batch-rename-dialog: Fix thread-unsafe code

When collecting distinct parent directories of selected files we were
accessing and possibly modifying the selected files GList from multiple
threads without any synchronization causing unpredictable corruption.
We were also performing operations in a background thread on
NautilusFile and NautilusDirectory which are not thread safe.

Identify distict parent dirs only once during dialog initialization and
store it in the instance struct because the selection does not change
during operation of the dialog. This eliminates thread-unsafe operations
when collecting and accessing the list of distinct parent directories.

Closes https://gitlab.gnome.org/GNOME/nautilus/-/issues/1552

1 files changed, 6 insertions, 5 deletions

diff --git a/src/nautilus-batch-rename-dialog.c b/src/nautilus-batch-rename-dialog.c
index bc456c7d2..dde67158e 100644
--- a/src/nautilus-batch-rename-dialog.c
+++ b/src/nautilus-batch-rename-dialog.c
@@ -89,6 +89,7 @@ struct _NautilusBatchRenameDialog
     gint conflicts_number;
 
     GList *duplicates;
+    GList *distinct_parent_directories;
     GCancellable *conflict_cancellable;
     gboolean checking_conflicts;
 
@@ -1265,7 +1266,6 @@ file_names_list_has_duplicates_async_thread (GTask        *task,
 {
     NautilusBatchRenameDialog *self;
     CheckConflictsData *task_data;
-    GList *directories;
     GList *l;
 
     self = g_task_get_source_object (task);
@@ -1275,13 +1275,11 @@ file_names_list_has_duplicates_async_thread (GTask        *task,
     g_mutex_init (&task_data->wait_ready_mutex);
     g_cond_init (&task_data->wait_ready_condition);
 
-    directories = batch_rename_files_get_distinct_parents (self->selection);
     /* check if this is the last call of the callback */
-    for (l = directories; l != NULL; l = l->next)
+    for (l = self->distinct_parent_directories; l != NULL; l = l->next)
     {
         if (g_task_return_error_if_cancelled (task))
         {
-            nautilus_directory_list_free (directories);
             return;
         }
 
@@ -1307,7 +1305,6 @@ file_names_list_has_duplicates_async_thread (GTask        *task,
     }
 
     g_task_return_boolean (task, TRUE);
-    nautilus_directory_list_free (directories);
 }
 
 static void
@@ -2079,6 +2076,7 @@ nautilus_batch_rename_dialog_finalize (GObject *object)
 
     nautilus_file_list_free (dialog->selection);
     nautilus_directory_unref (dialog->directory);
+    nautilus_directory_list_free (dialog->distinct_parent_directories);
 
     g_object_unref (dialog->size_group);
 
@@ -2212,6 +2210,8 @@ nautilus_batch_rename_dialog_new (GList             *selection,
 
     gtk_window_set_title (GTK_WINDOW (dialog), dialog_title->str);
 
+    dialog->distinct_parent_directories = batch_rename_files_get_distinct_parents (selection);
+
     add_tag (dialog, metadata_tags_constants[ORIGINAL_FILE_NAME]);
 
     nautilus_batch_rename_dialog_initialize_actions (dialog);
@@ -2267,6 +2267,7 @@ nautilus_batch_rename_dialog_init (NautilusBatchRenameDialog *self)
     gtk_label_set_max_width_chars (GTK_LABEL (self->conflict_label), 1);
 
     self->duplicates = NULL;
+    self->distinct_parent_directories = NULL;
     self->new_names = NULL;
 
     self->checking_conflicts = FALSE;