class Sprockets::StaticAsset

def write_to(filename, options = {})
  # Gzip contents if filename has '.gz'
  options[:compress] ||= File.extname(filename) == '.gz'
  FileUtils.mkdir_p File.dirname(filename)
  if options[:compress]
    # Open file and run it through `Zlib`
    pathname.open('rb') do |rd|
      File.open("#{filename}+", 'wb') do |wr|
        gz = Zlib::GzipWriter.new(wr, Zlib::BEST_COMPRESSION)
        gz.mtime = mtime.to_i
        buf = ""
        while rd.read(16384, buf)
          gz.write(buf)
        end
        gz.close
      end
    end
  else
    # If no compression needs to be done, we can just copy it into place.
    FileUtils.cp(pathname, "#{filename}+")
  end
  # Atomic write
  FileUtils.mv("#{filename}+", filename)
  # Set mtime correctly
  File.utime(mtime, mtime, filename)
  nil
ensure
  # Ensure tmp file gets cleaned up
  FileUtils.rm("#{filename}+") if File.exist?("#{filename}+")
end