lib/messages: Add new notmuch_message_list_t to internal interface.

Previously, the notmuch_messages_t object was a linked list built on
top of a linked-list node with the odd name of notmuch_message_list_t.

Now, we've got much more sane naming with notmuch_message_list_t being
a list built on a linked-list node named notmuch_message_node_t. And
now the public notmuch_messages_t object is a separate iterator based
on notmuch_message_node_t. This means the interfaces for the new
notmuch_message_list_t object are now made available to the library
internals.

lib/messages.c

@@ -22,72 +22,96 @@
 
 #include <glib.h> /* GList */
 
-typedef struct _message_list {
-    notmuch_message_t *message;
-    struct _message_list *next;
-} message_list_t;
 
 struct _notmuch_messages {
-    message_list_t *head;
+    notmuch_message_node_t *iterator;
-    message_list_t **tail;
 };
 
-/* Create a new notmuch_messages_t object, with 'ctx' as its talloc owner.
+/* Create a new notmuch_message_list_t object, with 'ctx' as its
+ * talloc owner.
  *
  * This function can return NULL in case of out-of-memory.
  */
+notmuch_message_list_t *
+_notmuch_message_list_create (const void *ctx)
+{
+    notmuch_message_list_t *list;
+
+    list = talloc (ctx, notmuch_message_list_t);
+    if (unlikely (list == NULL))
+	return NULL;
+
+    list->head = NULL;
+    list->tail = &list->head;
+
+    return list;
+}
+
+/* Append 'node' (which can of course point to an aribtrarily long
+ * list of nodes) to the end of 'list'.
+ */
+void
+_notmuch_message_list_append (notmuch_message_list_t *list,
+			      notmuch_message_node_t *node)
+{
+    *(list->tail) = node;
+    list->tail = &node->next;
+}
+
+/* Allocate a new node for 'message' and append it to the end of
+ * 'list'.
+ */
+void
+_notmuch_message_list_add_message (notmuch_message_list_t *list,
+				   notmuch_message_t *message)
+{
+    notmuch_message_node_t *node = talloc (list, notmuch_message_node_t);
+
+    node->message = message;
+    node->next = NULL;
+
+    _notmuch_message_list_append (list, node);
+}
+
 notmuch_messages_t *
-_notmuch_messages_create (void *ctx)
+_notmuch_messages_create (notmuch_message_list_t *list)
 {
     notmuch_messages_t *messages;
 
-    messages = talloc (ctx, notmuch_messages_t);
+    if (list->head == NULL)
+	return NULL;
+
+    messages = talloc (list, notmuch_messages_t);
     if (unlikely (messages == NULL))
 	return NULL;
 
-    messages->head = NULL;
+    messages->iterator = list->head;
-    messages->tail = &messages->head;
 
     return messages;
 }
 
-/* Add a new message to 'messages'.
- */
-void
-_notmuch_messages_add_message (notmuch_messages_t *messages,
-			       notmuch_message_t *message)
-{
-    message_list_t *new = talloc (messages, message_list_t);
-
-    new->message = message;
-    new->next = NULL;
-
-    *(messages->tail) = new;
-    messages->tail = &new->next;
-}
-
 notmuch_bool_t
 notmuch_messages_has_more (notmuch_messages_t *messages)
 {
-    return messages->head != NULL;
+    return (messages != NULL && messages->iterator != NULL);
 }
 
 notmuch_message_t *
 notmuch_messages_get (notmuch_messages_t *messages)
 {
-    if (messages->head == NULL)
+    if (messages->iterator == NULL)
 	return NULL;
 
-    return messages->head->message;
+    return messages->iterator->message;
 }
 
 void
 notmuch_messages_advance (notmuch_messages_t *messages)
 {
-    if (messages->head == NULL)
+    if (messages->iterator == NULL)
 	return;
 
-    messages->head = messages->head->next;
+    messages->iterator = messages->iterator->next;
 }
 
 void

lib/notmuch-private.h

@@ -280,13 +280,30 @@ notmuch_message_file_get_header (notmuch_message_file_t *message,
 
 /* messages.c */
 
-notmuch_messages_t *
+typedef struct _notmuch_message_node {
-_notmuch_messages_create (void *ctx);
+    notmuch_message_t *message;
+    struct _notmuch_message_node *next;
+} notmuch_message_node_t;
+
+typedef struct _notmuch_message_list {
+    notmuch_message_node_t *head;
+    notmuch_message_node_t **tail;
+} notmuch_message_list_t;
+
+notmuch_message_list_t *
+_notmuch_message_list_create (const void *ctx);
 
 void
-_notmuch_messages_add_message (notmuch_messages_t *messages,
+_notmuch_message_list_append (notmuch_message_list_t *list,
+			      notmuch_message_node_t *node);
+
+void
+_notmuch_message_list_add_message (notmuch_message_list_t *list,
 				   notmuch_message_t *message);
 
+notmuch_messages_t *
+_notmuch_messages_create (notmuch_message_list_t *list);
+
 /* date.c */
 
 /* Parse an RFC 8222 date string to a time_t value.

lib/query.cc

@@ -79,11 +79,11 @@ notmuch_query_search_messages (notmuch_query_t *query,
 {
     notmuch_database_t *notmuch = query->notmuch;
     const char *query_string = query->query_string;
-    notmuch_messages_t *messages;
+    notmuch_message_list_t *message_list;
     Xapian::MSetIterator i;
 
-    messages = _notmuch_messages_create (query);
+    message_list = _notmuch_message_list_create (query);
-    if (unlikely (messages == NULL))
+    if (unlikely (message_list == NULL))
 	return NULL;
 
     try {
@@ -134,7 +134,7 @@ notmuch_query_search_messages (notmuch_query_t *query,
 	    notmuch_message_t *message;
 	    notmuch_private_status_t status;
 
-	    message = _notmuch_message_create (messages, notmuch,
+	    message = _notmuch_message_create (message_list, notmuch,
 					       *i, &status);
 	    if (message == NULL)
 	    {
@@ -144,7 +144,7 @@ notmuch_query_search_messages (notmuch_query_t *query,
 		break;
 	    }
 
-	    _notmuch_messages_add_message (messages, message);
+	    _notmuch_message_list_add_message (message_list, message);
 	}
 
     } catch (const Xapian::Error &error) {
@@ -152,7 +152,7 @@ notmuch_query_search_messages (notmuch_query_t *query,
 		 error.get_msg().c_str());
     }
 
-    return messages;
+    return _notmuch_messages_create (message_list);
 }
 
 /* Glib objects force use to use a talloc destructor as well, (but not