[Spice-devel] [PATCH spice-server] event loop: improve implementation of watches

[Frediano Ziglio]

ping

> 
> Avoid having to destroy and create a new GSource every time
> we change event mask.
> Interfaces required for this patch are available since GLib 2.36.
> on Windows GPollFD::fd can be an HANDLE but not a socket.
> 
> Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
> ---
>  server/event-loop.c | 97 +++++++++++++++++++++++++++++++++++++++------
>  1 file changed, 85 insertions(+), 12 deletions(-)
> 
> diff --git a/server/event-loop.c b/server/event-loop.c
> index 80af2954f..33db4ffb0 100644
> --- a/server/event-loop.c
> +++ b/server/event-loop.c
> @@ -85,14 +85,6 @@ static void timer_remove(const SpiceCoreInterfaceInternal
> *iface,
>      g_free(timer);
>  }
>  
> -struct SpiceWatch {
> -    GMainContext *context;
> -    void *opaque;
> -    GSource *source;
> -    GIOChannel *channel;
> -    SpiceWatchFunc func;
> -};
> -
>  static GIOCondition spice_event_to_giocondition(int event_mask)
>  {
>      GIOCondition condition = 0;
> @@ -117,6 +109,15 @@ static int giocondition_to_spice_event(GIOCondition
> condition)
>      return event;
>  }
>  
> +#ifdef _WIN32
> +struct SpiceWatch {
> +    GMainContext *context;
> +    void *opaque;
> +    GSource *source;
> +    GIOChannel *channel;
> +    SpiceWatchFunc func;
> +};
> +
>  static gboolean watch_func(GIOChannel *source, GIOCondition condition,
>                             gpointer data)
>  {
> @@ -161,11 +162,7 @@ static SpiceWatch *watch_add(const
> SpiceCoreInterfaceInternal *iface,
>  
>      watch = g_new0(SpiceWatch, 1);
>      watch->context = iface->main_context;
> -#ifndef _WIN32
> -    watch->channel = g_io_channel_unix_new(fd);
> -#else
>      watch->channel = g_io_channel_win32_new_socket(fd);
> -#endif
>      watch->func = func;
>      watch->opaque = opaque;
>  
> @@ -184,6 +181,82 @@ static void watch_remove(const
> SpiceCoreInterfaceInternal *iface,
>      g_free(watch);
>  }
>  
> +#else
> +
> +struct SpiceWatch {
> +    GSource source;
> +    GPollFD pollfd;
> +};
> +
> +static gboolean
> +spice_watch_check(GSource *source)
> +{
> +    SpiceWatch *watch = SPICE_CONTAINEROF(source, SpiceWatch, source);
> +
> +    return watch->pollfd.events & watch->pollfd.revents;
> +}
> +
> +static gboolean
> +spice_watch_dispatch(GSource     *source,
> +                     GSourceFunc  callback,
> +                     gpointer     user_data)
> +{
> +    SpiceWatch *watch = SPICE_CONTAINEROF(source, SpiceWatch, source);
> +    SpiceWatchFunc func = (SpiceWatchFunc)(void*) callback;
> +
> +    func(watch->pollfd.fd,
> giocondition_to_spice_event(watch->pollfd.revents), user_data);
> +    /* timer might be free after func(), don't touch */
> +
> +    return G_SOURCE_CONTINUE;
> +}
> +
> +static GSourceFuncs spice_watch_funcs = {
> +    .check = spice_watch_check,
> +    .dispatch = spice_watch_dispatch,
> +};
> +
> +static void watch_update_mask(const SpiceCoreInterfaceInternal *iface,
> +                              SpiceWatch *watch, int event_mask)
> +{
> +    GIOCondition old_condition = watch->pollfd.events;
> +    GIOCondition new_condition = spice_event_to_giocondition(event_mask);
> +
> +    watch->pollfd.events = new_condition;
> +    if (old_condition && !new_condition) {
> +        g_source_remove_poll(&watch->source, &watch->pollfd);
> +    } else if (!old_condition && new_condition) {
> +        g_source_add_poll(&watch->source, &watch->pollfd);
> +    }
> +}
> +
> +static SpiceWatch *watch_add(const SpiceCoreInterfaceInternal *iface,
> +                             int fd, int event_mask, SpiceWatchFunc func,
> void *opaque)
> +{
> +    SpiceWatch *watch = (SpiceWatch *) g_source_new(&spice_watch_funcs,
> sizeof(SpiceWatch));
> +
> +    spice_return_val_if_fail(fd != -1, NULL);
> +    spice_return_val_if_fail(func != NULL, NULL);
> +
> +    watch->pollfd.fd = fd;
> +    watch->pollfd.events = 0;
> +
> +    g_source_set_callback(&watch->source,
> (GSourceFunc)(void*)(SpiceWatchFunc) func, opaque, NULL);
> +
> +    g_source_attach(&watch->source, iface->main_context);
> +
> +    watch_update_mask(iface, watch, event_mask);
> +
> +    return watch;
> +}
> +
> +static void watch_remove(const SpiceCoreInterfaceInternal *iface,
> +                         SpiceWatch *watch)
> +{
> +    g_source_destroy(&watch->source);
> +    g_source_unref(&watch->source);
> +}
> +#endif
> +
>  const SpiceCoreInterfaceInternal event_loop_core = {
>      .timer_add = timer_add,
>      .timer_start = timer_start,