Rewrite static theme assets and plugins directory (WordPress)

gistfile1.aw

<?php
// rewrite /wp-content/themes/theme-name/css/ to /css/
// rewrite /wp-content/themes/theme-name/js/  to /js/
// rewrite /wp-content/themes/theme-name/img/ to /img/
// rewrite /wp-content/plugins/ to /plugins/

function roots_flush_rewrites() {
  global $wp_rewrite;
  $wp_rewrite->flush_rules();
}

function roots_add_rewrites($content) {
  $theme_name = next(explode('/themes/', get_stylesheet_directory()));
  global $wp_rewrite;
  $roots_new_non_wp_rules = array(
    'css/(.*)'      => 'wp-content/themes/'. $theme_name . '/css/$1',
    'js/(.*)'       => 'wp-content/themes/'. $theme_name . '/js/$1',
    'img/(.*)'      => 'wp-content/themes/'. $theme_name . '/img/$1',
    'plugins/(.*)'  => 'wp-content/plugins/$1'
  );
  $wp_rewrite->non_wp_rules += $roots_new_non_wp_rules;
}

add_action('admin_init', 'roots_flush_rewrites');

function roots_clean_assets($content) {
    $theme_name = next(explode('/themes/', $content));
    $current_path = '/wp-content/themes/' . $theme_name;
    $new_path = '';
    $content = str_replace($current_path, $new_path, $content);
    return $content;
}

function roots_clean_plugins($content) {
    $current_path = '/wp-content/plugins';
    $new_path = '/plugins';
    $content = str_replace($current_path, $new_path, $content);
    return $content;
}

add_action('generate_rewrite_rules', 'roots_add_rewrites');
if (!is_admin()) {
  add_filter('plugins_url', 'roots_clean_plugins');
  add_filter('bloginfo', 'roots_clean_assets');
  add_filter('stylesheet_directory_uri', 'roots_clean_assets');
  add_filter('template_directory_uri', 'roots_clean_assets');
  add_filter('script_loader_src', 'roots_clean_plugins');
  add_filter('style_loader_src', 'roots_clean_plugins');

?>

Thanks for the contribution. Can you include some commenting or documentation on how this is to be used and what it might break?

On twenty thirteen theme, would this go in the functions.php?

just for completion: this go in functions.php, of course, in every theme.

Only variables should be passed by reference
error line
$theme_name = next(explode('/themes/', $content));

@Brushez check my fork and comment to get rid of that error.

$theme_name = next(explode('/themes/', $content));

to

$nval = explode( '/themes/', $content );
$theme_name = next( $nval );

$theme_name = next(explode('/themes/', get_stylesheet_directory()));

to

$mval = explode( '/themes/', get_stylesheet_directory() );
$theme_name = next( $mval );