lib/god/event_handler.rb

   1 module God
   2   class EventHandler
   3     @@actions = {}
   4     @@handler = nil
   5     @@loaded = false
   6
   7     def self.loaded?
   8       @@loaded
   9     end
  10
  11     def self.load
  12       begin
  13         case RUBY_PLATFORM
  14         when /darwin/i, /bsd/i
  15           require 'god/event_handlers/kqueue_handler'
  16           @@handler = KQueueHandler
  17         when /linux/i
  18           require 'god/event_handlers/netlink_handler'
  19           @@handler = NetlinkHandler
  20         else
  21           raise NotImplementedError, "Platform not supported for EventHandler"
  22         end
  23         @@loaded = true
  24       rescue
  25         require 'god/event_handlers/dummy_handler'
  26         @@handler = DummyHandler
  27         @@loaded = false
  28       end
  29     end
  30
  31     def self.register(pid, event, &block)
  32       @@actions[pid] ||= {}
  33       @@actions[pid][event] = block
  34       @@handler.register_process(pid, @@actions[pid].keys)
  35     end
  36
  37     def self.deregister(pid, event=nil)
  38       if watching_pid? pid
  39         if event.nil?
  40           @@actions.delete(pid)
  41           @@handler.register_process(pid, []) if system("kill -0 #{pid} &> /dev/null")
  42         else
  43           @@actions[pid].delete(event)
  44           @@handler.register_process(pid, @@actions[pid].keys) if system("kill -0 #{pid} &> /dev/null")
  45         end
  46       end
  47     end
  48
  49     def self.call(pid, event)
  50       @@actions[pid][event].call if watching_pid?(pid) && @@actions[pid][event]
  51     end
  52
  53     def self.watching_pid?(pid)
  54       @@actions[pid]
  55     end
  56
  57     def self.start
  58       Thread.new do
  59         loop do
  60           @@handler.handle_events
  61         end
  62       end
  63     end
  64
  65   end
  66 end