Handling Filesystem Events with GCD and Macruby

filesystem_events.rb

#!/usr/local/bin/macruby
framework 'Foundation'
include Dispatch

#``O_EVTONLY`` is defined as ``0x8000`` in the OS X header files.
# instead of RDONLY flag I use the O_EVTONLY flag to open() the file, otherwise we'll prevent the 
# volume that the file is on from being unmounted.

O_EVTONLY = 0x8000

file = File.open("/path/to/config.plist", O_EVTONLY)
q = Queue.new('org.macruby.gcd_filesystem_events.sources')
type = Source::VNODE
option = Source::VNODE_EXTEND

# hold the changes
@oldFile = file.read

Dispatch::Source.new(type, file, option, q) {  |src|
  src.suspend!
  puts "changed data: #{src.data} #{src.handle.path}" if src.suspended?
  src.resume!
  showChanges
  
  # to cancel
  src.cancel! 
}
# show last state and New State

def showChanges
  file = File.open("/path/to/config.plist", File::RDONLY).read
  warn @oldFile
  puts file
  puts "_________________________________"
  @oldFile = file
end

NSRunLoop.currentRunLoop.runUntilDate(NSDate.distantFuture)