Slowly working on adding Aria2 support to Homebrew Cask

AriaDownloadStrategy.rb

  class AriaDownloadStrategy < CurlDownloadStrategy

    def aria_args(options = {})
      aria = Pathname.new ENV["HOMEBREW_ARIA"]
      aria = Pathname.new "/usr/local/bin/aria2c" unless aria.exist?
      raise "#{aria} is not executable" unless aria.exist? && aria.executable?

      args = [
        aria.to_s,
        "--remote-time",
        "--location",
      ]

      case options[:user_agent]
      when :browser
        args << "--user-agent" << HOMEBREW_USER_AGENT_FAKE_SAFARI
      else
        args << "--user-agent" << HOMEBREW_USER_AGENT_CURL
      end

      unless options[:show_output]
        args << "--progress-bar" unless ARGV.verbose?
        args << "--verbose" if ENV["HOMEBREW_CURL_VERBOSE"]
        args << "--fail"
        args << "--silent" if !$stdout.tty? || ENV["TRAVIS"]
      end

      args << "--max-connection-per-server=#{ENV['HOMEBREW_ARIA_MAX_PER_SERVER']||8}"

      args += options[:extra_args] if options[:extra_args]
      args
    end

    def _fetch
      odebug "Calling aria2c with args #{cask_curl_args.utf8_inspect}"
      curl(*cask_aria_args)
    end
  end