From: MenTaLguY <mental@...>
Date: 2008-03-19T03:09:33+09:00
Subject: Re: Thread#raise, Thread#kill, and timeout.rb are unsafe

On Tue, 18 Mar 2008 14:04:40 +0900, Tanaka Akira <akr@fsij.org> wrote:
> Basically, asynchronous events should be queued.
> 
> * make a queue for each thread.
> * Thread#raise(exc) enqueue exc to the queue.
> * Thread.check_interrupt(klass) checks an exception which is
>   a kind of klass in the queue of the current thread.  If it
>   exists, the exception is raised.
> * other queue examining mechanism, such as sigpending, etc,
>   may be useful.
> 
> Thread.check_interrupt is a safe point.
> 
> However safe points is not only Thread.check_interrupt.
> Blocking operations, such as I/O, may or may not be safe
> points.  It is because Thread.check_interrupt with blocking
> operations causes race conditions.  So application must
> choose that make a blocking operation interruption safe or
> uninterruptible.
> 
> * Thread.blocking_interruptible(klass) { ... }
> * Thread.blocking_uninterruptible(klass) { ... }
> 
> Blocking operations in Thread.blocking_interruptible are
> safe points.

This sounds very good!  I hadn't considered anything like
blocking_interruptible, but it seems useful.

-mental