master/lib/guard.rb

require 'bundler'

module Guard
  
  autoload :UI,         'guard/ui'
  autoload :Dsl,        'guard/dsl'
  autoload :Interactor, 'guard/interactor'
  autoload :Listener,   'guard/listener'
  autoload :Watcher,    'guard/watcher'
  autoload :Notifier,   'guard/notifier'
  
  class << self
    attr_accessor :options, :guards, :listener
    
    def start(options = {})
      @options  = options
      @listener = Listener.new
      @guards   = []
      
      Dsl.evaluate_guardfile
      if guards.empty?
        UI.error "No guards found in Guardfile, too bad."
      else
        Interactor.init_signal_traps
        
        listener.on_change do |files|
          run do
            guards.each do |guard|
              paths = Watcher.match_files(guard, files)
              guard.run_on_change(paths) unless paths.empty?
            end
          end
        end
        
        UI.info "Guard is now watching at '#{Dir.pwd}'"
        guards.each(&:start)
        listener.start
      end
    end
    
    def add_guard(name, watchers = [], options = {})
      guard_class = get_guard_class(name)
      @guards << guard_class.new(watchers, options)
    end
    
    def get_guard_class(name)
      require "guard/#{name.downcase}"
      guard_class = ObjectSpace.each_object(Class).detect { |c| c.to_s.downcase.match "^guard::#{name.downcase}" }
    rescue LoadError
      UI.error "#{name} guard gem not found, try to add it to your Gemfile."
    end
    
    def locate_guard(name)
      spec = Bundler.load.specs.find{|s| s.name == "guard-#{name}" }
      UI.error "Could not find gem '#{name}' in the current Gemfile." unless spec
      spec.full_gem_path
    end
    
    def run
      listener.stop
      yield
      listener.start
    end
    
  end
end