Implement DBus server using glib

To remove third-party dbus lib dependency, use glib high API to handle
DBus server. DBusServer.cpp uses "C" stubs generated by gdbus-codege
(DBusControl.c, DBusControl.h).

Signed-off-by: Oleksandr Grytsov <oleksandr_grytsov@epam.com>
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Tested-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>

README.md

@@ -335,11 +335,13 @@ DisplayManager -c display.cfg -v *:Debug
 Getting introspect:
 
 ```bash
-dbus-send --session --print-reply --dest=com.epam.DisplayManager /com/epam/DisplayManager org.freedesktop.DBus.Introspectable.Introspect
+dbus-send --system --print-reply --dest=com.epam.DisplayManager /com/epam/DisplayManager org.freedesktop.DBus.Introspectable.Introspect
 ```
 
 Sending user event `1`:
 
 ```bash
-dbus-send --session --dest=com.epam.DisplayManager --type=method_call  /com/epam/DisplayManager com.epam.DisplayManager.Control.userEvent uint32:1
-```
+dbus-send --system --dest=com.epam.DisplayManager --type=method_call  /com/epam/DisplayManager com.epam.DisplayManager.Control.userEvent uint32:1
+```
+
+If DisplayManager is launched in session DBus mode, use `--session` instead of `--system`.

src/CMakeLists.txt

@@ -16,7 +16,13 @@ if(NOT ILM_COMMON_FOUND)
 	set(ILM_COMMON_LIBRARIES ilmCommon)
 endif()
 
-pkg_check_modules(DBUS_CXX REQUIRED dbus-cxx-1.0)
+pkg_check_modules(GLIB REQUIRED glib-2.0)
+pkg_check_modules(GIO REQUIRED gio-unix-2.0)
+
+find_program(GDBUS_CODEGEN NAMES gdbus-codegen)
+if (NOT GDBUS_CODEGEN)
+    message(SEND_ERROR "Can't find gdbus-codegen")
+endif()
 
 ################################################################################
 # CFLAGS
@@ -28,13 +34,24 @@ pkg_check_modules(DBUS_CXX REQUIRED dbus-cxx-1.0)
 
 include_directories(
 	.
+	${CMAKE_CURRENT_BINARY_DIR}
 	${CONFIG_INCLUDE_DIRS}
-	${DBUS_CXX_INCLUDE_DIRS}
+	${GLIB_INCLUDE_DIRS}
+	${GIO_INCLUDE_DIRS}
 	${ILM_CTRL_INCLUDE_DIRS}
 	${ILM_COMMON_INCLUDE_DIRS}
 )
 
-message(STATUS "DBUS_CXX_INCLUDE_DIRS              = ${DBUS_CXX_INCLUDE_DIRS}")
+message(STATUS "GIO_INCLUDE_DIRS              = ${GIO_INCLUDE_DIRS}")
+
+################################################################################
+# DBus stubs
+################################################################################
+
+add_custom_command(OUTPUT DBusControl.c
+    COMMAND ${GDBUS_CODEGEN} --interface-prefix com.epam.DisplayManager. --generate-c-code=DBusControl ${PROJECT_SOURCE_DIR}/src/com.epam.displaymanager.xml
+    DEPENDS ${PROJECT_SOURCE_DIR}/src/com.epam.displaymanager.xml
+)
 
 ################################################################################
 # Sources
@@ -44,7 +61,7 @@ set(SOURCES
 	main.cpp
 	ActionManager.cpp
 	Config.cpp
-	DBusControlAdapter.cpp
+	DBusControl.c
 	DBusServer.cpp
 	Display.cpp
 	DisplayManager.cpp
@@ -71,7 +88,8 @@ install(TARGETS ${PROJECT_NAME} RUNTIME DESTINATION bin)
 target_link_libraries(${PROJECT_NAME}
 	pthread
 	${CONFIG_LIBRARIES}
-	${DBUS_CXX_LIBRARIES}
+	${GLIB_LIBRARIES}
+	${GIO_LIBRARIES}
 	${ILM_CTRL_LIBRARIES}
 	${ILM_COMMON_LIBRARIES}
 )

src/DBusServer.cpp

@@ -20,63 +20,109 @@
 
 #include "DBusServer.hpp"
 
-#include "ActionManager.hpp"
+#include <glib-unix.h>
 
-using DBus::BUS_SESSION;
-using DBus::BUS_SYSTEM;
-using DBus::Dispatcher;
-using DBus::init;
+#include "ActionManager.hpp"
 
-using std::exception;
-using std::runtime_error;
-using std::shared_ptr;
+/*******************************************************************************
+ * Static
+ ******************************************************************************/
 
-DBusServer::DBusServer(ActionManager& actions, bool systemBus)
-    : mActions(actions), mLog("DBusServer")
+namespace {
+gboolean sTerminationHandler(gpointer data)
 {
-    LOG(mLog, DEBUG) << "Create";
+    LOG("main", INFO) << "Terminating...";
 
-    try {
-        init();
+    g_main_loop_quit(reinterpret_cast<GMainLoop*>(data));
 
-        mDispatcher = Dispatcher::create();
+    return false;
+}
+}  // namespace
 
-        if (systemBus) {
-            mConnection = mDispatcher->create_connection(BUS_SYSTEM);
-        }
-        else {
-            mConnection = mDispatcher->create_connection(BUS_SESSION);
-        }
+/*******************************************************************************
+ * DBusServer
+ ******************************************************************************/
 
-        if (mConnection->request_name("com.epam.DisplayManager",
-                                      DBUS_NAME_FLAG_REPLACE_EXISTING) !=
-            DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER) {
-            throw(runtime_error("Can't request DBus name"));
-        }
+DBusServer::DBusServer(ActionManager& actions, bool systemBus)
+    : mActions(actions), mLoop(nullptr), mLog("DBusServer")
+{
+    LOG(mLog, DEBUG) << "Create " << (systemBus ? "system" : "session")
+                     << " bus";
 
-        DBusControlAdapter::create(this);
+    mLoop = g_main_loop_new(NULL, FALSE);
 
-        mAdapter = DBusControlAdapter::create(this);
-        mConnection->register_object(mAdapter);
-    }
-    catch (const std::shared_ptr<DBus::Error> e) {
-        throw DmException(e->what());
-    }
+    g_unix_signal_add(SIGINT, sTerminationHandler, mLoop);
+    g_unix_signal_add(SIGTERM, sTerminationHandler, mLoop);
+
+    mBusId = g_bus_own_name(
+        (systemBus ? G_BUS_TYPE_SYSTEM : G_BUS_TYPE_SESSION), sBusName,
+        static_cast<GBusNameOwnerFlags>(
+            G_BUS_NAME_OWNER_FLAGS_ALLOW_REPLACEMENT |
+            G_BUS_NAME_OWNER_FLAGS_REPLACE),
+        DBusServer::sOnBusAcquired, nullptr, nullptr, this, nullptr);
 }
 
 DBusServer::~DBusServer()
 {
     LOG(mLog, DEBUG) << "Delete";
+
+    g_bus_unown_name(mBusId);
+    g_main_loop_unref(mLoop);
 }
 
-void DBusServer::userEvent(uint32_t event)
+/*******************************************************************************
+ * Public
+ ******************************************************************************/
+
+void DBusServer::run()
 {
-    try {
-        LOG(mLog, DEBUG) << "User event: " << event;
+    g_main_loop_run(mLoop);
+}
 
-        mActions.userEvent(event);
-    }
-    catch (const exception& e) {
-        LOG(mLog, ERROR) << e.what();
+/*******************************************************************************
+ * Private
+ ******************************************************************************/
+
+void DBusServer::sOnBusAcquired(GDBusConnection* connection, const gchar* name,
+                                gpointer userData)
+{
+    static_cast<DBusServer*>(userData)->onBusAcquired(connection, name);
+}
+
+void DBusServer::onBusAcquired(GDBusConnection* connection, const gchar* name)
+{
+    LOG(mLog, DEBUG) << "Bus acquired, name: " << name;
+
+    auto interface = control_skeleton_new();
+
+    g_signal_connect(interface, "handle-user-event",
+                     G_CALLBACK(DBusServer::sHandleUserEvent), this);
+
+    GError* error = nullptr;
+
+    if (!g_dbus_interface_skeleton_export(G_DBUS_INTERFACE_SKELETON(interface),
+                                          connection, sObjectPath, &error)) {
+        LOG(mLog, ERROR) << "Can't export interface: " << error->message;
+
+        g_main_loop_quit(mLoop);
     }
 }
+
+bool DBusServer::sHandleUserEvent(Control* interface,
+                                  GDBusMethodInvocation* invocation,
+                                  guint userEvent, gpointer userData)
+{
+    return static_cast<DBusServer*>(userData)->handleUserEvent(
+        interface, invocation, userEvent);
+}
+
+bool DBusServer::handleUserEvent(Control* interface,
+                                 GDBusMethodInvocation* invocation,
+                                 guint userEvent)
+{
+    LOG(mLog, DEBUG) << "User event received: " << userEvent;
+
+    mActions.userEvent(userEvent);
+
+    return false;
+}