Module: AttrCallback::Util

Defined in:
lib/attr_callback.rb

Constant Summary collapse

NoopProc = 
Proc.new{}

Class Method Summary collapse

Class Method Details

.define_callback_on_class(klass, name, options = {}) ⇒ Object 



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# File 'lib/attr_callback.rb', line 19

def define_callback_on_class(klass, name, options={})
  name = name.to_sym
  locking = options[:lock].nil? ? true : options[:lock]
  noop = options[:noop].nil? ? true : options[:noop]

  # Define the setter.  If the user specified :lock=>true, then the
  # setter will synchronize on @name_lock; otherwise, we just use
  # the standard attr_writer.
  if locking
    klass.__send__(:define_method, "#{name}=") do |value|
      AttrCallback::Util.get_or_create_mutex(self, name).synchronize {
        instance_variable_set("@#{name}", value)
      }
    end
  else
    klass.__send__(:attr_writer, name)
  end

  # Define the getter.  If the user specified :lock=>true, then the
  # getter will synchronize on @name_lock; otherwise, it won't.
  klass.__send__(:define_method, name) do |*args, &block|
    raise ArgumentError, "wrong number of arguments (#{args.length} for 0)" unless args.empty?

    if block.nil?
      if locking
        callback = AttrCallback::Util.get_or_create_mutex(self, name).synchronize { instance_variable_get("@#{name}") }
      else
        callback = instance_variable_get("@#{name}")
      end
      if noop and callback.nil?
        NoopProc
      else
        callback
      end
    else
      __send__("#{name}=", block)
    end
  end
end

.get_or_create_mutex(obj, name) ⇒ Object 



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# File 'lib/attr_callback.rb', line 10

def get_or_create_mutex(obj, name)
  mutex = obj.instance_variable_get("@#{name}_lock")
  if mutex.nil?
    obj.instance_variable_set("@#{name}_lock", Mutex.new)
  else
    mutex
  end
end