Class: Event::Selector::Select

Inherits:
Object
  • Object
show all
Defined in:
lib/event/selector/select.rb

Defined Under Namespace

Classes: Queue

Instance Method Summary collapse

Constructor Details

#initialize(loop) ⇒ Select

Returns a new instance of Select.



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# File 'lib/event/selector/select.rb', line 24

def initialize(loop)
	@loop = loop
	
	@readable = {}
	@writable = {}
	
	@ready = []
end

Instance Method Details

#close ⇒ Object 



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# File 'lib/event/selector/select.rb', line 33

def close
	@loop = nil
	@readable = nil
	@writable = nil
end

#io_read(fiber, io, buffer, length) ⇒ Object 



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# File 'lib/event/selector/select.rb', line 117

def io_read(fiber, io, buffer, length)
	offset = 0
	
	while length > 0
		# The maximum size we can read:
		maximum_size = buffer.size - offset
		
		case result = io.read_nonblock(maximum_size, exception: false)
		when :wait_readable
			self.io_wait(fiber, io, READABLE)
		when :wait_writable
			self.io_wait(fiber, io, WRITABLE)
		else
			break if result.empty?
			
			buffer.copy(result, offset)
			
			offset += result.bytesize
			length -= result.bytesize
		end
	end
	
	return offset
end

#io_wait(fiber, io, events) ⇒ Object 



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# File 'lib/event/selector/select.rb', line 97

def io_wait(fiber, io, events)
	remove_readable = remove_writable = false
	
	if (events & READABLE) > 0 or (events & PRIORITY) > 0
		@readable[io] = fiber
		remove_readable = true
	end
	
	if (events & WRITABLE) > 0
		@writable[io] = fiber
		remove_writable = true
	end
	
	@loop.transfer
ensure
	@readable.delete(io) if remove_readable
	@writable.delete(io) if remove_writable
end

#io_write(fiber, io, buffer, length) ⇒ Object 



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# File 'lib/event/selector/select.rb', line 142

def io_write(fiber, io, buffer, length)
	offset = 0
	
	while length > 0
		# From offset until the end:
		chunk = buffer.to_str(offset, length)
		case result = io.write_nonblock(chunk, exception: false)
		when :wait_readable
			self.io_wait(fiber, io, READABLE)
		when :wait_writable
			self.io_wait(fiber, io, WRITABLE)
		else
			offset += result
			length -= result
		end
	end
	
	return offset
end

#process_wait(fiber, pid, flags) ⇒ Object 



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# File 'lib/event/selector/select.rb', line 163

def process_wait(fiber, pid, flags)
	r, w = IO.pipe
	
	thread = Thread.new do
		Process::Status.wait(pid, flags)
	ensure
		w.close
	end
	
	self.io_wait(fiber, r, READABLE)
	
	return thread.value
ensure
	r.close
	w.close
	thread&.kill
end

#push(fiber) ⇒ Object

Append the given fiber into the ready list.



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# File 'lib/event/selector/select.rb', line 79

def push(fiber)
	@ready.push(fiber)
end

#raise(fiber, *arguments) ⇒ Object

Transfer to the given fiber and raise an exception. Put the current fiber into the ready list.



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# File 'lib/event/selector/select.rb', line 84

def raise(fiber, *arguments)
	queue = Queue.new(Fiber.current)
	@ready.push(queue)
	
	fiber.raise(*arguments)
ensure
	queue.nullify
end

#ready? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/event/selector/select.rb', line 93

def ready?
	@ready.any?
end

#resume(fiber, *arguments) ⇒ Object

Transfer from the current fiber to the specified fiber. Put the current fiber into the ready list.



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# File 'lib/event/selector/select.rb', line 59

def resume(fiber, *arguments)
	queue = Queue.new(Fiber.current)
	@ready.push(queue)
	
	fiber.transfer(*arguments)
ensure
	queue.nullify
end

#select(duration = nil) ⇒ Object 



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# File 'lib/event/selector/select.rb', line 194

def select(duration = nil)
	if pop_ready
		duration = 0
	end
	
	readable, writable, _ = ::IO.select(@readable.keys, @writable.keys, nil, duration)
	
	ready = Hash.new(0)
	
	readable&.each do |io|
		fiber = @readable.delete(io)
		ready[fiber] |= READABLE
	end
	
	writable&.each do |io|
		fiber = @writable.delete(io)
		ready[fiber] |= WRITABLE
	end
	
	ready.each do |fiber, events|
		fiber.transfer(events) if fiber.alive?
	end
end

#transfer ⇒ Object

Transfer from the current fiber to the event loop.



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# File 'lib/event/selector/select.rb', line 54

def transfer
	@loop.transfer
end

#yield ⇒ Object

Yield from the current fiber back to the event loop. Put the current fiber into the ready list.



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# File 'lib/event/selector/select.rb', line 69

def yield
	queue = Queue.new(Fiber.current)
	@ready.push(queue)
	
	@loop.transfer
ensure
	queue.nullify
end