fix: change unique_ptr with optional, ref #17

Author: pminev

code/ac/llama/Instance.cpp

@@ -117,12 +117,16 @@ void Instance::warmup() {
 }
 
 Session& Instance::startSession(const Session::InitParams params) {
-    if (m_session) {
+    if (m_session.has_value()) {
         throw_ex{} << "Session is already started. Stop it to start a new one.";
     }
 
-    m_session.reset(new Session(*this, m_lctx.get(), params));
+    m_session.emplace(*this, m_lctx.get(), params);
     return *m_session;
 }
 
+void Instance::stopSession() noexcept {
+    m_session.reset();
+}
+
 } // namespace ac::llama

code/ac/llama/Instance.hpp

@@ -35,7 +35,7 @@ class AC_LLAMA_EXPORT Instance {
 
     // only one session per instance can be active at a time
     Session& startSession(const Session::InitParams params);
-    void stopSession() noexcept { m_session.reset(); }
+    void stopSession() noexcept;
 
     const Model& model() const noexcept { return m_model; }
     Sampler& sampler() noexcept { return m_sampler; }
@@ -44,7 +44,7 @@ class AC_LLAMA_EXPORT Instance {
     Model& m_model;
     Sampler m_sampler;
     astl::c_unique_ptr<llama_context> m_lctx;
-    std::unique_ptr<Session> m_session;
+    std::optional<Session> m_session;
 };
 
 } // namespace ac::llama