class SprocketsFilter

SprocketsFilterTest.php in drupal/core/vendor/kriswallsmith/assetic/tests/Assetic/Test/Filter/SprocketsFilterTest.php

class SprocketsFilter implements FilterInterface {
  private $sprocketsLib;
  private $rubyBin;
  private $includeDirs;
  private $assetRoot;

  /**
   * Constructor.
   *
   * @param string $sprocketsLib Path to the Sprockets lib/ directory
   * @param string $rubyBin      Path to the ruby binary
   */
  public function __construct($sprocketsLib = null, $rubyBin = '/usr/bin/ruby') {
    $this->sprocketsLib = $sprocketsLib;
    $this->rubyBin = $rubyBin;
    $this->includeDirs = array();
  }
  public function addIncludeDir($directory) {
    $this->includeDirs[] = $directory;
  }
  public function setAssetRoot($assetRoot) {
    $this->assetRoot = $assetRoot;
  }

  /**
   * Hack around a bit, get the job done.
   */
  public function filterLoad(AssetInterface $asset) {
    static $format = <<<'EOF'
#!/usr/bin/env ruby

require %s
%s
options = { :load_path    => [],
            :source_files => [%s],
            :expand_paths => false }

%ssecretary = Sprockets::Secretary.new(options)
secretary.install_assets if options[:asset_root]
print secretary.concatenation

EOF;
    $more = '';
    foreach ($this->includeDirs as $directory) {
      $more .= 'options[:load_path] << ' . var_export($directory, true) . "\n";
    }
    if (null !== $this->assetRoot) {
      $more .= 'options[:asset_root] = ' . var_export($this->assetRoot, true) . "\n";
    }
    if ($more) {
      $more .= "\n";
    }
    $tmpAsset = tempnam(sys_get_temp_dir(), 'assetic_sprockets');
    file_put_contents($tmpAsset, $asset
      ->getContent());
    $input = tempnam(sys_get_temp_dir(), 'assetic_sprockets');
    file_put_contents($input, sprintf($format, $this->sprocketsLib ? sprintf('File.join(%s, \'sprockets\')', var_export($this->sprocketsLib, true)) : '\'sprockets\'', $this
      ->getHack($asset), var_export($tmpAsset, true), $more));
    $pb = new ProcessBuilder(array(
      $this->rubyBin,
      $input,
    ));
    $proc = $pb
      ->getProcess();
    $code = $proc
      ->run();
    unlink($tmpAsset);
    unlink($input);
    if (0 < $code) {
      throw FilterException::fromProcess($proc)
        ->setInput($asset
        ->getContent());
    }
    $asset
      ->setContent($proc
      ->getOutput());
  }
  public function filterDump(AssetInterface $asset) {
  }
  private function getHack(AssetInterface $asset) {
    static $format = <<<'EOF'

module Sprockets
  class Preprocessor
    protected
    def pathname_for_relative_require_from(source_line)
      Sprockets::Pathname.new(@environment, File.join(%s, location_from(source_line)))
    end
  end
end

EOF;
    $root = $asset
      ->getSourceRoot();
    $path = $asset
      ->getSourcePath();
    if ($root && $path) {
      return sprintf($format, var_export(dirname($root . '/' . $path), true));
    }
  }

}