lib: Add support for nested atomic sections.

notmuch_database_t now keeps a nesting count and we only start a
transaction or commit for the outermost atomic section.

Introduces a new error, NOTMUCH_STATUS_UNBALANCED_ATOMIC.

1 files changed, 1 insertions, 0 deletions

diff --git a/lib/database-private.h b/lib/database-private.h
index f7050097..88532d51 100644
--- a/lib/database-private.h
+++ b/lib/database-private.h
@@ -43,6 +43,7 @@ struct _notmuch_database {
 
     notmuch_bool_t needs_upgrade;
     notmuch_database_mode_t mode;
+    int atomic_nesting;
     Xapian::Database *xapian_db;
 
     unsigned int last_doc_id;