wrap sr_nacm_get_user

This adds a counterpart to setting NACM user. Sometimes, it might be
useful to get it as well.

Change-Id: I534a229eb536d63091904ab4f6268cb9da6dd3db

Author: peckato1

include/sysrepo-cpp/Session.hpp

@@ -100,6 +100,7 @@ class Session {
     void replaceConfig(std::optional<libyang::DataNode> config, const std::optional<std::string>& moduleName = std::nullopt, std::chrono::milliseconds timeout = std::chrono::milliseconds{0});
 
     void setNacmUser(const std::string& user);
+    std::optional<std::string> getNacmUser() const;
     [[nodiscard]] Subscription initNacm(
             SubscribeOptions opts = SubscribeOptions::Default,
             ExceptionHandler handler = nullptr,

src/Session.cpp

@@ -706,6 +706,15 @@ void Session::setNacmUser(const std::string& user)
     throwIfError(res, "Couldn't set NACM user", m_sess.get());
 }
 
+/**
+ * @brief Get the NACM user for this session.
+ */
+std::optional<std::string> Session::getNacmUser() const
+{
+    auto* username = sr_nacm_get_user(m_sess.get());
+    return username ? std::make_optional<std::string>(username) : std::nullopt;
+}
+
 /**
  * @brief Initializes NACM callbacks.
  *

tests/session.cpp

@@ -390,10 +390,14 @@ TEST_CASE("session")
         auto data = sess.getData("/test_module:denyAllLeaf");
         REQUIRE(data.value().findPath("/test_module:denyAllLeaf").value().asTerm().valueStr() == "AHOJ");
 
+        REQUIRE(!sess.getNacmUser());
+
         // check that repeated NACM initialization still works
         for (int i = 0; i < 3; ++i) {
             auto nacmSub = sess.initNacm();
             sess.setNacmUser("nobody");
+            REQUIRE(sess.getNacmUser() == "nobody");
+
             data = sess.getData("/test_module:denyAllLeaf");
             // After turning on NACM, we can't access the leaf.
             REQUIRE(!data);
@@ -408,6 +412,9 @@ TEST_CASE("session")
                     sysrepo::ErrorWithCode);
         }
 
+        REQUIRE(!!sess.getNacmUser());
+        REQUIRE(sess.getNacmUser() == "nobody");
+
         // duplicate NACM initialization should throw
         auto nacm = sess.initNacm();
         REQUIRE_THROWS_WITH_AS(auto x = sess.initNacm(),