node.module

<?php
// $Id$

/**
 * @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.
 */

define('NODE_NEW_LIMIT', time() - 30 * 24 * 60 * 60);

/**
 * Implementation of hook_help().
 */
function node_help($section) {
  switch ($section) {
    case 'admin/help#node':
      $output = '<p>'. t('All content in a website is stored and treated as <b>nodes</b>. Therefore nodes are any postings such as blogs, stories, polls and forums. The node module manages these content types and is one of the strengths of Drupal over other content management systems.') .'</p>';
      $output .= '<p>'. t('Treating all content as nodes allows the flexibility of creating new types of content. It also allows you to painlessly apply new features or changes to all content. Comments are not stored as nodes but are always associated with a node.') .'</p>';
      $output .= t('<p>Node module features</p>
<ul>
<li>The list tab provides an interface to search and sort all content on your site.</li>
<li>The configure settings tab has basic settings for content on your site.</li>
<li>The configure content types tab lists all content types for your site and lets you configure their default workflow.</li>
<li>The search tab lets you search all content on your site</li>
</ul>
');
      $output .= '<p>'. t('For more information please read the configuration and customization handbook <a href="@node">Node page</a>.', array('@node' => 'http://drupal.org/handbook/modules/node/')) .'</p>';
      return $output;
    case 'admin/content/search':
      return '<p>'. t('Enter a simple pattern to search for a post. Words are matched exactly. Phrases can be surrounded by quotes to do an exact search.') .'</p>';
    case 'admin/content/types':
      return '<p>'. t('Below is a list of all the content types on your site. All posts that exist on your site are instances of one of these content types.') .'</p>';
    case 'admin/content/types/add':
      return '<p>'. t('To create a new content type, enter the human-readable name, the machine-readable name, and all other relevant fields that are on this page. Once created, users of your site will be able to create posts that are instances of this content type.') .'</p>';
  }

  if (arg(0) == 'node' && is_numeric(arg(1)) && arg(2) == 'revisions') {
    return '<p>'. t('The revisions let you track differences between multiple versions of a post.') .'</p>';
  }

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

/**
 * Implementation of hook_cron().
 */
function node_cron() {
  db_query('DELETE FROM {history} WHERE timestamp < %d', NODE_NEW_LIMIT);
}

/**
 * Gather a listing of links to nodes.
 *
 * @param $result
 *   A DB result object from a query to fetch node objects. 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 $title
 *   A heading for the resulting list.
 *
 * @return
 *   An HTML list suitable as content for a block.
 */
function node_title_list($result, $title = NULL) {
  while ($node = db_fetch_object($result)) {
    $items[] = l($node->title, 'node/'. $node->nid, $node->comment_count ? array('title' => format_plural($node->comment_count, '1 comment', '@count comments')) : '');
  }

  return theme('node_list', $items, $title);
}

/**
 * Format a listing of links to nodes.
 */
function theme_node_list($items, $title = NULL) {
  return theme('item_list', $items, $title);
}

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

  if ($user->uid) {
    if (node_last_viewed($nid)) {
      db_query('UPDATE {history} SET timestamp = %d WHERE uid = %d AND nid = %d', time(), $user->uid, $nid);
    }
    else {
      @db_query('INSERT INTO {history} (uid, nid, timestamp) VALUES (%d, %d, %d)', $user->uid, $nid, time());
    }
  }
}

/**
 * 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_fetch_object(db_query("SELECT timestamp FROM {history} WHERE uid = %d AND nid = %d", $user->uid, $nid));
  }

  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;
}

/**
 * Automatically generate a teaser for a node body in a given format.
 */
function node_teaser($body, $format = NULL) {

  $size = variable_get('teaser_length', 600);

  // Find where the delimiter is in the body
  $delimiter = strpos($body, '<!--break-->');

  // If the size is zero, and there is no delimiter, the entire body is the teaser.
  if ($size == 0 && $delimiter === FALSE) {
    return $body;
  }

  // If a valid delimiter has been specified, use it to chop off the teaser.
  if ($delimiter !== FALSE) {
    return substr($body, 0, $delimiter);
  }

  // We check for the presence of the PHP evaluator filter in the current
  // format. If the body contains PHP code, we do not split it up to prevent
  // parse errors.
  if (isset($format)) {
    $filters = filter_list_format($format);
    if (isset($filters['filter/1']) && strpos($body, '<?') !== FALSE) {
      return $body;
    }
  }

  // If we have a short body, the entire body is the teaser.
  if (strlen($body) < $size) {
    return $body;
  }

  // The teaser may not be longer than maximum length specified. Initial slice.
  $teaser = truncate_utf8($body, $size);
  $position = 0;
  // Cache the reverse of the teaser.
  $reversed = strrev($teaser);

  // In some cases, no delimiter has been specified. In this case, we try to
  // split at paragraph boundaries.
  $breakpoints = array('</p>' => 0, '<br />' => 6, '<br>' => 4, "\n" => 1);
  // We use strpos on the reversed needle and haystack for speed.
  foreach ($breakpoints as $point => $offset) {
    $length = strpos($reversed, strrev($point));
    if ($length !== FALSE) {
      $position = - $length - $offset;
      return ($position == 0) ? $teaser : substr($teaser, 0, $position);
    }
  }

  // When even the first paragraph is too long, we try to split at the end of
  // the last full sentence.
  $breakpoints = array('. ' => 1, '! ' => 1, '? ' => 1, '。' => 0, '؟ ' => 1);
  $min_length = strlen($reversed);
  foreach ($breakpoints as $point => $offset) {
    $length = strpos($reversed, strrev($point));
    if ($length !== FALSE) {
      $min_length = min($length, $min_length);
      $position = 0 - $length - $offset;
    }
  }
  return ($position == 0) ? $teaser : substr($teaser, 0, $position);
}

/**
 * Builds a list of available node types, and returns all of part of this list
 * in the specified format.
 *
 * @param $op
 *   The format in which to return the list. When this is set to 'type',
 *   'module', or 'name', only the specified node type is returned. When set to
 *   'types' or 'names', all node types are returned.
 * @param $node
 *   A node object, array, or string that indicates the node type to return.
 *   Leave at default value (NULL) to return a list of all node types.
 * @param $reset
 *   Whether or not to reset this function's internal cache (defaults to
 *   FALSE).
 *
 * @return
 *   Either an array of all available node types, or a single node type, in a
 *   variable format.
 */
function node_get_types($op = 'types', $node = NULL, $reset = FALSE) {
  static $_node_types, $_node_names;

  if ($reset || !isset($_node_types)) {
    list($_node_types, $_node_names) = _node_types_build();
  }

  if ($node) {
    if (is_array($node)) {
      $type = $node['type'];
    }
    elseif (is_object($node)) {
      $type = $node->type;
    }
    elseif (is_string($node)) {
      $type = $node;
    }
    if (!isset($_node_types[$type])) {
      return FALSE;
    }
  }
  switch ($op) {
    case 'types':
      return $_node_types;
    case 'type':
      return $_node_types[$type];
    case 'module':
      return $_node_types[$type]->module;
    case 'names':
      return $_node_names;
    case 'name':
      return $_node_names[$type];
  }
}

/**
 * Resets the database cache of node types, and saves all new or non-modified
 * module-defined node types to the database.
 */
function node_types_rebuild() {
  _node_types_build();

  $node_types = node_get_types('types', NULL, TRUE);

  foreach ($node_types as $type => $info) {
    if (!empty($info->is_new)) {
      node_type_save($info);
    }
  }

  _node_types_build();
}

/**
 * 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 = db_num_rows(db_query("SELECT * FROM {node_type} WHERE type = '%s'", $existing_type));

  if ($is_existing) {
    db_query("UPDATE {node_type} SET type = '%s', name = '%s', module = '%s', has_title = %d, title_label = '%s', has_body = %d, body_label = '%s', description = '%s', help = '%s', min_word_count = %d, custom = %d, modified = %d, locked = %d WHERE type = '%s'", $info->type, $info->name, $info->module, $info->has_title, $info->title_label, $info->has_body, $info->body_label, $info->description, $info->help, $info->min_word_count, $info->custom, $info->modified, $info->locked, $existing_type);

    module_invoke_all('node_type', 'update', $info);
    return SAVED_UPDATED;
  }
  else {
    db_query("INSERT INTO {node_type} (type, name, module, has_title, title_label, has_body, body_label, description, help, min_word_count, custom, modified, locked, orig_type) VALUES ('%s', '%s', '%s', %d, '%s', %d, '%s', '%s', '%s', %d, %d, %d, %d, '%s')", $info->type, $info->name, $info->module, $info->has_title, $info->title_label, $info->has_body, $info->body_label, $info->description, $info->help, $info->min_word_count, $info->custom, $info->modified, $info->locked, $info->orig_type);

    module_invoke_all('node_type', 'insert', $info);
    return SAVED_NEW;
  }
}

/**
 * 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) {
  db_query("DELETE FROM {node_type} WHERE type = '%s'", $type);

  $info = node_get_types('type', $type);
  module_invoke_all('node_type', 'delete', $info);
}

/**
 * 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) {
  db_query("UPDATE {node} SET type = '%s' WHERE type = '%s'", $type, $old_type);
  return db_affected_rows();
}

/**
 * Builds the list of available node types, by querying hook_node_info() in all
 * modules, and by looking for node types in the database.
 *
 */
function _node_types_build() {
  $_node_types = array();
  $_node_names = array();

  $info_array = module_invoke_all('node_info');
  foreach ($info_array as $type => $info) {
    $info['type'] = $type;
    $_node_types[$type] = (object) _node_type_set_defaults($info);
    $_node_names[$type] = $info['name'];
  }

  $type_result = db_query(db_rewrite_sql('SELECT nt.type, nt.* FROM {node_type} nt ORDER BY nt.type ASC', 'nt', 'type'));
  while ($type_object = db_fetch_object($type_result)) {
    if (!isset($_node_types[$type_object->type]) || $type_object->modified) {
      $_node_types[$type_object->type] = $type_object;
      $_node_names[$type_object->type] = $type_object->name;

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

  asort($_node_names);

  return array($_node_types, $_node_names);
}

/**
 * Set default values for a node type defined through hook_node_info().
 */
function _node_type_set_defaults($info) {
  if (!isset($info['has_title'])) {
    $info['has_title'] = TRUE;
  }
  if ($info['has_title'] && !isset($info['title_label'])) {
    $info['title_label'] = t('Title');
  }

  if (!isset($info['has_body'])) {
    $info['has_body'] = TRUE;
  }
  if ($info['has_body'] && !isset($info['body_label'])) {
    $info['body_label'] = t('Body');
  }

  if (!isset($info['custom'])) {
    $info['custom'] = FALSE;
  }
  if (!isset($info['modified'])) {
    $info['modified'] = FALSE;
  }
  if (!isset($info['locked'])) {
    $info['locked'] = TRUE;
  }

  $info['orig_type'] = $info['type'];
  $info['is_new'] = TRUE;

  return $info;
}

/**
 * Determine whether a node hook exists.
 *
 * @param &$node
 *   Either a node object, node array, or a string containing the node type.
 * @param $hook
 *   A string containing the name of the hook.
 * @return
 *   TRUE iff the $hook exists in the node type of $node.
 */
function node_hook(&$node, $hook) {
  $module = node_get_types('module', $node);
  if ($module == 'node') {
    $module = 'node_content'; // Avoid function name collisions.
  }
  return module_hook($module, $hook);
}

/**
 * Invoke a node hook.
 *
 * @param &$node
 *   Either a node object, node array, 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)) {
    $module = node_get_types('module', $node);
    if ($module == 'node') {
      $module = 'node_content'; // Avoid function name collisions.
    }
    $function = $module .'_'. $hook;
    return ($function($node, $a2, $a3, $a4));
  }
}

/**
 * Invoke a hook_nodeapi() operation in all modules.
 *
 * @param &$node
 *   A node object.
 * @param $op
 *   A string containing the name of the nodeapi operation.
 * @param $a3, $a4
 *   Arguments to pass on to the hook, after the $node and $op arguments.
 * @return
 *   The returned value of the invoked hooks.
 */
function node_invoke_nodeapi(&$node, $op, $a3 = NULL, $a4 = NULL) {
  $return = array();
  foreach (module_implements('nodeapi') as $name) {
    $function = $name .'_nodeapi';
    $result = $function($node, $op, $a3, $a4);
    if (isset($result) && is_array($result)) {
      $return = array_merge($return, $result);
    }
    else if (isset($result)) {
      $return[] = $result;
    }
  }
  return $return;
}

/**
 * Load a node object from the database.
 *
 * @param $param
 *   Either the nid of the node or an array of conditions to match against in the database query
 * @param $revision
 *   Which numbered revision to load. Defaults to the current version.
 * @param $reset
 *   Whether to reset the internal node_load cache.
 *
 * @return
 *   A fully-populated node object.
 */
function node_load($param = array(), $revision = NULL, $reset = NULL) {
  static $nodes = array();

  if ($reset) {
    $nodes = array();
  }

  $cachable = ($revision == NULL);
  $arguments = array();
  if (is_numeric($param)) {
    if ($cachable && isset($nodes[$param])) {
      return is_object($nodes[$param]) ? drupal_clone($nodes[$param]) : $nodes[$param];
    }
    $cond = 'n.nid = %d';
    $arguments[] = $param;
  }
  else {
    // Turn the conditions into a query.
    foreach ($param as $key => $value) {
      $cond[] = 'n.'. db_escape_string($key) ." = '%s'";
      $arguments[] = $value;
    }
    $cond = implode(' AND ', $cond);
  }

  // Retrieve the node.
  // No db_rewrite_sql is applied so as to get complete indexing for search.
  if ($revision) {
    array_unshift($arguments, $revision);
    $node = db_fetch_object(db_query('SELECT n.nid, r.vid, n.type, n.status, n.created, n.changed, n.comment, n.promote, n.sticky, r.timestamp AS revision_timestamp, r.title, r.body, r.teaser, r.log, r.format, u.uid, u.name, u.picture, u.data FROM {node} n INNER JOIN {users} u ON u.uid = n.uid INNER JOIN {node_revisions} r ON r.nid = n.nid AND r.vid = %d WHERE '. $cond, $arguments));
  }
  else {
    $node = db_fetch_object(db_query('SELECT n.nid, n.vid, n.type, n.status, n.created, n.changed, n.comment, n.promote, n.sticky, r.timestamp AS revision_timestamp, r.title, r.body, r.teaser, r.log, r.format, u.uid, u.name, u.picture, u.data FROM {node} n INNER JOIN {users} u ON u.uid = n.uid INNER JOIN {node_revisions} r ON r.vid = n.vid WHERE '. $cond, $arguments));
  }

  if ($node->nid) {
    // Call the node specific callback (if any) and piggy-back the
    // results to the node or overwrite some values.
    if ($extra = node_invoke($node, 'load')) {
      foreach ($extra as $key => $value) {
        $node->$key = $value;
      }
    }

    if ($extra = node_invoke_nodeapi($node, 'load')) {
      foreach ($extra as $key => $value) {
        $node->$key = $value;
      }
    }
    if ($cachable) {
      $nodes[$node->nid] = is_object($node) ? drupal_clone($node) : $node;
    }
  }

  return $node;
}

/**
 * Save a node object into the database.
 */
function node_save(&$node) {
  global $user;

  $node->is_new = FALSE;

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

    $node->nid = db_next_id('{node}_nid');
    $node->vid = db_next_id('{node_revisions}_vid');
  }
  else {
    // We need to ensure that all node fields are filled.
    $node_current = node_load($node->nid);
    foreach ($node as $field => $data) {
      $node_current->$field = $data;
    }
    $node = $node_current;

    if (!empty($node->revision)) {
      $node->old_vid = $node->vid;
      $node->vid = db_next_id('{node_revisions}_vid');
    }
  }

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

  // Split off revisions data to another structure
  $revisions_table_values = array('nid' => $node->nid, 'vid' => $node->vid,
                     'title' => $node->title, 'body' => $node->body,
                     'teaser' => $node->teaser, 'timestamp' => $node->changed,
                     'uid' => $user->uid, 'format' => $node->format);
  $revisions_table_types = array('nid' => '%d', 'vid' => '%d',
                     'title' => "'%s'", 'body' => "'%s'",
                     'teaser' => "'%s'", 'timestamp' => '%d',
                     'uid' => '%d', 'format' => '%d');
  if (!empty($node->log) || $node->is_new) {
    // Only store the log message if there's something to store; this prevents
    // existing log messages from being unintentionally overwritten by a blank
    // message. A new revision will have an empty log message (or $node->log).
    $revisions_table_values['log'] = $node->log;
    $revisions_table_types['log'] = "'%s'";
  }
  $node_table_values = array('nid' => $node->nid, 'vid' => $node->vid,
                    'title' => $node->title, 'type' => $node->type, 'uid' => $node->uid,
                    'status' => $node->status, 'created' => $node->created,
                    'changed' => $node->changed, 'comment' => $node->comment,
                    'promote' => $node->promote, 'sticky' => $node->sticky);
  $node_table_types = array('nid' => '%d', 'vid' => '%d',
                    'title' => "'%s'", 'type' => "'%s'", 'uid' => '%d',
                    'status' => '%d', 'created' => '%d',
                    'changed' => '%d', 'comment' => '%d',
                    'promote' => '%d', 'sticky' => '%d');

  //Generate the node table query and the
  //the node_revisions table query
  if ($node->is_new) {
    $node_query = 'INSERT INTO {node} ('. implode(', ', array_keys($node_table_types)) .') VALUES ('. implode(', ', $node_table_types) .')';
    $revisions_query = 'INSERT INTO {node_revisions} ('. implode(', ', array_keys($revisions_table_types)) .') VALUES ('. implode(', ', $revisions_table_types) .')';
  }
  else {
    $arr = array();
    foreach ($node_table_types as $key => $value) {
      $arr[] = $key .' = '. $value;
    }
    $node_table_values[] = $node->nid;
    $node_query = 'UPDATE {node} SET '. implode(', ', $arr) .' WHERE nid = %d';
    if (!empty($node->revision)) {
      $revisions_query = 'INSERT INTO {node_revisions} ('. implode(', ', array_keys($revisions_table_types)) .') VALUES ('. implode(', ', $revisions_table_types) .')';
    }
    else {
      $arr = array();
      foreach ($revisions_table_types as $key => $value) {
        $arr[] = $key .' = '. $value;
      }
      $revisions_table_values[] = $node->vid;
      $revisions_query = 'UPDATE {node_revisions} SET '. implode(', ', $arr) .' WHERE vid = %d';
    }
  }

  // Insert the node into the database:
  db_query($node_query, $node_table_values);
  db_query($revisions_query, $revisions_table_values);

  // Call the node specific callback (if any):
  if ($node->is_new) {
    node_invoke($node, 'insert');
    node_invoke_nodeapi($node, 'insert');
  }
  else {
    node_invoke($node, 'update');
    node_invoke_nodeapi($node, 'update');
  }

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

  // Clear the cache so an anonymous poster can see the node being added or updated.
  cache_clear_all();
}

/**
 * Generate a display of the given node.
 *
 * @param $node
 *   A node array or node object.
 * @param $teaser
 *   Whether to display the teaser only, as on the main page.
 * @param $page
 *   Whether the node is being displayed by itself as a page.
 * @param $links
 *   Whether or not to display node links. Links are omitted for node previews.
 *
 * @return
 *   An HTML representation of the themed node.
 */
function node_view($node, $teaser = FALSE, $page = FALSE, $links = TRUE) {
  $node = (object)$node;

  $node = node_build_content($node, $teaser, $page);

  if ($links) {
    $node->links = module_invoke_all('link', 'node', $node, !$page);
    drupal_alter('link', $node->links, $node);
  }

  // Set the proper node part, then unset unused $node part so that a bad
  // theme can not open a security hole.
  $content = drupal_render($node->content);
  if ($teaser) {
    $node->teaser = $content;
    unset($node->body);
  }
  else {
    $node->body = $content;
    unset($node->teaser);
  }

  // Allow modules to modify the fully-built node.
  node_invoke_nodeapi($node, 'alter', $teaser, $page);

  return theme('node', $node, $teaser, $page);
}

/**
 * Apply filters and build the node's standard elements.
 */
function node_prepare($node, $teaser = FALSE) {
  // First we'll overwrite the existing node teaser and body with
  // the filtered copies! Then, we'll stick those into the content
  // array and set the read more flag if appropriate.
  $node->readmore = (strlen($node->teaser) < strlen($node->body));

  if ($teaser == FALSE) {
    $node->body = check_markup($node->body, $node->format, FALSE);
  }
  else {
    $node->teaser = check_markup($node->teaser, $node->format, FALSE);
  }

  $node->content['body'] = array(
    '#value' => $teaser ? $node->teaser : $node->body,
    '#weight' => 0,
  );

  return $node;
}

/**
 * Builds a structured array representing the node's content.
 *
 * @param $node
 *   A node object.
 * @param $teaser
 *   Whether to display the teaser only, as on the main page.
 * @param $page
 *   Whether the node is being displayed by itself as a page.
 *
 * @return
 *   An structured array containing the individual elements
 *   of the node's body.
 */
function node_build_content($node, $teaser = FALSE, $page = FALSE) {
  // Remove the delimiter (if any) that separates the teaser from the body.
  $node->body = str_replace('<!--break-->', '', $node->body);

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

  // Allow modules to make their own additions to the node.
  node_invoke_nodeapi($node, 'view', $teaser, $page);

  return $node;
}

/**
 * Generate a page displaying a single node, along with its comments.
 */
function node_show($node, $cid) {
  $output = node_view($node, FALSE, TRUE);

  if (function_exists('comment_render') && $node->comment) {
    $output .= comment_render($node, $cid);
  }

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

  return $output;
}

/**
 * Implementation of hook_perm().
 */
function node_perm() {
  $perms = array('administer content types', 'administer nodes', 'access content', 'view revisions', 'revert revisions');

  foreach (node_get_types() as $type) {
    if ($type->module == 'node') {
      $name = check_plain($type->type);
      $perms[] = 'create '. $name .' content';
      $perms[] = 'edit own '. $name .' content';
      $perms[] = 'edit '. $name .' content';
    }
  }

  return $perms;
}

/**
 * Implementation of hook_search().
 */
function node_search($op = 'search', $keys = NULL) {
  switch ($op) {
    case 'name':
      return t('Content');

    case 'reset':
      variable_del('node_cron_last');
      variable_del('node_cron_last_nid');
      return;

    case 'status':
      $last = variable_get('node_cron_last', 0);
      $last_nid = variable_get('node_cron_last_nid', 0);
      $total = db_result(db_query('SELECT COUNT(*) FROM {node} WHERE status = 1'));
      $remaining = db_result(db_query('SELECT COUNT(*) FROM {node} n LEFT JOIN {node_comment_statistics} c ON n.nid = c.nid WHERE n.status = 1 AND ((GREATEST(n.created, n.changed, c.last_comment_timestamp) = %d AND n.nid > %d ) OR (n.created > %d OR n.changed > %d OR c.last_comment_timestamp > %d))', $last, $last_nid, $last, $last, $last));
      return array('remaining' => $remaining, 'total' => $total);

    case 'admin':
      $form = array();
      // 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>');

      $ranking = array('node_rank_relevance' => t('Keyword relevance'),
                       'node_rank_recent' => t('Recently posted'));
      if (module_exists('comment')) {
        $ranking['node_rank_comments'] = t('Number of comments');
      }
      if (module_exists('statistics') && variable_get('statistics_count_content_views', 0)) {
        $ranking['node_rank_views'] = t('Number of views');
      }

      // Note: reversed to reflect that higher number = higher ranking.
      $options = drupal_map_assoc(range(0, 10));
      foreach ($ranking as $var => $title) {
        $form['content_ranking']['factors'][$var] = array('#title' => $title, '#type' => 'select', '#options' => $options, '#default_value' => variable_get($var, 5));
      }
      return $form;

    case 'search':
      // Build matching conditions
      list($join1, $where1) = _db_rewrite_sql();
      $arguments1 = array();
      $conditions1 = 'n.status = 1';

      if ($type = search_query_extract($keys, 'type')) {
        $types = array();
        foreach (explode(',', $type) as $t) {
          $types[] = "n.type = '%s'";
          $arguments1[] = $t;
        }
        $conditions1 .= ' AND ('. implode(' OR ', $types) .')';
        $keys = search_query_insert($keys, 'type');
      }

      if ($category = search_query_extract($keys, 'category')) {
        $categories = array();
        foreach (explode(',', $category) as $c) {
          $categories[] = "tn.tid = %d";
          $arguments1[] = $c;
        }
        $conditions1 .= ' AND ('. implode(' OR ', $categories) .')';
        $join1 .= ' INNER JOIN {term_node} tn ON n.nid = tn.nid';
        $keys = search_query_insert($keys, 'category');
      }

      // Build ranking expression (we try to map each parameter to a
      // uniform distribution in the range 0..1).
      $ranking = array();
      $arguments2 = array();
      $join2 = '';
      // Used to avoid joining on node_comment_statistics twice
      $stats_join = FALSE;
      $total = 0;
      if ($weight = (int)variable_get('node_rank_relevance', 5)) {
        // Average relevance values hover around 0.15
        $ranking[] = '%d * i.relevance';
        $arguments2[] = $weight;
        $total += $weight;
      }
      if ($weight = (int)variable_get('node_rank_recent', 5)) {
        // Exponential decay with half-life of 6 months, starting at last indexed node
        $ranking[] = '%d * POW(2, (GREATEST(n.created, n.changed, c.last_comment_timestamp) - %d) * 6.43e-8)';
        $arguments2[] = $weight;
        $arguments2[] = (int)variable_get('node_cron_last', 0);
        $join2 .= ' INNER JOIN {node} n ON n.nid = i.sid LEFT JOIN {node_comment_statistics} c ON c.nid = i.sid';
        $stats_join = TRUE;
        $total += $weight;
      }
      if (module_exists('comment') && $weight = (int)variable_get('node_rank_comments', 5)) {
        // Inverse law that maps the highest reply count on the site to 1 and 0 to 0.
        $scale = variable_get('node_cron_comments_scale', 0.0);
        $ranking[] = '%d * (2.0 - 2.0 / (1.0 + c.comment_count * %f))';
        $arguments2[] = $weight;
        $arguments2[] = $scale;
        if (!$stats_join) {
          $join2 .= ' LEFT JOIN {node_comment_statistics} c ON c.nid = i.sid';
        }
        $total += $weight;
      }
      if (module_exists('statistics') && variable_get('statistics_count_content_views', 0) &&
          $weight = (int)variable_get('node_rank_views', 5)) {
        // Inverse law that maps the highest view count on the site to 1 and 0 to 0.
        $scale = variable_get('node_cron_views_scale', 0.0);
        $ranking[] = '%d * (2.0 - 2.0 / (1.0 + nc.totalcount * %f))';
        $arguments2[] = $weight;
        $arguments2[] = $scale;
        $join2 .= ' LEFT JOIN {node_counter} nc ON nc.nid = i.sid';
        $total += $weight;
      }
      $select2 = (count($ranking) ? implode(' + ', $ranking) : 'i.relevance') .' AS score';

      // Do search
      $find = do_search($keys, 'node', 'INNER JOIN {node} n ON n.nid = i.sid '. $join1 .' INNER JOIN {users} u ON n.uid = u.uid', $conditions1 . (empty($where1) ? '' : ' AND '. $where1), $arguments1, $select2, $join2, $arguments2);

      // Load results
      $results = array();
      foreach ($find as $item) {
        // Build the node body.
        $node = node_load($item->sid);
        $node = node_build_content($node, FALSE, FALSE);
        $node->body = drupal_render($node->content);

        // Fetch comments for snippet
        $node->body .= module_invoke('comment', 'nodeapi', $node, 'update index');
        // Fetch terms for snippet
        $node->body .= module_invoke('taxonomy', 'nodeapi', $node, 'update index');

        $extra = node_invoke_nodeapi($node, 'search result');
        $results[] = array('link' => url('node/'. $item->sid, array('absolute' => TRUE)),
                           'type' => node_get_types('name', $node),
                           'title' => $node->title,
                           'user' => theme('username', $node),
                           'date' => $node->changed,
                           'node' => $node,
                           'extra' => $extra,
                           'score' => $item->score / $total,
                           'snippet' => search_excerpt($keys, $node->body));
      }
      return $results;
  }
}

/**
 * Implementation of hook_user().
 */
function node_user($op, &$edit, &$user) {
  if ($op == 'delete') {
    db_query('UPDATE {node} SET uid = 0 WHERE uid = %d', $user->uid);
    db_query('UPDATE {node_revisions} SET uid = 0 WHERE uid = %d', $user->uid);
  }
}

function theme_node_search_admin($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', $header, $rows);

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

/**
 * Menu callback; presents general node configuration options.
 */
function node_configure() {
  // Only show rebuild button if there is 0 or more than 2 rows in node_access table, or if there are modules that implement node_grant.
  if (db_result(db_query('SELECT COUNT(*) FROM {node_access}')) != 1 || count(module_implements('node_grants')) > 0) {
    $status = '<p>'. t('If the site is experiencing problems with permissions to content, you may have to rebuild the permissions cache. Possible causes for permission problems are disabling modules or configuration changes to permissions. Rebuilding will remove all privileges to posts, and replace them with permissions based on the current modules and settings.') .'</p>';
    $status .= '<p>'. t('Rebuilding may take some time if there is a lot of content or complex permission settings. After rebuilding has completed posts will automatically use the new permissions.') .'</p>';

    $form['access'] = array('#type' => 'fieldset', '#title' => t('Node access status'));
    $form['access']['status'] = array('#value' => $status);
    $form['access']['rebuild'] = array('#type' => 'submit', '#value' => t('Rebuild permissions'));
  }

  $form['default_nodes_main'] = array(
    '#type' => 'select', '#title' => t('Number of posts on main page'), '#default_value' => variable_get('default_nodes_main', 10),
    '#options' =>  drupal_map_assoc(array(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30)),
    '#description' => t('The default maximum number of posts to display per page on overview pages such as the main page.')
  );
  $form['teaser_length'] = array(
    '#type' => 'select', '#title' => t('Length of trimmed posts'), '#default_value' => variable_get('teaser_length', 600),
    '#options' => array(0 => t('Unlimited'), 200 => t('200 characters'), 400 => t('400 characters'), 600 => t('600 characters'),
      800 => t('800 characters'), 1000 => t('1000 characters'), 1200 => t('1200 characters'), 1400 => t('1400 characters'),
      1600 => t('1600 characters'), 1800 => t('1800 characters'), 2000 => t('2000 characters')),
    '#description' => t("The maximum number of characters used in the trimmed version of a post. Drupal will use this setting to determine at which offset long posts should be trimmed. The trimmed version of a post is typically used as a teaser when displaying the post on the main page, in XML feeds, etc. To disable teasers, set to 'Unlimited'. Note that this setting will only affect new or updated content and will not affect existing teasers.")
  );

  $form['node_preview'] = array(
    '#type' => 'radios', '#title' => t('Preview post'), '#default_value' => variable_get('node_preview', 0),
    '#options' => array(t('Optional'), t('Required')), '#description' => t('Must users preview posts before submitting?')
  );

  return system_settings_form($form);
}

/**
 * Form validate callback.
 */
function node_configure_validate($form_id, $form_values) {
  if ($form_values['op'] == t('Rebuild permissions')) {
    drupal_goto('admin/content/node-settings/rebuild');
  }
}

/**
 * Menu callback: confirm rebuilding of permissions.
 */
function node_configure_rebuild_confirm() {
  return confirm_form(array(), t('Are you sure you want to rebuild node permissions on the site?'),
                  'admin/content/node-settings', t('This will wipe all current node permissions and rebuild them based on current settings. Rebuilding the permissions may take a while so please be patient. This action cannot be undone.'), t('Rebuild permissions'), t('Cancel'));
}

/**
 * Handler for wipe confirmation
 */
function node_configure_rebuild_confirm_submit($form_id, &$form) {
  node_access_rebuild();
  drupal_set_message(t('The node access table has been rebuilt.'));
  return 'admin/content/node-settings';
}

/**
 * Retrieve the comment mode for the given node ID (none, read, or read/write).
 */
function node_comment_mode($nid) {
  static $comment_mode;
  if (!isset($comment_mode[$nid])) {
    $comment_mode[$nid] = db_result(db_query('SELECT comment FROM {node} WHERE nid = %d', $nid));
  }
  return $comment_mode[$nid];
}

/**
 * Implementation of hook_link().
 */
function node_link($type, $node = NULL, $teaser = FALSE) {
  $links = array();

  if ($type == 'node') {
    if ($teaser == 1 && $node->teaser && $node->readmore) {
      $links['node_read_more'] = array(
        'title' => t('Read more'),
        'href' => "node/$node->nid",
        'attributes' => array('title' => t('Read the rest of this posting.'))
      );
    }
  }

  return $links;
}

function _node_revision_access($node) {
  return (user_access('view revisions') || user_access('administer nodes')) && node_access('view', $node) && db_result(db_query('SELECT COUNT(vid) FROM {node_revisions} WHERE nid = %d', $node->nid)) > 1;
}

/**
 * Implementation of hook_menu().
 */