diff --git a/lib/motion/util/version.rb b/lib/motion/util/version.rb new file mode 100644 index 00000000..bd94886c --- /dev/null +++ b/lib/motion/util/version.rb @@ -0,0 +1,47 @@ +module Motion; module Util + class Version + include Comparable + + def initialize(version) + @version = version.to_s + unless @version =~ /^[.0-9]+$/ + raise ArgumentError, "A version may only contain periods and digits." + end + end + + def to_s + @version + end + + def segments + @segments ||= @version.split('.').map(&:to_i) + end + + # This is pretty much vendored straight from RubyGems, except we don’t + # care about string segments for our purposes. + # + # https://github.com/rubygems/rubygems/blob/81d806d818baeb5dcb6398ca631d772a003d078e/lib/rubygems/version.rb + # + def <=>(other) + return unless Version === other + return 0 if @version == other.to_s + + lhsegments = segments + rhsegments = other.segments + + lhsize = lhsegments.size + rhsize = rhsegments.size + limit = (lhsize > rhsize ? lhsize : rhsize) - 1 + + i = 0 + while i <= limit + lhs, rhs = lhsegments[i] || 0, rhsegments[i] || 0 + i += 1 + next if lhs == rhs + return lhs <=> rhs + end + + return 0 + end + end +end; end