protected static function get_mime_extensions()
{
$mime_types = wp_get_mime_types();
$extensions = array();
foreach ($mime_types as $ext => $mime) {
$ext = explode('|', $ext);
$extensions[$mime] = $ext;
$mime_parts = explode('/', $mime);
if (empty($extensions[$mime_parts[0]])) {
$extensions[$mime_parts[0]] = array();
}
$extensions[$mime_parts[0]] = $extensions[$mime_parts[0] . '/*'] = array_merge($extensions[$mime_parts[0]], $ext);
}
return $extensions;
}