class Opal::Util::Command

def command_installed?(cmd, install_comment)
  command_installed = Command::INSTALLED[cmd.to_s] ||= which(cmd)
  $stderr.puts %Q("#{cmd}" command not found#{install_comment}) unless command_installed
  command_installed
end

def hide_stderr
  if (/mswin|mingw/ =~ RUBY_PLATFORM).nil?
    '2> /dev/null'
  else
    '2> nul'
  end
end

def initialize(command, options, message = nil)
  @command, @options, @message = command, options, message
  return unless command_installed? command, message
end

def which(cmd)
  exts = ENV['PATHEXT'] ? ENV['PATHEXT'].split(';') : ['']
  ENV['PATH'].split(File::PATH_SEPARATOR).find do |path|
    exts.find { |ext|
      exe = File.join(path, "#{cmd}#{ext}")
      exe if File.executable? exe
    }
  end
end