core/selection: Cancel selection transfer requests after a timeout

When a selection owner advertises a mime type, but does not provide the
content upon a request for the mime type content, the requesting side
might wait indefinitely on the content.
To avoid this situation, add a timeout source, which will cancel the
selection transfer request after a certain timeout (15 seconds) passed.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1874>
This commit is contained in:
Pascal Nowack 2021-06-24 05:44:22 +02:00 committed by Marge Bot
parent 20db6af4e6
commit 537e2dfafe

View File

@ -39,6 +39,10 @@ struct TransferRequest
GInputStream *istream;
GOutputStream *ostream;
gssize len;
GSource *timeout_source;
GCancellable *cancellable;
GCancellable *external_cancellable;
gulong cancellable_signal_handler;
};
enum
@ -174,10 +178,39 @@ meta_selection_get_mimetypes (MetaSelection *selection,
return meta_selection_source_get_mimetypes (selection->owners[selection_type]);
}
static gboolean
cancel_transfer_request (gpointer user_data)
{
TransferRequest *request = user_data;
g_cancellable_cancel (request->cancellable);
if (request->cancellable_signal_handler)
{
g_assert (request->external_cancellable);
g_cancellable_disconnect (request->external_cancellable,
request->cancellable_signal_handler);
request->cancellable_signal_handler = 0;
g_object_unref (request->external_cancellable);
}
return G_SOURCE_REMOVE;
}
static void
on_external_cancellable_cancelled (GCancellable *external_cancellable,
TransferRequest *request)
{
g_cancellable_cancel (request->cancellable);
g_source_destroy (request->timeout_source);
g_clear_pointer (&request->timeout_source, g_source_unref);
}
static TransferRequest *
transfer_request_new (GOutputStream *ostream,
MetaSelectionType selection_type,
gssize len)
ssize_t len,
GCancellable *external_cancellable)
{
TransferRequest *request;
@ -185,12 +218,44 @@ transfer_request_new (GOutputStream *ostream,
request->ostream = g_object_ref (ostream);
request->selection_type = selection_type;
request->len = len;
request->cancellable = g_cancellable_new ();
request->timeout_source = g_timeout_source_new_seconds (15);
g_source_set_callback (request->timeout_source, cancel_transfer_request,
request, NULL);
g_source_attach (request->timeout_source, NULL);
if (external_cancellable)
{
request->external_cancellable = g_object_ref (external_cancellable);
request->cancellable_signal_handler =
g_cancellable_connect (external_cancellable,
G_CALLBACK (on_external_cancellable_cancelled),
request, NULL);
}
return request;
}
static void
transfer_request_free (TransferRequest *request)
{
if (request->cancellable_signal_handler)
{
g_assert (request->external_cancellable);
g_cancellable_disconnect (request->external_cancellable,
request->cancellable_signal_handler);
request->cancellable_signal_handler = 0;
g_object_unref (request->external_cancellable);
}
if (request->timeout_source)
{
g_source_destroy (request->timeout_source);
g_clear_pointer (&request->timeout_source, g_source_unref);
}
g_clear_object (&request->cancellable);
g_clear_object (&request->istream);
g_clear_object (&request->ostream);
g_free (request);
@ -362,6 +427,7 @@ meta_selection_transfer_async (MetaSelection *selection,
GAsyncReadyCallback callback,
gpointer user_data)
{
TransferRequest *transfer_request;
GTask *task;
g_return_if_fail (META_IS_SELECTION (selection));
@ -372,12 +438,14 @@ meta_selection_transfer_async (MetaSelection *selection,
task = g_task_new (selection, cancellable, callback, user_data);
g_task_set_source_tag (task, meta_selection_transfer_async);
g_task_set_task_data (task,
transfer_request_new (output, selection_type, size),
transfer_request = transfer_request_new (output, selection_type, size,
cancellable);
g_task_set_task_data (task, transfer_request,
(GDestroyNotify) transfer_request_free);
meta_selection_source_read_async (selection->owners[selection_type],
mimetype,
cancellable,
transfer_request->cancellable,
(GAsyncReadyCallback) source_read_cb,
task);
}