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

[Matthew Barnes <mbarnes src gnome org>]

commit 4b0acd291daa0ff3d785a7512c7b9644a9a7048b
Author: Matthew Barnes <mbarnes redhat com>
Date:   Fri Mar 8 09:26:33 2013 -0500

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

 addressbook/libebook/e-book-client.c |   65 +++++++++++++++++++++------------
 1 files changed, 41 insertions(+), 24 deletions(-)
---
diff --git a/addressbook/libebook/e-book-client.c b/addressbook/libebook/e-book-client.c
index 7ba9f10..cc88113 100644
--- a/addressbook/libebook/e-book-client.c
+++ b/addressbook/libebook/e-book-client.c
@@ -71,7 +71,7 @@ struct _AsyncContext {
 };
 
 struct _SignalClosure {
-       EClient *client;
+       GWeakRef client;
        gchar *property_name;
        gchar *error_message;
 };
@@ -130,7 +130,7 @@ async_context_free (AsyncContext *async_context)
 static void
 signal_closure_free (SignalClosure *signal_closure)
 {
-       g_object_unref (signal_closure->client);
+       g_weak_ref_set (&signal_closure->client, NULL);
 
        g_free (signal_closure->property_name);
        g_free (signal_closure->error_message);
@@ -338,10 +338,14 @@ static gboolean
 book_client_emit_backend_died_idle_cb (gpointer user_data)
 {
        SignalClosure *signal_closure = user_data;
+       EClient *client;
 
-       g_signal_emit_by_name (
-               signal_closure->client,
-               "backend-died");
+       client = g_weak_ref_get (&signal_closure->client);
+
+       if (client != NULL) {
+               g_signal_emit_by_name (client, "backend-died");
+               g_object_unref (client);
+       }
 
        return FALSE;
 }
@@ -350,11 +354,16 @@ static gboolean
 book_client_emit_backend_error_idle_cb (gpointer user_data)
 {
        SignalClosure *signal_closure = user_data;
+       EClient *client;
 
-       g_signal_emit_by_name (
-               signal_closure->client,
-               "backend-error",
-               signal_closure->error_message);
+       client = g_weak_ref_get (&signal_closure->client);
+
+       if (client != NULL) {
+               g_signal_emit_by_name (
+                       client, "backend-error",
+                       signal_closure->error_message);
+               g_object_unref (client);
+       }
 
        return FALSE;
 }
@@ -363,21 +372,29 @@ static gboolean
 book_client_emit_backend_property_changed_idle_cb (gpointer user_data)
 {
        SignalClosure *signal_closure = user_data;
-       gchar *prop_value = NULL;
+       EClient *client;
 
-       /* XXX Despite appearances, this function does not block. */
-       e_client_get_backend_property_sync (
-               signal_closure->client,
-               signal_closure->property_name,
-               &prop_value, NULL, NULL);
+       client = g_weak_ref_get (&signal_closure->client);
 
-       if (prop_value != NULL) {
-               g_signal_emit_by_name (
-                       signal_closure->client,
-                       "backend-property-changed",
+       if (client != NULL) {
+               gchar *prop_value = NULL;
+
+               /* XXX Despite appearances, this function does not block. */
+               e_client_get_backend_property_sync (
+                       client,
                        signal_closure->property_name,
-                       prop_value);
-               g_free (prop_value);
+                       &prop_value, NULL, NULL);
+
+               if (prop_value != NULL) {
+                       g_signal_emit_by_name (
+                               client,
+                               "backend-property-changed",
+                               signal_closure->property_name,
+                               prop_value);
+                       g_free (prop_value);
+               }
+
+               g_object_unref (client);
        }
 
        return FALSE;
@@ -393,7 +410,7 @@ book_client_dbus_proxy_error_cb (EDBusAddressBook *dbus_proxy,
        SignalClosure *signal_closure;
 
        signal_closure = g_slice_new0 (SignalClosure);
-       signal_closure->client = g_object_ref (client);
+       g_weak_ref_set (&signal_closure->client, client);
        signal_closure->error_message = g_strdup (error_message);
 
        main_context = e_client_ref_main_context (client);
@@ -472,7 +489,7 @@ book_client_dbus_proxy_notify_cb (EDBusAddressBook *dbus_proxy,
                SignalClosure *signal_closure;
 
                signal_closure = g_slice_new0 (SignalClosure);
-               signal_closure->client = g_object_ref (client);
+               g_weak_ref_set (&signal_closure->client, client);
                signal_closure->property_name = g_strdup (backend_prop_name);
 
                main_context = e_client_ref_main_context (client);
@@ -500,7 +517,7 @@ book_client_name_vanished_cb (GDBusConnection *connection,
        SignalClosure *signal_closure;
 
        signal_closure = g_slice_new0 (SignalClosure);
-       signal_closure->client = g_object_ref (client);
+       g_weak_ref_set (&signal_closure->client, client);
 
        main_context = e_client_ref_main_context (client);