From: ara.t.howard@...
Date: 2007-02-17T00:34:07+09:00
Subject: Re: Thread.current.parent and Thread.current.ancestors

On Fri, 16 Feb 2007, Erik Veenstra wrote:

> It doesn't work with Thread#start (==fork)...
>
> Thread#start doesn't reuse Thread.new. Neither does
> rb_thread_create(), which is used in e.g. TK.
>
> All three methods (new, start/fork and rb_thread_create()) come
> together in rb_thread_alloc(). That's the place where the
> parent should be set. The problem is that you can't redefine
> rb_thread_alloc() in Ruby... ;[

hrrrm.  good point, this is the best i've come up with:


harp:~ > cat a.rb
class Thread
   class << self
     alias_method "__new__", "new"
     def new *a, &b
       child '__new__', *a, &b
     end
     alias_method "__start__", "start"
     def start *a, &b
       child '__start__', *a, &b
     end
   private
     def child as, *a, &b
       parent = Thread.current
       send(as, *a) do |*a|
         Thread.current.parent = parent
         b.call *a
       end
     end
   end
   def parent
     self['parent']
   end
   def parent= parent
     self['parent'] = parent
   end
   def ancestors
     return self['ancestors'] if self['ancestors']
     list = [t = self]
     while((t = t.parent))
       list << t
     end
     self['ancestors'] = list
   end
end


Thread.new{ Thread.new{ Thread.new{ sleep 0.42 and p [Thread.current, Thread.current.ancestors] } } }
Thread.start{ Thread.start{ Thread.start{ sleep 0.42 and p [Thread.current, Thread.current.ancestors] } } }

STDIN.gets


harp:~ > ruby a.rb
[#<Thread:0xb75cc0f8 run>, [#<Thread:0xb75cc0f8 run>, #<Thread:0xb75cc24c dead>, #<Thread:0xb75cc3a0 dead>, #<Thread:0xb75da748 sleep>]]
[#<Thread:0xb75cc508 run>, [#<Thread:0xb75cc508 run>, #<Thread:0xb75cc65c dead>, #<Thread:0xb75cc7b0 dead>, #<Thread:0xb75da748 sleep>]]


> I really like this Thread.current.parent or Thread.parent.
> There's at least one place where I really, really need it
> myself... Something for Ruby 1.8.6?... ;]

RCR?

-a
-- 
we can deny everything, except that we have the possibility of being better.
simply reflect on that.
- the dalai lama