[cfe-dev] libclang cancellation of long running tasks

[John Sully]

Hi Jonathan,

I don't understand how std::future::wait_for would allow me to cancel a
running libclang operation.

I'm not asking how to do this asynchronously - I already have that
working.  I need a way to stop performing work when the results become
obsolete. I could always shutdown the thread its on but that would leave
things in an undefined state.


On Mon, Jan 12, 2015 at 6:04 PM, Jonathan Roelofs <jonathan at codesourcery.com
> wrote:

> John,
>
> It should be fairly straightforward for you to implement this behavior in
> your application using std::future::wait_for.
>
>
> Jon
>
> On 1/12/15 6:33 PM, John Sully wrote:
>
>> Yes it already runs on a separate thread; however when its known the
>> result is no longer necessary (for example the user changed the cursor
>> location - negating the need for autocomplete at the previous location)
>> the separate thread still runs consuming resources.
>>
>> On slower devices like laptops these operations can take a long time.
>> Even if we are willing to accept the waste of cycles (and battery
>> life!), the processor has a limited number of cores and responsiveness
>> will be poor if too many "zombie" jobs are still running.
>>
>> I'm willing to add this functionality and submit it upstream if
>> necessary, but prior to doing so I wanted to reach out to current
>> developers.  It would be unfortunate to invest significant effort only
>> to find my patch can't be accepted for an avoidable reason.
>>
>>
>> On Mon, Jan 12, 2015 at 4:09 PM, Sean Silva <chisophugis at gmail.com
>> <mailto:chisophugis at gmail.com>> wrote:
>>
>>     Have you tried running libclang on a separate thread?
>>
>>     On Sun, Jan 11, 2015 at 7:59 PM, John Sully <john at csquare.ca
>>     <mailto:john at csquare.ca>> wrote:
>>
>>         I'm in the process of writing an editor based upon libclang, and
>>         a major issue I'm hitting is the inability to cancel long
>>         running tasks.  The primary tasks are parsing and creation of
>>         auto-complete results.
>>
>>         Is there already functionality to do this that I've missed?
>>
>>         If not, I would like to implement this as its a requirement to
>>         get good responsiveness out of my editor.  Has there been any
>>         prior discussions on how this should be implemented?
>>
>>         _______________________________________________
>>         cfe-dev mailing list
>>         cfe-dev at cs.uiuc.edu <mailto:cfe-dev at cs.uiuc.edu>
>>         http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>>
>>
>>
>>
>>
>> _______________________________________________
>> cfe-dev mailing list
>> cfe-dev at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>>
>>
> --
> Jon Roelofs
> jonathan at codesourcery.com
> CodeSourcery / Mentor Embedded
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-dev/attachments/20150112/f0d008dd/attachment.html>