[vlc-devel] [PATCH 4/6] fetcher: use vlc_executor_t

[Romain Vimont]

On Tue, Sep 08, 2020 at 12:36:09PM +0200, Alexandre Janniaux wrote:
> Hi,
> 
> I like the end result very much

Cool, thank you :) But I still have mixed feelings overall [1]

[1] https://mailman.videolan.org/pipermail/vlc-devel/2020-September/137226.html

> though the race condition
> on Cancel is a bit inconvenient. I don't have any better way
> for now anyway.

An interrupt() callback so that we could just _CancelAll() and forget?
</troll>

(or even a vlc_interrupt_t passed as a parameter to the run() callback?)

I agree that in the end the user both requests the cancelation and
provide the actual interruption mechanism.

But the executor knows better if interrupt() must be called and when to
call it easily without race conditions.

Instead, here, the user has to store a list of all its submitted tasks
for the sole purpose of canceling them all on delete. And it must cancel
them one by one, because the executor must indicate whether the task
has been actually dequeued or not, to avoid race conditions.

(In addition, semantically, I consider the interruption implementation
to be part of a task: in theory, the creator of the task could be
different from the one submitting it, even if in practice it's the same
for our use cases.)

Regards