self extracting ruby archiver

ruby_archive.rb

#!/usr/bin/env ruby

class RubyArchive

  require 'rubygems/package'
  require 'zlib'

  attr_reader :path

  class Archive

    def initialize(path, object)
      @path   = path
      @object = object
      @data, @tar = StringIO.new, StringIO.new
    end

    def empty?
      @object.size.zero?
    end

    def compressed_files
      Gem::Package::TarReader.new(Zlib::GzipReader.new @object).tap(&:rewind)
    end

    def uncompressed_files
      Dir.glob(File.join @path, '{,**/{*,.*}}').map &File.method(:open)
    end

    def make_dir(directory)
      Dir.mkdir File.join(@path, directory.full_name), directory.header.mode
    end

    def make_file(file)
      File.open(File.join(@path, file.full_name), 'wb') do |f|
        f.write file.read
        f.chmod file.header.mode
      end
    end

    def add_dir(directory)
      tar_writer.mkdir directory.path, directory.stat.mode
    end

    def add_file(file)
      tar_writer.add_file(file.path, file.stat.mode) { |f| f.write file.read }
    end

    def finalize
      @tar.seek 0
      gzip_writer.write @tar.read
      @tar.close
      gzip_writer.finish
      @data.seek 0
    end

    def write
      File.open(filename, 'wb') do |file|
        file.write File.read(__FILE__)
        file.write @data.read
        file.chmod 0o755
      end
    end

    def filename
      @path.gsub(/\//, '') + '-archive.rb'
    end

    def gzip_writer
      @gzip_writer ||=  Zlib::GzipWriter.new(@data)
    end

    def tar_writer
      @tar_writer  ||= Gem::Package::TarWriter.new(@tar)
    end
  end

  def initialize(path)
    @path    = path
    @archive = Archive.new @path, StringIO.new(DATA.read)

    yield self
  end

  def usage
    @archive.empty? ? 'dir_or_file_to_compress' : 'dir_to_decompress_archive_to'
  end

  def run
    @archive.empty? ? compress : decompress
  end

  def decompress
    @archive.compressed_files.each do |object|
      if object.directory?
        @archive.make_dir object
      else
        @archive.make_file object
      end
    end

    system "ls -la #@path" # change me to turn this into an installer
    puts 'Extraction complete.'
  end

  def compress
    @archive.uncompressed_files.each do |object|
      if File.directory? object
        @archive.add_dir object
      else
        @archive.add_file object
      end
    end

    @archive.finalize
    @archive.write
    puts 'Compression complete.'
  end

  def self.start(path)
    new(path) do |ruby_archive|
      if ruby_archive.path
        ruby_archive.run
      else
        puts %|usage: #{__FILE__} /path/to/#{ruby_archive.usage}|
      end
    end
  end
end

RubyArchive.start ARGV.shift

__END__