From: Adam Michalski <a.michalski2@partner.samsung.com>
Date: Tue, 10 May 2022 15:03:39 +0000 (+0200)
Subject: Implement server-side GetCurrentUser method
X-Git-Tag: submit/tizen/20220603.143851~1^2~12
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e8bf58db8b49890b8349defeb11fffe0b9c20504;p=platform%2Fcore%2Fsystem%2Fsessiond.git

Implement server-side GetCurrentUser method

Change-Id: I765ee5179e4cf4f9c849a7946ee18f5e0fc47b01
---

diff --git a/sessiond/src/main.cpp b/sessiond/src/main.cpp
index 5fb4f39..518bb89 100644
--- a/sessiond/src/main.cpp
+++ b/sessiond/src/main.cpp
@@ -93,6 +93,10 @@ struct main_loop {
 };
 
 struct sessiond_context {
+	/* A special value representing the state
+	 * before any sub session is switched to. */
+	static constexpr int INITIAL_SUB_SESSION_ID = 0;
+
 	sessiond_context() : data(xml), id(bus_name, glib_bus_connected, glib_name_lost, this), loop()
 	{
 	}
@@ -176,6 +180,8 @@ struct sessiond_context {
 				vals_to_g_variant(session_uid, switch_id, prev_subsession_id, next_subsession_id), &err))
 			g_error_throw(err, "Failed to emit a signal: ");
 
+		last_subsession_per_session[session_uid] = next_subsession_id;
+
 		wait_switch.try_emplace(session_uid, session_uid, connection, "SwitchUserCompleted");
 		wait_switch.at(session_uid).on_start(switch_id, { prev_subsession_id, next_subsession_id });
 
@@ -292,6 +298,23 @@ struct sessiond_context {
 		g_dbus_method_invocation_return_value(invocation, ret);
 	}
 
+	void on_get_current_user(GDBusMethodInvocation *invocation, std::string_view sender, GVariant *parameters)
+	{
+		auto [ session_uid ] = tuple_from_g_variant<int>(parameters);
+
+		if (session_uid <= 0) {
+			g_dbus_method_invocation_return_dbus_error(invocation, "org.freedesktop.DBus.Error.InvalidArgs", "Negative UID passed");
+			return;
+		}
+
+		int subsession_id = INITIAL_SUB_SESSION_ID;
+		if (last_subsession_per_session.contains(session_uid))
+			subsession_id = last_subsession_per_session.at(session_uid);
+
+		auto ret = vals_to_g_variant(subsession_id);
+		g_dbus_method_invocation_return_value(invocation, ret);
+	}
+
 	static void glib_bus_connected(GDBusConnection *conn, const gchar *name, gpointer user_data)
 	{
 		auto self = static_cast<sessiond_context *>(user_data);
@@ -378,6 +401,10 @@ struct sessiond_context {
 					"<arg name=\"session_uid\"        type=\"i\" direction=\"in\"/>"
 					"<arg name=\"subsession_id_list\" type=\"ai\" direction=\"out\"/>"
 				"</method>"
+				"<method name=\"GetCurrentUser\">"
+					"<arg name=\"session_uid\"        type=\"i\" direction=\"in\"/>"
+					"<arg name=\"subsession_id\"      type=\"i\" direction=\"out\"/>"
+				"</method>"
 				"<signal name=\"AddUserStarted\">"
 					"<arg name=\"session_uid\"        type=\"i\" direction=\"out\"/>"
 					"<arg name=\"subsession_id\"      type=\"i\" direction=\"out\"/>"
@@ -413,7 +440,7 @@ struct sessiond_context {
 			std::pair<
 				std::string_view,
 				void (sessiond_context::*)(GDBusMethodInvocation *, std::string_view, GVariant *)
-			>, 10> methods = {
+			>, 11> methods = {
 		std::make_pair("AddUser",        &sessiond_context::on_add_user),
 		std::make_pair("RemoveUser",     &sessiond_context::on_remove_user),
 		std::make_pair("SwitchUser",     &sessiond_context::on_switch_user),
@@ -424,14 +451,20 @@ struct sessiond_context {
 		std::make_pair("RemoveUserDone", &sessiond_context::on_remove_user_done),
 		std::make_pair("SwitchUserDone", &sessiond_context::on_switch_user_done),
 		std::make_pair("GetUserList",    &sessiond_context::on_get_user_list),
+		std::make_pair("GetCurrentUser", &sessiond_context::on_get_current_user),
 	};
 
 	// TODO: Currently, the first parameter is always a single-element tuple.
 	// Consider simplifying wait_manager.
+	// N.B. Although GLib is multi-threaded, the following data structures do not need
+	// to be protected by mutexes as all of them are accessed from DBus handlers only.
 	std::unordered_map<int, wait_manager<std::tuple<int>, std::tuple<>>> wait_add;
 	std::unordered_map<int, wait_manager<std::tuple<int>, std::tuple<>>> wait_remove;
 	std::unordered_map<int, wait_manager<std::tuple<uint64_t>, std::tuple<int, int>>> wait_switch;
 
+	// used for tracking subsession switches for each `session_uid`
+	std::unordered_map<int, int> last_subsession_per_session;
+
 	uint64_t switch_id = 0;
 
 	introspection_data data;