db: introduce gnutls_db_set_add_function

This adds a way to store an entry if it is not found in the database,
so that the implementation can provide atomic test-and-set.

Signed-off-by: Daiki Ueno <dueno@redhat.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/lib/db.c b/lib/db.c
index e01e5b94c5..414816fcc8 100644
--- a/lib/db.c
+++ b/lib/db.c
@@ -56,6 +56,29 @@ gnutls_db_set_retrieve_function(gnutls_session_t session,
 }
 
 /**
+ * gnutls_db_set_add_function:
+ * @session: is a #gnutls_session_t type.
+ * @add_func: is the function.
+ *
+ * Sets the function that will be used to store an entry if it is not
+ * already present in the resumed sessions database.  This function returns 0
+ * if the entry is successfully stored, and a negative error code
+ * otherwise.  In particular, if the entry is found in the database,
+ * it returns %GNUTLS_E_DB_ENTRY_EXISTS.
+ *
+ * The first argument to @add_func will be null unless
+ * gnutls_db_set_ptr() has been called.
+ *
+ * Since: 3.6.5
+ **/
+void
+gnutls_db_set_add_function(gnutls_session_t session,
+			   gnutls_db_add_func add_func)
+{
+	session->internals.db_add_func = add_func;
+}
+
+/**
  * gnutls_db_set_remove_function:
  * @session: is a #gnutls_session_t type.
  * @rem_func: is the function.