2 issues and 1 proposal for runInUnboundThread

[Simon Marlow]

On 14/10/2010 23:00, Bas van Dijk wrote:
> Hello,
>
> I found two small issues in Control.Concurrent:
>
> * Both runInBoundThread and runInUnboundThread use throw instead of
> throwIO. It's nicer to use throwIO in an IO context instead of throw
> because it guarantees ordering with respect to other IO actions.
>
> * runInUnboundThread explicitly checks the blocked status of the
> current thread which is redundant because mask also performs this
> check.
>
> I also have a new proposal:
>
> When you throw an asynchronous exception to a thread which is
> executing: `runInUnboundThread m`, m will keep executing and there's
> no way to kill it.
 >
> I propose to catch asynchronous exceptions in runInUnboundThread and
> throw them to the thread which is executing m. m in turn can decide to
> catch or ignore them. In case m decides to ignore them or to rethrow
> them, the exception will be rethrown in the current thread:
>
> runInUnboundThread :: IO a ->  IO a
> runInUnboundThread action = do
>    bound<- isCurrentThreadBound
>    if bound
>      then do
>        mv<- newEmptyMVar
>        mask $ \restore ->  do
>          tid<- forkIO $ Exception.try (restore action)>>= putMVar mv
>          let wait = takeMVar mv `Exception.catch` \(e :: SomeException) ->
>                       Exception.throwTo tid e>>  wait
>          wait>>= unsafeResult
>      else action
>
> unsafeResult :: Either SomeException a ->  IO a
> unsafeResult = either Exception.throwIO return

I think it's ok, no objections here.  Do you have a use for 
runInUnboundThread, incidentally?

Cheers,
	Simon