node_clone.php

<?php

/**
 *  Clones a node by directly saving it.
 */
function clone_node_save($nid) {
  if (is_numeric($nid)) {
    global $user;

    $node = node_load($nid);
    if (isset($node->nid) && clone_is_permitted($node->type)) {
      $original_node = drupal_clone($node);

      $node->nid = NULL;
      $node->vid = NULL;
      $node->tnid = NULL;
      $node->name = $user->name;
      $node->uid = $user->uid;
      $node->created = NULL;
      $node->menu = clone_node_clone_menu_link($original_node);
      $node->book['mlid'] = NULL;
      $node->path = NULL;
      $node->files = array();
      $node->title = t('Clone of !title', array('!title' => $node->title));
      // Add an extra property as a flag.
      $node->clone_from_original_nid = $original_node->nid;

      if (variable_get('clone_reset_'. $node->type, FALSE)) {
        $node_options = variable_get('node_options_'. $node->type, array('status', 'promote'));
        // Fill in the default values.
        foreach (array('status', 'moderate', 'promote', 'sticky', 'revision') as $key) {
          $node->$key = in_array($key, $node_options);
        }
      }
      // Let other modules do special fixing up.
      // The function signature is: hook_clone_node_alter(&$node, $original_node, $method)
      // Where $method is either 'prepopulate' or 'save-edit'.
      drupal_alter("clone_node", $node, $original_node, "save-edit");

      node_save($node);
      return $node->nid;
    }
  }
}