Class: EventMachine::Completion

Inherits:
Object
  • Object
show all
Includes:
Deferrable
Defined in:
lib/em/completion.rb

Constant Summary

Constants included from Deferrable

Deferrable::Pool

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Deferrable

future

Constructor Details

#initialize ⇒ Completion

Returns a new instance of Completion.



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# File 'lib/em/completion.rb', line 171

def initialize
  @state = :unknown
  @callbacks = Hash.new { |h,k| h[k] = [] }
  @value = []
  @timeout_timer = nil
end

Instance Attribute Details

#state ⇒ Object (readonly)

Returns the value of attribute state.



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# File 'lib/em/completion.rb', line 169

def state
  @state
end

#value ⇒ Object (readonly)

Returns the value of attribute value.



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# File 'lib/em/completion.rb', line 169

def value
  @value
end

Instance Method Details

#callback(*a, &b) ⇒ Object

Callbacks are called when you enter (or are in) a :succeeded state.



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# File 'lib/em/completion.rb', line 206

def callback(*a, &b)
  stateback(:succeeded, *a, &b)
end

#cancel_callback(*a, &b) ⇒ Object

Remove a callback. N.B. Some callbacks cannot be deleted. Usage is NOT recommended, this is an anti-pattern.



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# File 'lib/em/completion.rb', line 272

def cancel_callback(*a, &b)
  @callbacks[:succeeded].delete(EM::Callback(*a, &b))
end

#cancel_errback(*a, &b) ⇒ Object

Remove an errback. N.B. Some errbacks cannot be deleted. Usage is NOT recommended, this is an anti-pattern.



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# File 'lib/em/completion.rb', line 266

def cancel_errback(*a, &b)
  @callbacks[:failed].delete(EM::Callback(*a, &b))
end

#cancel_timeout ⇒ Object

Disable the timeout



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# File 'lib/em/completion.rb', line 257

def cancel_timeout
  if @timeout_timer
    @timeout_timer.cancel
    @timeout_timer = nil
  end
end

#change_state(state, *args) ⇒ Object Also known as: set_deferred_status

Enter a new state, setting the result value if given. If the state is one of :succeeded or :failed, then :completed callbacks will also be called.



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# File 'lib/em/completion.rb', line 224

def change_state(state, *args)
  @value = args
  @state = state

  EM.schedule { execute_callbacks }
end

#completed? ⇒ Boolean

Indicates that we've reached some kind of completion state, by default this is :succeeded or :failed. Due to these semantics, the :completed state is reserved for internal use.

Returns:

  • (Boolean) 


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# File 'lib/em/completion.rb', line 237

def completed?
  completion_states.any? { |s| state == s }
end

#completion(*a, &b) ⇒ Object

Completions are called when you enter (or are in) either a :failed or a :succeeded state. They are stored as a special (reserved) state called :completed.



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# File 'lib/em/completion.rb', line 218

def completion(*a, &b)
  stateback(:completed, *a, &b)
end

#completion_states ⇒ Object

Completion states simply returns a list of completion states, by default this is :succeeded and :failed.



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# File 'lib/em/completion.rb', line 243

def completion_states
  [:succeeded, :failed]
end

#errback(*a, &b) ⇒ Object

Errbacks are called when you enter (or are in) a :failed state.



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# File 'lib/em/completion.rb', line 211

def errback(*a, &b)
  stateback(:failed, *a, &b)
end

#fail(*args) ⇒ Object Also known as: set_deferred_failure

Enter the :failed state, setting the result value if given.



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# File 'lib/em/completion.rb', line 186

def fail(*args)
  change_state(:failed, *args)
end

#stateback(state, *a, &b) ⇒ Object

Statebacks are called when you enter (or are in) the named state.



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# File 'lib/em/completion.rb', line 193

def stateback(state, *a, &b)
  # The following is quite unfortunate special casing for :completed
  # statebacks, but it's a necessary evil for latent completion
  # definitions.

  if :completed == state || !completed? || @state == state
    @callbacks[state] << EM::Callback(*a, &b)
  end
  execute_callbacks
  self
end

#succeed(*args) ⇒ Object Also known as: set_deferred_success

Enter the :succeeded state, setting the result value if given.



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# File 'lib/em/completion.rb', line 179

def succeed(*args)
  change_state(:succeeded, *args)
end

#timeout(time, *args) ⇒ Object

Schedule a time which if passes before we enter a completion state, this deferrable will be failed with the given arguments.



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# File 'lib/em/completion.rb', line 249

def timeout(time, *args)
  cancel_timeout
  @timeout_timer = EM::Timer.new(time) do
    fail(*args) unless completed?
  end
end