[PATCH virt-viewer v2] iso-dialog: Avoid crash when closing dialog early

["Eduardo Lima (Etrunko)" <etrunko@xxxxxxxxxx>]

We must take into account that users can close the dialog at anytime,
even during an operation of fetch or set ISO has not been finished. This
will cause the callbacks for those operations to be invoked with an
invalid object, crashing the application.

To fix this issue we need to pass a GCancellable to the asynchronous
operations, so they can be cancelled if the dialog happens to get closed
before they complete.

Signed-off-by: Eduardo Lima (Etrunko) <etrunko@xxxxxxxxxx>
---
v2:
 * Move call to g_cancellable_cancel() to response handler.
 * Don't leak error objects if operation is cancelled.
---
 src/remote-viewer-iso-list-dialog.c | 42 ++++++++++++++++++++++++++++++-------
 1 file changed, 34 insertions(+), 8 deletions(-)

diff --git a/src/remote-viewer-iso-list-dialog.c b/src/remote-viewer-iso-list-dialog.c
index 2ab5435..ed51ffa 100644
--- a/src/remote-viewer-iso-list-dialog.c
+++ b/src/remote-viewer-iso-list-dialog.c
@@ -42,6 +42,7 @@ struct _RemoteViewerISOListDialogPrivate
     GtkWidget *stack;
     GtkWidget *tree_view;
     OvirtForeignMenu *foreign_menu;
+    GCancellable *cancellable;
 };
 
 enum RemoteViewerISOListDialogModel
@@ -66,6 +67,8 @@ remote_viewer_iso_list_dialog_dispose(GObject *object)
     RemoteViewerISOListDialog *self = REMOTE_VIEWER_ISO_LIST_DIALOG(object);
     RemoteViewerISOListDialogPrivate *priv = self->priv;
 
+    g_clear_object(&priv->cancellable);
+
     if (priv->foreign_menu) {
         g_signal_handlers_disconnect_by_data(priv->foreign_menu, object);
         g_clear_object(&priv->foreign_menu);
@@ -157,17 +160,24 @@ fetch_iso_names_cb(OvirtForeignMenu *foreign_menu,
         const gchar *msg = error ? error->message : _("Failed to fetch CD names");
         gchar *markup = g_strdup_printf("<b>%s</b>", msg);
 
+        g_debug("Error fetching ISO names: %s", msg);
+        if (error && error->code == G_IO_ERROR_CANCELLED)
+            goto end;
+
         gtk_label_set_markup(GTK_LABEL(priv->status), markup);
         gtk_spinner_stop(GTK_SPINNER(priv->spinner));
         remote_viewer_iso_list_dialog_show_error(self, msg);
         gtk_dialog_set_response_sensitive(GTK_DIALOG(self), GTK_RESPONSE_NONE, TRUE);
         g_free(markup);
-        g_clear_error(&error);
-        return;
+        goto end;
     }
 
+    g_clear_object(&priv->cancellable);
     g_list_foreach(iso_list, (GFunc) remote_viewer_iso_list_dialog_foreach, self);
     remote_viewer_iso_list_dialog_show_files(self);
+
+end:
+    g_clear_error(&error);
 }
 
 
@@ -177,7 +187,10 @@ remote_viewer_iso_list_dialog_refresh_iso_list(RemoteViewerISOListDialog *self)
     RemoteViewerISOListDialogPrivate *priv = self->priv;
 
     gtk_list_store_clear(priv->list_store);
-    ovirt_foreign_menu_fetch_iso_names_async(priv->foreign_menu, NULL,
+
+    priv->cancellable = g_cancellable_new();
+    ovirt_foreign_menu_fetch_iso_names_async(priv->foreign_menu,
+                                             priv->cancellable,
                                              (GAsyncReadyCallback) fetch_iso_names_cb,
                                              self);
 }
@@ -190,8 +203,10 @@ remote_viewer_iso_list_dialog_response(GtkDialog *dialog,
     RemoteViewerISOListDialog *self = REMOTE_VIEWER_ISO_LIST_DIALOG(dialog);
     RemoteViewerISOListDialogPrivate *priv = self->priv;
 
-    if (response_id != GTK_RESPONSE_NONE)
+    if (response_id != GTK_RESPONSE_NONE) {
+        g_cancellable_cancel(priv->cancellable);
         return;
+    }
 
     gtk_spinner_start(GTK_SPINNER(priv->spinner));
     gtk_label_set_markup(GTK_LABEL(priv->status), _("<b>Loading...</b>"));
@@ -223,7 +238,9 @@ remote_viewer_iso_list_dialog_toggled(GtkCellRendererToggle *cell_renderer G_GNU
     gtk_dialog_set_response_sensitive(GTK_DIALOG(self), GTK_RESPONSE_NONE, FALSE);
     gtk_widget_set_sensitive(priv->tree_view, FALSE);
 
-    ovirt_foreign_menu_set_current_iso_name_async(priv->foreign_menu, active ? NULL : name, NULL,
+    priv->cancellable = g_cancellable_new();
+    ovirt_foreign_menu_set_current_iso_name_async(priv->foreign_menu, active ? NULL : name,
+                                                  priv->cancellable,
                                                   (GAsyncReadyCallback)ovirt_foreign_menu_iso_name_changed,
                                                   self);
     gtk_tree_path_free(tree_path);
@@ -308,12 +325,18 @@ ovirt_foreign_menu_iso_name_changed(OvirtForeignMenu *foreign_menu,
      * change the ISO back to the original, avoiding a possible inconsistency.
      */
     if (!ovirt_foreign_menu_set_current_iso_name_finish(foreign_menu, result, &error)) {
-        remote_viewer_iso_list_dialog_show_error(self, error ? error->message : _("Failed to change CD"));
-        g_clear_error(&error);
+        const gchar *msg = error ? error->message : _("Failed to change CD");
+        g_debug("Error changing ISO: %s", msg);
+
+        if (error && error->code == G_IO_ERROR_CANCELLED)
+            goto end;
+
+        remote_viewer_iso_list_dialog_show_error(self, msg);
     }
 
+    g_clear_object(&priv->cancellable);
     if (!gtk_tree_model_get_iter_first(model, &iter))
-        return;
+        goto end;
 
     current_iso = ovirt_foreign_menu_get_current_iso_name(foreign_menu);
 
@@ -340,6 +363,9 @@ ovirt_foreign_menu_iso_name_changed(OvirtForeignMenu *foreign_menu,
     gtk_dialog_set_response_sensitive(GTK_DIALOG(self), GTK_RESPONSE_NONE, TRUE);
     gtk_widget_set_sensitive(priv->tree_view, TRUE);
     g_free(current_iso);
+
+end:
+    g_clear_error(&error);
 }
 
 GtkWidget *
-- 
2.9.3

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