Module: Psyllium::FiberClassMethods

Included in:
Fiber
Defined in:
lib/psyllium/fiber.rb

Overview

Meant to be used with extend on Fiber class.

Instance Method Summary collapse

Instance Method Details

#start(*args, &block) ⇒ Object

A new method is used to create Psyllium Fibers for several reasons:

  1. This ensures that existing behavior for Fibers is not changed.

  2. Modifying the actual instances variables of Fibers does not work well with certain schedulers like Async which expect to also wrap the given block in another block.

  3. The start method is also available on the Thread class, so this makes it easy to change out one for the other.

Raises:

  • (ArgumentError) 


47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
 
# File 'lib/psyllium/fiber.rb', line 47

def start(*args, &block)
  raise ArgumentError.new('No block given') unless block

  Fiber.schedule do
    state = state_get(create_missing: true)
    state.mutex.synchronize do
      state.started = true
      state.value = block.call(*args)
    rescue StandardError => e
      state.exception = e
    ensure
      state.joined = true
    end
  end
end

#state_get(fiber: Fiber.current, create_missing: false) ⇒ Object 



63
64
65
66
67
68
69
70
71
72
73
 
# File 'lib/psyllium/fiber.rb', line 63

def state_get(fiber: Fiber.current, create_missing: false)
  # Psyllium state is a thread local variable because Fibers cannot (yet)
  # migrate across threads anyway.
  #
  # A `WeakKeyMap` is used so that when a Fiber is garbage collected, the
  # associated Psyllium::State will be garbage collected as well.
  state = Thread.current.thread_variable_get(:psyllium_state) || Thread.current.thread_variable_set(
    :psyllium_state, ObjectSpace::WeakKeyMap.new
  )
  create_missing ? (state[fiber] ||= State.new) : state[fiber]
end