Class: EventMachine::Defer::DeferredPromise

Inherits:
Promise
  • Object
show all
Defined in:
lib/em-promise/defer.rb

Instance Method Summary collapse

Constructor Details

#initialize(defer) ⇒ DeferredPromise

Returns a new instance of DeferredPromise.



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# File 'lib/em-promise/defer.rb', line 13

def initialize(defer)
	@defer = defer
end

Instance Method Details

#then(callback = nil, errback = nil, &blk) ⇒ Object 



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# File 'lib/em-promise/defer.rb', line 18

def then(callback = nil, errback = nil, &blk)
	result = Defer.new
	
	callback ||= blk
	
	wrappedCallback = proc { |value|
		begin
			result.resolve(callback.nil? ? value : callback.call(value))
		rescue => e
			warn "\nUnhandled exception: #{e.message}\n#{e.backtrace.join("\n")}\n"
			result.reject(e);
		end
	}
	
	wrappedErrback = proc { |reason|
		begin
			result.resolve(errback.nil? ? Defer.reject(reason) : errback.call(reason))
		rescue => e
			warn "Unhandled exception: #{e.message}\n#{e.backtrace.join("\n")}\n"
			result.reject(e);
		end
	}
	
	#
	# Schedule as we are touching arrays
	# => Everything else is locally scoped
	#
	EM.schedule do
		pending_array = pending
		
		if pending_array.nil?
			value.then(wrappedCallback, wrappedErrback)
		else
			pending_array << [wrappedCallback, wrappedErrback]
		end
	end
	
	result.promise
end