Charles, I really sure there is no need for `while true` in your numeric
handling cas -
the nature of cas is "change if no one changes yet", so that your `while
true` violates natures of cas.


2013/4/16 headius (Charles Nutter) <headius / headius.com>

>
> Issue #8259 has been updated by headius (Charles Nutter).
>
>
> I have completed adding the numeric logic to the atomic gem and pushed
> 1.1.8.
>
> The version for JRuby is here:
> https://github.com/headius/ruby-atomic/blob/master/ext/org/jruby/ext/atomic/AtomicReferenceLibrary.java#L129
>
> The version for MRI, Rubinius, and others is here:
> https://github.com/headius/ruby-atomic/blob/master/lib/atomic/numeric_cas_wrapper.rb
> ----------------------------------------
> Feature #8259: Atomic attributes accessors
> https://bugs.ruby-lang.org/issues/8259#change-38617
>
> Author: funny_falcon (Yura Sokolov)
> Status: Open
> Priority: Normal
> Assignee:
> Category:
> Target version:
>
>
> =begin
> Motivated by this gist ((<URL:https://gist.github.com/jstorimer/5298581>))
> and atomic gem
>
> I propose Class.attr_atomic which will add methods for atomic swap and CAS:
>
>   class MyNode
>     attr_accessor :item
>     attr_atomic :successor
>
>     def initialize(item, successor)
>       @item = item
>       @successor = successor
>     end
>   end
>   node = MyNode.new(i, other_node)
>
>   # attr_atomic ensures at least #{attr} reader method exists. May be, it
> should
>   # be sure it does volatile access.
>   node.successor
>
>   # #{attr}_cas(old_value, new_value) do CAS: atomic compare and swap
>   if node.successor_cas(other_node, new_node)
>     print "there were no interleaving with other threads"
>   end
>
>   # #{attr}_swap atomically swaps value and returns old value.
>   # It ensures that no other thread interleaves getting old value and
> setting
>   # new one by cas (or other primitive if exists, like in Java 8)
>   node.successor_swap(new_node)
>
> It will be very simple for MRI cause of GIL, and it will use atomic
> primitives for
> other implementations.
>
> Note: both (({#{attr}_swap})) and (({#{attr}_cas})) should raise an error
> if instance variable were not explicitly set before.
>
> Example for nonblocking queue: ((<URL:
> https://gist.github.com/funny-falcon/5370416>))
>
> Something similar should be proposed for Structs. May be override same
> method as (({Struct.attr_atomic}))
>
> Open question for reader:
> should (({attr_atomic :my_attr})) ensure that #my_attr reader method
> exists?
> Should it guarantee that (({#my_attr})) provides 'volatile' access?
> May be, (({attr_reader :my_attr})) already ought to provide 'volatile'
> semantic?
> May be, semantic of (({@my_attr})) should have volatile semantic (i doubt
> for that)?
> =end
>
>
>
> --
> http://bugs.ruby-lang.org/
>
>