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class Module
# Synchronize access around a method, delegating synchronization to a
# particular mutex. A mutex (either a Mutex, or any object that responds to
# #synchronize and yields to a block) must be provided as a final :with option.
# The :with option should be a symbol or string, and can represent a method,
# constant, or instance or class variable.
# Example:
# class SharedCache
# @@lock = Mutex.new
# def expire
# ...
# end
# synchronize :expire, :with => :@@lock
# end
def synchronize(*methods)
options = methods.extract_options!
unless options.is_a?(Hash) && with = options[:with]
raise ArgumentError, "Synchronization needs a mutex. Supply an options hash with a :with key as the last argument (e.g. synchronize :hello, :with => :@mutex)."
end
methods.each do |method|
if instance_methods.include?("#{method}_without_synchronization")
raise ArgumentError, "#{method} is already synchronized. Double synchronization is not currently supported."
end
module_eval(<<-EOS, __FILE__, __LINE__)
def #{method}_with_synchronization(*args, &block)
#{with}.synchronize do
#{method}_without_synchronization(*args,&block)
end
end
EOS
alias_method_chain method, :synchronization
end
end
end
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