class Sass::Exec::SassConvert

def process_file(input, output)
  if input.is_a?(File)
    @options[:from] ||=
      case input.path
      when /\.scss$/; :scss
      when /\.sass$/; :sass
      when /\.less$/; :less
      when /\.css$/; :css
      end
  elsif @options[:in_place]
    raise "Error: the --in-place option requires a filename."
  end
  if output.is_a?(File)
    @options[:to] ||=
      case output.path
      when /\.scss$/; :scss
      when /\.sass$/; :sass
      end
  end
  @options[:from] ||= :css
  @options[:to] ||= :sass
  @options[:for_engine][:syntax] = @options[:from]
  out =
    ::Sass::Util.silence_sass_warnings do
      if @options[:from] == :css
        require 'sass/css'
        ::Sass::CSS.new(input.read, @options[:for_tree]).render(@options[:to])
      elsif @options[:from] == :less
        require 'sass/less'
        try_less_note
        input = input.read if input.is_a?(IO) && !input.is_a?(File) # Less is dumb
        Less::Engine.new(input).to_tree.to_sass_tree.send("to_#{@options[:to]}", @options[:for_tree])
      else
        if input.is_a?(File)
          ::Sass::Engine.for_file(input.path, @options[:for_engine])
        else
          ::Sass::Engine.new(input.read, @options[:for_engine])
        end.to_tree.send("to_#{@options[:to]}", @options[:for_tree])
      end
    end
  output = File.open(input.path, 'w') if @options[:in_place]
  output.write(out)
rescue ::Sass::SyntaxError => e
  raise e if @options[:trace]
  file = " of #{e.sass_filename}" if e.sass_filename
  raise "Error on line #{e.sass_line}#{file}: #{e.message}\n  Use --trace for backtrace"
rescue LoadError => err
  handle_load_error(err)
end