module Spruz::Write

def write(filename, content = nil, mode = 'w')
  temp = File.new(filename + ".tmp.#$$.#{Time.now.to_f}", mode)
  if content.nil? and block_given?
    yield temp
  elsif !content.nil?
    temp.write content
  else
    raise ArgumentError, "either content or block argument required"
  end
  temp.close
  File.rename temp.path, filename
ensure
  temp and !temp.closed? and temp.close
  File.file?(temp.path) and File.unlink temp.path
end