    # File lib/compass/commands/watch_project.rb, line 61
          def perform
            Signal.trap("INT") do
              puts ""
              exit 0
            end

            check_for_sass_files!(new_compiler_instance)
            recompile

            require 'fssm'

            if options[:poll]
              require "fssm/backends/polling"
              # have to silence the ruby warning about chaning a constant.
              stderr, $stderr = $stderr, StringIO.new
              FSSM::Backends.const_set("Default", FSSM::Backends::Polling)
              $stderr = stderr
            end

            action = FSSM::Backends::Default.to_s == "FSSM::Backends::Polling" ? "polling" : "watching"

            puts ">>> Compass is #{action} for changes. Press Ctrl-C to Stop."

            begin
            FSSM.monitor do |monitor|
              Compass.configuration.sass_load_paths.each do |load_path|
                load_path = load_path.root if load_path.respond_to?(:root)
                next unless load_path.is_a? String
                monitor.path load_path do |path|
                  path.glob '**/*.s[ac]ss'

                  path.update &method(:recompile)
                  path.delete {|base, relative| remove_obsolete_css(base,relative); recompile(base, relative)}
                  path.create &method(:recompile)
                end
              end
              Compass.configuration.watches.each do |glob, callback|
                monitor.path Compass.configuration.project_path do |path|
                  path.glob glob
                  path.update do |base, relative|
                    puts ">>> Change detected to: #{relative}"
                    callback.call(base, relative)
                  end
                  path.create do |base, relative|
                    puts ">>> New file detected: #{relative}"
                    callback.call(base, relative)
                  end
                  path.delete do |base, relative|
                    puts ">>> File Removed: #{relative}"
                    callback.call(base, relative)
                  end
                end
              end

            end
          rescue FSSM::CallbackError => e
            # FSSM catches exit? WTF.
            if e.message =~ /exit/
              exit
            end
          end
          end