[1/2] Add glib support to main loop

This allows GSources to be used to register callback events in QEMU.  This is
useful as it allows us to take greater advantage of glib and also because it
allows us to write code that is more easily testable outside of QEMU since we
can make use of glib's main loop in unit tests.

All new code should use glib's callback mechanisms for registering fd events
which are very well documented at:

http://developer.gnome.org/glib/stable/glib-The-Main-Event-Loop.html

And:

http://developer.gnome.org/gio/stable/

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
---
 vl.c |   74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 74 insertions(+), 0 deletions(-)

On 08/22/2011 08:12 AM, Anthony Liguori wrote:
> This allows GSources to be used to register callback events in QEMU.  This is
> useful as it allows us to take greater advantage of glib and also because it
> allows us to write code that is more easily testable outside of QEMU since we
> can make use of glib's main loop in unit tests.
>
> All new code should use glib's callback mechanisms for registering fd events
> which are very well documented at:
>
> http://developer.gnome.org/glib/stable/glib-The-Main-Event-Loop.html
>
> And:
>
> http://developer.gnome.org/gio/stable/
>
> Signed-off-by: Anthony Liguori<aliguori@us.ibm.com>

Applied both of these.

Regards,

Anthony Liguori

> ---
>   vl.c |   74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>   1 files changed, 74 insertions(+), 0 deletions(-)
>
> diff --git a/vl.c b/vl.c
> index 06a6f80..d661e8e 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -111,6 +111,8 @@ int main(int argc, char **argv)
>   #define main qemu_main
>   #endif /* CONFIG_COCOA */
>
> +#include<glib.h>
> +
>   #include "hw/hw.h"
>   #include "hw/boards.h"
>   #include "hw/usb.h"
> @@ -1321,6 +1323,75 @@ void qemu_system_vmstop_request(int reason)
>       qemu_notify_event();
>   }
>
> +static GPollFD poll_fds[1024 * 2]; /* this is probably overkill */
> +static int n_poll_fds;
> +static int max_priority;
> +
> +static void glib_select_fill(int *max_fd, fd_set *rfds, fd_set *wfds,
> +                             fd_set *xfds, struct timeval *tv)
> +{
> +    GMainContext *context = g_main_context_default();
> +    int i;
> +    int timeout = 0, cur_timeout;
> +
> +    g_main_context_prepare(context,&max_priority);
> +
> +    n_poll_fds = g_main_context_query(context, max_priority,&timeout,
> +                                      poll_fds, ARRAY_SIZE(poll_fds));
> +    g_assert(n_poll_fds<= ARRAY_SIZE(poll_fds));
> +
> +    for (i = 0; i<  n_poll_fds; i++) {
> +        GPollFD *p =&poll_fds[i];
> +
> +        if ((p->events&  G_IO_IN)) {
> +            FD_SET(p->fd, rfds);
> +            *max_fd = MAX(*max_fd, p->fd);
> +        }
> +        if ((p->events&  G_IO_OUT)) {
> +            FD_SET(p->fd, wfds);
> +            *max_fd = MAX(*max_fd, p->fd);
> +        }
> +        if ((p->events&  G_IO_ERR)) {
> +            FD_SET(p->fd, xfds);
> +            *max_fd = MAX(*max_fd, p->fd);
> +        }
> +    }
> +
> +    cur_timeout = (tv->tv_sec * 1000) + ((tv->tv_usec + 500) / 1000);
> +    if (timeout>= 0&&  timeout<  cur_timeout) {
> +        tv->tv_sec = timeout / 1000;
> +        tv->tv_usec = (timeout % 1000) * 1000;
> +    }
> +}
> +
> +static void glib_select_poll(fd_set *rfds, fd_set *wfds, fd_set *xfds,
> +                             bool err)
> +{
> +    GMainContext *context = g_main_context_default();
> +
> +    if (!err) {
> +        int i;
> +
> +        for (i = 0; i<  n_poll_fds; i++) {
> +            GPollFD *p =&poll_fds[i];
> +
> +            if ((p->events&  G_IO_IN)&&  FD_ISSET(p->fd, rfds)) {
> +                p->revents |= G_IO_IN;
> +            }
> +            if ((p->events&  G_IO_OUT)&&  FD_ISSET(p->fd, wfds)) {
> +                p->revents |= G_IO_OUT;
> +            }
> +            if ((p->events&  G_IO_ERR)&&  FD_ISSET(p->fd, xfds)) {
> +                p->revents |= G_IO_ERR;
> +            }
> +        }
> +    }
> +
> +    if (g_main_context_check(context, max_priority, poll_fds, n_poll_fds)) {
> +        g_main_context_dispatch(context);
> +    }
> +}
> +
>   void main_loop_wait(int nonblocking)
>   {
>       fd_set rfds, wfds, xfds;
> @@ -1346,8 +1417,10 @@ void main_loop_wait(int nonblocking)
>       FD_ZERO(&rfds);
>       FD_ZERO(&wfds);
>       FD_ZERO(&xfds);
> +
>       qemu_iohandler_fill(&nfds,&rfds,&wfds,&xfds);
>       slirp_select_fill(&nfds,&rfds,&wfds,&xfds);
> +    glib_select_fill(&nfds,&rfds,&wfds,&xfds,&tv);
>
>       qemu_mutex_unlock_iothread();
>       ret = select(nfds + 1,&rfds,&wfds,&xfds,&tv);
> @@ -1355,6 +1428,7 @@ void main_loop_wait(int nonblocking)
>
>       qemu_iohandler_poll(&rfds,&wfds,&xfds, ret);
>       slirp_select_poll(&rfds,&wfds,&xfds, (ret<  0));
> +    glib_select_poll(&rfds,&wfds,&xfds, (ret<  0));
>
>       qemu_run_all_timers();
>