From: transfire@...
Date: 2006-07-11T01:21:47+09:00
Subject: Re: instance_exec

Okay, I think I've improved it some more:

require 'thread'

class Proc
  MethodMutexes = Hash.new do |hash, key|
    hash[key] = Mutex.new
  end

  # Creates a local method based on a Proc.
  def to_method(name=nil, recv=nil)
    unless name
      n = 0
      n += 1 while recv.respond_to?(name = "__to_method_#{n}")
    end
    recv ||= eval("self", self)
    klass = recv.class
    MethodMutexes[klass => name].synchronize do
      begin
        klass.send(:define_method, name, &self)
        return recv.method(name)
      ensure
        klass.send(:remove_method, name) unless name
      end
    end
  end
end

> This can create a lot of different symbols, leading to large memory leaks.
>
> >       recv ||= eval("self", self)
> >       klass = recv.class
> >       MethodMutexes[klass => name].synchronize do
>         ============================
>
> This makes the memleak even heavier, going from potentially ~70 bytes to
> nearly 300 bytes per call...

I don't understand this though. isn't the memory freed when done? Or is
some symbol getting created in the process, or ?

> >         begin
> >           klass.send(:define_method, name, &self)
>             ==========
>
> This will fail if the class was frozen.

Ah, I see if the _klass_ is frozen. But that will fail regardless won't
it? You can;t even include a module (ef InstanceExecHelper) in a frozen
class. Right?

Thanks,
T.