Paolo Bonzini <pbonz...@redhat.com> writes:
> I misread the glib manual, g_source_remove does not let you re-attach
> the source later. This behavior (called "blocking" the source in glib)
> is present in glib's source code, but private and not available outside
> glib; hence, we have to resort to re-creating the source every time.
>
> In fact, g_source_remove and g_source_destroy are the same thing,
> except g_source_destroy is O(1) while g_source_remove scans a potentially
> very long list of GSources in the current main loop. Ugh. Better
> use g_source_destroy explicitly, and leave "tags" to those dummies who
> cannot track their pointers' lifetimes.
>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Tested-by: Anthony Liguori <aligu...@us.ibm.com>
Regards,
Anthony Liguori
> ---
> qemu-char.c | 17 +++++++++++++----
> 1 file changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/qemu-char.c b/qemu-char.c
> index dd410ce..eae17fc 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -596,9 +596,11 @@ typedef struct IOWatchPoll
> {
> GSource parent;
>
> + GIOChannel *channel;
> GSource *src;
>
> IOCanReadHandler *fd_can_read;
> + GSourceFunc fd_read;
> void *opaque;
> } IOWatchPoll;
>
> @@ -611,15 +613,19 @@ static gboolean io_watch_poll_prepare(GSource *source,
> gint *timeout_)
> {
> IOWatchPoll *iwp = io_watch_poll_from_source(source);
> bool now_active = iwp->fd_can_read(iwp->opaque) > 0;
> - bool was_active = g_source_get_context(iwp->src) != NULL;
> + bool was_active = iwp->src != NULL;
> if (was_active == now_active) {
> return FALSE;
> }
>
> if (now_active) {
> + iwp->src = g_io_create_watch(iwp->channel, G_IO_IN | G_IO_ERR |
> G_IO_HUP);
> + g_source_set_callback(iwp->src, iwp->fd_read, iwp->opaque, NULL);
> g_source_attach(iwp->src, NULL);
> } else {
> - g_source_remove(g_source_get_id(iwp->src));
> + g_source_destroy(iwp->src);
> + g_source_unref(iwp->src);
> + iwp->src = NULL;
> }
> return FALSE;
> }
> @@ -638,7 +644,9 @@ static gboolean io_watch_poll_dispatch(GSource *source,
> GSourceFunc callback,
> static void io_watch_poll_finalize(GSource *source)
> {
> IOWatchPoll *iwp = io_watch_poll_from_source(source);
> + g_source_destroy(iwp->src);
> g_source_unref(iwp->src);
> + iwp->src = NULL;
> }
>
> static GSourceFuncs io_watch_poll_funcs = {
> @@ -659,8 +667,9 @@ static guint io_add_watch_poll(GIOChannel *channel,
> iwp = (IOWatchPoll *) g_source_new(&io_watch_poll_funcs,
> sizeof(IOWatchPoll));
> iwp->fd_can_read = fd_can_read;
> iwp->opaque = user_data;
> - iwp->src = g_io_create_watch(channel, G_IO_IN | G_IO_ERR | G_IO_HUP);
> - g_source_set_callback(iwp->src, (GSourceFunc)fd_read, user_data, NULL);
> + iwp->channel = channel;
> + iwp->fd_read = (GSourceFunc) fd_read;
> + iwp->src = NULL;
>
> return g_source_attach(&iwp->parent, NULL);
> }
> --
> 1.8.1.4
