class Bundler::Fetcher

def gemspec_cached_path(spec_file_name)

cached gem specification path, if one exists 
def gemspec_cached_path(spec_file_name)
  paths = Bundler.rubygems.spec_cache_dirs.map {|dir| File.join(dir, spec_file_name) }
  paths.find {|path| File.file? path }
end