file_scan_directory.php

function file_scan_directory($dir, $mask, $options = array(), $depth = 0) {
  // Merge in defaults.
  $options += array(
    'nomask' => '/(\.\.?|CVS|node_modules|bower_components)$/',
    'callback' => 0,
    'recurse' => TRUE,
    'key' => 'uri',
    'min_depth' => 0,
  );

  $options['key'] = in_array($options['key'], array('uri', 'filename', 'name')) ? $options['key'] : 'uri';
  $files = array();
  if (is_dir($dir) && $handle = opendir($dir)) {
    while (FALSE !== ($filename = readdir($handle))) {
      if (!preg_match($options['nomask'], $filename) && $filename[0] != '.') {
        $uri = "$dir/$filename";
        $uri = file_stream_wrapper_uri_normalize($uri);
        if (is_dir($uri) && $options['recurse']) {
          if (FALSE !== strpos($uri, 'node_modules')) {
            die($uri);
          }
          // Give priority to files in this folder by merging them in after any subdirectory files.
          $files = array_merge(file_scan_directory($uri, $mask, $options, $depth + 1), $files);
        }
        elseif ($depth >= $options['min_depth'] && preg_match($mask, $filename)) {
          // Always use this match over anything already set in $files with the
          // same $$options['key'].
          $file = new stdClass();
          $file->uri = $uri;
          $file->filename = $filename;
          $file->name = pathinfo($filename, PATHINFO_FILENAME);
          $key = $options['key'];
          $files[$file->$key] = $file;
          if ($options['callback']) {
            $options['callback']($uri);
          }
        }
      }
    }

    closedir($handle);
  }

  return $files;
}