Module: LSync::EventHandler
Overview
Basic event handling and delegation.
Instance Method Summary collapse
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#abort!(persistent = false) ⇒ Object
Abort the current event handler.
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#fire(event, *args) ⇒ Object
Fire an event which calls all registered event handlers in the order they were defined.
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#on(event, &block) ⇒ Object
Register an event handler which may be triggered when an event is fired.
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#try(*arguments) ⇒ Object
Try executing a given block of code and fire appropriate events.
Instance Method Details
#abort!(persistent = false) ⇒ Object
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.
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# File 'lib/lsync/event_handler.rb', line 85 def abort!(persistent = false) @aborted = true if persistent throw abort_name end |
#fire(event, *args) ⇒ Object
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.
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# 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_eval &handler else handler.call end end end return handled end |
#on(event, &block) ⇒ Object
Register an event handler which may be triggered when an event is fired.
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# File 'lib/lsync/event_handler.rb', line 26 def on(event, &block) @events ||= {} @events[event] ||= [] @events[event] << block end |
#try(*arguments) ⇒ Object
Try executing a given block of code and fire appropriate events.
The sequence of events (registered via #on) are as follows:
:prepare
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Fired before the block is executed. May call #abort! to cancel execution.
:success
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Fired after the block of code has executed without raising an exception.
:failure
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Fired if an exception is thrown during normal execution.
:done
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Fired at the end of execution regardless of failure.
If #abort! has been called in the past, this function returns immediately.
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# 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 |