#!/usr/bin/ruby

require 'rubygems/package'

module RubyGemsProv
  module Helpers
    # If there is some prelease version files, such as rc1 (i.e. non-numeric
    # field), prepend this field by tilde instead of dot.
    def self.normalize_prerelease(version)
      if version.prerelease?
        prerelease = version.version.sub /^#{version.release}\./, ''
        "#{version.release}~#{prerelease}"
      else
        version.release
      end
    end
  end

  # Reports all functionality gem provides.
  def self.provides
    while filename = gets
      filename.strip!
      begin
        specification = Gem::Specification.load filename

        puts "rubygem(#{specification.name}) = #{Helpers::normalize_prerelease(specification.version)}"
      rescue => e
        # Ignore all errors.
      end
    end
  end
end

if __FILE__ == $0
  RubyGemsProv::provides
end