Suggestion: dbus_connection_set_suspended to temporarily suspend DBUS-Input

[Seth Nickell]

Won't this cause, e.g., other dbus services calling you to time out 
waiting for a reply?

On Mon, 27 Sep 2004 8:23am, Friedemann KleintFa. metis wrote:
> Hi,
>
> I would like to suggest the following patch:
>
> - API extension:
>
>     dbus_connection_set_suspended(DBusConnection *connection,
>                                   dbus_bool_t suspended)
>
>     Suspends dispatching of DBUS-Messages.
>
> - Aim:
>
>     There are  situations    (mainly in GUI-applications) in which
>     one does not want IPC-messages   to interfer with normal event
>     processing for a limited amount of time.
>
>     For example,    the application  may   perform   some  lenghty
>     operation in a background  thread and does mainloop-iterations
>     while waiting for the thread  to   terminate.   In  this case,
>     only expose-events should be processed.
>
>     There should be a function to suspend DBUS-input. On resuming,
>     all pending messages should be delivered.
>
>     So far, the Qt/Glib  bindings offer no such function;  one
>     would have to re-do the mainloop integration.
>
> - Solution:
>
>    Havoc suggested setting the receive   size  to a low value, but
>    this causes messages to be lost.
>
>    I added  a   "suspended" flag the  connection-structure   which
>    causes  _dbus_connection_get_dispatch_status_unlocked()      to
>    return  DISPATCH_COMPLETE    if set. There might a more elegant
>    way to do this?
>
> -Friedemann Kleint
>
>
> --------------- Patch (applicable to dbus-0.22)-------------
> --- dbus-0.22/dbus/dbus-connection.c.orig	2004-09-27 11:16:41.010029000 
> +0200
> +++ dbus-0.22/dbus/dbus-connection.c	2004-09-27 13:29:45.340001000 
> +0200
> @@ -203,6 +203,7 @@
>    DBusDispatchStatusFunction dispatch_status_function; /**< Function 
> on dispatch status changes  */
>    void *dispatch_status_data; /**< Application data for 
> dispatch_status_function */
>    DBusFreeFunction free_dispatch_status_data; /**< free 
> dispatch_status_data */
> +  dbus_bool_t suspended; /**< Message dispatching suspended */
>
>    DBusDispatchStatus last_dispatch_status; /**< The last dispatch 
> status we reported to the application. */
>
> @@ -905,6 +906,7 @@
>    connection->pending_replies = pending_replies;
>    connection->outgoing_counter = outgoing_counter;
>    connection->filter_list = NULL;
> +  connection->suspended =  FALSE;
>    connection->last_dispatch_status = DBUS_DISPATCH_COMPLETE; /* so 
> we're notified first time there's data */
>    connection->objects = objects;
>    connection->exit_on_disconnect = FALSE;
> @@ -2340,6 +2342,8 @@
>  static DBusDispatchStatus
>  _dbus_connection_get_dispatch_status_unlocked (DBusConnection 
> *connection)
>  {
> +  if (connection->suspended)
> +    return DBUS_DISPATCH_COMPLETE;
>    if (connection->n_incoming > 0)
>      return DBUS_DISPATCH_DATA_REMAINS;
>    else if (!_dbus_transport_queue_messages (connection->transport))
> @@ -2408,6 +2412,27 @@
>  }
>
>  /**
> + * Suspend dispatching of messages.
> + *
> + * @param connection the connection.
> + * @param suspended flag indicating state.
> + */
> +
> +void
> +dbus_connection_set_suspended(DBusConnection *connection,
> +                              dbus_bool_t suspended)
> +{
> +    _dbus_return_if_fail (connection != NULL);
> +
> +    CONNECTION_LOCK (connection);
> +
> +    connection->suspended = suspended;
> +
> +    CONNECTION_UNLOCK (connection);
> +}
> +
> +
> +/**
>   * Gets the current state (what we would currently return
>   * from dbus_connection_dispatch()) but doesn't actually
>   * dispatch any messages.
> --- dbus-0.22/dbus/dbus-connection.h.orig	2004-09-27 11:16:50.980001000 
> +0200
> +++ dbus-0.22/dbus/dbus-connection.h	2004-09-27 13:25:03.390000000 
> +0200
> @@ -104,6 +104,8 @@
>                                                                   
> DBusMessage                *message);
>  DBusMessage*       dbus_connection_pop_message                  
> (DBusConnection             *connection);
>  DBusDispatchStatus dbus_connection_get_dispatch_status          
> (DBusConnection             *connection);
> +void               dbus_connection_set_suspended                
> (DBusConnection *connection,
> +                                                                 
> dbus_bool_t suspended);
>  DBusDispatchStatus dbus_connection_dispatch                     
> (DBusConnection             *connection);
>  dbus_bool_t        dbus_connection_send                         
> (DBusConnection             *connection,
> --
> dbus mailing list
> dbus at freedesktop.org
> http://freedesktop.org/mailman/listinfo/dbus
-Seth