EMFolderTreeModel: Fix a circular dependency between model and its data

The model stores GtkTreeRowReference-s in its private data, but these
references ref the model, thus there is a circular dependency between
internal data and the object itself, effectively causing memory leaks.

With this fixed, the CamelSession is correctly freed at the end of
the application.

3 files changed, 29 insertions, 4 deletions

diff --git a/mail/e-mail-backend.c b/mail/e-mail-backend.c
index 83ee93d45e..8e45ae101f 100644
--- a/mail/e-mail-backend.c
+++ b/mail/e-mail-backend.c
@@ -923,6 +923,8 @@ mail_backend_dispose (GObject *object)
 	priv = E_MAIL_BACKEND_GET_PRIVATE (object);
 
 	if (priv->session != NULL) {
+		em_folder_tree_model_free_default ();
+
 		g_signal_handlers_disconnect_matched (
 			priv->session, G_SIGNAL_MATCH_DATA,
 			0, 0, NULL, NULL, object);
diff --git a/mail/em-folder-tree-model.c b/mail/em-folder-tree-model.c
index 789bb20e38..3597b6ec6c 100644
--- a/mail/em-folder-tree-model.c
+++ b/mail/em-folder-tree-model.c
@@ -844,17 +844,39 @@ em_folder_tree_model_new (void)
 	return g_object_new (EM_TYPE_FOLDER_TREE_MODEL, NULL);
 }
 
-EMFolderTreeModel *
-em_folder_tree_model_get_default (void)
+static EMFolderTreeModel *
+em_folder_tree_manage_default (gboolean do_create)
 {
-	static EMFolderTreeModel *default_folder_tree_model;
+	static EMFolderTreeModel *default_folder_tree_model = NULL;
 
-	if (G_UNLIKELY (default_folder_tree_model == NULL))
+	if (do_create && G_UNLIKELY (default_folder_tree_model == NULL)) {
 		default_folder_tree_model = em_folder_tree_model_new ();
+	} else if (!do_create && G_UNLIKELY (default_folder_tree_model != NULL)) {
+		/* This is necessary, due to circular dependency between stored GtkTreeRwoReference
+		   and the model itself. */
+		g_mutex_lock (&default_folder_tree_model->priv->store_index_lock);
+		g_hash_table_remove_all (default_folder_tree_model->priv->store_index);
+		g_mutex_unlock (&default_folder_tree_model->priv->store_index_lock);
+
+		g_object_unref (default_folder_tree_model);
+		default_folder_tree_model = NULL;
+	}
 
 	return default_folder_tree_model;
 }
 
+EMFolderTreeModel *
+em_folder_tree_model_get_default (void)
+{
+	return em_folder_tree_manage_default (TRUE);
+}
+
+void
+em_folder_tree_model_free_default (void)
+{
+	em_folder_tree_manage_default (FALSE);
+}
+
 GtkTreeSelection *
 em_folder_tree_model_get_selection (EMFolderTreeModel *model)
 {
diff --git a/mail/em-folder-tree-model.h b/mail/em-folder-tree-model.h
index 3684082e98..60c884a872 100644
--- a/mail/em-folder-tree-model.h
+++ b/mail/em-folder-tree-model.h
@@ -101,6 +101,7 @@ EMFolderTreeModel *
 		em_folder_tree_model_new	(void);
 EMFolderTreeModel *
 		em_folder_tree_model_get_default (void);
+void		em_folder_tree_model_free_default (void);
 GtkTreeSelection *
 		em_folder_tree_model_get_selection
 					(EMFolderTreeModel *model);