Commit 1c08a117 authored by Jonathon Jongsma's avatar Jonathon Jongsma
Browse files

Add SpiceSession::disconnected signal



Previously, an application was required to determine whether a session
had been disconnected by listening for the SpiceSession::channel-destroy
signal for each individual channel. The Application had to keep track of
whether all channels had been destroyed.

An additional difficulty is that when a SpiceSession::channel-destroy
signal is emitted, the channel object has not been freed yet, so any
shutdown/de-allocation actions have not yet happened. This became
significant since virt-viewer exits the application in response to the
last 'channel-destroy' signal, which means that the channel objects are
never properly freed. This is particularly problematic for the usbredir
channel, which might need to disconnect USB devices asynchronously, and
if the application exits before that process has completed, the USB
devices may not be available on the client machine.

With this patch, the SpiceSession still emits the 'channel-destroy'
signal for each channel when it is disconnected. But it also internally
tracks which channels have been destroyed, and waits for them to be
freed. When all channels are freed, it emits an additional
'disconnected' signal.  An application can be confident that all
channels have been freed by this point, and the application can exit
safely.

Signed-off-by: default avatarJonathon Jongsma <jjongsma@redhat.com>
Acked-by: Marc-André Lureau's avatarMarc-André Lureau <marcandre.lureau@gmail.com>
parent 4b730b1a
Pipeline #773 passed with stage
in 4 minutes and 26 seconds
......@@ -94,6 +94,7 @@ struct _SpiceSessionPrivate {
int protocol;
SpiceChannel *cmain; /* weak reference */
Ring channels;
guint channels_destroying;
guint32 mm_time;
gboolean client_provided_sockets;
guint64 mm_time_at_clock;
......@@ -210,6 +211,7 @@ enum {
SPICE_SESSION_CHANNEL_NEW,
SPICE_SESSION_CHANNEL_DESTROY,
SPICE_SESSION_MM_TIME_RESET,
SPICE_SESSION_DISCONNECTED,
SPICE_SESSION_LAST_SIGNAL,
};
......@@ -343,6 +345,8 @@ spice_session_dispose(GObject *gobject)
g_warn_if_fail(s->migration_left == NULL);
g_warn_if_fail(s->after_main_init == 0);
g_warn_if_fail(s->disconnecting == 0);
g_warn_if_fail(s->channels_destroying == 0);
g_warn_if_fail(ring_is_empty(&s->channels));
g_clear_object(&s->audio_manager);
g_clear_object(&s->usb_manager);
......@@ -1313,6 +1317,23 @@ static void spice_session_class_init(SpiceSessionClass *klass)
1,
SPICE_TYPE_CHANNEL);
/**
* SpiceSession::disconnected:
* @session: the session that emitted the signal
*
* The #SpiceSession::disconnected signal is emitted when all channels have been destroyed.
* Since: 0.35
**/
signals[SPICE_SESSION_DISCONNECTED] =
g_signal_new("disconnected",
G_OBJECT_CLASS_TYPE(gobject_class),
G_SIGNAL_RUN_FIRST,
0, NULL, NULL,
g_cclosure_marshal_VOID__VOID,
G_TYPE_NONE,
0,
NULL);
/**
* SpiceSession::mm-time-reset:
* @session: the session that emitted the signal
......@@ -2269,6 +2290,17 @@ void spice_session_channel_new(SpiceSession *session, SpiceChannel *channel)
g_signal_emit(session, signals[SPICE_SESSION_CHANNEL_NEW], 0, channel);
}
static void channel_finally_destroyed(gpointer data, GObject *channel)
{
SpiceSession *session = SPICE_SESSION(data);
SpiceSessionPrivate *s = session->priv;
s->channels_destroying--;
if (ring_is_empty(&s->channels) && (s->channels_destroying == 0)) {
g_signal_emit(session, signals[SPICE_SESSION_DISCONNECTED], 0);
}
g_object_unref(session);
}
static void spice_session_channel_destroy(SpiceSession *session, SpiceChannel *channel)
{
g_return_if_fail(SPICE_IS_SESSION(session));
......@@ -2302,6 +2334,12 @@ static void spice_session_channel_destroy(SpiceSession *session, SpiceChannel *c
g_clear_object(&channel->priv->session);
spice_channel_disconnect(channel, SPICE_CHANNEL_NONE);
/* Wait until the channel is properly freed so that we can emit a
* 'disconnected' signal */
s->channels_destroying++;
g_object_weak_ref(G_OBJECT(channel), channel_finally_destroyed, g_object_ref(session));
g_object_unref(channel);
}
......
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