def link(repo_sha, position)
      # symlink to the checked out cookbook only if it was actually checked out
      if repo_dir = @registered_checkouts[repo_sha]
        checkout_path = CookbookPathMapping.checkout_path(repo_dir, position)
        raise ArgumentError.new("Missing directory cannot be linked: #{checkout_path}") unless File.directory?(checkout_path)
        repose_path   = CookbookPathMapping.repose_path(@repose_root, repo_sha, position)
        FileUtils.mkdir_p(File.dirname(repose_path))
        Platform.filesystem.create_symlink(checkout_path, repose_path)
        return true
      end
      false
    end
def link(repo_sha, position)
      # symlink to the checked out cookbook only if it was actually checked out
      if repo_dir = @registered_checkouts[repo_sha]
        checkout_path = CookbookPathMapping.checkout_path(repo_dir, position)
        raise ArgumentError.new("Missing directory cannot be linked: #{checkout_path}") unless File.directory?(checkout_path)
        repose_path   = CookbookPathMapping.repose_path(@repose_root, repo_sha, position)
        FileUtils.mkdir_p(File.dirname(repose_path))
        Platform.filesystem.create_symlink(checkout_path, repose_path)
        return true
      end
      false
    end
Creates a symlink from the checked out cookbook to the expected repose download location

 === Parameters
 repo_sha (String) :: unique identifier of the cookbook repository
 position (String) :: repo relative ppath of the cookbook

 === Returns
 true if link was created, false otherwise