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rails--rails/activesupport/lib/active_support/duration.rb
2012-09-17 00:22:18 -05:00

108 lines
2.9 KiB
Ruby

require 'active_support/basic_object'
require 'active_support/core_ext/array/conversions'
require 'active_support/core_ext/object/acts_like'
module ActiveSupport
# Provides accurate date and time measurements using Date#advance and
# Time#advance, respectively. It mainly supports the methods on Numeric.
#
# 1.month.ago # equivalent to Time.now.advance(months: -1)
class Duration < BasicObject
attr_accessor :value, :parts
def initialize(value, parts) #:nodoc:
@value, @parts = value, parts
end
# Adds another Duration or a Numeric to this Duration. Numeric values
# are treated as seconds.
def +(other)
if Duration === other
Duration.new(value + other.value, @parts + other.parts)
else
Duration.new(value + other, @parts + [[:seconds, other]])
end
end
# Subtracts another Duration or a Numeric from this Duration. Numeric
# values are treated as seconds.
def -(other)
self + (-other)
end
def -@ #:nodoc:
Duration.new(-value, parts.map { |type,number| [type, -number] })
end
def is_a?(klass) #:nodoc:
Duration == klass || value.is_a?(klass)
end
alias :kind_of? :is_a?
# Returns +true+ if +other+ is also a Duration instance with the
# same +value+, or if <tt>other == value</tt>.
def ==(other)
if Duration === other
other.value == value
else
other == value
end
end
def self.===(other) #:nodoc:
other.is_a?(Duration)
rescue ::NoMethodError
false
end
# Calculates a new Time or Date that is as far in the future
# as this Duration represents.
def since(time = ::Time.current)
sum(1, time)
end
alias :from_now :since
# Calculates a new Time or Date that is as far in the past
# as this Duration represents.
def ago(time = ::Time.current)
sum(-1, time)
end
alias :until :ago
def inspect #:nodoc:
consolidated = parts.inject(::Hash.new(0)) { |h,(l,r)| h[l] += r; h }
parts = [:years, :months, :days, :minutes, :seconds].map do |length|
n = consolidated[length]
"#{n} #{n == 1 ? length.to_s.singularize : length.to_s}" if n.nonzero?
end.compact
parts = ["0 seconds"] if parts.empty?
parts.to_sentence(:locale => :en)
end
def as_json(options = nil) #:nodoc:
to_i
end
protected
def sum(sign, time = ::Time.current) #:nodoc:
parts.inject(time) do |t,(type,number)|
if t.acts_like?(:time) || t.acts_like?(:date)
if type == :seconds
t.since(sign * number)
else
t.advance(type => sign * number)
end
else
raise ::ArgumentError, "expected a time or date, got #{time.inspect}"
end
end
end
private
def method_missing(method, *args, &block) #:nodoc:
value.send(method, *args, &block)
end
end
end