#!/usr/bin/ruby

 # This script watches modifications on the given directory, using the new # FSEvents API in Leopard.

 require 'osx/foundation'

 OSX.require_framework '/System/Library/Frameworks/CoreServices.framework/Frameworks/CarbonCore.framework'

 include OSX

 require 'set'

 require 'optparse'

 require 'ostruct'

 $COMMAND = File.basename($0)

 $USAGE = "Usage: #{$COMMAND} [OPTIONS] <command> [<args> ...]"

 def die(s)

   $stderr.puts s

   exit 1

 end

 options = OpenStruct.new

 options.directoriesOnly = false

 options.outputFile = "-"

 opts = OptionParser.new do |opts|

   opts.banner = $USAGE

   opts.separator ""

   opts.separator "Specific options:"

   opts.on("-d", "--dir-only", "Only display directories") do

     options.directoriesOnly = true

   end

   opts.on("-o", "--output FILE", "Write output to a file") do |fileName|

     options.outputFile = fileName

   end

   opts.on_tail("-h", "--help", "Show this message") do

     puts opts

     exit

   end

 end

 opts.parse!(ARGV)

 die $USAGE unless ARGV.size >= 1

 if options.outputFile == "-"

   outputHandle = $stdout.clone

 else

   outputHandle = File.open(options.outputFile, "w")

 end

 path = "/"

 startId = FSEventsGetCurrentEventId()

 # Used to compare with mtime, which only has second accuracy

 startTime = Time.now.to_i

 fork do

   begin

     exec(*ARGV)

   rescue SystemCallError  => e

     puts e.message

     exit 127

   end

 end

 pid = Process.wait

 returnCode = $? >> 8

 sleep(0.1)

 allPaths = Set.new

 fsevents_cb = proc do |stream, ctx, numEvents, paths, marks, eventIDs|

   paths.regard_as('*')

   numEvents.times do |n|

     allPaths.add(paths[n])

   end

 end

 stream = FSEventStreamCreate(

   KCFAllocatorDefault,

   fsevents_cb,

   nil,

   [path],

   startId,

   1.0,

   KFSEventStreamCreateFlagNoDefer)

 die "Failed to create the FSEventStream" unless stream

 FSEventStreamScheduleWithRunLoop(

   stream,

   CFRunLoopGetCurrent(),

   KCFRunLoopDefaultMode)

 ok = FSEventStreamStart(stream)

 die "Failed to start the FSEventStream" unless ok

 FSEventStreamFlushSync(stream)

 allPaths.sort.each do |path|

   if File.exists?(path)

     outputHandle.puts path

     if (!options.directoriesOnly)

       Dir.foreach(path) do |file|

         fullPath = File.join(path, file)

         stat = File.stat(fullPath)

         if (stat.mtime.to_i >= startTime)

           outputHandle.puts "  #{file}"

         end

       end

     end

   else

     outputHandle.puts "#{path} !"

   end

 end

 FSEventStreamStop(stream)

 FSEventStreamInvalidate(stream)

 FSEventStreamRelease(stream)

 outputHandle.flush

 exit(returnCode)