These are called directly, rather than via a vtable. They will
help add common metadata to search/show/reply
---
 devel/schemata   |  1 +
 sprinter-utils.c | 41 +++++++++++++++++++++++++++++++++++++++++
 sprinter.h       |  7 +++++++
 3 files changed, 49 insertions(+)
 create mode 100644 sprinter-utils.c

diff --git a/devel/schemata b/devel/schemata
index 41dc4a6..98a1b2b 100644
--- a/devel/schemata
+++ b/devel/schemata
@@ -147,6 +147,7 @@ search_files = [string*]
 search_tags = [string*]
 
 thread_summary = {
+    database:       database_metadata
     thread:         threadid,
     timestamp:      unix_time,
     date_relative:  string,   # user-friendly timestamp
diff --git a/sprinter-utils.c b/sprinter-utils.c
new file mode 100644
index 0000000..2ba588e
--- /dev/null
+++ b/sprinter-utils.c
@@ -0,0 +1,41 @@
+#include "notmuch-client.h"
+#include "sprinter.h"
+
+notmuch_status_t
+sprinter_start_output (sprinter_t *sp,
+		       const notmuch_query_t *query,
+		       const char *query_type)
+{
+    long int rev;
+    const char *uuid;
+    notmuch_database_t *notmuch;
+
+    sp->begin_list (sp);
+
+    if (sp->type != NOTMUCH_SPRINTER_TEXT && notmuch_format_version >= 3) {
+	notmuch = notmuch_query_get_database (query);
+
+	rev = notmuch_database_get_revision (notmuch, &uuid);
+
+	sp->begin_map (sp);
+	sp->map_key (sp, "query_type");
+	sp->string (sp, query_type);
+
+	sp->map_key (sp, "uuid");
+	sp->string (sp, uuid);
+
+	sp->map_key (sp, "lastmod");
+	sp->integer (sp, rev);
+
+	sp->end (sp);
+
+    }
+    return NOTMUCH_STATUS_SUCCESS;
+}
+
+notmuch_status_t
+sprinter_finish_output (sprinter_t *sp)
+{
+    sp->end (sp); /* map */
+    return NOTMUCH_STATUS_SUCCESS;
+}
diff --git a/sprinter.h b/sprinter.h
index 7e58f69..4873f69 100644
--- a/sprinter.h
+++ b/sprinter.h
@@ -91,4 +91,11 @@ sprinter_json_create (const void *ctx, FILE *stream);
 struct sprinter *
 sprinter_sexp_create (const void *ctx, FILE *stream);
 
+notmuch_status_t
+sprinter_start_output (struct sprinter *sp,
+		       const notmuch_query_t *query,
+		       const char *query_type);
+
+notmuch_status_t
+sprinter_finish_output (struct sprinter *sp);
 #endif // NOTMUCH_SPRINTER_H
-- 
2.1.4