[evolution-data-server] ECalBackend: Use weak references in signal closures.

[Matthew Barnes <mbarnes src gnome org>]

commit deaeb97083f37fd8d437940a794d863146aecf7d
Author: Matthew Barnes <mbarnes redhat com>
Date:   Fri Mar 8 09:45:39 2013 -0500

    ECalBackend: Use weak references in signal closures.
    
    Helps prevent the object from surviving beyond its natural life.

 calendar/libedata-cal/e-cal-backend.c |   19 ++++++++++++-------
 1 files changed, 12 insertions(+), 7 deletions(-)
---
diff --git a/calendar/libedata-cal/e-cal-backend.c b/calendar/libedata-cal/e-cal-backend.c
index 328d7bf..f3753f5 100644
--- a/calendar/libedata-cal/e-cal-backend.c
+++ b/calendar/libedata-cal/e-cal-backend.c
@@ -64,7 +64,7 @@ struct _ECalBackendPrivate {
 };
 
 struct _SignalClosure {
-       ECalBackend *backend;
+       GWeakRef backend;
        icaltimezone *cached_zone;
 };
 
@@ -96,7 +96,7 @@ G_DEFINE_TYPE_WITH_CODE (
 static void
 signal_closure_free (SignalClosure *signal_closure)
 {
-       g_object_unref (signal_closure->backend);
+       g_weak_ref_set (&signal_closure->backend, NULL);
 
        /* The icaltimezone is cached in ECalBackend's internal
         * "zone_cache" hash table and must not be freed here. */
@@ -213,11 +213,16 @@ static gboolean
 cal_backend_emit_timezone_added_idle_cb (gpointer user_data)
 {
        SignalClosure *signal_closure = user_data;
+       ECalBackend *backend;
 
-       g_signal_emit_by_name (
-               signal_closure->backend,
-               "timezone-added",
-               signal_closure->cached_zone);
+       backend = g_weak_ref_get (&signal_closure->backend);
+
+       if (backend != NULL) {
+               g_signal_emit_by_name (
+                       backend, "timezone-added",
+                       signal_closure->cached_zone);
+               g_object_unref (backend);
+       }
 
        return FALSE;
 }
@@ -425,7 +430,7 @@ cal_backend_add_cached_timezone (ETimezoneCache *cache,
                 * internally cached icaltimezone alive for the
                 * duration of the idle callback. */
                signal_closure = g_slice_new0 (SignalClosure);
-               signal_closure->backend = g_object_ref (cache);
+               g_weak_ref_set (&signal_closure->backend, cache);
                signal_closure->cached_zone = cached_zone;
 
                main_context = e_backend_ref_main_context (E_BACKEND (cache));