[vlc-devel] [PATCH 1/4] poll: only wait and call WSAEnumNetworkEvents() if select() reported nothing

[Steve Lhomme]

With this fix I get FD_WRITE twice on my accept()'ed socket meaning we
don't just get the first free one from the connection establishment.

On Tue, Dec 1, 2015 at 10:40 AM, Steve Lhomme <robux4 at videolabs.io> wrote:
> do the WSACloseEvent() afterwards for both cases
> ---
>  compat/poll.c | 91 ++++++++++++++++++++++++++++++++---------------------------
>  1 file changed, 50 insertions(+), 41 deletions(-)
>
> diff --git a/compat/poll.c b/compat/poll.c
> index fa94c93..e7351a4 100644
> --- a/compat/poll.c
> +++ b/compat/poll.c
> @@ -190,55 +190,64 @@ int poll(struct pollfd *fds, unsigned nfds, int timeout)
>              ret = WSA_WAIT_EVENT_0 + i;
>      }
>
> +    unsigned count = 0;
>      if (ret == WSA_WAIT_FAILED)
> +    {
>          ret = WSAWaitForMultipleEvents(nfds, evts, FALSE, to, TRUE);
>
> -    unsigned count = 0;
> +        for (unsigned i = 0; i < nfds; i++)
> +        {
> +            WSANETWORKEVENTS ne;
> +
> +            if (WSAEnumNetworkEvents(fds[i].fd, evts[i], &ne))
> +                memset(&ne, 0, sizeof (ne));
> +
> +            if (ne.lNetworkEvents & FD_CONNECT)
> +            {
> +                fds[i].revents |= POLLWRNORM;
> +                if (ne.iErrorCode[FD_CONNECT_BIT] != 0)
> +                    fds[i].revents |= POLLERR;
> +            }
> +            if (ne.lNetworkEvents & FD_CLOSE)
> +            {
> +                fds[i].revents |= (fds[i].events & POLLRDNORM) | POLLHUP;
> +                if (ne.iErrorCode[FD_CLOSE_BIT] != 0)
> +                    fds[i].revents |= POLLERR;
> +            }
> +            if (ne.lNetworkEvents & FD_ACCEPT)
> +            {
> +                fds[i].revents |= POLLRDNORM;
> +                if (ne.iErrorCode[FD_ACCEPT_BIT] != 0)
> +                    fds[i].revents |= POLLERR;
> +            }
> +            if (ne.lNetworkEvents & FD_OOB)
> +            {
> +                fds[i].revents |= POLLPRI;
> +                if (ne.iErrorCode[FD_OOB_BIT] != 0)
> +                    fds[i].revents |= POLLERR;
> +            }
> +            if (ne.lNetworkEvents & FD_READ)
> +            {
> +                fds[i].revents |= POLLRDNORM;
> +                if (ne.iErrorCode[FD_READ_BIT] != 0)
> +                    fds[i].revents |= POLLERR;
> +            }
> +            if (ne.lNetworkEvents & FD_WRITE)
> +            {
> +                fds[i].revents |= POLLWRNORM;
> +                if (ne.iErrorCode[FD_WRITE_BIT] != 0)
> +                    fds[i].revents |= POLLERR;
> +            }
> +        }
> +    }
> +
>      for (unsigned i = 0; i < nfds; i++)
>      {
> -        WSANETWORKEVENTS ne;
> -
> -        if (WSAEnumNetworkEvents(fds[i].fd, evts[i], &ne))
> -            memset(&ne, 0, sizeof (ne));
> +        /* events already found with select */

Oops, this line can be removed when merging.

> +        /* unhook the event before we close it, otherwise the socket may fail */
>          WSAEventSelect(fds[i].fd, evts[i], 0);
>          WSACloseEvent(evts[i]);
>
> -        if (ne.lNetworkEvents & FD_CONNECT)
> -        {
> -            fds[i].revents |= POLLWRNORM;
> -            if (ne.iErrorCode[FD_CONNECT_BIT] != 0)
> -                fds[i].revents |= POLLERR;
> -        }
> -        if (ne.lNetworkEvents & FD_CLOSE)
> -        {
> -            fds[i].revents |= (fds[i].events & POLLRDNORM) | POLLHUP;
> -            if (ne.iErrorCode[FD_CLOSE_BIT] != 0)
> -                fds[i].revents |= POLLERR;
> -        }
> -        if (ne.lNetworkEvents & FD_ACCEPT)
> -        {
> -            fds[i].revents |= POLLRDNORM;
> -            if (ne.iErrorCode[FD_ACCEPT_BIT] != 0)
> -                fds[i].revents |= POLLERR;
> -        }
> -        if (ne.lNetworkEvents & FD_OOB)
> -        {
> -            fds[i].revents |= POLLPRI;
> -            if (ne.iErrorCode[FD_OOB_BIT] != 0)
> -                fds[i].revents |= POLLERR;
> -        }
> -        if (ne.lNetworkEvents & FD_READ)
> -        {
> -            fds[i].revents |= POLLRDNORM;
> -            if (ne.iErrorCode[FD_READ_BIT] != 0)
> -                fds[i].revents |= POLLERR;
> -        }
> -        if (ne.lNetworkEvents & FD_WRITE)
> -        {
> -            fds[i].revents |= POLLWRNORM;
> -            if (ne.iErrorCode[FD_WRITE_BIT] != 0)
> -                fds[i].revents |= POLLERR;
> -        }
>          count += fds[i].revents != 0;
>      }
>
> --
> 2.6.3
>