Publicly we are only exposing the non-ghost documents (of "type"
"mail").  But internally we might want to inspect the ghost messages
as well.

This changeset adds two new private interfaces to queries to recover
information about alternate document types.
---
 lib/notmuch-private.h | 11 +++++++++++
 lib/query.cc          | 18 ++++++++++++++++--
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/lib/notmuch-private.h b/lib/notmuch-private.h
index 5dd4770..d95bf31 100644
--- a/lib/notmuch-private.h
+++ b/lib/notmuch-private.h
@@ -477,6 +477,17 @@ void
 _notmuch_doc_id_set_remove (notmuch_doc_id_set_t *doc_ids,
                             unsigned int doc_id);
 
+/* querying xapian documents by type (e.g. "mail" or "ghost"): */
+notmuch_status_t
+_notmuch_query_search_documents (notmuch_query_t *query,
+				 const char *type,
+				 notmuch_messages_t **out);
+
+notmuch_status_t
+_notmuch_query_count_documents (notmuch_query_t *query,
+				const char *type,
+				unsigned *count_out);
+
 /* message.cc */
 
 void
diff --git a/lib/query.cc b/lib/query.cc
index e627bfc..77a7926 100644
--- a/lib/query.cc
+++ b/lib/query.cc
@@ -187,6 +187,14 @@ notmuch_status_t
 notmuch_query_search_messages_st (notmuch_query_t *query,
 				  notmuch_messages_t **out)
 {
+    return _notmuch_query_search_documents (query, "mail", out);
+}
+
+notmuch_status_t
+_notmuch_query_search_documents (notmuch_query_t *query,
+				 const char *type,
+				 notmuch_messages_t **out)
+{
     notmuch_database_t *notmuch = query->notmuch;
     const char *query_string = query->query_string;
     notmuch_mset_messages_t *messages;
@@ -208,7 +216,7 @@ notmuch_query_search_messages_st (notmuch_query_t *query,
 	Xapian::Enquire enquire (*notmuch->xapian_db);
 	Xapian::Query mail_query (talloc_asprintf (query, "%s%s",
 						   _find_prefix ("type"),
-						   "mail"));
+						   type));
 	Xapian::Query string_query, final_query, exclude_query;
 	Xapian::MSet mset;
 	Xapian::MSetIterator iterator;
@@ -554,6 +562,12 @@ notmuch_query_count_messages (notmuch_query_t *query)
 notmuch_status_t
 notmuch_query_count_messages_st (notmuch_query_t *query, unsigned *count_out)
 {
+    return _notmuch_query_count_documents (query, "mail", count_out);
+}
+
+notmuch_status_t
+_notmuch_query_count_documents (notmuch_query_t *query, const char *type, unsigned *count_out)
+{
     notmuch_database_t *notmuch = query->notmuch;
     const char *query_string = query->query_string;
     Xapian::doccount count = 0;
@@ -562,7 +576,7 @@ notmuch_query_count_messages_st (notmuch_query_t *query, unsigned *count_out)
 	Xapian::Enquire enquire (*notmuch->xapian_db);
 	Xapian::Query mail_query (talloc_asprintf (query, "%s%s",
 						   _find_prefix ("type"),
-						   "mail"));
+						   type));
 	Xapian::Query string_query, final_query, exclude_query;
 	Xapian::MSet mset;
 	unsigned int flags = (Xapian::QueryParser::FLAG_BOOLEAN |
-- 
2.8.0.rc3