Currently, a message is owned by its iterator (messages object) and,
ultimately, its query. This unfortunately makes encapsulating query
logic difficult because there is no way to return a message after
disposing of the query used to find the message (other than looking it
up again in the database by id).

This patch adds a function `notmuch_message_own` that reparents a
message onto the database making it the user's job to destroy it.
---
 lib/message.cc |  6 ++++++
 lib/notmuch.h  | 12 ++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/lib/message.cc b/lib/message.cc
index 26b5e76..014363f 100644
--- a/lib/message.cc
+++ b/lib/message.cc
@@ -1657,6 +1657,12 @@ notmuch_message_thaw (notmuch_message_t *message)
 }
 
 void
+notmuch_message_own (notmuch_message_t *message)
+{
+    talloc_steal(message->notmuch, message);
+}
+
+void
 notmuch_message_destroy (notmuch_message_t *message)
 {
     talloc_free (message);
diff --git a/lib/notmuch.h b/lib/notmuch.h
index 310a8b8..c80d7aa 100644
--- a/lib/notmuch.h
+++ b/lib/notmuch.h
@@ -1629,6 +1629,18 @@ notmuch_message_freeze (notmuch_message_t *message);
 notmuch_status_t
 notmuch_message_thaw (notmuch_message_t *message);
 
+
+/**
+ * Reparent a notmuch_message_t object onto the database.
+ *
+ * Calling this function allows a notmuch_message_t object to outlive its
+ * query. The message will automatically be reclaimed when the database is
+ * destroyed but if you want to free its memory before then, you should call
+ * notmuch_message_destroy.
+ */
+void
+notmuch_message_own (notmuch_message_t *message);
+
 /**
  * Destroy a notmuch_message_t object.
  *
-- 
2.6.2