vendor/rails/activesupport/lib/active_support/duration.rb

   1 require 'active_support/basic_object'
   2
   3 module ActiveSupport
   4   # Provides accurate date and time measurements using Date#advance and
   5   # Time#advance, respectively. It mainly supports the methods on Numeric,
   6   # such as in this example:
   7   #
   8   #   1.month.ago       # equivalent to Time.now.advance(:months => -1)
   9   class Duration < BasicObject
  10     attr_accessor :value, :parts
  11
  12     def initialize(value, parts) #:nodoc:
  13       @value, @parts = value, parts
  14     end
  15
  16     # Adds another Duration or a Numeric to this Duration. Numeric values
  17     # are treated as seconds.
  18     def +(other)
  19       if Duration === other
  20         Duration.new(value + other.value, @parts + other.parts)
  21       else
  22         Duration.new(value + other, @parts + [[:seconds, other]])
  23       end
  24     end
  25
  26     # Subtracts another Duration or a Numeric from this Duration. Numeric
  27     # values are treated as seconds.
  28     def -(other)
  29       self + (-other)
  30     end
  31
  32     def -@ #:nodoc:
  33       Duration.new(-value, parts.map { |type,number| [type, -number] })
  34     end
  35
  36     def is_a?(klass) #:nodoc:
  37       klass == Duration || super
  38     end
  39
  40     # Returns true if <tt>other</tt> is also a Duration instance with the
  41     # same <tt>value</tt>, or if <tt>other == value</tt>.
  42     def ==(other)
  43       if Duration === other
  44         other.value == value
  45       else
  46         other == value
  47       end
  48     end
  49
  50     def self.===(other) #:nodoc:
  51       other.is_a?(Duration) rescue super
  52     end
  53
  54     # Calculates a new Time or Date that is as far in the future
  55     # as this Duration represents.
  56     def since(time = ::Time.current)
  57       sum(1, time)
  58     end
  59     alias :from_now :since
  60
  61     # Calculates a new Time or Date that is as far in the past
  62     # as this Duration represents.
  63     def ago(time = ::Time.current)
  64       sum(-1, time)
  65     end
  66     alias :until :ago
  67
  68     def inspect #:nodoc:
  69       consolidated = parts.inject(::Hash.new(0)) { |h,part| h[part.first] += part.last; h }
  70       [:years, :months, :days, :minutes, :seconds].map do |length|
  71         n = consolidated[length]
  72         "#{n} #{n == 1 ? length.to_s.singularize : length.to_s}" if n.nonzero?
  73       end.compact.to_sentence(:locale => :en)
  74     end
  75
  76     protected
  77
  78       def sum(sign, time = ::Time.current) #:nodoc:
  79         parts.inject(time) do |t,(type,number)|
  80           if t.acts_like?(:time) || t.acts_like?(:date)
  81             if type == :seconds
  82               t.since(sign * number)
  83             else
  84               t.advance(type => sign * number)
  85             end
  86           else
  87             raise ::ArgumentError, "expected a time or date, got #{time.inspect}"
  88           end
  89         end
  90       end
  91
  92     private
  93
  94       def method_missing(method, *args, &block) #:nodoc:
  95         value.send(method, *args)
  96       end
  97   end
  98 end