class Idler

public

Since stable-v2.

parameter　maximum_load　Numeric

The maximum load before we start shedding work.

parameter　backoff　Numeric

The initial backoff time, used for delaying work.

parameter　parent　Interface(:async) | Nil

The parent task to use for async operations.

def initialize(maximum_load = 0.8, backoff: 0.01, parent: nil)
	@maximum_load = maximum_load
	@backoff = backoff
	@parent = parent
end

asynchronous

Executes the given block concurrently.

parameter　arguments　Array

The arguments to pass to the block.

parameter　parent　Interface(:async) | Nil

The parent task to use for async operations.

parameter　options　Hash

The options to pass to the task.

yields　{|task| ...}

When the system is idle, the block will be executed in a new task.

def async(*arguments, parent: (@parent or Task.current), **options, &block)
	wait
	
	# It is crucial that we optimistically execute the child task, so that we prevent a tight loop invoking this method from consuming all available resources.
	parent.async(*arguments, **options, &block)
end

def wait
	scheduler = Fiber.scheduler
	backoff = nil
	
	while true
		load = scheduler.load
		
		break if load < @maximum_load
		
		if backoff
			sleep(backoff)
			backoff *= 2.0
		else
			scheduler.yield
			backoff = @backoff
		end
	end
end