#                                                                          
# File 'cachemanager.rb' created on 28 gen 2008 at 18:31:05.                    
#
# See 'dokkit.rb' or +LICENSE+ for licence information.                      
#                                                                          
# (C) 2006, 2007 Andrea Fazzi <andrea.fazzi@alca.le.it> (and contributors). 
#                                                                          

require 'singleton'
require 'rake'
require 'yaml'

module Dokkit
  class CacheManager
    include Singleton
    def init(cache_filename = 'deps.yaml', cache_dir = '.cache')
      @cache_filename = cache_filename
      @cache_dir = cache_dir
      @complete_cache_filename = File.join(cache_dir, cache_filename)
      @deps = {}
      load if File.exists?(@complete_cache_filename)
      at_exit { save }
    end
    def add_dependency(task_name, dep)
      @deps[task_name] ||= []
      @deps[task_name] << dep unless (dep.nil? or @deps[task_name].include?(dep))
    end
    def load
      File.open(@complete_cache_filename) do |file|
        @deps = YAML::load(file)
        @deps.each do |task, dep|
          file task => dep
        end
      end
    end
    def save
      unless @deps.empty?
        mkdir_p(cache_dir, :verbose => false) unless File.exists?(cache_dir)
        File.open(@complete_cache_filename, 'w') do |file|
          file.write YAML::dump(@deps)
        end
      end
    end
    def clean_deps
      @deps.clear
    end
    def clean
      clean_deps
      rm_rf(cache_dir, :verbose => false) unless cache_dir == '.'
    end
    def deps
      @deps
    end
    def cache_dir
      @cache_dir
    end
    def cache_filename
      @cache_filename
    end
  end
end