Fixes #15892

2002-10-04  Rodrigo Moya <rodrigo@ximian.com>

	Fixes #15892

	* idl/evolution-calendar.idl: added notifyErrorOccurred method to
	the Listener interface, so that backends can notify clients of errors
	that can't be reported otherwise.

	* pcs/cal.[ch] (cal_notify_error): new function.

	* pcs/cal-backend-file.c (save): made to save to temporary file and
	then moved to the correct file, so that we don't lose any data if
	there's a problem while saving.
	(notify_error): new function for notifying error messages to clients.

	* cal-client/cal-listener.[ch]: added new callback function for getting
	error messages from backends.
	(impl_notifyErrorOccurred): new method implementation.
	(cal_listener_class_init): initialize new epv member.
	(cal_listener_init, cal_listener_destroy, cal_listener_construct,
	 cal_listener_new): initialize new function pointer.

	* cal-client/cal-client.[ch]: adapted to changes in CalListener class.
	(cal_client_class_init): added "backend_error" signal to CalClient class.
	(backend_error_cb): callback for "error_occurred" signal on the CalListener,
	which just emits the "backend_error" signal of CalClient.

	* gui/gnome-cal.c (gnome_calendar_construct): connect to "backend_error"
	signal on the CalClient's we create.
	(backend_error_cb): display error message on error from backend.

	* gui/e-tasks.c: likewise.

svn path=/trunk/; revision=18329

11 files changed, 222 insertions, 26 deletions

diff --git a/calendar/ChangeLog b/calendar/ChangeLog
index 4c5fc899f7..330373f4ed 100644
--- a/calendar/ChangeLog
+++ b/calendar/ChangeLog
@@ -1,3 +1,36 @@
+2002-10-04  Rodrigo Moya <rodrigo@ximian.com>
+
+	Fixes #15892
+
+	* idl/evolution-calendar.idl: added notifyErrorOccurred method to
+	the Listener interface, so that backends can notify clients of errors
+	that can't be reported otherwise.
+
+	* pcs/cal.[ch] (cal_notify_error): new function.
+
+	* pcs/cal-backend-file.c (save): made to save to temporary file and
+	then moved to the correct file, so that we don't lose any data if
+	there's a problem while saving.
+	(notify_error): new function for notifying error messages to clients.
+
+	* cal-client/cal-listener.[ch]: added new callback function for getting
+	error messages from backends.
+	(impl_notifyErrorOccurred): new method implementation.
+	(cal_listener_class_init): initialize new epv member.
+	(cal_listener_init, cal_listener_destroy, cal_listener_construct,
+	 cal_listener_new): initialize new function pointer.
+
+	* cal-client/cal-client.[ch]: adapted to changes in CalListener class.
+	(cal_client_class_init): added "backend_error" signal to CalClient class.
+	(backend_error_cb): callback for "error_occurred" signal on the CalListener,
+	which just emits the "backend_error" signal of CalClient.
+
+	* gui/gnome-cal.c (gnome_calendar_construct): connect to "backend_error"
+	signal on the CalClient's we create.
+	(backend_error_cb): display error message on error from backend.
+
+	* gui/e-tasks.c: likewise.
+
 2002-10-02  Rodrigo Moya <rodrigo@ximian.com>
 
 	* gui/alarm-notify/notify-main.c (alarm_notify_factory_fn): removed
diff --git a/calendar/cal-client/cal-client.c b/calendar/cal-client/cal-client.c
index ae4ab40c94..ec5401fb0f 100644
--- a/calendar/cal-client/cal-client.c
+++ b/calendar/cal-client/cal-client.c
@@ -86,6 +86,7 @@ enum {
 	CAL_SET_MODE,
 	OBJ_UPDATED,
 	OBJ_REMOVED,
+	BACKEND_ERROR,
 	CATEGORIES_CHANGED,
 	FORGET_PASSWORD,
 	BACKEND_DIED,
@@ -188,6 +189,14 @@ cal_client_class_init (CalClientClass *class)
 				gtk_marshal_NONE__STRING,
 				GTK_TYPE_NONE, 1,
 				GTK_TYPE_STRING);
+	cal_client_signals[BACKEND_ERROR] =
+		gtk_signal_new ("backend_error",
+				GTK_RUN_FIRST,
+				object_class->type,
+				GTK_SIGNAL_OFFSET (CalClientClass, backend_error),
+				gtk_marshal_NONE__STRING,
+				GTK_TYPE_NONE, 1,
+				GTK_TYPE_STRING);
 	cal_client_signals[CATEGORIES_CHANGED] =
 		gtk_signal_new ("categories_changed",
 				GTK_RUN_FIRST,
@@ -561,6 +570,16 @@ obj_removed_cb (CalListener *listener, const GNOME_Evolution_Calendar_CalObjUID
 	gtk_signal_emit (GTK_OBJECT (client), cal_client_signals[OBJ_REMOVED], uid);
 }
 
+/* Handle the error_occurred signal from the listener */
+static void
+backend_error_cb (CalListener *listener, const char *message, gpointer data)
+{
+	CalClient *client;
+
+	client = CAL_CLIENT (data);
+	gtk_signal_emit (GTK_OBJECT (client), cal_client_signals[BACKEND_ERROR], message);
+}
+
 /* Handle the categories_changed signal from the listener */
 static void
 categories_changed_cb (CalListener *listener, const GNOME_Evolution_Calendar_StringSeq *categories,
@@ -752,6 +771,7 @@ real_open_calendar (CalClient *client, const char *str_uri, gboolean only_if_exi
 					   cal_set_mode_cb,
 					   obj_updated_cb,
 					   obj_removed_cb,
+					   backend_error_cb,
 					   categories_changed_cb,
 					   client);
 	if (!priv->listener) {
diff --git a/calendar/cal-client/cal-client.h b/calendar/cal-client/cal-client.h
index e7a1649a0c..bb1a02e8e6 100644
--- a/calendar/cal-client/cal-client.h
+++ b/calendar/cal-client/cal-client.h
@@ -107,6 +107,8 @@ struct _CalClientClass {
 	void (* obj_updated) (CalClient *client, const char *uid);
 	void (* obj_removed) (CalClient *client, const char *uid);
 
+	void (* backend_error) (CalClient *client, const char *message);
+
 	void (* categories_changed) (CalClient *client, GPtrArray *categories);
 
 	void (* forget_password) (CalClient *client, const char *key);
diff --git a/calendar/cal-client/cal-listener.c b/calendar/cal-client/cal-listener.c
index c3fe31e60d..b96f0848fe 100644
--- a/calendar/cal-client/cal-listener.c
+++ b/calendar/cal-client/cal-listener.c
@@ -30,6 +30,7 @@ struct CalListenerPrivate {
 	CalListenerCalSetModeFn cal_set_mode_fn;
 	CalListenerObjUpdatedFn obj_updated_fn;
 	CalListenerObjRemovedFn obj_removed_fn;
+	CalListenerErrorOccurredFn error_occurred_fn;
 	CalListenerCategoriesChangedFn categories_changed_fn;
 	gpointer fn_data;
 
@@ -57,6 +58,9 @@ static void impl_notifyObjUpdated (PortableServer_Servant servant,
 static void impl_notifyObjRemoved (PortableServer_Servant servant,
 				   GNOME_Evolution_Calendar_CalObjUID uid,
 				   CORBA_Environment *ev);
+static void impl_notifyErrorOccurred (PortableServer_Servant servant,
+				      const CORBA_char *message,
+				      CORBA_Environment *ev);
 static void impl_notifyCategoriesChanged (PortableServer_Servant servant,
 					  const GNOME_Evolution_Calendar_StringSeq *categories,
 					  CORBA_Environment *ev);
@@ -84,6 +88,7 @@ cal_listener_class_init (CalListenerClass *class)
 	class->epv.notifyCalSetMode = impl_notifyCalSetMode;
 	class->epv.notifyObjUpdated = impl_notifyObjUpdated;
 	class->epv.notifyObjRemoved = impl_notifyObjRemoved;
+	class->epv.notifyErrorOccurred = impl_notifyErrorOccurred;
 	class->epv.notifyCategoriesChanged = impl_notifyCategoriesChanged;
 
 	object_class->destroy = cal_listener_destroy;
@@ -101,6 +106,7 @@ cal_listener_init (CalListener *listener)
 	priv->cal_opened_fn = NULL;
 	priv->obj_updated_fn = NULL;
 	priv->obj_removed_fn = NULL;
+	priv->error_occurred_fn = NULL;
 	priv->categories_changed_fn = NULL;
 
 	priv->notify = TRUE;
@@ -122,6 +128,7 @@ cal_listener_destroy (GtkObject *object)
 	priv->cal_opened_fn = NULL;
 	priv->obj_updated_fn = NULL;
 	priv->obj_removed_fn = NULL;
+	priv->error_occurred_fn = NULL;
 	priv->categories_changed_fn = NULL;
 	priv->fn_data = NULL;
 
@@ -228,6 +235,25 @@ impl_notifyObjRemoved (PortableServer_Servant servant,
 	(* priv->obj_removed_fn) (listener, uid, priv->fn_data);
 }
 
+/* ::notifyErrorOccurred method */
+static void
+impl_notifyErrorOccurred (PortableServer_Servant servant,
+			  const CORBA_char *message,
+			  CORBA_Environment *ev)
+{
+	CalListener *listener;
+	CalListenerPrivate *priv;
+
+	listener = CAL_LISTENER (bonobo_object_from_servant (servant));
+	priv = listener->priv;
+
+	if (!priv->notify)
+		return;
+
+	g_assert (priv->error_occurred_fn != NULL);
+	(* priv->error_occurred_fn) (listener, message, priv->fn_data);
+}
+
 /* ::notifyCategoriesChanged method */
 static void
 impl_notifyCategoriesChanged (PortableServer_Servant servant,
@@ -258,6 +284,7 @@ impl_notifyCategoriesChanged (PortableServer_Servant servant,
  * calendar was updated.
  * @obj_removed_fn: Function that will be called to notify that an object in the
  * calendar was removed.
+ * @error_occurred_fn: Function that will be called to notify errors.
  * @categories_changed_fn: Function that will be called to notify that the list
  * of categories that are present in the calendar's objects has changed.
  * @fn_data: Closure data pointer that will be passed to the notification
@@ -274,6 +301,7 @@ cal_listener_construct (CalListener *listener,
 			CalListenerCalSetModeFn cal_set_mode_fn,
 			CalListenerObjUpdatedFn obj_updated_fn,
 			CalListenerObjRemovedFn obj_removed_fn,
+			CalListenerErrorOccurredFn error_occurred_fn,
 			CalListenerCategoriesChangedFn categories_changed_fn,
 			gpointer fn_data)
 {
@@ -285,6 +313,7 @@ cal_listener_construct (CalListener *listener,
  	g_return_val_if_fail (cal_set_mode_fn != NULL, NULL);
 	g_return_val_if_fail (obj_updated_fn != NULL, NULL);
 	g_return_val_if_fail (obj_removed_fn != NULL, NULL);
+	g_return_val_if_fail (error_occurred_fn != NULL, NULL);
 	g_return_val_if_fail (categories_changed_fn != NULL, NULL);
 
 	priv = listener->priv;
@@ -293,6 +322,7 @@ cal_listener_construct (CalListener *listener,
 	priv->cal_set_mode_fn = cal_set_mode_fn;
 	priv->obj_updated_fn = obj_updated_fn;
 	priv->obj_removed_fn = obj_removed_fn;
+	priv->error_occurred_fn = error_occurred_fn;
 	priv->categories_changed_fn = categories_changed_fn;
 	priv->fn_data = fn_data;
 
@@ -307,6 +337,7 @@ cal_listener_construct (CalListener *listener,
  * calendar was updated.
  * @obj_removed_fn: Function that will be called to notify that an object in the
  * calendar was removed.
+ * @error_occurred_fn: Function that will be called to notify errors.
  * @categories_changed_fn: Function that will be called to notify that the list
  * of categories that are present in the calendar's objects has changed.
  * @fn_data: Closure data pointer that will be passed to the notification
@@ -321,6 +352,7 @@ cal_listener_new (CalListenerCalOpenedFn cal_opened_fn,
 		  CalListenerCalSetModeFn cal_set_mode_fn,
 		  CalListenerObjUpdatedFn obj_updated_fn,
 		  CalListenerObjRemovedFn obj_removed_fn,
+		  CalListenerErrorOccurredFn error_occurred_fn,
 		  CalListenerCategoriesChangedFn categories_changed_fn,
 		  gpointer fn_data)
 {
@@ -329,6 +361,7 @@ cal_listener_new (CalListenerCalOpenedFn cal_opened_fn,
 	g_return_val_if_fail (cal_opened_fn != NULL, NULL);
 	g_return_val_if_fail (obj_updated_fn != NULL, NULL);
 	g_return_val_if_fail (obj_removed_fn != NULL, NULL);
+	g_return_val_if_fail (error_occurred_fn != NULL, NULL);
 	g_return_val_if_fail (categories_changed_fn != NULL, NULL);
 
 	listener = gtk_type_new (CAL_LISTENER_TYPE);
@@ -337,6 +370,7 @@ cal_listener_new (CalListenerCalOpenedFn cal_opened_fn,
 				       cal_set_mode_fn,
 				       obj_updated_fn,
 				       obj_removed_fn,
+				       error_occurred_fn,
 				       categories_changed_fn,
 				       fn_data);
 }
diff --git a/calendar/cal-client/cal-listener.h b/calendar/cal-client/cal-listener.h
index c7488e6e97..4d557a1fbc 100644
--- a/calendar/cal-client/cal-listener.h
+++ b/calendar/cal-client/cal-listener.h
@@ -69,6 +69,10 @@ typedef void (* CalListenerObjRemovedFn) (CalListener *listener,
 					  const GNOME_Evolution_Calendar_CalObjUID uid,
 					  gpointer data);
 
+typedef void (* CalListenerErrorOccurredFn) (CalListener *listener,
+					     const char *message,
+					     gpointer data);
+
 typedef void (* CalListenerCategoriesChangedFn) (CalListener *listener,
 						 const GNOME_Evolution_Calendar_StringSeq *categories,
 						 gpointer data);
@@ -81,6 +85,7 @@ CalListener *cal_listener_construct (CalListener *listener,
 				     CalListenerCalSetModeFn cal_set_mode_fn,
 				     CalListenerObjUpdatedFn obj_updated_fn,
 				     CalListenerObjRemovedFn obj_removed_fn,
+				     CalListenerErrorOccurredFn error_occurred_fn,
 				     CalListenerCategoriesChangedFn categories_changed_fn,
 				     gpointer fn_data);
 
@@ -88,6 +93,7 @@ CalListener *cal_listener_new (CalListenerCalOpenedFn cal_opened_fn,
 			       CalListenerCalSetModeFn cal_set_mode_fn,
 			       CalListenerObjUpdatedFn obj_updated_fn,
 			       CalListenerObjRemovedFn obj_removed_fn,
+			       CalListenerErrorOccurredFn error_occurred_fn,
 			       CalListenerCategoriesChangedFn categories_changed_fn,
 			       gpointer fn_data);
 
diff --git a/calendar/gui/e-tasks.c b/calendar/gui/e-tasks.c
index d0097cc015..17cce37bd2 100644
--- a/calendar/gui/e-tasks.c
+++ b/calendar/gui/e-tasks.c
@@ -67,6 +67,7 @@ static void setup_widgets (ETasks *tasks);
 static void e_tasks_destroy (GtkObject *object);
 
 static void cal_opened_cb (CalClient *client, CalClientOpenStatus status, gpointer data);
+static void backend_error_cb (CalClient *client, const char *message, gpointer data);
 
 /* Signal IDs */
 enum {
@@ -248,6 +249,8 @@ e_tasks_construct (ETasks *tasks)
 
 	gtk_signal_connect (GTK_OBJECT (priv->client), "cal_opened",
 			    GTK_SIGNAL_FUNC (cal_opened_cb), tasks);
+	gtk_signal_connect (GTK_OBJECT (priv->client), "backend_error",
+			    GTK_SIGNAL_FUNC (backend_error_cb), tasks);
 	gtk_signal_connect (GTK_OBJECT (priv->client), "categories_changed",
 			    GTK_SIGNAL_FUNC (client_categories_changed_cb), tasks);
 
@@ -452,6 +455,22 @@ cal_opened_cb				(CalClient	*client,
 	}
 }
 
+/* Callback from the calendar client when an error occurs in the backend */
+static void
+backend_error_cb (CalClient *client, const char *message, gpointer data)
+{
+	ETasks *tasks;
+	ETasksPrivate *priv;
+	char *errmsg;
+
+	tasks = E_TASKS (data);
+	priv = tasks->priv;
+
+	errmsg = g_strdup_printf (_("Error on %s:\n %s"), cal_client_get_uri (client), message);
+	gnome_error_dialog_parented (errmsg, GTK_WINDOW (gtk_widget_get_toplevel (GTK_WIDGET (tasks))));
+	g_free (errmsg);
+}
+
 /**
  * e_tasks_get_cal_client:
  * @tasks: An #ETasks.
diff --git a/calendar/gui/gnome-cal.c b/calendar/gui/gnome-cal.c
index 32f6cd15ed..5885185e73 100644
--- a/calendar/gui/gnome-cal.c
+++ b/calendar/gui/gnome-cal.c
@@ -1730,6 +1730,22 @@ client_categories_changed_cb (CalClient *client, GPtrArray *categories, gpointer
 	free_categories (merged);
 }
 
+/* Callback when we get an error message from the backend */
+static void
+backend_error_cb (CalClient *client, const char *message, gpointer data)
+{
+	GnomeCalendar *gcal;
+	GnomeCalendarPrivate *priv;
+	char *errmsg;
+
+	gcal = GNOME_CALENDAR (data);
+	priv = gcal->priv;
+
+	errmsg = g_strdup_printf (_("Error on %s:\n %s"), cal_client_get_uri (client), message);
+	gnome_error_dialog_parented (errmsg, GTK_WINDOW (gtk_widget_get_toplevel (GTK_WIDGET (gcal))));
+	g_free (errmsg);
+}
+
 /* Callback when the backend dies */
 static void
 backend_died_cb (CalClient *client, gpointer data)
@@ -1779,6 +1795,8 @@ gnome_calendar_construct (GnomeCalendar *gcal)
 
 	gtk_signal_connect (GTK_OBJECT (priv->client), "cal_opened",
 			    GTK_SIGNAL_FUNC (client_cal_opened_cb), gcal);
+	gtk_signal_connect (GTK_OBJECT (priv->client), "backend_error",
+			    GTK_SIGNAL_FUNC (backend_error_cb), gcal);
 	gtk_signal_connect (GTK_OBJECT (priv->client), "categories_changed",
 			    GTK_SIGNAL_FUNC (client_categories_changed_cb), gcal);
 	gtk_signal_connect (GTK_OBJECT (priv->client), "backend_died",
@@ -1801,7 +1819,9 @@ gnome_calendar_construct (GnomeCalendar *gcal)
 		return NULL;
 
 	gtk_signal_connect (GTK_OBJECT (priv->task_pad_client), "cal_opened",
-			    GTK_SIGNAL_FUNC (client_cal_opened_cb), gcal);
+			    GTK_SIGNAL_FUNC (client_cal_opened_cb), gcal);	
+	gtk_signal_connect (GTK_OBJECT (priv->client), "backend_error",
+			    GTK_SIGNAL_FUNC (backend_error_cb), gcal);
 	gtk_signal_connect (GTK_OBJECT (priv->task_pad_client), "categories_changed",
 			    GTK_SIGNAL_FUNC (client_categories_changed_cb), gcal);
 	gtk_signal_connect (GTK_OBJECT (priv->task_pad_client), "backend_died",
diff --git a/calendar/idl/evolution-calendar.idl b/calendar/idl/evolution-calendar.idl
index 78fe0ba07a..c7abc2ca7e 100644
--- a/calendar/idl/evolution-calendar.idl
+++ b/calendar/idl/evolution-calendar.idl
@@ -263,6 +263,9 @@ module Calendar {
 
 		/* Called from a Calendar when the list of categories changes */
 		void notifyCategoriesChanged (in StringSeq categories);
+
+		/* Called from a Calendar when there is an error not notified otherwise */
+		void notifyErrorOccurred (in string message);
 	};
 
 	/* Handle to a live query on a calendar */
diff --git a/calendar/pcs/cal-backend-file.c b/calendar/pcs/cal-backend-file.c
index 4fd65904cc..2def3bb57b 100644
--- a/calendar/pcs/cal-backend-file.c
+++ b/calendar/pcs/cal-backend-file.c
@@ -282,11 +282,11 @@ static void
 save (CalBackendFile *cbfile)
 {
 	CalBackendFilePrivate *priv;
-	GnomeVFSURI *uri;
+	GnomeVFSURI *uri, *backup_uri;
 	GnomeVFSHandle *handle = NULL;
 	GnomeVFSResult result;
 	GnomeVFSFileSize out;
-	gchar *tmp;
+	gchar *tmp, *backup_uristr;
 	char *buf;
 	
 	priv = cbfile->priv;
@@ -297,43 +297,54 @@ save (CalBackendFile *cbfile)
 	if (!uri)
 		goto error;
 
-	/* Make a backup copy of the file if it exists */
+	/* save calendar to backup file */
 	tmp = gnome_vfs_uri_to_string (uri, GNOME_VFS_URI_HIDE_NONE);
-	if (tmp) {
-		GnomeVFSURI *backup_uri;
-		gchar *backup_uristr;
-		
-		backup_uristr = g_strconcat (tmp, "~", NULL);
-		backup_uri = gnome_vfs_uri_new (backup_uristr);
-		
-		result = gnome_vfs_move_uri (uri, backup_uri, TRUE);
-		gnome_vfs_uri_unref (backup_uri);
+	if (!tmp) {
+		gnome_vfs_uri_unref (uri);
+		goto error;
+	}
 		
-		g_free (tmp);
-		g_free (backup_uristr);
+	backup_uristr = g_strconcat (tmp, "~", NULL);
+	backup_uri = gnome_vfs_uri_new (backup_uristr);
+
+	g_free (tmp);
+	g_free (backup_uristr);
+
+	if (!backup_uri) {
+		gnome_vfs_uri_unref (uri);
+		goto error;
 	}
 	
-	/* Now write the new file out */
-	result = gnome_vfs_create_uri (&handle, uri, 
-				       GNOME_VFS_OPEN_WRITE,
-				       FALSE, 0666);
-	
-	if (result != GNOME_VFS_OK)
+	result = gnome_vfs_create_uri (&handle, backup_uri,
+                                       GNOME_VFS_OPEN_WRITE,
+                                       FALSE, 0666);
+	if (result != GNOME_VFS_OK) {
+		gnome_vfs_uri_unref (uri);
+		gnome_vfs_uri_unref (backup_uri);
 		goto error;
-	
+	}
+
 	buf = icalcomponent_as_ical_string (priv->icalcomp);
 	result = gnome_vfs_write (handle, buf, strlen (buf) * sizeof (char), &out);
-
-	if (result != GNOME_VFS_OK)
+	gnome_vfs_close (handle);
+	if (result != GNOME_VFS_OK) {
+		gnome_vfs_uri_unref (uri);
+		gnome_vfs_uri_unref (backup_uri);
 		goto error;
+	}
+
+	/* now copy the temporary file to the real file */
+	result = gnome_vfs_move_uri (backup_uri, uri, TRUE);
 
-	gnome_vfs_close (handle);
 	gnome_vfs_uri_unref (uri);
+	gnome_vfs_uri_unref (backup_uri);
+	if (result != GNOME_VFS_OK)
+		goto error;
 
 	return;
 	
  error:
-	g_warning ("Error writing calendar file.");
+	notify_error (cbfile, gnome_vfs_result_to_string (result));
 	return;
 }
 
@@ -1713,6 +1724,23 @@ notify_remove (CalBackendFile *cbfile, const char *uid)
 	}
 }
 
+/* Notifies a backend's clients that an error has occurred */
+static void
+notify_error (CalBackendFile *cbfile, const char *message)
+{
+	CalBackendFilePrivate *priv;
+	GList *l;
+
+	priv = cbfile->priv;
+
+	for (l = CAL_BACKEND (cbfile)->clients; l; l = l->next) {
+		Cal *cal;
+
+		cal = CAL (l->data);
+		cal_notify_error (cal, message);
+	}
+}
+
 /* Used from g_hash_table_foreach_remove(); removes and frees a category */
 static gboolean
 remove_category_cb (gpointer key, gpointer value, gpointer data)
diff --git a/calendar/pcs/cal.c b/calendar/pcs/cal.c
index 60fcdc59ad..861cc47c89 100644
--- a/calendar/pcs/cal.c
+++ b/calendar/pcs/cal.c
@@ -874,6 +874,36 @@ cal_notify_remove (Cal *cal, const char *uid)
 }
 
 /**
+ * cal_notify_error
+ * @cal: A calendar client interface.
+ * @message: Error message.
+ *
+ * Notify a calendar client of an error occurred in the backend.
+ */
+void
+cal_notify_error (Cal *cal, const char *message)
+{
+	CalPrivate *priv;
+	CORBA_Environment ev;
+
+	g_return_if_fail (cal != NULL);
+	g_return_if_fail (IS_CAL (cal));
+	g_return_if_fail (message != NULL);
+
+	priv = cal->priv;
+	g_return_if_fail (priv->listener != CORBA_OBJECT_NIL);
+
+	CORBA_exception_init (&ev);
+	GNOME_Evolution_Calendar_Listener_notifyErrorOccurred (priv->listener, (char *) message, &ev);
+
+	if (BONOBO_EX (&ev))
+		g_message ("cal_notify_remove(): could not notify the listener "
+			   "about a removed object");
+
+	CORBA_exception_free (&ev);
+}
+
+/**
  * cal_notify_categories_changed:
  * @cal: A calendar client interface.
  * @categories: List of categories.
diff --git a/calendar/pcs/cal.h b/calendar/pcs/cal.h
index 9b6636b9d0..52889b4f9a 100644
--- a/calendar/pcs/cal.h
+++ b/calendar/pcs/cal.h
@@ -66,6 +66,7 @@ void cal_notify_mode (Cal *cal,
 		      GNOME_Evolution_Calendar_CalMode mode);
 void cal_notify_update (Cal *cal, const char *uid);
 void cal_notify_remove (Cal *cal, const char *uid);
+void cal_notify_error (Cal *cal, const char *message);
 
 void cal_notify_categories_changed (Cal *cal, GNOME_Evolution_Calendar_StringSeq *categories);