def find_all(req)
        res = []

        name = req.dependency.name

        @all[name].each do |uri, ver, plat|
          if req.dependency.match? name, ver
            res << IndexSpecification.new(self, name, ver, uri, plat)
          end
        end

        res
      end
Return an array of IndexSpecification objects matching
DependencyRequest +req+.