Bug 621945 – Filter outgoing messages in GDBusConnection

This patch breaks some rarely-used public API (only known user is
dconf).

This patch is based on work from Peng Huang <shawn.p.huang@gmail.com>.

See https://bugzilla.gnome.org/show_bug.cgi?id=621945

Signed-off-by: David Zeuthen <davidz@redhat.com>
This commit is contained in:
David Zeuthen 2010-06-21 16:08:53 -04:00
parent a4cd39e741
commit 45411ccbe3
5 changed files with 130 additions and 31 deletions

View File

@ -1624,6 +1624,7 @@ on_worker_message_received (GDBusWorker *worker,
{
consumed_by_filter = filters[n].func (connection,
message,
TRUE,
filters[n].user_data);
if (consumed_by_filter)
break;
@ -1673,6 +1674,52 @@ on_worker_message_received (GDBusWorker *worker,
g_free (filters);
}
/* Called in worker's thread */
static gboolean
on_worker_message_about_to_be_sent (GDBusWorker *worker,
GDBusMessage *message,
gpointer user_data)
{
GDBusConnection *connection = G_DBUS_CONNECTION (user_data);
FilterCallback *filters;
gboolean consumed_by_filter;
guint num_filters;
guint n;
//g_debug ("in on_worker_message_about_to_be_sent");
g_object_ref (connection);
/* First collect the set of callback functions */
CONNECTION_LOCK (connection);
num_filters = connection->priv->filters->len;
filters = g_new0 (FilterCallback, num_filters);
for (n = 0; n < num_filters; n++)
{
FilterData *data = connection->priv->filters->pdata[n];
filters[n].func = data->filter_function;
filters[n].user_data = data->user_data;
}
CONNECTION_UNLOCK (connection);
/* the call the filters in order (without holding the lock) */
consumed_by_filter = FALSE;
for (n = 0; n < num_filters; n++)
{
consumed_by_filter = filters[n].func (connection,
message,
FALSE,
filters[n].user_data);
if (consumed_by_filter)
break;
}
g_object_unref (connection);
g_free (filters);
return consumed_by_filter;
}
/* Called in worker's thread - we must not block */
static void
on_worker_closed (GDBusWorker *worker,
@ -1831,6 +1878,7 @@ initable_init (GInitable *initable,
connection->priv->worker = _g_dbus_worker_new (connection->priv->stream,
connection->priv->capabilities,
on_worker_message_received,
on_worker_message_about_to_be_sent,
on_worker_closed,
connection);
@ -2266,11 +2314,11 @@ static guint _global_filter_id = 1;
* is removed or %NULL.
*
* Adds a message filter. Filters are handlers that are run on all
* incoming messages, prior to standard dispatch. Filters are run in
* the order that they were added. The same handler can be added as a
* filter more than once, in which case it will be run more than once.
* Filters added during a filter callback won't be run on the message
* being processed.
* incoming and outgoing messages, prior to standard dispatch. Filters
* are run in the order that they were added. The same handler can be
* added as a filter more than once, in which case it will be run more
* than once. Filters added during a filter callback won't be run on
* the message being processed.
*
* Note that filters are run in a dedicated message handling thread so
* they can't block and, generally, can't do anything but signal a
@ -2279,6 +2327,14 @@ static guint _global_filter_id = 1;
* g_dbus_connection_signal_subscribe() or
* g_dbus_connection_call() instead.
*
* If a filter consumes an incoming message (by returning %TRUE), the
* message is not dispatched anywhere else - not even the standard
* dispatch machinery (that API such as
* g_dbus_connection_signal_subscribe() and
* g_dbus_connection_send_message_with_reply() relies on) will see the
* message. Similary, if a filter consumes an outgoing message, the
* message will not be sent to the other peer.
*
* Returns: A filter identifier that can be used with
* g_dbus_connection_remove_filter().
*

View File

@ -469,6 +469,8 @@ void g_dbus_connection_signal_unsubscribe (GDBusConnection
* GDBusMessageFilterFunction:
* @connection: A #GDBusConnection.
* @message: A #GDBusMessage.
* @incoming: %TRUE if it is a message received from the other peer, %FALSE if it is
* a message to be sent to the other peer.
* @user_data: User data passed when adding the filter.
*
* Signature for function used in g_dbus_connection_add_filter().
@ -480,6 +482,7 @@ void g_dbus_connection_signal_unsubscribe (GDBusConnection
*/
typedef gboolean (*GDBusMessageFilterFunction) (GDBusConnection *connection,
GDBusMessage *message,
gboolean incoming,
gpointer user_data);
guint g_dbus_connection_add_filter (GDBusConnection *connection,

View File

@ -355,6 +355,7 @@ struct GDBusWorker
GDBusCapabilityFlags capabilities;
GCancellable *cancellable;
GDBusWorkerMessageReceivedCallback message_received_callback;
GDBusWorkerMessageAboutToBeSentCallback message_about_to_be_sent_callback;
GDBusWorkerDisconnectedCallback disconnected_callback;
gpointer user_data;
@ -424,13 +425,24 @@ _g_dbus_worker_emit_disconnected (GDBusWorker *worker,
}
static void
_g_dbus_worker_emit_message (GDBusWorker *worker,
GDBusMessage *message)
_g_dbus_worker_emit_message_received (GDBusWorker *worker,
GDBusMessage *message)
{
if (!worker->stopped)
worker->message_received_callback (worker, message, worker->user_data);
}
static gboolean
_g_dbus_worker_emit_message_about_to_be_sent (GDBusWorker *worker,
GDBusMessage *message)
{
gboolean ret;
ret = FALSE;
if (!worker->stopped)
ret = worker->message_about_to_be_sent_callback (worker, message, worker->user_data);
return ret;
}
static void _g_dbus_worker_do_read_unlocked (GDBusWorker *worker);
/* called in private thread shared by all GDBusConnection instances (without read-lock held) */
@ -627,7 +639,7 @@ _g_dbus_worker_do_read_cb (GInputStream *input_stream,
}
/* yay, got a message, go deliver it */
_g_dbus_worker_emit_message (worker, message);
_g_dbus_worker_emit_message_received (worker, message);
g_object_unref (message);
/* start reading another message! */
@ -720,7 +732,7 @@ message_to_write_data_free (MessageToWriteData *data)
/* ---------------------------------------------------------------------------------------------------- */
/* called in private thread shared by all GDBusConnection instances (with write-lock held) */
/* called in private thread shared by all GDBusConnection instances (without write-lock held) */
static gboolean
write_message (GDBusWorker *worker,
MessageToWriteData *data,
@ -848,29 +860,39 @@ write_message_in_idle_cb (gpointer user_data)
GDBusWorker *worker = user_data;
gboolean more_writes_are_pending;
MessageToWriteData *data;
gboolean message_was_dropped;
GError *error;
g_mutex_lock (worker->write_lock);
data = g_queue_pop_head (worker->write_queue);
g_assert (data != NULL);
error = NULL;
if (!write_message (worker,
data,
&error))
{
/* TODO: handle */
_g_dbus_worker_emit_disconnected (worker, TRUE, error);
g_error_free (error);
}
message_to_write_data_free (data);
more_writes_are_pending = (g_queue_get_length (worker->write_queue) > 0);
worker->write_is_pending = more_writes_are_pending;
g_mutex_unlock (worker->write_lock);
/* Note that write_lock is only used for protecting the @write_queue
* and @write_is_pending fields of the GDBusWorker struct ... which we
* need to modify from arbitrary threads in _g_dbus_worker_send_message().
*
* Therefore, it's fine to drop it here when calling back into user
* code and then writing the message out onto the GIOStream since this
* function only runs on the worker thread.
*/
message_was_dropped = _g_dbus_worker_emit_message_about_to_be_sent (worker, data->message);
if (G_LIKELY (!message_was_dropped))
{
error = NULL;
if (!write_message (worker,
data,
&error))
{
/* TODO: handle */
_g_dbus_worker_emit_disconnected (worker, TRUE, error);
g_error_free (error);
}
}
message_to_write_data_free (data);
return more_writes_are_pending;
}
@ -928,16 +950,18 @@ _g_dbus_worker_thread_begin_func (gpointer user_data)
}
GDBusWorker *
_g_dbus_worker_new (GIOStream *stream,
GDBusCapabilityFlags capabilities,
GDBusWorkerMessageReceivedCallback message_received_callback,
GDBusWorkerDisconnectedCallback disconnected_callback,
gpointer user_data)
_g_dbus_worker_new (GIOStream *stream,
GDBusCapabilityFlags capabilities,
GDBusWorkerMessageReceivedCallback message_received_callback,
GDBusWorkerMessageAboutToBeSentCallback message_about_to_be_sent_callback,
GDBusWorkerDisconnectedCallback disconnected_callback,
gpointer user_data)
{
GDBusWorker *worker;
g_return_val_if_fail (G_IS_IO_STREAM (stream), NULL);
g_return_val_if_fail (message_received_callback != NULL, NULL);
g_return_val_if_fail (message_about_to_be_sent_callback != NULL, NULL);
g_return_val_if_fail (disconnected_callback != NULL, NULL);
worker = g_new0 (GDBusWorker, 1);
@ -945,6 +969,7 @@ _g_dbus_worker_new (GIOStream *stream,
worker->read_lock = g_mutex_new ();
worker->message_received_callback = message_received_callback;
worker->message_about_to_be_sent_callback = message_about_to_be_sent_callback;
worker->disconnected_callback = disconnected_callback;
worker->user_data = user_data;
worker->stream = g_object_ref (stream);

View File

@ -39,6 +39,10 @@ typedef void (*GDBusWorkerMessageReceivedCallback) (GDBusWorker *worker,
GDBusMessage *message,
gpointer user_data);
typedef gboolean (*GDBusWorkerMessageAboutToBeSentCallback) (GDBusWorker *worker,
GDBusMessage *message,
gpointer user_data);
typedef void (*GDBusWorkerDisconnectedCallback) (GDBusWorker *worker,
gboolean remote_peer_vanished,
GError *error,
@ -50,6 +54,7 @@ typedef void (*GDBusWorkerDisconnectedCallback) (GDBusWorker *worker,
GDBusWorker *_g_dbus_worker_new (GIOStream *stream,
GDBusCapabilityFlags capabilities,
GDBusWorkerMessageReceivedCallback message_received_callback,
GDBusWorkerMessageAboutToBeSentCallback message_about_to_be_sent_callback,
GDBusWorkerDisconnectedCallback disconnected_callback,
gpointer user_data);

View File

@ -555,20 +555,29 @@ test_connection_signals (void)
typedef struct
{
guint num_handled;
guint num_outgoing;
guint32 serial;
} FilterData;
static gboolean
filter_func (GDBusConnection *connection,
GDBusMessage *message,
gboolean incoming,
gpointer user_data)
{
FilterData *data = user_data;
guint32 reply_serial;
reply_serial = g_dbus_message_get_reply_serial (message);
if (reply_serial == data->serial)
data->num_handled += 1;
if (incoming)
{
reply_serial = g_dbus_message_get_reply_serial (message);
if (reply_serial == data->serial)
data->num_handled += 1;
}
else
{
data->num_outgoing += 1;
}
return FALSE;
}
@ -638,6 +647,7 @@ test_connection_filter (void)
g_assert (r != NULL);
g_object_unref (r);
g_assert_cmpint (data.num_handled, ==, 3);
g_assert_cmpint (data.num_outgoing, ==, 3);
_g_object_wait_for_single_ref (c);
g_object_unref (c);