class Build::Files::State

def self.dirty?(inputs, outputs)
	if outputs.missing?
		# puts "Output file missing: #{output_state.missing.inspect}"
		return true
	end
	
	# If there are no inputs or no outputs, we are always clean:
	if inputs.empty? or outputs.empty?
		return false
	end
	
	oldest_output_time = outputs.oldest_time
	newest_input_time = inputs.newest_time
	
	if newest_input_time and oldest_output_time
		# We are dirty if any inputs are newer (bigger) than any outputs:
		return newest_input_time > oldest_output_time
	end
	
	return true
end