Access checking for comments.php

/**
 * Access checking for comments
 */
function _comment_resource_access($op='view', $args=array()) {
  if (user_access('administer comments')) {
    return TRUE;
  }

  if ($op=='create') {
    $comment = (object)$args[0];
  }
  else {
    $comment = _comment_load($args[0]);
  }

  switch ($op) {
    case 'view':
      // Check if the user has access to comments and that the node has comments enabled
      return user_access('access comments') && _comment_resource_node_access($comment->nid);
    case 'edit':
      // Check if the user may edit the comment, and has access to the input format
      return comment_access('edit', $comment) && filter_access($comment->format);
    case 'create':
      // Check if the user may post comments, and has access to the used format and
      // check if the node has comments enabled, and that the user has access to the node
      return user_access('post comments') && filter_access($comment->format) && 
        _comment_resource_node_access($comment->nid, COMMENT_NODE_READ_WRITE);
    case 'delete':
      // Check if the user may edit the comment
      return comment_access('edit', $comment);
  }
}


function _comment_resource_node_access($nid, $comment=COMMENT_NODE_READ) {
  /* 
   * TODO: Check if we really have to perform a full node load here,
   * it could be enough to load nid, type, uid, comment, status, format.
  */
  
  // Check if the node has comments enabled, and that the user has access to the node
  $node = node_load($comment->nid);
  return $node->comment >= $comment && node_access('view', $node);
}