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

[Matthew Barnes <mbarnes src gnome org>]

commit 3ebd841e29c7db318e8eeed2ea0140e3148e3461
Author: Matthew Barnes <mbarnes redhat com>
Date:   Fri Mar 8 09:51:45 2013 -0500

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

 camel/camel-folder.c |   94 +++++++++++++++++++++++++++++++-------------------
 1 files changed, 58 insertions(+), 36 deletions(-)
---
diff --git a/camel/camel-folder.c b/camel/camel-folder.c
index cf61797..ce257c6 100644
--- a/camel/camel-folder.c
+++ b/camel/camel-folder.c
@@ -50,7 +50,7 @@
 #define w(x)
 
 typedef struct _AsyncContext AsyncContext;
-typedef struct _SignalData SignalData;
+typedef struct _SignalClosure SignalClosure;
 typedef struct _FolderFilterData FolderFilterData;
 
 struct _CamelFolderPrivate {
@@ -100,8 +100,8 @@ struct _CamelFolderChangeInfoPrivate {
        CamelMemPool *uid_pool; /* pool used to store copies of uid strings */
 };
 
-struct _SignalData {
-       CamelFolder *folder;
+struct _SignalClosure {
+       GWeakRef folder;
        gchar *folder_name;
 };
 
@@ -169,30 +169,37 @@ async_context_free (AsyncContext *async_context)
 }
 
 static void
-signal_data_free (SignalData *signal_data)
+signal_closure_free (SignalClosure *signal_closure)
 {
-       if (signal_data->folder != NULL)
-               g_object_unref (signal_data->folder);
+       g_weak_ref_set (&signal_closure->folder, NULL);
 
-       g_free (signal_data->folder_name);
+       g_free (signal_closure->folder_name);
 
-       g_slice_free (SignalData, signal_data);
+       g_slice_free (SignalClosure, signal_closure);
 }
 
 static gboolean
 folder_emit_changed_cb (gpointer user_data)
 {
-       SignalData *signal_data = user_data;
-       CamelFolderChangeInfo *changes;
+       SignalClosure *signal_closure = user_data;
+       CamelFolder *folder;
+
+       folder = g_weak_ref_get (&signal_closure->folder);
+
+       if (folder != NULL) {
+               CamelFolderChangeInfo *changes;
 
-       camel_folder_lock (signal_data->folder, CAMEL_FOLDER_CHANGE_LOCK);
-       changes = signal_data->folder->priv->pending_changes;
-       signal_data->folder->priv->pending_changes = NULL;
-       camel_folder_unlock (signal_data->folder, CAMEL_FOLDER_CHANGE_LOCK);
+               camel_folder_lock (folder, CAMEL_FOLDER_CHANGE_LOCK);
+               changes = folder->priv->pending_changes;
+               folder->priv->pending_changes = NULL;
+               camel_folder_unlock (folder, CAMEL_FOLDER_CHANGE_LOCK);
 
-       g_signal_emit (signal_data->folder, signals[CHANGED], 0, changes);
+               g_signal_emit (folder, signals[CHANGED], 0, changes);
 
-       camel_folder_change_info_free (changes);
+               camel_folder_change_info_free (changes);
+
+               g_object_unref (folder);
+       }
 
        return FALSE;
 }
@@ -200,9 +207,15 @@ folder_emit_changed_cb (gpointer user_data)
 static gboolean
 folder_emit_deleted_cb (gpointer user_data)
 {
-       SignalData *signal_data = user_data;
+       SignalClosure *signal_closure = user_data;
+       CamelFolder *folder;
 
-       g_signal_emit (signal_data->folder, signals[DELETED], 0);
+       folder = g_weak_ref_get (&signal_closure->folder);
+
+       if (folder != NULL) {
+               g_signal_emit (folder, signals[DELETED], 0);
+               g_object_unref (folder);
+       }
 
        return FALSE;
 }
@@ -210,12 +223,18 @@ folder_emit_deleted_cb (gpointer user_data)
 static gboolean
 folder_emit_renamed_cb (gpointer user_data)
 {
-       SignalData *signal_data = user_data;
+       SignalClosure *signal_closure = user_data;
+       CamelFolder *folder;
+
+       folder = g_weak_ref_get (&signal_closure->folder);
 
-       g_signal_emit (
-               signal_data->folder,
-               signals[RENAMED], 0,
-               signal_data->folder_name);
+       if (folder != NULL) {
+               g_signal_emit (
+                       folder,
+                       signals[RENAMED], 0,
+                       signal_closure->folder_name);
+               g_object_unref (folder);
+       }
 
        return FALSE;
 }
@@ -2898,7 +2917,7 @@ camel_folder_delete (CamelFolder *folder)
        CamelStore *parent_store;
        CamelService *service;
        CamelSession *session;
-       SignalData *signal_data;
+       SignalClosure *signal_closure;
        const gchar *full_name;
 
        g_return_if_fail (CAMEL_IS_FOLDER (folder));
@@ -2926,14 +2945,15 @@ camel_folder_delete (CamelFolder *folder)
        service = CAMEL_SERVICE (parent_store);
        session = camel_service_ref_session (service);
 
-       signal_data = g_slice_new0 (SignalData);
-       signal_data->folder = g_object_ref (folder);
+       signal_closure = g_slice_new0 (SignalClosure);
+       g_weak_ref_set (&signal_closure->folder, folder);
 
        /* Prioritize ahead of GTK+ redraws. */
        camel_session_idle_add (
                session, G_PRIORITY_HIGH_IDLE,
                folder_emit_deleted_cb,
-               signal_data, (GDestroyNotify) signal_data_free);
+               signal_closure,
+               (GDestroyNotify) signal_closure_free);
 
        g_object_unref (session);
 }
@@ -2959,7 +2979,7 @@ camel_folder_rename (CamelFolder *folder,
        CamelStore *parent_store;
        CamelService *service;
        CamelSession *session;
-       SignalData *signal_data;
+       SignalClosure *signal_closure;
        gchar *old_name;
 
        g_return_if_fail (CAMEL_IS_FOLDER (folder));
@@ -2978,15 +2998,16 @@ camel_folder_rename (CamelFolder *folder,
        service = CAMEL_SERVICE (parent_store);
        session = camel_service_ref_session (service);
 
-       signal_data = g_slice_new0 (SignalData);
-       signal_data->folder = g_object_ref (folder);
-       signal_data->folder_name = old_name;  /* transfer ownership */
+       signal_closure = g_slice_new0 (SignalClosure);
+       g_weak_ref_set (&signal_closure->folder, folder);
+       signal_closure->folder_name = old_name;  /* transfer ownership */
 
        /* Prioritize ahead of GTK+ redraws. */
        camel_session_idle_add (
                session, G_PRIORITY_HIGH_IDLE,
                folder_emit_renamed_cb,
-               signal_data, (GDestroyNotify) signal_data_free);
+               signal_closure,
+               (GDestroyNotify) signal_closure_free);
 
        g_object_unref (session);
 }
@@ -3031,7 +3052,7 @@ camel_folder_changed (CamelFolder *folder,
                CamelStore *parent_store;
                CamelService *service;
                CamelSession *session;
-               SignalData *signal_data;
+               SignalClosure *signal_closure;
 
                parent_store = camel_folder_get_parent_store (folder);
 
@@ -3041,13 +3062,14 @@ camel_folder_changed (CamelFolder *folder,
                pending_changes = camel_folder_change_info_new ();
                folder->priv->pending_changes = pending_changes;
 
-               signal_data = g_slice_new0 (SignalData);
-               signal_data->folder = g_object_ref (folder);
+               signal_closure = g_slice_new0 (SignalClosure);
+               g_weak_ref_set (&signal_closure->folder, folder);
 
                camel_session_idle_add (
                        session, G_PRIORITY_LOW,
                        folder_emit_changed_cb,
-                       signal_data, (GDestroyNotify) signal_data_free);
+                       signal_closure,
+                       (GDestroyNotify) signal_closure_free);
 
                g_object_unref (session);
        }