module LSync::EventHandler
Basic event handling and delegation.
Public Instance Methods
Abort the current event handler. Aborting an event handler persistently implies that in the future it will still be aborted; thus calling try
will have no effect.
# File lib/lsync/event_handler.rb, line 85 def abort!(persistent = false) @aborted = true if persistent throw abort_name end
Fire an event which calls all registered event handlers in the order they were defined. The first argument is used to instance_eval any handlers.
# File lib/lsync/event_handler.rb, line 35 def fire(event, *args) handled = false scope = args.shift if @events && @events[event] @events[event].each do |handler| handled = true if scope scope.instance_exec *args, &handler else handler.call end end end return handled end
Register an event handler which may be triggered when an event is fired.
# File lib/lsync/event_handler.rb, line 26 def on(event, &block) @events ||= {} @events[event] ||= [] @events[event] << block end
Try executing a given block of code and fire appropriate events.
The sequence of events (registered via on
) are as follows:
:prepare
-
Fired before the block is executed. May call
abort!
to cancel execution. :success
-
Fired after the block of code has executed without raising an exception.
:failure
-
Fired if an exception is thrown during normal execution.
:done
-
Fired at the end of execution regardless of failure.
If abort!
has been called in the past, this function returns immediately.
# File lib/lsync/event_handler.rb, line 64 def try(*arguments) return if @aborted begin catch(abort_name) do fire(:prepare, *arguments) yield fire(:success, *arguments) end rescue Exception => error # Propagage the exception unless it was handled in some specific way. raise unless fire(:failure, *arguments + [error]) ensure fire(:done, *arguments) end end
Private Instance Methods
The name used for throwing abortions.
# File lib/lsync/event_handler.rb, line 94 def abort_name ("abort_" + self.class.name).downcase.to_sym end