TIME))
    ->condition('type', 'node')
    ->execute();
}

/**
 * Implements hook_search_status().
 */
function node_search_status() {
  $total = db_query('SELECT COUNT(*) FROM {node} WHERE status = :status', array(':status' => NODE_PUBLISHED))->fetchField();
  $remaining = db_query("SELECT COUNT(*) FROM {node} n LEFT JOIN {search_dataset} d ON d.type = 'node' AND d.sid = n.nid WHERE n.status = :status AND d.sid IS NULL OR d.reindex <> 0", array(':status' => NODE_PUBLISHED))->fetchField();
  return array('remaining' => $remaining, 'total' => $total);
}

/**
 * Implements hook_search_admin().
 */
function node_search_admin() {
  // Output form for defining rank factor weights.
  $form['content_ranking'] = array(
    '#type' => 'fieldset',
    '#title' => t('Content ranking'),
  );
  $form['content_ranking']['#theme'] = 'node_search_admin';
  $form['content_ranking']['info'] = array(
    '#value' => '<em>' . t('The following numbers control which properties the content search should favor when ordering the results. Higher numbers mean more influence, zero means the property is ignored. Changing these numbers does not require the search index to be rebuilt. Changes take effect immediately.') . '</em>'
  );

  // Note: reversed to reflect that higher number = higher ranking.
  $options = drupal_map_assoc(range(0, 10));
  foreach (module_invoke_all('ranking') as $var => $values) {
    $form['content_ranking']['factors']['node_rank_' . $var] = array(
      '#title' => $values['title'],
      '#type' => 'select',
      '#options' => $options,
      '#default_value' => variable_get('node_rank_' . $var, 0),
    );
  }
  return $form;
}

/**
 * Implements hook_search_execute().
 */
function node_search_execute($keys = NULL) {
  // Build matching conditions
  $query = db_select('search_index', 'i', array('target' => 'slave'))->extend('SearchQuery')->extend('PagerDefault');
  $query->join('node', 'n', 'n.nid = i.sid');
  $query
    ->condition('n.status', 1)
    ->addTag('node_access')
    ->searchExpression($keys, 'node');

  // Insert special keywords.
  $query->setOption('type', 'n.type');
  $query->setOption('language', 'n.language');
  if ($query->setOption('term', 'tn.nid')) {
    $query->join('taxonomy_term_node', 'tn', 'n.vid = tn.vid');
  }
  // Only continue if the first pass query matches.
  if (!$query->executeFirstPass()) {
    return array();
  }

  // Add the ranking expressions.
  _node_rankings($query);

  // Add a count query.
  $inner_query = clone $query;
  $count_query = db_select($inner_query->fields('i', array('sid')), NULL, array('target' => 'slave'));
  $count_query->addExpression('COUNT(*)');
  $query->setCountQuery($count_query);
  $find = $query
    ->limit(10)
    ->execute();

  // Load results.
  $results = array();
  foreach ($find as $item) {
    // Render the node.
    $node = node_load($item->sid);
    $build = node_build($node, 'search_result');
    unset($build['#theme']);
    $node->rendered = drupal_render($build);

    // Fetch comments for snippet.
    $node->rendered .= ' ' . module_invoke('comment', 'node_update_index', $node);
    // Fetch terms for snippet.
    $node->rendered .= ' ' . module_invoke('taxonomy', 'node_update_index', $node);

    $extra = module_invoke_all('node_search_result', $node);

    $results[] = array(
      'link' => url('node/' . $item->sid, array('absolute' => TRUE)),
      'type' => check_plain(node_type_get_name($node)),
      'title' => $node->title[LANGUAGE_NONE][0]['value'],
      'user' => theme('username', array('account' => $node)),
      'date' => $node->changed,
      'node' => $node,
      'extra' => $extra,
      'score' => $item->calculated_score,
      'snippet' => search_excerpt($keys, $node->rendered),
    );
  }
  return $results;
}

/**
 * Implements hook_ranking().
 */
function node_ranking() {
  // Create the ranking array and add the basic ranking options.
  $ranking = array(
    'relevance' => array(
      'title' => t('Keyword relevance'),
      // Average relevance values hover around 0.15
      'score' => 'i.relevance',
    ),
    'sticky' => array(
      'title' => t('Content is sticky at top of lists'),
      // The sticky flag is either 0 or 1, which is automatically normalized.
      'score' => 'n.sticky',
    ),
    'promote' => array(
      'title' => t('Content is promoted to the front page'),
      // The promote flag is either 0 or 1, which is automatically normalized.
      'score' => 'n.promote',
    ),
  );

  // Add relevance based on creation or changed date.
  if ($node_cron_last = variable_get('node_cron_last', 0)) {
    $ranking['recent'] = array(
      'title' => t('Recently posted'),
      // Exponential decay with half-life of 6 months, starting at last indexed node
      'score' => 'POW(2.0, (GREATEST(n.created, n.changed) - :node_cron_last) * 6.43e-8)',
      'arguments' => array(':node_cron_last' => $node_cron_last),
    );
  }
  return $ranking;
}

/**
 * Implements hook_user_cancel().
 */
function node_user_cancel($edit, $account, $method) {
  switch ($method) {
    case 'user_cancel_block_unpublish':
      // Unpublish nodes (current revisions).
      module_load_include('inc', 'node', 'node.admin');
      $nodes = db_select('node', 'n')
        ->fields('n', array('nid'))
        ->condition('uid', $account->uid)
        ->execute()
        ->fetchCol();
      node_mass_update($nodes, array('status' => 0));
      break;

    case 'user_cancel_reassign':
      // Anonymize nodes (current revisions).
      module_load_include('inc', 'node', 'node.admin');
      $nodes = db_select('node', 'n')
        ->fields('n', array('nid'))
        ->condition('uid', $account->uid)
        ->execute()
        ->fetchCol();
      node_mass_update($nodes, array('uid' => 0));
      // Anonymize old revisions.
      db_update('node_revision')
        ->fields(array('uid' => 0))
        ->condition('uid', $account->uid)
        ->execute();
      // Clean history.
      db_delete('history')
        ->condition('uid', $account->uid)
        ->execute();
      break;

    case 'user_cancel_delete':
      // Delete nodes (current revisions).
      // @todo Introduce node_mass_delete() or make node_mass_update() more flexible.
      $nodes = db_select('node', 'n')
        ->fields('n', array('nid'))
        ->condition('uid', $account->uid)
        ->execute()
        ->fetchCol();
      node_delete_multiple($nodes);
      // Delete old revisions.
      $revisions = db_query('SELECT vid FROM {node_revision} WHERE uid = :uid', array(':uid' => $account->uid))->fetchCol();
      foreach ($revisions as $revision) {
        node_revision_delete($revision);
      }
      // Clean history.
      db_delete('history')
        ->condition('uid', $account->uid)
          ->execute();
      break;
  }
}

/**
 * Theme the content ranking part of the search settings admin page.
 *
 * @ingroup themeable
 */
function theme_node_search_admin($variables) {
  $form = $variables['form'];

  $output = drupal_render($form['info']);

  $header = array(t('Factor'), t('Weight'));
  foreach (element_children($form['factors']) as $key) {
    $row = array();
    $row[] = $form['factors'][$key]['#title'];
    unset($form['factors'][$key]['#title']);
    $row[] = drupal_render($form['factors'][$key]);
    $rows[] = $row;
  }
  $output .= theme('table', array('header' => $header, 'rows' => $rows));

  $output .= drupal_render_children($form);
  return $output;
}

function _node_revision_access($node, $op = 'view') {
  $access = &drupal_static(__FUNCTION__, array());
  if (!isset($access[$node->vid])) {
    $node_current_revision = node_load($node->nid);
    $is_current_revision = $node_current_revision->vid == $node->vid;
    // There should be at least two revisions. If the vid of the given node
    // and the vid of the current revision differs, then we already have two
    // different revisions so there is no need for a separate database check.
    // Also, if you try to revert to or delete the current revision, that's
    // not good.
    if ($is_current_revision && (db_query('SELECT COUNT(vid) FROM {node_revision} WHERE nid = :nid', array(':nid' => $node->nid))->fetchField() == 1 || $op == 'update' || $op == 'delete')) {
      $access[$node->vid] = FALSE;
    }
    elseif (user_access('administer nodes')) {
      $access[$node->vid] = TRUE;
    }
    else {
      $map = array('view' => 'view revisions', 'update' => 'revert revisions', 'delete' => 'delete revisions');
      // First check the user permission, second check the access to the
      // current revision and finally, if the node passed in is not the current
      // revision then access to that, too.
      $access[$node->vid] = isset($map[$op]) && user_access($map[$op]) && node_access($op, $node_current_revision) && ($is_current_revision || node_access($op, $node));
    }
  }
  return $access[$node->vid];
}

function _node_add_access() {
  $types = node_type_get_types();
  foreach ($types as $type) {
    if (node_hook($type->type, 'form') && node_access('create', $type->type)) {
      return TRUE;
    }
  }
  if (user_access('administer content types')) {
    // There are no content types defined that the user has permission to create,
    // but the user does have the permission to administer the content types, so
    // grant them access to the page anyway.
    return TRUE;
  }
  return FALSE;
}

/**
 * Implements hook_menu().
 */
function node_menu() {
  $items['admin/content'] = array(
    'title' => 'Content',
    'description' => 'Find and manage content.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('node_admin_content'),
    'access arguments' => array('access content overview'),
    'weight' => -10,
    'file' => 'node.admin.inc',
  );
  $items['admin/content/node'] = array(
    'title' => 'Content',
    'description' => "View, edit, and delete your site's content.",
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => -10,
  );

  $items['admin/reports/status/rebuild'] = array(
    'title' => 'Rebuild permissions',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('node_configure_rebuild_confirm'),
    // Any user than can potentially trigger a node_access_needs_rebuild(TRUE)
    // has to be allowed access to the 'node access rebuild' confirm form.
    'access arguments' => array('access administration pages'),
    'type' => MENU_CALLBACK,
    'file' => 'node.admin.inc',
  );

  $items['admin/structure/types'] = array(
    'title' => 'Content types',
    'description' => 'Manage content types, including default status, front page promotion, comment settings, etc.',
    'page callback' => 'node_overview_types',
    'access arguments' => array('administer content types'),
    'file' => 'content_types.inc',
  );
  $items['admin/structure/types/list'] = array(
    'title' => 'List',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => -10,
  );
  $items['admin/structure/types/add'] = array(
    'title' => 'Add content type',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('node_type_form'),
    'access arguments' => array('administer content types'),
    'type' => MENU_LOCAL_ACTION,
    'file' => 'content_types.inc',
  );
  $items['admin/structure/types/manage/%node_type'] = array(
    'title' => 'Edit content type',
    'title callback' => 'node_type_page_title',
    'title arguments' => array(4),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('node_type_form', 4),
    'access arguments' => array('administer content types'),
    'file' => 'content_types.inc',
  );
  $items['admin/structure/types/manage/%node_type/edit'] = array(
    'title' => 'Edit',
    'type' => MENU_DEFAULT_LOCAL_TASK,
  );
  $items['admin/structure/types/manage/%node_type/delete'] = array(
    'title' => 'Delete',
    'page arguments' => array('node_type_delete_confirm', 4),
    'access arguments' => array('administer content types'),
    'type' => MENU_CALLBACK,
    'file' => 'content_types.inc',
  );

  $items['node'] = array(
    'title' => 'Content',
    'page callback' => 'node_page_default',
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );
  $items['node/add'] = array(
    'title' => 'Add new content',
    'page callback' => 'node_add_page',
    'access callback' => '_node_add_access',
    'weight' => 1,
    'menu_name' => 'management',
    'theme callback' => '_node_custom_theme',
    'file' => 'node.pages.inc',
  );
  $items['rss.xml'] = array(
    'title' => 'RSS feed',
    'page callback' => 'node_feed',
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );
  // @todo Remove this loop when we have a 'description callback' property.
  // Reset internal static cache of _node_types_build(), forces to rebuild the
  // node type information.
  drupal_static_reset('_node_types_build');
  foreach (node_type_get_types() as $type) {
    $type_url_str = str_replace('_', '-', $type->type);
    $items['node/add/' . $type_url_str] = array(
      'title' => $type->name,
      'title callback' => 'check_plain',
      'page callback' => 'node_add',
      'page arguments' => array(2),
      'access callback' => 'node_access',
      'access arguments' => array('create', $type->type),
      'description' => $type->description,
      'file' => 'node.pages.inc',
    );
  }
  $items['node/%node'] = array(
    'page callback' => 'node_page_view',
    'page arguments' => array(1),
    'access callback' => 'node_access',
    'access arguments' => array('view', 1),
    'type' => MENU_CALLBACK,
  );
  $items['node/%node/view'] = array(
    'title' => 'View',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => -10,
  );
  $items['node/%node/edit'] = array(
    'title' => 'Edit',
    'page callback' => 'node_page_edit',
    'page arguments' => array(1),
    'access callback' => 'node_access',
    'access arguments' => array('update', 1),
    'theme callback' => '_node_custom_theme',
    'weight' => 0,
    'type' => MENU_LOCAL_TASK,
    'context' => MENU_CONTEXT_PAGE | MENU_CONTEXT_INLINE,
    'file' => 'node.pages.inc',
  );
  $items['node/%node/delete'] = array(
    'title' => 'Delete',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('node_delete_confirm', 1),
    'access callback' => 'node_access',
    'access arguments' => array('delete', 1),
    'weight' => 1,
    'type' => MENU_LOCAL_TASK,
    'context' => MENU_CONTEXT_INLINE,
    'file' => 'node.pages.inc',
  );
  $items['node/%node/revisions'] = array(
    'title' => 'Revisions',
    'page callback' => 'node_revision_overview',
    'page arguments' => array(1),
    'access callback' => '_node_revision_access',
    'access arguments' => array(1),
    'weight' => 2,
    'type' => MENU_LOCAL_TASK,
    'file' => 'node.pages.inc',
  );
  $items['node/%node/revisions/%/view'] = array(
    'title' => 'Revisions',
    'load arguments' => array(3),
    'page callback' => 'node_show',
    'page arguments' => array(1, TRUE),
    'access callback' => '_node_revision_access',
    'access arguments' => array(1),
    'type' => MENU_CALLBACK,
  );
  $items['node/%node/revisions/%/revert'] = array(
    'title' => 'Revert to earlier revision',
    'load arguments' => array(3),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('node_revision_revert_confirm', 1),
    'access callback' => '_node_revision_access',
    'access arguments' => array(1, 'update'),
    'type' => MENU_CALLBACK,
    'file' => 'node.pages.inc',
  );
  $items['node/%node/revisions/%/delete'] = array(
    'title' => 'Delete earlier revision',
    'load arguments' => array(3),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('node_revision_delete_confirm', 1),
    'access callback' => '_node_revision_access',
    'access arguments' => array(1, 'delete'),
    'type' => MENU_CALLBACK,
    'file' => 'node.pages.inc',
  );
  return $items;
}

/**
 * Implements hook_menu_local_tasks_alter().
 */
function node_menu_local_tasks_alter(&$data, $router_item, $root_path) {
  // Add action link to 'node/add' on 'admin/content' page.
  if ($root_path == 'admin/content') {
    $item = menu_get_item('node/add');
    if ($item['access']) {
      $data['actions']['output'][] = array(
        '#theme' => 'menu_local_action',
        '#link' => $item,
      );
    }
  }
}

/**
 * Title callback for a node type.
 */
function node_type_page_title($type) {
  return $type->name;
}

/**
 * Title callback.
 */
function node_page_title($node) {
  return $node->title;
}

/**
 * Theme callback for creating and editing nodes.
 */
function _node_custom_theme() {
  // Use the administration theme if the site is configured to use it for
  // nodes.
  if (variable_get('node_admin_theme')) {
    return variable_get('admin_theme');
  }
}

/**
 * Implements hook_init().
 */
function node_init() {
  drupal_add_css(drupal_get_path('module', 'node') . '/node.css');
}

function node_last_changed($nid) {
  return db_query('SELECT changed FROM {node} WHERE nid = :nid', array(':nid' => $nid))->fetch()->changed;
}

/**
 * Return a list of all the existing revision numbers.
 */
function node_revision_list($node) {
  $revisions = array();
  $result = db_query('SELECT r.vid, r.title, r.log, r.uid, n.vid AS current_vid, r.timestamp, u.name FROM {node_revision} r LEFT JOIN {node} n ON n.vid = r.vid INNER JOIN {users} u ON u.uid = r.uid WHERE r.nid = :nid ORDER BY r.timestamp DESC', array(':nid' => $node->nid));
  foreach ($result as $revision) {
    $revisions[$revision->vid] = $revision;
  }

  return $revisions;
}

/**
 * Implements hook_block_info().
 */
function node_block_info() {
  $blocks['syndicate']['info'] = t('Syndicate');
  // Not worth caching.
  $blocks['syndicate']['cache'] = DRUPAL_NO_CACHE;
  return $blocks;
}

/**
 * Implements hook_block_view().
 */
function node_block_view($delta = '') {
  $block['subject'] = t('Syndicate');
  $block['content'] = theme('feed_icon', array('url' => url('rss.xml'), 'title' => t('Syndicate')));

  return $block;
}

/**
 * A generic function for generating RSS feeds from a set of nodes.
 *
 * @param $nids
 *   An array of node IDs (nid). Defaults to FALSE so empty feeds can be
 *   generated with passing an empty array, if no items are to be added
 *   to the feed.
 * @param $channel
 *   An associative array containing title, link, description and other keys,
 *   to be parsed by format_rss_channel() and format_xml_elements().
 *   A list of channel elements can be found at the @link http://cyber.law.harvard.edu/rss/rss.html RSS 2.0 Specification. @endlink
 *   The link should be an absolute URL.
 */
function node_feed($nids = FALSE, $channel = array()) {
  global $base_url, $language;

  if ($nids === FALSE) {
    $nids = db_select('node', 'n')
      ->fields('n', array('nid', 'created'))
      ->condition('n.promote', 1)
      ->condition('status', 1)
      ->orderBy('n.created', 'DESC')
      ->range(0, variable_get('feed_default_items', 10))
      ->addTag('node_access')
      ->execute()
      ->fetchCol();
  }

  $item_length = variable_get('feed_item_length', 'fulltext');
  $namespaces = array('xmlns:dc' => 'http://purl.org/dc/elements/1.1/');
  $teaser = ($item_length == 'teaser');

  // Load all nodes to be rendered.
  $nodes = node_load_multiple($nids);
  $items = '';
  foreach ($nodes as $node) {
    $item_text = '';

    $node->link = url("node/$node->nid", array('absolute' => TRUE));
    $node->rss_namespaces = array();
    $node->rss_elements = array(
      array('key' => 'pubDate', 'value' => gmdate('r', $node->created)),
      array('key' => 'dc:creator', 'value' => $node->name),
      array('key' => 'guid', 'value' => $node->nid . ' at ' . $base_url, 'attributes' => array('isPermaLink' => 'false'))
    );

    // The node gets built and modules add to or modify $node->rss_elements
    // and $node->rss_namespaces.
    $build = node_build($node, 'rss');
    unset($build['#theme']);

    if (!empty($node->rss_namespaces)) {
      $namespaces = array_merge($namespaces, $node->rss_namespaces);
    }

    if ($item_length != 'title') {
      // We render node contents and force links to be last.
      $build['links']['#weight'] = 1000;
      $item_text .= drupal_render($build);
    }

    $items .= format_rss_item($node->title[LANGUAGE_NONE][0]['value'], $node->link, $item_text, $node->rss_elements);
  }

  $channel_defaults = array(
    'version'     => '2.0',
    'title'       => variable_get('site_name', 'Drupal'),
    'link'        => $base_url,
    'description' => variable_get('feed_description', ''),
    'language'    => $language->language
  );
  $channel_extras = array_diff_key($channel, $channel_defaults);
  $channel = array_merge($channel_defaults, $channel);

  $output = "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n";
  $output .= "<rss version=\"" . $channel["version"] . "\" xml:base=\"" . $base_url . "\" " . drupal_attributes($namespaces) . ">\n";
  $output .= format_rss_channel($channel['title'], $channel['link'], $channel['description'], $items, $channel['language'], $channel_extras);
  $output .= "</rss>\n";

  drupal_add_http_header('Content-Type', 'application/rss+xml; charset=utf-8');
  print $output;
}

/**
 * Construct a drupal_render() style array from an array of loaded nodes.
 *
 * @param $nodes
 *   An array of nodes as returned by node_load_multiple().
 * @param $build_mode
 *   Build mode, e.g. 'full', 'teaser'...
 * @param $weight
 *   An integer representing the weight of the first node in the list.
 * @return
 *   An array in the format expected by drupal_render().
 */
function node_build_multiple($nodes, $build_mode = 'teaser', $weight = 0) {
  field_attach_prepare_view('node', $nodes, $build_mode);
  $build = array();
  foreach ($nodes as $node) {
    $build['nodes'][$node->nid] = node_build($node, $build_mode);
    $build['nodes'][$node->nid]['#weight'] = $weight;
    $weight++;
  }
  $build['nodes']['#sorted'] = TRUE;
  return $build;
}

/**
 * Menu callback; Generate a listing of promoted nodes.
 */
function node_page_default() {
  $select = db_select('node', 'n')
    ->fields('n', array('nid'))
    ->condition('promote', 1)
    ->condition('status', 1)
    ->orderBy('sticky', 'DESC')
    ->orderBy('created', 'DESC')
    ->extend('PagerDefault')
    ->limit(variable_get('default_nodes_main', 10))
    ->addTag('node_access');

  $nids = $select->execute()->fetchCol();

  if (!empty($nids)) {
    $nodes = node_load_multiple($nids);
    $build = node_build_multiple($nodes);

    $feed_url = url('rss.xml', array('absolute' => TRUE));
    drupal_add_feed($feed_url, variable_get('site_name', 'Drupal') . ' ' . t('RSS'));
    $build['pager'] = array(
      '#theme' => 'pager',
      '#weight' => 5,
    );
    drupal_set_title('');
  }
  else {
    drupal_set_title(t('Welcome to @site-name', array('@site-name' => variable_get('site_name', 'Drupal'))), PASS_THROUGH);

    $default_message = '<p>' . t('No front page content has been created yet.') . '</p>';

    $default_links = array();
    if (_node_add_access()) {
      $default_links[] = l(t('Create content'), 'node/add');
    }
    if (user_access('administer site configuration')) {
      $default_links[] = l(t('Change the default front page'), 'admin/config/system/site-information');
    }
    if (!empty($default_links)) {
      $default_message .= theme('item_list', array('items' => $default_links));
    }

    $build['default_message'] = array(
      '#markup' => $default_message,
      '#prefix' => '<div id="first-time">',
      '#suffix' => '</div>',
    );
  }
  return $build;
}

/**
 * Menu callback; view a single node.
 */
function node_page_view($node) {
  $return = node_show($node);
  if (isset($return['nodes'][$node->nid]['title'])) {
    // Get the language that was determined by language fallback logic during the
    // field_attach_display() workflow.
    // @todo That logic should be made available separately.
    $langcode = $return['nodes'][$node->nid]['title']['#language'];
    drupal_set_title($node->title[$langcode][0]['value']);
  }
  // Set the node path as the canonical URL to prevent duplicate content.
  drupal_add_html_head_link(array('rel' => 'canonical', 'href' => url('node/' . $node->nid)), TRUE);
  // Set the non-aliased path as a default shortlink.
  drupal_add_html_head_link(array('rel' => 'shortlink', 'href' => url('node/' . $node->nid, array('alias' => TRUE))), TRUE);
  return $return;
}

/**
 * Implements hook_update_index().
 */
function node_update_index() {
  $limit = (int)variable_get('search_cron_limit', 100);

  $result = db_query_range("SELECT n.nid FROM {node} n LEFT JOIN {search_dataset} d ON d.type = 'node' AND d.sid = n.nid WHERE d.sid IS NULL OR d.reindex <> 0 ORDER BY d.reindex ASC, n.nid ASC", 0, $limit, array(), array('target' => 'slave'));

  foreach ($result as $node) {
    _node_index_node($node);
  }
}

/**
 * Index a single node.
 *
 * @param $node
 *   The node to index.
 */
function _node_index_node($node) {
  $node = node_load($node->nid);

  // Save the changed time of the most recent indexed node, for the search
  // results half-life calculation.
  variable_set('node_cron_last', $node->changed);

  // Render the node.
  $build = node_build($node, 'search_index');
  unset($build['#theme']);
  $node->rendered = drupal_render($build);

  $text = '<h1>' . check_plain($node->title[LANGUAGE_NONE][0]['value']) . '</h1>' . $node->rendered;

  // Fetch extra data normally not visible
  $extra = module_invoke_all('node_update_index', $node);
  foreach ($extra as $t) {
    $text .= $t;
  }

  // Update index
  search_index($node->nid, 'node', $text);
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function node_form_search_form_alter(&$form, $form_state) {
  if ($form['module']['#value'] == 'node' && user_access('use advanced search')) {
    // Keyword boxes:
    $form['advanced'] = array(
      '#type' => 'fieldset',
      '#title' => t('Advanced search'),
      '#collapsible' => TRUE,
      '#collapsed' => TRUE,
      '#attributes' => array('class' => array('search-advanced')),
    );
    $form['advanced']['keywords'] = array(
      '#prefix' => '<div class="criterion">',
      '#suffix' => '</div>',
    );
    $form['advanced']['keywords']['or'] = array(
      '#type' => 'textfield',
      '#title' => t('Containing any of the words'),
      '#size' => 30,
      '#maxlength' => 255,
    );
    $form['advanced']['keywords']['phrase'] = array(
      '#type' => 'textfield',
      '#title' => t('Containing the phrase'),
      '#size' => 30,
      '#maxlength' => 255,
    );
    $form['advanced']['keywords']['negative'] = array(
      '#type' => 'textfield',
      '#title' => t('Containing none of the words'),
      '#size' => 30,
      '#maxlength' => 255,
    );

    // Taxonomy box:
    if ($taxonomy = module_invoke('taxonomy', 'form_all', 1)) {
      $form['advanced']['term'] = array(
        '#type' => 'select',
        '#title' => t('Only in the term(s)'),
        '#prefix' => '<div class="criterion">',
        '#size' => 10,
        '#suffix' => '</div>',
        '#options' => $taxonomy,
        '#multiple' => TRUE,
      );
    }

    // Node types:
    $types = array_map('check_plain', node_type_get_names());
    $form['advanced']['type'] = array(
      '#type' => 'checkboxes',
      '#title' => t('Only of the type(s)'),
      '#prefix' => '<div class="criterion">',
      '#suffix' => '</div>',
      '#options' => $types,
    );
    $form['advanced']['submit'] = array(
      '#type' => 'submit',
      '#value' => t('Advanced search'),
      '#prefix' => '<div class="action">',
      '#suffix' => '</div>',
    );

    // Languages:
    $language_options = array();
    foreach (language_list('language') as $key => $object) {
      $language_options[$key] = $object->name;
    }
    if (count($language_options) > 1) {
      $form['advanced']['language'] = array(
        '#type' => 'checkboxes',
        '#title' => t('Languages'),
        '#prefix' => '<div class="criterion">',
        '#suffix' => '</div>',
        '#options' => $language_options,
      );
    }

    $form['#validate'][] = 'node_search_validate';
  }
}

/**
 * Form API callback for the search form. Registered in node_form_alter().
 */
function node_search_validate($form, &$form_state) {
  // Initialize using any existing basic search keywords.
  $keys = $form_state['values']['processed_keys'];

  // Insert extra restrictions into the search keywords string.
  if (isset($form_state['values']['type']) && is_array($form_state['values']['type'])) {
    // Retrieve selected types - Forms API sets the value of unselected
    // checkboxes to 0.
    $form_state['values']['type'] = array_filter($form_state['values']['type']);
    if (count($form_state['values']['type'])) {
      $keys = search_expression_insert($keys, 'type', implode(',', array_keys($form_state['values']['type'])));
    }
  }

  if (isset($form_state['values']['term']) && is_array($form_state['values']['term'])) {
    $keys = search_expression_insert($keys, 'term', implode(',', $form_state['values']['term']));
  }
  if (isset($form_state['values']['language']) && is_array($form_state['values']['language'])) {
    $keys = search_expression_insert($keys, 'language', implode(',', array_filter($form_state['values']['language'])));
  }
  if ($form_state['values']['or'] != '') {
    if (preg_match_all('/ ("[^"]+"|[^" ]+)/i', ' ' . $form_state['values']['or'], $matches)) {
      $keys .= ' ' . implode(' OR ', $matches[1]);
    }
  }
  if ($form_state['values']['negative'] != '') {
    if (preg_match_all('/ ("[^"]+"|[^" ]+)/i', ' ' . $form_state['values']['negative'], $matches)) {
      $keys .= ' -' . implode(' -', $matches[1]);
    }
  }
  if ($form_state['values']['phrase'] != '') {
    $keys .= ' "' . str_replace('"', ' ', $form_state['values']['phrase']) . '"';
  }
  if (!empty($keys)) {
    form_set_value($form['basic']['inline']['processed_keys'], trim($keys), $form_state);
  }
}

/**
 * @defgroup node_access Node access rights
 * @{
 * The node access system determines who can do what to which nodes.
 *
 * In determining access rights for a node, node_access() first checks
 * whether the user has the "bypass node access" permission. Such users have
 * unrestricted access to all nodes. user 1 will always pass this check.
 *
 * Next, all implementations of hook_node_access() will be called. Each
 * implementation may explicitly allow, explicitly deny, or ignore the access
 * request. If at least one module says to deny the request, it will be rejected.
 * If no modules deny the request and at least one says to allow it, the request
 * will be permitted.
 *
 * If all modules ignore the access request, then the node_access table is used
 * to determine access. All node access modules are queried using
 * hook_node_grants() to assemble a list of "grant IDs" for the user. This list
 * is compared against the table. If any row contains the node ID in question
 * (or 0, which stands for "all nodes"), one of the grant IDs returned, and a
 * value of TRUE for the operation in question, then access is granted. Note
 * that this table is a list of grants; any matching row is sufficient to
 * grant access to the node.
 *
 * In node listings, the process above is followed except that
 * hook_node_access() is not called on each node for performance reasons and for
 * proper functioning of the pager system. When adding a node listing to your
 * module, be sure to use a dynamic query created by db_select() and add a tag
 * of "node_access" to ensure that only nodes to which the user has access
 * are retrieved.
 *
 * Note: Even a single module returning NODE_ACCESS_DENY from hook_node_access()
 * will block access to the node. Therefore, implementers should take care to
 * not deny access unless they really intend to. Unless a module wishes to
 * actively deny access it should return NODE_ACCESS_IGNORE (or simply return
 * nothing) to allow other modules or the node_access table to control access.
 *
 * To see how to write a node access module of your own, see
 * node_access_example.module.
 */

/**
 * Determine whether the current user may perform the given operation on the
 * specified node.
 *
 * @param $op
 *   The operation to be performed on the node. Possible values are:
 *   - "view"
 *   - "update"
 *   - "delete"
 *   - "create"
 * @param $node
 *   The node object on which the operation is to be performed, or node type
 *   (e.g. 'forum') for "create" operation.
 * @param $account
 *   Optional, a user object representing the user for whom the operation is to
 *   be performed. Determines access for a user other than the current user.
 * @return
 *   TRUE if the operation may be performed, FALSE otherwise.
 */
function node_access($op, $node, $account = NULL) {
  global $user;

  if (!$node || !in_array($op, array('view', 'update', 'delete', 'create'), TRUE)) {
    // If there was no node to check against, or the $op was not one of the
    // supported ones, we return access denied.
    return FALSE;
  }
  // If no user object is supplied, the access check is for the current user.
  if (empty($account)) {
    $account = $user;
  }

  if (user_access('bypass node access', $account)) {
    return TRUE;
  }

  if (!user_access('access content', $account)) {
    return FALSE;
  }

  // We grant access to the node if both of the following conditions are met:
  // - No modules say to deny access.
  // - At least one module says to grant access.
  // If no module specified either allow or deny, we fall back to the
  // node_access table.
  $access = module_invoke_all('node_access', $node, $op, $account);
  if (in_array(NODE_ACCESS_DENY, $access, TRUE)) {
    return FALSE;
  }
  elseif (in_array(NODE_ACCESS_ALLOW, $access, TRUE)) {
    return TRUE;
  }

  // Check if authors can view their own unpublished nodes.
  if ($op == 'view' && !$node->status && user_access('view own unpublished content', $account) && $account->uid == $node->uid && $account->uid != 0) {
    return TRUE;
  }

  // If the module did not override the access rights, use those set in the
  // node_access table.
  if ($op != 'create' && $node->nid) {
    $query = db_select('node_access');
    $query->addExpression('1');
    $query->condition('grant_' . $op, 1, '>=');
    $nids = db_or()->condition('nid', $node->nid);
    if ($node->status) {
      $nids->condition('nid', 0);
    }
    $query->condition($nids);
    $query->range(0, 1);

    $grants = db_or();
    foreach (node_access_grants($op, $account) as $realm => $gids) {
      foreach ($gids as $gid) {
        $grants->condition(db_and()
          ->condition('gid', $gid)
          ->condition('realm', $realm)
        );
      }
    }
    if (count($grants) > 0) {
      $query->condition($grants);
    }
    return (bool) $query
      ->execute()
      ->fetchField();
  }

  return FALSE;
}

/**
 * Implements hook_node_access().
 */
function node_node_access($node, $op, $account) {
  $type = is_string($node) ? $node : $node->type;

  if (in_array($type, node_permissions_get_configured_types())) {
    if ($op == 'create' && user_access('create ' . $type . ' content', $account)) {
      return NODE_ACCESS_ALLOW;
    }

    if ($op == 'update') {
      if (user_access('edit any ' . $type . ' content', $account) || (user_access('edit own ' . $type . ' content', $account) && ($account->uid == $node->uid))) {
        return NODE_ACCESS_ALLOW;
      }
    }

    if ($op == 'delete') {
      if (user_access('delete any ' . $type . ' content', $account) || (user_access('delete own ' . $type . ' content', $account) && ($account->uid == $node->uid))) {
        return NODE_ACCESS_ALLOW;
      }
    }
  }

  return NODE_ACCESS_IGNORE;
}

/**
 * Helper function to generate standard node permission list for a given type.
 *
 * @param $type
 *   The machine-readable name of the node type.
 * @return array
 *   An array of permission names and descriptions.
 */
function node_list_permissions($type) {
  $info = node_type_get_type($type);
  $type = check_plain($info->type);

  // Build standard list of node permissions for this type.
  $perms = array(
    "create $type content" => array(
      'title' => t('Create new %type_name content', array('%type_name' => $info->name)),
    ),
    "edit own $type content" => array(
      'title' => t('Edit own %type_name content', array('%type_name' => $info->name)),
    ),
    "edit any $type content" => array(
      'title' => t('Edit any %type_name content', array('%type_name' => $info->name)),
    ),
    "delete own $type content" => array(
      'title' => t('Delete own %type_name content', array('%type_name' => $info->name)),
    ),
    "delete any $type content" => array(
      'title' => t('Delete any %type_name content', array('%type_name' => $info->name)),
    ),
  );

  return $perms;
}

/**
 * Returns an array of node types that should be managed by permissions.
 *
 * By default, this will include all node types in the system. To exclude a
 * specific node from getting permissions defined for it, set the
 * node_permissions_$type variable to 0. Core does not provide an interface
 * for doing so, however, contrib modules may exclude their own nodes in
 * hook_install(). Alternatively, contrib modules may configure all node types
 * at once, or decide to apply some other hook_node_access() implementation
 * to some or all node types.
 *
 * @return
 *   An array of node types managed by this module.
 */
function node_permissions_get_configured_types() {

  $configured_types = array();

  foreach (node_type_get_types() as $type => $info) {
    if (variable_get('node_permissions_' . $type, 1)) {
      $configured_types[] = $type;
    }
  }

  return $configured_types;
}

/**
 * Fetch an array of permission IDs granted to the given user ID.
 *
 * The implementation here provides only the universal "all" grant. A node
 * access module should implement hook_node_grants() to provide a grant
 * list for the user.
 *
 * After the default grants have been loaded, we allow modules to alter
 * the grants array by reference. This hook allows for complex business
 * logic to be applied when integrating multiple node access modules.
 *
 * @param $op
 *   The operation that the user is trying to perform.
 * @param $account
 *   The user object for the user performing the operation. If omitted, the
 *   current user is used.
 * @return
 *   An associative array in which the keys are realms, and the values are
 *   arrays of grants for those realms.
 */
function node_access_grants($op, $account = NULL) {

  if (!isset($account)) {
    $account = $GLOBALS['user'];
  }

  // Fetch node access grants from other modules.
  $grants = module_invoke_all('node_grants', $account, $op);
  // Allow modules to alter the assigned grants.
  drupal_alter('node_grants', $grants, $account, $op);

  return array_merge(array('all' => array(0)), $grants);
}

/**
 * Determine whether the user has a global viewing grant for all nodes.
 */
function node_access_view_all_nodes() {
  static $access;

  if (!isset($access)) {
    // If no modules implement the node access system, access is always true.
    if (!module_implements('node_grants')) {
      $access = TRUE;
    }
    else {
      $query = db_select('node_access');
      $query->addExpression('COUNT(*)');
      $query
        ->condition('nid', 0)
        ->condition('grant_view', 1, '>=');

      $grants = db_or();
      foreach (node_access_grants('view') as $realm => $gids) {
        foreach ($gids as $gid) {
          $grants->condition(db_and()
            ->condition('gid', $gid)
            ->condition('realm', $realm)
          );
        }
      }
      if (count($grants) > 0 ) {
        $query->condition($grants);
      }
      $access = $query
        ->execute()
        ->fetchField();
      }
  }

  return $access;
}


/**
 * Implements hook_query_TAG_alter().
 */
function node_query_node_access_alter(QueryAlterableInterface $query) {
  // Skip the extra expensive alterations if site has no node access control
  // modules.
  if (!node_access_view_all_nodes()) {
    // Prevent duplicate records.
    $query->distinct();
    // The recognized operations are 'view', 'update', 'delete'.
    if (!$op = $query->getMetaData('op')) {
      $op = 'view';
    }
    // Skip the extra joins and conditions for node admins.
    if (!user_access('bypass node access')) {
      // The node_access table has the access grants for any given node.
      $access_alias = $query->join('node_access', 'na', 'na.nid = n.nid');
      $or = db_or();
      // If any grant exists for the specified user, then user has access to the
      // node for the specified operation.
      foreach (node_access_grants($op, $query->getMetaData('account')) as $realm => $gids) {
        foreach ($gids as $gid) {
          $or->condition(db_and()
            ->condition("{$access_alias}.gid", $gid)
            ->condition("{$access_alias}.realm", $realm)
          );
        }
      }

      if (count($or->conditions())) {
        $query->condition($or);
      }

      $query->condition("{$access_alias}.grant_$op", 1, '>=');
    }
  }
}

/**
 * Gets the list of node access grants and writes them to the database.
 *
 * This function is called when a node is saved, and can also be called by
 * modules if something other than a node save causes node access permissions to
 * change. It collects all node access grants for the node from
 * hook_node_access_records() implementations, allows these grants to be altered
 * via hook_node_access_records_alter() implementations, and saves the collected
 * and altered grants to the database.
 *
 * @param $node
 *   The $node to acquire grants for.
 */
function node_access_acquire_grants($node) {
  $grants = module_invoke_all('node_access_records', $node);
  // Let modules alter the grants.
  drupal_alter('node_access_records', $grants, $node);
  // If no grants are set, then use the default grant.
  if (empty($grants)) {
    $grants[] = array('realm' => 'all', 'gid' => 0, 'grant_view' => 1, 'grant_update' => 0, 'grant_delete' => 0);
  }
  else {
    // Retain grants by highest priority.
    $grant_by_priority = array();
    foreach ($grants as $g) {
      $grant_by_priority[intval($g['priority'])][] = $g;
    }
    krsort($grant_by_priority);
    $grants = array_shift($grant_by_priority);
  }

  node_access_write_grants($node, $grants);
}

/**
 * Writes a list of grants to the database, deleting any previously saved ones.
 *
 * If a realm is provided, it will only delete grants from that realm, but it
 * will always delete a grant from the 'all' realm. Modules that utilize
 * node_access can use this function when doing mass updates due to widespread
 * permission changes.
 *
 * @param $node
 *   The $node being written to. All that is necessary is that it contains a
 *   nid.
 * @param $grants
 *   A list of grants to write. Each grant is an array that must contain the
 *   following keys: realm, gid, grant_view, grant_update, grant_delete.
 *   The realm is specified by a particular module; the gid is as well, and
 *   is a module-defined id to define grant privileges. each grant_* field
 *   is a boolean value.
 * @param $realm
 *   If provided, only read/write grants for that realm.
 * @param $delete
 *   If false, do not delete records. This is only for optimization purposes,
 *   and assumes the caller has already performed a mass delete of some form.
 */
function node_access_write_grants($node, $grants, $realm = NULL, $delete = TRUE) {
  if ($delete) {
    $query = db_delete('node_access')->condition('nid', $node->nid);
    if ($realm) {
      $query->condition('realm', array($realm, 'all'), 'IN');
    }
    $query->execute();
  }

  // Only perform work when node_access modules are active.
  if (count(module_implements('node_grants'))) {
    $query = db_insert('node_access')->fields(array('nid', 'realm', 'gid', 'grant_view', 'grant_update', 'grant_delete'));
    foreach ($grants as $grant) {
      if ($realm && $realm != $grant['realm']) {
        continue;
      }
      // Only write grants; denies are implicit.
      if ($grant['grant_view'] || $grant['grant_update'] || $grant['grant_delete']) {
        $grant['nid'] = $node->nid;
        $query->values($grant);
      }
    }
    $query->execute();
  }
}

/**
 * Flag / unflag the node access grants for rebuilding, or read the current
 * value of the flag.
 *
 * When the flag is set, a message is displayed to users with 'access
 * administration pages' permission, pointing to the 'rebuild' confirm form.
 * This can be used as an alternative to direct node_access_rebuild calls,
 * allowing administrators to decide when they want to perform the actual
 * (possibly time consuming) rebuild.
 * When unsure the current user is an adminisrator, node_access_rebuild
 * should be used instead.
 *
 * @param $rebuild
 *   (Optional) The boolean value to be written.
  * @return
 *   (If no value was provided for $rebuild) The current value of the flag.
 */
function node_access_needs_rebuild($rebuild = NULL) {
  if (!isset($rebuild)) {
    return variable_get('node_access_needs_rebuild', FALSE);
  }
  elseif ($rebuild) {
    variable_set('node_access_needs_rebuild', TRUE);
  }
  else {
    variable_del('node_access_needs_rebuild');
  }
}

/**
 * Rebuild the node access database. This is occasionally needed by modules
 * that make system-wide changes to access levels.
 *
 * When the rebuild is required by an admin-triggered action (e.g module
 * settings form), calling node_access_needs_rebuild(TRUE) instead of
 * node_access_rebuild() lets the user perform his changes and actually
 * rebuild only once he is done.
 *
 * Note : As of Drupal 6, node access modules are not required to (and actually
 * should not) call node_access_rebuild() in hook_enable/disable anymore.
 *
 * @see node_access_needs_rebuild()
 *
 * @param $batch_mode
 *   Set to TRUE to process in 'batch' mode, spawning processing over several
 *   HTTP requests (thus avoiding the risk of PHP timeout if the site has a
 *   large number of nodes).
 *   hook_update_N and any form submit handler are safe contexts to use the
 *   'batch mode'. Less decidable cases (such as calls from hook_user,
 *   hook_taxonomy, etc...) might consider using the non-batch mode.
 */
function node_access_rebuild($batch_mode = FALSE) {
  db_delete('node_access')->execute();
  // Only recalculate if the site is using a node_access module.
  if (count(module_implements('node_grants'))) {
    if ($batch_mode) {
      $batch = array(
        'title' => t('Rebuilding content access permissions'),
        'operations' => array(
          array('_node_access_rebuild_batch_operation', array()),
        ),
        'finished' => '_node_access_rebuild_batch_finished'
      );
      batch_set($batch);
    }
    else {
      // Try to allocate enough time to rebuild node grants
      drupal_set_time_limit(240);

      $nids = db_query("SELECT nid FROM {node}")->fetchCol();
      foreach ($nids as $nid) {
        $node = node_load($nid, NULL, TRUE);
        // To preserve database integrity, only acquire grants if the node
        // loads successfully.
        if (!empty($node)) {
          node_access_acquire_grants($node);
        }
      }
    }
  }
  else {
    // Not using any node_access modules. Add the default grant.
    db_insert('node_access')
      ->fields(array(
        'nid' => 0,
        'realm' => 'all',
        'gid' => 0,
        'grant_view' => 1,
        'grant_update' => 0,
        'grant_delete' => 0,
      ))
      ->execute();
  }

  if (!isset($batch)) {
    drupal_set_message(t('Content permissions have been rebuilt.'));
    node_access_needs_rebuild(FALSE);
    cache_clear_all();
  }
}

/**
 * Batch operation for node_access_rebuild_batch.
 *
 * This is a multistep operation : we go through all nodes by packs of 20.
 * The batch processing engine interrupts processing and sends progress
 * feedback after 1 second execution time.
 */
function _node_access_rebuild_batch_operation(&$context) {
  if (empty($context['sandbox'])) {
    // Initiate multistep processing.
    $context['sandbox']['progress'] = 0;
    $context['sandbox']['current_node'] = 0;
    $context['sandbox']['max'] = db_query('SELECT COUNT(DISTINCT nid) FROM {node}')->fetchField();
  }

  // Process the next 20 nodes.
  $limit = 20;
  $nids = db_query_range("SELECT nid FROM {node} WHERE nid > :nid ORDER BY nid ASC", 0, $limit, array(':nid' => $context['sandbox']['current_node']))->fetchCol();
  $nodes = node_load_multiple($nids, array(), TRUE);
  foreach ($nodes as $node) {
    // To preserve database integrity, only acquire grants if the node
    // loads successfully.
    if (!empty($node)) {
      node_access_acquire_grants($node);
    }
    $context['sandbox']['progress']++;
    $context['sandbox']['current_node'] = $node->nid;
  }

  // Multistep processing : report progress.
  if ($context['sandbox']['progress'] != $context['sandbox']['max']) {
    $context['finished'] = $context['sandbox']['progress'] / $context['sandbox']['max'];
  }
}

/**
 * Post-processing for node_access_rebuild_batch.
 */
function _node_access_rebuild_batch_finished($success, $results, $operations) {
  if ($success) {
    drupal_set_message(t('The content access permissions have been rebuilt.'));
    node_access_needs_rebuild(FALSE);
  }
  else {
    drupal_set_message(t('The content access permissions have not been properly rebuilt.'), 'error');
  }
  cache_clear_all();
}

/**
 * @} End of "defgroup node_access".
 */


/**
 * @defgroup node_content Hook implementations for user-created content types.
 * @{
 */

/**
 * Implements hook_form().
 */
function node_content_form($node, $form_state) {
  // It is impossible to define a content type without implementing hook_form()
  // so simply return an empty array().
  // @todo: remove this requirement.
  return array();
}

/**
 * @} End of "defgroup node_content".
 */

/**
 * Implements hook_forms().
 * All node forms share the same form handler.
 */
function node_forms() {
  $forms = array();
  if ($types = node_type_get_types()) {
    foreach (array_keys($types) as $type) {
      $forms[$type . '_node_form']['callback'] = 'node_form';
    }
  }
  return $forms;
}

/**
 * Implements hook_action_info().
 */
function node_action_info() {
  return array(
    'node_publish_action' => array(
      'type' => 'node',
      'label' => t('Publish content'),
      'configurable' => FALSE,
      'behavior' => array('changes_property'),
      'triggers' => array('node_presave', 'comment_insert', 'comment_update', 'comment_delete'),
    ),
    'node_unpublish_action' => array(
      'type' => 'node',
      'label' => t('Unpublish content'),
      'configurable' => FALSE,
      'behavior' => array('changes_property'),
      'triggers' => array('node_presave', 'comment_insert', 'comment_update', 'comment_delete'),
    ),
    'node_make_sticky_action' => array(
      'type' => 'node',
      'label' => t('Make content sticky'),
      'configurable' => FALSE,
      'behavior' => array('changes_property'),
      'triggers' => array('node_presave', 'comment_insert', 'comment_update', 'comment_delete'),
    ),
    'node_make_unsticky_action' => array(
      'type' => 'node',
      'label' => t('Make content unsticky'),
      'configurable' => FALSE,
      'behavior' => array('changes_property'),
      'triggers' => array('node_presave', 'comment_insert', 'comment_update', 'comment_delete'),
    ),
    'node_promote_action' => array(
      'type' => 'node',
      'label' => t('Promote content to front page'),
      'configurable' => FALSE,
      'behavior' => array('changes_property'),
      'triggers' => array('node_presave', 'comment_insert', 'comment_update', 'comment_delete'),
    ),
    'node_unpromote_action' => array(
      'type' => 'node',
      'label' => t('Remove content from front page'),
      'configurable' => FALSE,
      'behavior' => array('changes_property'),
      'triggers' => array('node_presave', 'comment_insert', 'comment_update', 'comment_delete'),
    ),
    'node_assign_owner_action' => array(
      'type' => 'node',
      'label' => t('Change the author of content'),
      'configurable' => TRUE,
      'behavior' => array('changes_property'),
      'triggers' => array('node_presave', 'comment_insert', 'comment_update', 'comment_delete'),
    ),
    'node_save_action' => array(
      'type' => 'node',
      'label' => t('Save content'),
      'configurable' => FALSE,
      'triggers' => array('comment_insert', 'comment_update', 'comment_delete'),
    ),
    'node_unpublish_by_keyword_action' => array(
      'type' => 'node',
      'label' => t('Unpublish content containing keyword(s)'),
      'configurable' => TRUE,
      'triggers' => array('node_presave', 'node_insert', 'node_update'),
    ),
  );
}

/**
 * Implements a Drupal action: sets the status of a node to 1 (published).
 */
function node_publish_action($node, $context = array()) {
  $node->status = NODE_PUBLISHED;
  watchdog('action', 'Set @type %title to published.', array('@type' => node_type_get_name($node), '%title' => $node->title[LANGUAGE_NONE][0]['value']));
}

/**
 * Implements a Drupal action: sets the status of a node to 0 (unpublished).
 */
function node_unpublish_action($node, $context = array()) {
  $node->status = NODE_NOT_PUBLISHED;
  watchdog('action', 'Set @type %title to unpublished.', array('@type' => node_type_get_name($node), '%title' => $node->title[LANGUAGE_NONE][0]['value']));
}

/**
 * Implements a Drupal action: sets sticky-at-top-of-list property to 1.
 */
function node_make_sticky_action($node, $context = array()) {
  $node->sticky = NODE_STICKY;
  watchdog('action', 'Set @type %title to sticky.', array('@type' => node_type_get_name($node), '%title' => $node->title[LANGUAGE_NONE][0]['value']));
}

/**
 * Implements a Drupal action: sets sticky-at-top-of-list property to 0.
 */
function node_make_unsticky_action($node, $context = array()) {
  $node->sticky = NODE_NOT_STICKY;
  watchdog('action', 'Set @type %title to unsticky.', array('@type' => node_type_get_name($node), '%title' => $node->title[LANGUAGE_NONE][0]['value']));
}

/**
 * Implements a Drupal action: sets the promote property of a node to 1.
 */
function node_promote_action($node, $context = array()) {
  $node->promote = NODE_PROMOTED;
  watchdog('action', 'Promoted @type %title to front page.', array('@type' => node_type_get_name($node), '%title' => $node->title[LANGUAGE_NONE][0]['value']));
}

/**
 * Implements a Drupal action: sets the promote property of a node to 0.
 */
function node_unpromote_action($node, $context = array()) {
  $node->promote = NODE_NOT_PROMOTED;
  watchdog('action', 'Removed @type %title from front page.', array('@type' => node_type_get_name($node), '%title' => $node->title[LANGUAGE_NONE][0]['value']));
}

/**
 * Implements a Drupal action: saves a node.
 */
function node_save_action($node) {
  node_save($node);
  watchdog('action', 'Saved @type %title', array('@type' => node_type_get_name($node), '%title' => $node->title[LANGUAGE_NONE][0]['value']));
}

/**
 * Implements a configurable Drupal action: assigns ownership of node to user.
 */
function node_assign_owner_action($node, $context) {
  $node->uid = $context['owner_uid'];
  $owner_name = db_query("SELECT name FROM {users} WHERE uid = :uid", array(':uid' => $context['owner_uid']))->fetchField();
  watchdog('action', 'Changed owner of @type %title to uid %name.', array('@type' =>  node_type_get_type($node), '%title' => $node->title[LANGUAGE_NONE][0]['value'], '%name' => $owner_name));
}

/**
 * Generates settings form for node_assign_owner_action().
 */
function node_assign_owner_action_form($context) {
  $description = t('The username of the user to which you would like to assign ownership.');
  $count = db_query("SELECT COUNT(*) FROM {users}")->fetchField();
  $owner_name = '';
  if (isset($context['owner_uid'])) {
    $owner_name = db_query("SELECT name FROM {users} WHERE uid = :uid", array(':uid' => $context['owner_uid']))->fetchField();
  }

  // Use dropdown for fewer than 200 users; textbox for more than that.
  if (intval($count) < 200) {
    $options = array();
    $result = db_query("SELECT uid, name FROM {users} WHERE uid > 0 ORDER BY name");
    foreach ($result as $data) {
      $options[$data->name] = $data->name;
    }
    $form['owner_name'] = array(
      '#type' => 'select',
      '#title' => t('Username'),
      '#default_value' => $owner_name,
      '#options' => $options,
      '#description' => $description,
    );
  }
  else {
    $form['owner_name'] = array(
      '#type' => 'textfield',
      '#title' => t('Username'),
      '#default_value' => $owner_name,
      '#autocomplete_path' => 'user/autocomplete',
      '#size' => '6',
      '#maxlength' => '60',
      '#description' => $description,
    );
  }
  return $form;
}

/**
 * Validates settings form for node_assign_owner_action().
 */
function node_assign_owner_action_validate($form, $form_state) {
  $exists = (bool) db_query_range('SELECT 1 FROM {users} WHERE name = :name', 0, 1, array(':name' => $form_state['values']['owner_name']))->fetchField();
  if (!$exists) {
    form_set_error('owner_name', t('Please enter a valid username.'));
  }
}

/**
 * Saves settings form for node_assign_owner_action().
 */
function node_assign_owner_action_submit($form, $form_state) {
  // Username can change, so we need to store the ID, not the username.
  $uid = db_query('SELECT uid from {users} WHERE name = :name', array(':name' => $form_state['values']['owner_name']))->fetchField();
  return array('owner_uid' => $uid);
}

/**
 * Generates settings form for node_unpublish_by_keyword_action().
 */
function node_unpublish_by_keyword_action_form($context) {
  $form['keywords'] = array(
    '#title' => t('Keywords'),
    '#type' => 'textarea',
    '#description' => t('The content will be unpublished if it contains any of the phrases above. Use a case-sensitive, comma-separated list of phrases. Example: funny, bungee jumping, "Company, Inc."'),
    '#default_value' => isset($context['keywords']) ? drupal_implode_tags($context['keywords']) : '',
  );
  return $form;
}

/**
 * Saves settings form for node_unpublish_by_keyword_action().
 */
function node_unpublish_by_keyword_action_submit($form, $form_state) {
  return array('keywords' => drupal_explode_tags($form_state['values']['keywords']));
}

/**
 * Implements a configurable Drupal action: unpublish node containing keywords.
 *
 * @param $node
 *   A node object.
 * @param $context
 *   An array providing more information about the context of the call to this
 *   action.
 */
function node_unpublish_by_keyword_action($node, $context) {
  foreach ($context['keywords'] as $keyword) {
    if (strpos(drupal_render(node_build(clone $node)), $keyword) !== FALSE || strpos($node->title, $keyword) !== FALSE) {
      $node->status = NODE_NOT_PUBLISHED;
      watchdog('action', 'Set @type %title to unpublished.', array('@type' => node_type_get_name($node), '%title' => $node->title[LANGUAGE_NONE][0]['value']));
      break;
    }
  }
}

/**
 * Implements hook_requirements().
 */
function node_requirements($phase) {
  $requirements = array();
  // Ensure translations don't break at install time
  $t = get_t();
  // Only show rebuild button if there are either 0, or 2 or more, rows
  // in the {node_access} table, or if there are modules that
  // implement hook_node_grants().
  $grant_count = db_query('SELECT COUNT(*) FROM {node_access}')->fetchField();
  if ($grant_count != 1 || count(module_implements('node_grants')) > 0) {
    $value = format_plural($grant_count, 'One permission in use', '@count permissions in use', array('@count' => $grant_count));
  } else {
    $value = $t('Disabled');
  }
  $description = $t('If the site is experiencing problems with permissions to content, you may have to rebuild the permissions cache. Rebuilding will remove all privileges to content and replace them with permissions based on the current modules and settings. Rebuilding may take some time if there is a lot of content or complex permission settings. After rebuilding has completed, content will automatically use the new permissions.');

  $requirements['node_access'] = array(
    'title' => $t('Node Access Permissions'),
    'value' => $value,
    'description' => $description . ' ' . l(t('Rebuild permissions'), 'admin/reports/status/rebuild'),
  );
  return $requirements;
}

/**
 * Controller class for nodes.
 *
 * This extends the DrupalDefaultEntityController class, adding required
 * special handling for node objects.
 */
class NodeController extends DrupalDefaultEntityController {
  protected function attachLoad(&$nodes) {
    // Create an array of nodes for each content type and pass this to the
    // object type specific callback.
    $typed_nodes = array();
    foreach ($nodes as $id => $object) {
      // The value loaded in $object->title is the one stored in {node}.title,
      // which is used for building list queries. By unsetting it here, we
      // allow DrupalDefaultEntityController:attachLoad() to populate it along
      // with all the other field values for consistency.
      unset($object->title);
      $typed_nodes[$object->type][$id] = $object;
    }

    // Call object type specific callbacks on each typed array of nodes.
    foreach ($typed_nodes as $node_type => $nodes_of_type) {
      if (node_hook($node_type, 'load')) {
        $function = node_type_get_base($node_type) . '_load';
        $function($nodes_of_type);
      }
    }
    $this->hookLoadArguments[] = array_keys($typed_nodes);
    parent::attachLoad($nodes);
  }
}