Load sessions lazily from db

src/Cache.cpp

@@ -318,26 +318,46 @@ Cache::saveInboundMegolmSession(const MegolmSessionIndex &index,
         auto txn = lmdb::txn::begin(env_);
         lmdb::dbi_put(txn, inboundMegolmSessionDb_, lmdb::val(key), lmdb::val(pickled));
         txn.commit();
+}
 
+mtx::crypto::InboundGroupSessionPtr
+Cache::getInboundMegolmSession(const MegolmSessionIndex &index)
 {
-                std::unique_lock<std::mutex> lock(session_storage.group_inbound_mtx);
-                session_storage.group_inbound_sessions[key] = std::move(session);
+        using namespace mtx::crypto;
+
+        try {
+                auto txn        = lmdb::txn::begin(env_, nullptr, MDB_RDONLY);
+                std::string key = json(index).dump();
+                lmdb::val value;
+
+                if (lmdb::dbi_get(txn, inboundMegolmSessionDb_, lmdb::val(key), value)) {
+                        auto session = unpickle<InboundSessionObject>(
+                          std::string(value.data(), value.size()), SECRET);
+                        return session;
                 }
+        } catch (std::exception &e) {
+                nhlog::db()->error("Failed to get inbound megolm session {}", e.what());
         }
 
-OlmInboundGroupSession *
-Cache::getInboundMegolmSession(const MegolmSessionIndex &index)
-{
-        std::unique_lock<std::mutex> lock(session_storage.group_inbound_mtx);
-        return session_storage.group_inbound_sessions[json(index).dump()].get();
+        return nullptr;
 }
 
 bool
 Cache::inboundMegolmSessionExists(const MegolmSessionIndex &index)
 {
-        std::unique_lock<std::mutex> lock(session_storage.group_inbound_mtx);
-        return session_storage.group_inbound_sessions.find(json(index).dump()) !=
-               session_storage.group_inbound_sessions.end();
+        using namespace mtx::crypto;
+
+        try {
+                auto txn        = lmdb::txn::begin(env_, nullptr, MDB_RDONLY);
+                std::string key = json(index).dump();
+                lmdb::val value;
+
+                return lmdb::dbi_get(txn, inboundMegolmSessionDb_, lmdb::val(key), value);
+        } catch (std::exception &e) {
+                nhlog::db()->error("Failed to get inbound megolm session {}", e.what());
+        }
+
+        return false;
 }
 
 void
@@ -545,18 +565,6 @@ Cache::restoreSessions()
         auto txn = lmdb::txn::begin(env_, nullptr, MDB_RDONLY);
         std::string key, value;
 
-        //
-        // Inbound Megolm Sessions
-        //
-        {
-                auto cursor = lmdb::cursor::open(txn, inboundMegolmSessionDb_);
-                while (cursor.get(key, value, MDB_NEXT)) {
-                        auto session = unpickle<InboundSessionObject>(value, SECRET);
-                        session_storage.group_inbound_sessions[key] = std::move(session);
-                }
-                cursor.close();
-        }
-
         //
         // Outbound Megolm Sessions
         //
@@ -4173,7 +4181,7 @@ saveInboundMegolmSession(const MegolmSessionIndex &index,
 {
         instance_->saveInboundMegolmSession(index, std::move(session));
 }
-OlmInboundGroupSession *
+mtx::crypto::InboundGroupSessionPtr
 getInboundMegolmSession(const MegolmSessionIndex &index)
 {
         return instance_->getInboundMegolmSession(index);

src/Cache.h

@@ -256,7 +256,7 @@ exportSessionKeys();
 void
 saveInboundMegolmSession(const MegolmSessionIndex &index,
                          mtx::crypto::InboundGroupSessionPtr session);
-OlmInboundGroupSession *
+mtx::crypto::InboundGroupSessionPtr
 getInboundMegolmSession(const MegolmSessionIndex &index);
 bool
 inboundMegolmSessionExists(const MegolmSessionIndex &index);

src/CacheCryptoStructs.h

@@ -55,13 +55,11 @@ from_json(const nlohmann::json &obj, MegolmSessionIndex &msg);
 struct OlmSessionStorage
 {
         // Megolm sessions
-        std::map<std::string, mtx::crypto::InboundGroupSessionPtr> group_inbound_sessions;
         std::map<std::string, mtx::crypto::OutboundGroupSessionPtr> group_outbound_sessions;
         std::map<std::string, OutboundGroupSessionData> group_outbound_session_data;
 
         // Guards for accessing megolm sessions.
         std::mutex group_outbound_mtx;
-        std::mutex group_inbound_mtx;
 };
 
 struct StoredOlmSession

src/Cache_p.h

@@ -246,7 +246,8 @@ public:
         //
         void saveInboundMegolmSession(const MegolmSessionIndex &index,
                                       mtx::crypto::InboundGroupSessionPtr session);
-        OlmInboundGroupSession *getInboundMegolmSession(const MegolmSessionIndex &index);
+        mtx::crypto::InboundGroupSessionPtr getInboundMegolmSession(
+          const MegolmSessionIndex &index);
         bool inboundMegolmSessionExists(const MegolmSessionIndex &index);
 
         //

src/Olm.cpp

@@ -534,7 +534,7 @@ handle_key_request_message(const mtx::events::DeviceEvent<mtx::events::msg::KeyR
                 return;
         }
 
-        auto session_key = mtx::crypto::export_session(session);
+        auto session_key = mtx::crypto::export_session(session.get());
         //
         // Prepare the m.room_key event.
         //
@@ -584,7 +584,8 @@ decryptEvent(const MegolmSessionIndex &index,
         std::string msg_str;
         try {
                 auto session = cache::client()->getInboundMegolmSession(index);
-                auto res = olm::client()->decrypt_group_message(session, event.content.ciphertext);
+                auto res =
+                  olm::client()->decrypt_group_message(session.get(), event.content.ciphertext);
                 msg_str = std::string((char *)res.data.data(), res.data.size());
         } catch (const lmdb::error &e) {
                 return {DecryptionErrorCode::DbError, e.what(), std::nullopt};

src/timeline/EventStore.cpp

@@ -604,7 +604,8 @@ EventStore::decryptEvent(const IdIndex &idx,
         std::string msg_str;
         try {
                 auto session = cache::client()->getInboundMegolmSession(index);
-                auto res     = olm::client()->decrypt_group_message(session, e.content.ciphertext);
+                auto res =
+                  olm::client()->decrypt_group_message(session.get(), e.content.ciphertext);
                 msg_str = std::string((char *)res.data.data(), res.data.size());
         } catch (const lmdb::error &e) {
                 nhlog::db()->critical("failed to retrieve megolm session with index ({}, {}, {})",