Class: Cordis::Fiber

Inherits:
Object
  • Object
show all
Defined in:
lib/cordis/fiber.rb

Overview

Fiber (upstream 4.0's new name for EffectScope): the lifecycle unit of a plugin, and also the collector of revertible effects (the paper's phi accumulator). Note: the clash with Ruby core's ::Fiber is deliberate, to match upstream naming; Cordis never uses core Fiber directly.

Defined Under Namespace

Classes: Entry

Constant Summary collapse

INACTIVE = 
:__inactive__

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(parent_ctx, config: nil, inject: {}, runtime: nil) ⇒ Fiber

Returns a new instance of Fiber.



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# File 'lib/cordis/fiber.rb', line 18

def initialize(parent_ctx, config: nil, inject: {}, runtime: nil)
  @config = config
  @inject = inject
  @runtime = runtime
  @disposables = []
  @provided = {} # name => isolate key (for boundary-crossing notify on state change)
  @internal_store = {} # currently satisfied dependencies (name => Impl), continuously updated
  @store = nil         # snapshot taken while loading; nil means unloaded
  @current_epoch = INACTIVE
  @target_epoch = INACTIVE
  @inertia = nil       # in-flight load/unload transition task
  @error = nil
  @state = :pending

  if runtime.nil? # root fiber
    @uid = 0
    @ctx = parent_ctx
    @parent_fiber = nil
    @current_epoch = @target_epoch = ''
    @store = {}
    @state = :active
    return
  end

  @uid = parent_ctx.root.registry.next_uid
  @parent_fiber = parent_ctx.fiber
  @parent_ctx = parent_ctx
  @ctx = parent_ctx.extend(fiber: self)
  # inject with a Hash config doubles as an intercept entry on the plugin's ctx
  # (mirrors upstream fiber.ts:139)
  inject.each { |dep, cfg| @ctx = @ctx.intercept(dep, cfg) if cfg.is_a?(Hash) }
  runtime.fibers << self
  @ctx.events.emit('internal/plugin', self)
  inject.each_key { |name| check_impl(name) }
  # a plugin is itself a revertible effect on the parent fiber (mirrors upstream fiber.ts:170)
  @entry = parent_ctx.fiber.effect('ctx.plugin()') do
    refresh
    -> { terminate }
  end
end

Instance Attribute Details

#config ⇒ Object (readonly)

Returns the value of attribute config.



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# File 'lib/cordis/fiber.rb', line 15

def config
  @config
end

#ctx ⇒ Object (readonly)

Returns the value of attribute ctx.



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# File 'lib/cordis/fiber.rb', line 15

def ctx
  @ctx
end

#error ⇒ Object (readonly)

Returns the value of attribute error.



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# File 'lib/cordis/fiber.rb', line 15

def error
  @error
end

#inject ⇒ Object (readonly)

Returns the value of attribute inject.



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# File 'lib/cordis/fiber.rb', line 15

def inject
  @inject
end

#parent_ctx ⇒ Object (readonly)

Returns the value of attribute parent_ctx.



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# File 'lib/cordis/fiber.rb', line 15

def parent_ctx
  @parent_ctx
end

#parent_fiber ⇒ Object (readonly)

Returns the value of attribute parent_fiber.



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# File 'lib/cordis/fiber.rb', line 15

def parent_fiber
  @parent_fiber
end

#provided ⇒ Object (readonly)

Returns the value of attribute provided.



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# File 'lib/cordis/fiber.rb', line 15

def provided
  @provided
end

#runtime ⇒ Object (readonly)

Returns the value of attribute runtime.



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# File 'lib/cordis/fiber.rb', line 15

def runtime
  @runtime
end

#state ⇒ Object (readonly)

Returns the value of attribute state.



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# File 'lib/cordis/fiber.rb', line 15

def state
  @state
end

#store ⇒ Object (readonly)

Returns the value of attribute store.



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# File 'lib/cordis/fiber.rb', line 15

def store
  @store
end

#uid ⇒ Object (readonly)

Returns the value of attribute uid.



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# File 'lib/cordis/fiber.rb', line 15

def uid
  @uid
end

Instance Method Details

#assert_active ⇒ Object

Raises:



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# File 'lib/cordis/fiber.rb', line 84

def assert_active
  return if @store && %i[loading active].include?(@state)

  raise InactiveEffectError, 'cannot create effect on inactive context'
end

#await ⇒ Object

Wait for all in-flight transitions to finish (while, not if: transitions chain).

Raises:



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# File 'lib/cordis/fiber.rb', line 91

def await
  while (task = @inertia)
    task.wait
  end
  raise @error if @error

  self
end

#check_impl(name) ⇒ Object

-- coeffect machinery (dependency-graph updates are fully synchronous; only load/unload execution is async) --



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# File 'lib/cordis/fiber.rb', line 123

def check_impl(name)
  impl = @ctx.root.services[@ctx.isolate_key(name)]
  if impl && impl.fiber.state == :active
    @internal_store[name] = impl
  else
    @internal_store.delete(name)
  end
end

#dispose ⇒ Object 



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# File 'lib/cordis/fiber.rb', line 100

def dispose
  return restart if root?

  @entry.call
  nil
end

#disposed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/cordis/fiber.rb', line 60

def disposed? = @uid.nil?

#effect(label = nil, &block) ⇒ Object

Apply a side effect and collect its inverse. The block returns: nil (nothing), a callable (single disposer), or an Array/Enumerator of callables (multi-step disposers, reverted in reverse order — upstream's function* effects). If setup raises midway, already-collected disposers are rolled back in reverse, then re-raised.



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# File 'lib/cordis/fiber.rb', line 72

def effect(label = nil, &block)
  assert_active
  disposers = collect_disposers(block, rollback: true)
  entry = Entry.new(disposers, label)
  @disposables << entry
  lambda do
    next unless @disposables.reject! { |e| e.equal?(entry) }

    entry.disposers.reverse_each(&:call)
  end
end

#name ⇒ Object 



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# File 'lib/cordis/fiber.rb', line 62

def name
  return 'root' if root?

  @runtime.name || 'plugin'
end

#refresh ⇒ Object 



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# File 'lib/cordis/fiber.rb', line 132

def refresh
  epoch = ''
  @inject.each_key do |name|
    impl = @internal_store[name]
    if impl.nil?
      epoch = INACTIVE
      break
    end
    epoch = "#{epoch}:#{impl.fiber.uid}"
  end
  set_epoch(epoch)
end

#restart ⇒ Object 



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# File 'lib/cordis/fiber.rb', line 107

def restart
  set_epoch(INACTIVE)
  await # wait for the unload first (refreshing right away would set the target back
  # to the original epoch and coalesce the unload intent away)
  refresh
  await
end

#root? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/cordis/fiber.rb', line 59

def root? = @runtime.nil?

#update(config) ⇒ Object 



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# File 'lib/cordis/fiber.rb', line 115

def update(config)
  @config = config
  restart
end