runs an arbitrary commands when files change

rego.rb

#! /usr/bin/env ruby

## rego command to run -- files to watch
#
# rego command_to_run on @ -- {lib/*,test/*}
#
  require 'time'
  require 'pathname'
  require 'rubygems'

  pos = ARGV.index('--')

  if pos
    command = ARGV[0...pos].join(' ')
    paths = ARGV[pos + 1 .. -1]
  else
    command = ARGV[0..-1].join(' ')
    paths = []
  end

  command = 'echo @' if paths.empty?
  paths = %w[.] if paths.empty?

  paths.map!{|path| test(?d, path) ? [path, Dir.glob(File.join(path, '**/**'))] : path}
  paths.flatten!
  paths.compact!
  paths.uniq!
  paths.map! do |path|
    Pathname.new(path).realpath.to_s
  end

##
#
  require 'yaml'
  #STDERR.puts({command => paths}.to_yaml)
  #STDERR.puts
  puts "## #{ command }"
  puts "#"
  puts paths.join("\n")
  puts

##
#
  directories = []
  files = []
  paths.each do |path|
    if test(?d, path)
      directories.push(path)
    else
      files.push(path)
      directories.push(File.dirname(path))
    end
  end
  directories.uniq!
  files.uniq!

  stats = {} 

  files.each do |file|
    begin
      stats[file] = File.stat(file)
    rescue
      nil
    end
  end

  require 'rb-fsevent'
  fsevent = FSEvent.new

  n = '0'
  line = '#' * 42
  $running = false

  rego = proc do |*args|
    entry = args.shift
    cmd = entry ? command.gsub(/@/, entry) : command
    puts line
    puts "# rego.#{ n } @ #{ Time.now.strftime('%H:%M:%S') } - #{ cmd }"
    puts
    system(cmd)
    puts
    puts "# rego.#{ n } @ #{ Time.now.strftime('%H:%M:%S') } - #{ $?.exitstatus }"
    puts
    n.succ!
  end

  rego[ false ]

  fsevent.watch(directories) do |*args|
    unless $running
      $running = true

      args.flatten.each do |dir|
        glob = File.join(dir, '**/**')
        entries = Dir.glob(glob)

        entries.each do |entry|
          entry = File.expand_path(entry)
          next unless stats.has_key?(entry)

          begin
            stats[entry] ||= File.stat(entry)
            before = stats[entry]
            after = File.stat(entry)
          rescue
            next
          end

          unless before.mtime == after.mtime
            stats[entry] = after
            rego[ entry ]
          end
        end
      end
    end
    $running = false
  end

  fsevent.run




=begin
require 'rb-inotify'
notifier = INotify::Notifier.new
notifier.watch(paths, :modify) {puts "foo.txt was modified!"}
#notifier.watch("path/to/bar", :moved_to, :create) do |event|
  #puts "#{event.name} is now in path/to/bar!"
#end
notifier.run
=end



#exit

=begin

require 'directory_watcher'
dw = DirectoryWatcher.new(paths, :scanner => :rev)

dw.add_observer do |*args|
  args.each{|event| puts event}
end

dw.start

trap('INT'){ exit! }
sleep
=end