From: Sean O'Halpin <sean.ohalpin@...>
Date: 2008-07-12T08:31:25+09:00
Subject: Re: Thread-safe priority queue?

On Thu, Jul 10, 2008 at 8:03 PM, Joel VanderWerf
<vjoel@path.berkeley.edu> wrote:
> Joel VanderWerf wrote:
>>
>> Joel VanderWerf wrote:
>>>
>>> Looks like a race condition in that...
>>
>> Proposed fix, using a condition var... still needs some eyeballing and
>> some tests:
>
> That was not quite right either (because cond.signal only wakes the waiter,
> and doesn't schedule it). The following seems to complete without deadlocks
> or starvation.
>
Thanks for taking the time to do this Joel. You can see why I was
hoping it had already been done... ;)

I resurrected the Queue code from an old copy of 1.8.4 I had lying
around and went with that + your original version of the
PriorityQueue. Still putting it through its paces. I'll give your new
version a whirl too.

@Roger - just putting a mutex around all the access methods isn't
sufficient unfortunately (see Joel's code for evidence). I want the
calling thread to block if there's nothing in the queue (like the
standard lib Queue behaves). And once I start putting that machinery
in, I might as well write the whole thing myself. I was hoping to
avoid that (trying to be virtuous :)

Regards,
Sean