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

[Matthew Barnes <mbarnes src gnome org>]

commit f22f8c320657381a5bebe0f7c47523091faf0551
Author: Matthew Barnes <mbarnes redhat com>
Date:   Fri Mar 8 10:03:15 2013 -0500

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

 camel/camel-subscribable.c |   71 ++++++++++++++++++++++++++------------------
 1 files changed, 42 insertions(+), 29 deletions(-)
---
diff --git a/camel/camel-subscribable.c b/camel/camel-subscribable.c
index 331103e..e19dc2b 100644
--- a/camel/camel-subscribable.c
+++ b/camel/camel-subscribable.c
@@ -26,14 +26,14 @@
 #include "camel-vtrash-folder.h"
 
 typedef struct _AsyncContext AsyncContext;
-typedef struct _SignalData SignalData;
+typedef struct _SignalClosure SignalClosure;
 
 struct _AsyncContext {
        gchar *folder_name;
 };
 
-struct _SignalData {
-       CamelSubscribable *subscribable;
+struct _SignalClosure {
+       GWeakRef subscribable;
        CamelFolderInfo *folder_info;
 };
 
@@ -56,26 +56,31 @@ async_context_free (AsyncContext *async_context)
 }
 
 static void
-signal_data_free (SignalData *signal_data)
+signal_closure_free (SignalClosure *signal_closure)
 {
-       if (signal_data->subscribable != NULL)
-               g_object_unref (signal_data->subscribable);
+       g_weak_ref_set (&signal_closure->subscribable, NULL);
 
-       if (signal_data->folder_info != NULL)
-               camel_folder_info_free (signal_data->folder_info);
+       if (signal_closure->folder_info != NULL)
+               camel_folder_info_free (signal_closure->folder_info);
 
-       g_slice_free (SignalData, signal_data);
+       g_slice_free (SignalClosure, signal_closure);
 }
 
 static gboolean
 subscribable_emit_folder_subscribed_cb (gpointer user_data)
 {
-       SignalData *signal_data = user_data;
+       SignalClosure *signal_closure = user_data;
+       CamelSubscribable *subscribable;
 
-       g_signal_emit (
-               signal_data->subscribable,
-               signals[FOLDER_SUBSCRIBED], 0,
-               signal_data->folder_info);
+       subscribable = g_weak_ref_get (&signal_closure->subscribable);
+
+       if (subscribable != NULL) {
+               g_signal_emit (
+                       subscribable,
+                       signals[FOLDER_SUBSCRIBED], 0,
+                       signal_closure->folder_info);
+               g_object_unref (subscribable);
+       }
 
        return FALSE;
 }
@@ -83,12 +88,18 @@ subscribable_emit_folder_subscribed_cb (gpointer user_data)
 static gboolean
 subscribable_emit_folder_unsubscribed_cb (gpointer user_data)
 {
-       SignalData *signal_data = user_data;
+       SignalClosure *signal_closure = user_data;
+       CamelSubscribable *subscribable;
+
+       subscribable = g_weak_ref_get (&signal_closure->subscribable);
 
-       g_signal_emit (
-               signal_data->subscribable,
-               signals[FOLDER_UNSUBSCRIBED], 0,
-               signal_data->folder_info);
+       if (subscribable != NULL) {
+               g_signal_emit (
+                       subscribable,
+                       signals[FOLDER_UNSUBSCRIBED], 0,
+                       signal_closure->folder_info);
+               g_object_unref (subscribable);
+       }
 
        return FALSE;
 }
@@ -623,7 +634,7 @@ camel_subscribable_folder_subscribed (CamelSubscribable *subscribable,
 {
        CamelService *service;
        CamelSession *session;
-       SignalData *signal_data;
+       SignalClosure *signal_closure;
 
        g_return_if_fail (CAMEL_IS_SUBSCRIBABLE (subscribable));
        g_return_if_fail (folder_info != NULL);
@@ -631,15 +642,16 @@ camel_subscribable_folder_subscribed (CamelSubscribable *subscribable,
        service = CAMEL_SERVICE (subscribable);
        session = camel_service_ref_session (service);
 
-       signal_data = g_slice_new0 (SignalData);
-       signal_data->subscribable = g_object_ref (subscribable);
-       signal_data->folder_info = camel_folder_info_clone (folder_info);
+       signal_closure = g_slice_new0 (SignalClosure);
+       g_weak_ref_set (&signal_closure->subscribable, subscribable);
+       signal_closure->folder_info = camel_folder_info_clone (folder_info);
 
        /* Prioritize ahead of GTK+ redraws. */
        camel_session_idle_add (
                session, G_PRIORITY_HIGH_IDLE,
                subscribable_emit_folder_subscribed_cb,
-               signal_data, (GDestroyNotify) signal_data_free);
+               signal_closure,
+               (GDestroyNotify) signal_closure_free);
 
        g_object_unref (session);
 }
@@ -662,7 +674,7 @@ camel_subscribable_folder_unsubscribed (CamelSubscribable *subscribable,
 {
        CamelService *service;
        CamelSession *session;
-       SignalData *signal_data;
+       SignalClosure *signal_closure;
 
        g_return_if_fail (CAMEL_IS_SUBSCRIBABLE (subscribable));
        g_return_if_fail (folder_info != NULL);
@@ -670,15 +682,16 @@ camel_subscribable_folder_unsubscribed (CamelSubscribable *subscribable,
        service = CAMEL_SERVICE (subscribable);
        session = camel_service_ref_session (service);
 
-       signal_data = g_slice_new0 (SignalData);
-       signal_data->subscribable = g_object_ref (subscribable);
-       signal_data->folder_info = camel_folder_info_clone (folder_info);
+       signal_closure = g_slice_new0 (SignalClosure);
+       g_weak_ref_set (&signal_closure->subscribable, subscribable);
+       signal_closure->folder_info = camel_folder_info_clone (folder_info);
 
        /* Prioritize ahead of GTK+ redraws. */
        camel_session_idle_add (
                session, G_PRIORITY_HIGH_IDLE,
                subscribable_emit_folder_unsubscribed_cb,
-               signal_data, (GDestroyNotify) signal_data_free);
+               signal_closure,
+               (GDestroyNotify) signal_closure_free);
 
        g_object_unref (session);
 }