Add some logging to help understand what's going on

1 files changed, 11 insertions, 2 deletions

diff --git a/include/olm/ratchet.hh b/include/olm/ratchet.hh
index 2393e5b..071e349 100644
--- a/include/olm/ratchet.hh
+++ b/include/olm/ratchet.hh
@@ -29,7 +29,6 @@ struct ChainKey {
     SharedKey key;
 };
 
-
 struct MessageKey {
     std::uint32_t index;
     SharedKey key;
@@ -82,8 +81,18 @@ struct Ratchet {
     /** The last error that happened encrypting or decrypting a message. */
     ErrorCode last_error;
 
+    /**
+     * A count of the number of times the root key has been advanced; this is
+     * maintained purely for diagnostics.
+     *
+     * If sender_chain is empty, this will be the index of the current receiver
+     * chain (odd for Alice, even for Bob); otherwise, the index of the current
+     * sender chain (even for Alice, odd for Bob).
+     */
+    std::uint32_t chain_index;
+
     /** The root key is used to generate chain keys from the ephemeral keys.
-     * A new root_key derived each time a chain key is derived. */
+     * A new root_key derived each time a new chain is started. */
     SharedKey root_key;
 
     /** The sender chain is used to send messages. Each time a new ephemeral