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# Copyright 2011-2013 Amazon.com, Inc. or its affiliates. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"). You
# may not use this file except in compliance with the License. A copy of
# the License is located at
#
# http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file is
# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
# ANY KIND, either express or implied. See the License for the specific
# language governing permissions and limitations under the License.
module AWS
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
end
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