lib: Move notmuch_messages_t code from query.cc to new messages.c

The new object is simply a linked-list of notmuch_message_t objects,
(unlike the old object which contained a couple of Xapian iterators).
This works now by the query code immediately iterator over all results
and creating notmuch_message_t objects for them, (rather than waiting
to create the objects until the notmuch_messages_get call as we did
earlier).

The point of this change is to allow other instances of lists of
messages, (such as in notmuch_thread_t), that are not directly related
to Xapian search results.

1 files changed, 97 insertions, 0 deletions

diff --git a/lib/messages.c b/lib/messages.c
new file mode 100644
index 00000000..8b627750
--- /dev/null
+++ b/lib/messages.c
@@ -0,0 +1,97 @@
+/* messages.c - Iterator for a set of messages
+ *
+ * Copyright © 2009 Carl Worth
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see http://www.gnu.org/licenses/ .
+ *
+ * Author: Carl Worth <cworth@cworth.org>
+ */
+
+#include "notmuch-private.h"
+
+#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;
+    message_list_t **tail;
+};
+
+/* Create a new notmuch_messages_t object, with 'ctx' as its talloc owner.
+ *
+ * This function can return NULL in case of out-of-memory.
+ */
+notmuch_messages_t *
+_notmuch_messages_create (void *ctx)
+{
+    notmuch_messages_t *messages;
+
+    messages = talloc (ctx, notmuch_messages_t);
+    if (unlikely (messages == NULL))
+	return NULL;
+
+    messages->head = NULL;
+    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;
+}
+
+notmuch_message_t *
+notmuch_messages_get (notmuch_messages_t *messages)
+{
+    if (messages->head == NULL)
+	return NULL;
+
+    return messages->head->message;
+}
+
+void
+notmuch_messages_advance (notmuch_messages_t *messages)
+{
+    if (messages->head == NULL)
+	return;
+
+    messages->head = messages->head->next;
+}
+
+void
+notmuch_messages_destroy (notmuch_messages_t *messages)
+{
+    talloc_free (messages);
+}