Module: Interloper::ClassMethods

Defined in:
lib/interloper.rb

Instance Method Summary collapse

Instance Method Details

#after(*method_names, &callback) ⇒ Object


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# File 'lib/interloper.rb', line 131

def after(*method_names, &callback)
  interloper_module.define_interloper_methods(*method_names, interloper_const_name)
  interloper_module.add_callbacks(:after, *method_names, &callback)
end

#ancestor_interloper_moduleModule

Returns The nearest ancstors tha is an interloper module.

Returns:

  • (Module)

    The nearest ancstors tha is an interloper module.


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# File 'lib/interloper.rb', line 160

def ancestor_interloper_module
  ancestors.detect do |ancestor|
     ancestor.respond_to?(:interloper_module) && (ancestor != self)
  end.interloper_module
end

#before(*method_names, &callback) ⇒ Object


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# File 'lib/interloper.rb', line 126

def before(*method_names, &callback)
  interloper_module.define_interloper_methods(*method_names, interloper_const_name)
  interloper_module.add_callbacks(:before, *method_names, &callback)
end

#generate_interloper_moduleObject


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# File 'lib/interloper.rb', line 54

def generate_interloper_module
  Module.new do
    class << self
      # @return [Array] The list of available hooks.
      def hooks
        [:before, :after]
      end

      # @return [Hash] The default hash for tracking callbacks to methods.
      def default_callbacks
        {}.tap do |callbacks|
          hooks.each do |hook|
            callbacks[hook] = {}
          end
        end
      end

      # @param [Symbol] hook Optional name of a hook. See .hook method in
      #   this module.
      # @param [Symbol] method_name Optional name of a method.
      # @return [Hash, Array] A hash or array of callbacks. If the 'hook'
      #   param is provided, it will return a hash of callbacks keyed by
      #   method name. If both 'hook' and 'method_name' are provided, will
      #   return an array of callbacks for the given hook and method.
      def callbacks(hook=nil, method_name=nil)
        @callbacks ||= default_callbacks
        if hook && method_name
          # Returns callback stack for a given method and hook. If there
          # aren't callbacks in the stack, return something enumberable to
          # be loop-friendly.
          @callbacks.fetch(hook).fetch(method_name, [])
        elsif hook
          # Return all callbacks for a given hook, e.g. :before.
          @callbacks.fetch(hook)
        else
          @callbacks
        end
      end

      def run_callbacks(hook, method_name, object_context, *orig_args, &orig_block)
        callbacks(hook, method_name).each do |callback|
          object_context.instance_exec *orig_args, &callback
        end
      end

      def add_callbacks(hook, *method_names, &callback)
        method_names.each do |method_name|
          callbacks[hook][method_name] ||= []
          callbacks[hook][method_name] << callback
        end
      end

      def define_interloper_methods(*method_names, interloper_module_name)
        method_names.each do |method_name|
          unless instance_methods.include? method_name
            module_eval do
              eval <<-CODE
                def #{method_name}(*args, &block)
                  self.class.const_get(:#{interloper_module_name}).run_callbacks(:before, :#{method_name}, self, *args, &block)
                  return_val = super(*args, &block)
                  self.class.const_get(:#{interloper_module_name}).run_callbacks(:after, :#{method_name}, self, *args, &block)
                  return_val
                end
              CODE
            end
          end
        end
      end
    end
  end
end

#inherit_callbacks_after(*method_names) ⇒ Object


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# File 'lib/interloper.rb', line 147

def inherit_callbacks_after(*method_names)
  inherited_callbacks(:after, *method_names).each do |callback|
    after(*method_names, &callback)
  end
end

#inherit_callbacks_before(*method_names) ⇒ Object


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# File 'lib/interloper.rb', line 141

def inherit_callbacks_before(*method_names)
  inherited_callbacks(:before, *method_names).each do |callback|
    before(*method_names, &callback)
  end
end

#inherit_callbacks_for(*method_names) ⇒ Object


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# File 'lib/interloper.rb', line 136

def inherit_callbacks_for(*method_names)
  inherit_callbacks_before(*method_names)
  inherit_callbacks_after(*method_names)
end

#inherited_callbacks(hook, *method_names) ⇒ Object


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# File 'lib/interloper.rb', line 153

def inherited_callbacks(hook, *method_names)
  method_names.map do |method_name|
    ancestor_interloper_module.callbacks[hook][method_name]
  end.flatten
end

#interloper_const_nameObject


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# File 'lib/interloper.rb', line 15

def interloper_const_name
  if self.name
    "Interloper"
  else
    "AnonymousInterloper#{self.object_id}"
  end.to_sym
end

#interloper_moduleObject

Generates an Interloper module that is namespaced under the including class, if one does not already exist. Then prepends the Interloper module to the including class.

Returns:

  • Module the Interloper module that was prepended to the including class.


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# File 'lib/interloper.rb', line 28

def interloper_module
  unless prepended? interloper_const_name
    const_set(interloper_const_name, generate_interloper_module)
    prepend const_get(interloper_const_name)
  end
  const_get(interloper_const_name)
end

#prepended?(const_name) ⇒ Boolean

Returns Boolean True if the interloper module has already been prepnded;] false otherwise.

Returns:

  • (Boolean)

    Boolean True if the interloper module has already been prepnded;] false otherwise.


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# File 'lib/interloper.rb', line 38

def prepended?(const_name)
  if self.name
    # If we are not anonymous, then check for the interloper constant name
    # in the list of prepended modules.
    prepended_modules.include? const_name
  else
    # If we are an anonymous class, check for the anonymous interloper
    # module name in the list of constants defined for this class.
    self.constants.include? interloper_const_name
  end
end

#prepended_modulesObject


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# File 'lib/interloper.rb', line 50

def prepended_modules
  ancestors.slice(0, ancestors.find_index(self))
end