This very simple module contains only one externally useful function:
include_check_path($path, $source = NULL, $type = 'file')Verifies or installs a file or directory into the include repository.
$path The target path to install, relative to the include file root. If $path is empty or ends in a trailing slash, it is interpreted as a directory name, and both $source and $type are ignored.
$source (optional) The file data, or a uri where it may be found. If unset or empty, then $path is a directory name, and $type is ignored.
$type (optional) A string which determines how $source is to be interpreted. Must be one of the following:
'dir' : $path is a directory name, and $source is ignored.
'file' : (Default) realpath($source) is a local file.
'url' : $source is a string containing the file data.
TRUE if the file was found or installed; otherwise FALSE.