module Core

# Mixin that provides a generic callback facility for asynchronous

# tasks that can either succeed or fail.

module AsyncHandle

# Called to signal success and fire off the success and complete callbacks.

def signal_success

__send_signal(:success)

end

# Called to signal failure and fire off the failure and complete callbacks.

def signal_failure

__send_signal(:failure)

end

# Registers a callback to be called on successful completion of

# the task.

#

# handle.on_success { puts "It worked!" }

#

# If this is called when the task has already completed

# successfully, it will call the callback immediately.

def on_success(&block)

if @_async_status == :success

block.call

else

(@_async_callbacks ||= []) << { :success => block }

end

end

# Registers a callback to be called when the task fails.

#

# handle.on_failure { puts "It didn't work!" }

#

# If this is called when the task has already failed, it will

# call the callback immediately.

def on_failure(&block)

if @_async_status == :failure

block.call

else

(@_async_callbacks ||= []) << { :failure => block }

end

end

# Registers a callback to be called when the task is complete,

# regardless of its status. Yields the status to the block.

#

# handle.on_complete do |status|

# puts "It #{status == :success ? 'did' : 'did not'} work!"

# end

#

# If this is called when the task has already completed, it will

# call the callback immediately.

def on_complete(&block)

if !@_async_status.nil?

block.call(@_async_status)

else

(@_async_callbacks ||= []) << {

:failure => lambda { block.call(:failure) },

:success => lambda { block.call(:success) }

}

end

end

private

def __send_signal(kind)

@_async_status = kind

@_async_callbacks.map do |cb|

cb[kind]

end.compact.each {|block| block.call } if @_async_callbacks

end

end

end