core: Make MetaContext manage the MetaSessionManager singleton

Make this core object own the MetaSessionManager, for the window management
code to access.

At this level, we will be able to integrate with systemd notification
system, and use systemd fdstore to keep the mapped memory warm for
us for the case of soft reboot. This is at the moment not implemented
here.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3825>

src/core/meta-context-main.c

@@ -32,6 +32,7 @@
 #include "backends/meta-monitor.h"
 #include "backends/meta-monitor-manager-private.h"
 #include "backends/meta-virtual-monitor.h"
+#include "core/meta-session-manager.h"
 #include "meta/meta-backend.h"
 
 #ifdef HAVE_X11
@@ -88,6 +89,8 @@ struct _MetaContextMain
 
   MetaContextMainOptions options;
 
+  MetaSessionManager *session_manager;
+
   MetaCompositorType compositor_type;
 
   GList *persistent_virtual_monitors;
@@ -524,12 +527,13 @@ meta_context_main_create_backend (MetaContext  *context,
   g_assert_not_reached ();
 }
 
-#ifdef HAVE_X11
 static void
 meta_context_main_notify_ready (MetaContext *context)
 {
   MetaContextMain *context_main = META_CONTEXT_MAIN (context);
+  g_autoptr (GError) error = NULL;
 
+#ifdef HAVE_X11
   if (!context_main->options.sm.disable)
     {
       meta_session_init (context,
@@ -538,8 +542,16 @@ meta_context_main_notify_ready (MetaContext *context)
     }
   g_clear_pointer (&context_main->options.sm.client_id, g_free);
   g_clear_pointer (&context_main->options.sm.save_file, g_free);
+#endif
+
+  context_main->session_manager =
+    meta_session_manager_new (meta_context_get_nick (context), &error);
+
+  if (!context_main->session_manager)
+    g_critical ("Could not create session manager: %s", error->message);
 }
 
+#ifdef HAVE_X11
 static gboolean
 meta_context_main_is_x11_sync (MetaContext *context)
 {
@@ -549,6 +561,14 @@ meta_context_main_is_x11_sync (MetaContext *context)
 }
 #endif
 
+static MetaSessionManager *
+meta_context_main_get_session_manager (MetaContext *context)
+{
+  MetaContextMain *context_main = META_CONTEXT_MAIN (context);
+
+  return context_main->session_manager;
+}
+
 #ifdef HAVE_NATIVE_BACKEND
 static gboolean
 add_virtual_monitor_cb (const char  *option_name,
@@ -730,6 +750,10 @@ meta_context_main_finalize (GObject *object)
 
   g_list_free_full (context_main->persistent_virtual_monitors, g_object_unref);
   context_main->persistent_virtual_monitors = NULL;
+
+  if (context_main->session_manager)
+    meta_session_manager_save_sync (context_main->session_manager, NULL);
+  g_clear_object (&context_main->session_manager);
 #endif
 
   G_OBJECT_CLASS (meta_context_main_parent_class)->finalize (object);
@@ -761,10 +785,11 @@ meta_context_main_class_init (MetaContextMainClass *klass)
   context_class->is_replacing = meta_context_main_is_replacing;
   context_class->setup = meta_context_main_setup;
   context_class->create_backend = meta_context_main_create_backend;
-#ifdef HAVE_X11
   context_class->notify_ready = meta_context_main_notify_ready;
+#ifdef HAVE_X11
   context_class->is_x11_sync = meta_context_main_is_x11_sync;
 #endif
+  context_class->get_session_manager = meta_context_main_get_session_manager;
 }
 
 static void

src/core/meta-context-private.h

@@ -20,6 +20,7 @@
 
 #include "core/meta-private-enums.h"
 #include "core/meta-service-channel.h"
+#include "core/meta-session-manager.h"
 #include "core/util-private.h"
 #include "meta/meta-backend.h"
 #include "meta/meta-context.h"
@@ -56,6 +57,8 @@ struct _MetaContextClass
 #ifdef HAVE_X11
   gboolean (* is_x11_sync) (MetaContext *context);
 #endif
+
+  MetaSessionManager * (* get_session_manager) (MetaContext *context);
 };
 
 const char * meta_context_get_name (MetaContext *context);
@@ -86,3 +89,5 @@ meta_context_get_profiler (MetaContext *context);
 void meta_context_set_trace_file (MetaContext *context,
                                   const char  *trace_file);
 #endif
+
+MetaSessionManager * meta_context_get_session_manager (MetaContext *context);

src/core/meta-context.c

@@ -979,3 +979,9 @@ meta_context_get_debug_control (MetaContext *context)
 
   return priv->debug_control;
 }
+
+MetaSessionManager *
+meta_context_get_session_manager (MetaContext *context)
+{
+  return META_CONTEXT_GET_CLASS (context)->get_session_manager (context);
+}