code: private function findRealPath($path)
      {
          $path = str_replace(['/', '\\'], DIRECTORY_SEPARATOR, $path);
          $pathParts = explode(DIRECTORY_SEPARATOR, $path);
  
          $realPathParts = [];
          foreach ($pathParts as $pathPart) {
              if ($pathPart === '..') {
                  array_pop($realPathParts);
              } else {
                  $realPathParts[] = $pathPart;
              }
          }
  
          return implode(DIRECTORY_SEPARATOR, $realPathParts);
      }
docs: Returns canonicalized absolute pathname.
  Unlike regular `realpath()` this method does not expand symlinks and does not check path existence.
  @param string $path raw path
  @return string canonicalized absolute pathname