brew/Library/Homebrew/cask/lib/hbc/utils/tty.rb

# originally from Homebrew utils.rb

class Hbc::Utils::Tty
  COLORS = {
             black:   0,
             red:     1,
             green:   2,
             yellow:  3,
             blue:    4,
             magenta: 5,
             cyan:    6,
             white:   7,
             default: 9,
           }.freeze

  ATTRIBUTES = {
                 reset:         0,
                 bold:          1,
                 dim:           2,
                 italic:        3,
                 underline:     4,
                 blink:         5,
                 inverse:       7,
                 invisible:     8,
                 strikethrough: 9,
                 normal:        22,
               }.freeze

  @sequence = []

  class << self
    COLORS.keys.each do |sym|
      define_method(sym) do
        foreground(COLORS[sym])
      end
      define_method("fg_#{sym}".to_sym) do
        foreground(COLORS[sym])
      end
      define_method("bg_#{sym}".to_sym) do
        background(COLORS[sym])
      end
    end

    ATTRIBUTES.keys.each do |sym|
      define_method(sym) do
        deferred_emit(ATTRIBUTES[sym])
      end
    end

    def width
      `/usr/bin/tput cols`.strip.to_i
    end

    def truncate(str)
      str.to_s[0, width - 4]
    end

    private

    def foreground(color)
      deferred_emit(to_foreground_code(color))
    end

    def background(color)
      deferred_emit(to_background_code(color))
    end

    def to_color_code(space, color)
      return unless (num = to_color_number(color))
      return space + num if num < space
      return space + 9 if num > space
      num
    end

    def to_foreground_code(color)
      to_color_code(30, color)
    end

    def to_background_code(color)
      to_color_code(40, color)
    end

    def to_color_number(color)
      COLORS[color] || color.is_a?(Integer) ? color : nil
    end

    def to_attribute_number(attribute)
      ATTRIBUTES[attribute] || attribute.is_a?(Integer) ? attribute : nil
    end

    def sanitize_integer(arg)
      return arg.to_i if arg.is_a?(Integer)
      return 0        if arg.to_s =~ %r{^0+$}
      if arg.respond_to?(:to_i) && (int = arg.to_i) > 0
        return int
      end
      $stderr.puts "Warning: bad Tty code #{arg}"
      ATTRIBUTES[:reset]
    end

    def deferred_emit(*codes)
      @sequence.concat Array(*codes).map(&method(:sanitize_integer))
      Hbc::Utils::Tty
    end

    def to_s
      sequence = @sequence
      @sequence = []
      return "" unless $stdout.tty?
      if sequence.empty?
        $stderr.puts "Warning: empty Tty sequence"
        sequence = [ATTRIBUTES[:reset]]
      end
      "#{initiate}#{sequence.join(';')}#{terminate}"
    end

    def initiate
      "\033["
    end

    def terminate
      "m"
    end
  end
end