+ in_reply_to = _notmuch_message_get_in_reply_to (message);
+ THREAD_DEBUG ("checking message = %s in_reply_to=%s",
+ notmuch_message_get_message_id (message), in_reply_to);
+
+ if (in_reply_to && (! EMPTY_STRING (in_reply_to)) &&
+ g_hash_table_lookup_extended (thread->message_hash,
+ in_reply_to, NULL,
+ (void **) &parent)) {
+ _notmuch_message_add_reply (parent, message);
+ return true;
+ } else {
+ return false;
+ }
+}
+
+static void
+_parent_or_toplevel (notmuch_thread_t *thread, notmuch_message_t *message)
+{
+ size_t max_depth = 0;
+ notmuch_message_t *new_parent;
+ notmuch_message_t *parent = NULL;
+ const notmuch_string_list_t *references =
+ _notmuch_message_get_references (message);
+
+ THREAD_DEBUG ("trying to reparent via references: %s",
+ notmuch_message_get_message_id (message));
+
+ for (notmuch_string_node_t *ref_node = references->head;
+ ref_node; ref_node = ref_node->next) {
+ THREAD_DEBUG ("checking reference=%s", ref_node->string);
+ if ((g_hash_table_lookup_extended (thread->message_hash,
+ ref_node->string, NULL,
+ (void **) &new_parent))) {
+ size_t new_depth = _notmuch_message_get_thread_depth (new_parent);
+ THREAD_DEBUG ("got depth %lu", new_depth);
+ if (new_depth > max_depth || ! parent) {
+ THREAD_DEBUG ("adding at depth %lu parent=%s", new_depth, ref_node->string);
+ max_depth = new_depth;
+ parent = new_parent;
+ }
+ }
+ }
+ if (parent) {
+ THREAD_DEBUG ("adding reply %s to parent=%s",
+ notmuch_message_get_message_id (message),
+ notmuch_message_get_message_id (parent));
+ _notmuch_message_add_reply (parent, message);
+ } else {
+ THREAD_DEBUG ("adding as toplevel %s",
+ notmuch_message_get_message_id (message));
+ _notmuch_message_list_add_message (thread->toplevel_list, message);
+ }
+}
+
+static void
+_resolve_thread_relationships (notmuch_thread_t *thread)
+{
+ notmuch_message_node_t *node, *first_node;
+ notmuch_message_t *message;
+ void *local;
+ notmuch_message_list_t *maybe_toplevel_list;
+
+ first_node = thread->message_list->head;
+ if (! first_node)
+ return;
+
+ local = talloc_new (thread);
+ maybe_toplevel_list = _notmuch_message_list_create (local);
+
+ for (node = first_node->next; node; node = node->next) {