Class: WrapMethod

Inherits:
Monitor
  • Object
show all
Includes:
Singleton
Defined in:
lib/agent/wrap_method.rb

Constant Summary collapse

@@wrapped = 
[]

Instance Method Summary collapse

Instance Method Details

#key(clazz, method) ⇒ Object 



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# File 'lib/agent/wrap_method.rb', line 9

def key(clazz, method)
  clazz.to_s + ":" + method.to_s
end

#wrap(clazz, methodName, &block) ⇒ Object 



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# File 'lib/agent/wrap_method.rb', line 13

def wrap(clazz, methodName, &block)
  methodKey = key(clazz, methodName)
  if @@wrapped.index(methodKey) != nil
    raise methodKey + " Previously wrapped"
  end
  synchronize do
    clazz.instance_methods.each do |inst_method|
      if inst_method == methodName
        # crack the class
        clazz.instance_eval do
          # rename the original method
          inst_method_sym = inst_method.to_sym
          renamed_inst_method_sym = ("insight_wrapped_" + inst_method).to_sym
          puts "Aliasing " + inst_method.to_s + " -> " + renamed_inst_method_sym.to_s + "\n"
          alias_method renamed_inst_method_sym, inst_method_sym
          insight_method_name = ("insight_wrapper_" + inst_method).to_sym

          # Define a new method which executes our code at the beginning
          # and end
          puts "Creating " + insight_method_name.to_s + "\n"
          define_method insight_method_name do |*args, &argblock|
            block.call(:enter, clazz, inst_method, *args)
            if renamed_inst_method_sym.is_a?(Symbol)
              val = send(renamed_inst_method_sym, *args, &argblock)
            else
              val = renamed_inst_method_sym.call(*args, &argblock)
            end
            block.call(:exit, clazz, inst_method, *args)
          end

          # Alias our method over the original one
          puts "Aliasing " + inst_method.to_s + " -> " + insight_method_name.to_s + "\n"            
          alias_method inst_method_sym, insight_method_name
        end
        @@wrapped << methodKey
        @@wrapped.sort
      end
    end
  end
end