SimpleProgressbar.rb

=begin

https://github.com/bitboxer/simple_progressbar.git

Copyright (c) 2010 Bodo Tasche

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

=end

class SimpleProgressbar
  def initialize
    @last_length = 0
    @title = ""
    @progress = 0
  end

  def show(title, &block)
    @title = title
    print @title + " "
    start_progress
    # thanks to http://www.dcmanges.com/blog/ruby-dsls-instance-eval-with-delegation
    @self_before_instance_eval = eval "self", block.binding
    instance_eval(&block)
    finish_progress
  end

  def interrupt
    # TODO: Make some of the strings constants so we don't have to use a magic number here.
    progressbar_length = 16 + @last_length + @title.length
    move_cursor = "\e[#{progressbar_length}D"
    print move_cursor + (" " * progressbar_length) + move_cursor
    STDOUT.flush
    yield
    puts
    print @title + " "
    render_progress(@progress)
  end

  def progress(percent)
    print "\e[#{15 + @last_length}D"
    render_progress(percent)
  end

  def method_missing(method, *args, &block)
    @self_before_instance_eval.send method, *args, &block
  end

  private

  def render_progress(percent)
    @progress = percent
    print "["

    print "*" * [(percent/10).to_i, 10].min
    print " " * [10 - (percent/10).to_i, 0].max

    if percent.class != Float
      printable_percent = "%3s" % percent
    else
      non_decimal_digits = (Math.log(percent) / Math.log(10)).truncate + 1
      printable_percent = (non_decimal_digits < 3 ? " " * (3 - non_decimal_digits) : "") + percent.to_s
    end

    print "]\e[32m #{printable_percent}\e[0m %"

    new_length = printable_percent.length
    if @last_length > new_length
      print " " * (@last_length - new_length)
      print "\e[#{@last_length - new_length}D"
    end
    @last_length = new_length

    STDOUT.flush
  end

  def start_progress
    render_progress(0)
  end

  def finish_progress
    puts
  end
end