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