Strips trailing whitespace from source files

strip_whitespace.rb

#!/usr/bin/env ruby

require 'pathname'

# files and extensions to process
FILES      = %w[ capfile Capfile Dockerfile Gemfile Gemfile.devtools Gemfile.lock Guardfile CHANGELOG LICENSE Manifest README README.rdoc README_FOR_APP RUNNING_UNIT_TESTS Rakefile RUBY-STYLE SPECS TODO USAGE Vagrantfile .autotest .gitattributes .gitignore .htaccess .rspec .rcov .rvmrc .travis.yml .vimrc ].freeze
EXTENSIONS = %w[ builder cabal cgi coffee conf css deface deploy erb example fcgi feature handlebars haml hs htc htm html jinja js json key markdown md opts pem php rabl rake ratom rb rcsv rdf rdoc reek rhtml rip rjs rpdf ru rxml sake sass scss sh sls smil sql svg thor txt vcf xml yml ].freeze

paths = ARGV.flat_map(&Pathname.method(:glob))
paths.each do |path_in|
  # TODO: check to see if this excludes hidden fields
  start_path = path_in.directory? ? path_in.join('**/*') : path_in

  Pathname.glob((start_path).to_s).each do |path|
    unless path.file? && path.size? && path.readable? && path.writable? && (FILES.include?(path.basename.to_s) || EXTENSIONS.include?(path.extname[1..-1]))
#      puts "Skipping #{path}" if path.file?
      next
    end

    # replace leading whitespace (including tabs) with spaces
    # replace trailing whitespace with a newline
    document = path.open('r') do |fh|
      fh.map { |line| line.gsub(/\G\t/, '  ').rstrip << "\n" }.join.rstrip
    end << "\n"

    # truncate the file if it is empty
    document = '' if document.strip.empty?

    # skip it if the file was not modified
    next if document == path.read

    puts "Modifying #{path}"
    path.open('w') { |fh| fh.write document }
  end
end