[gdm] Switch User item should be hidden when VT switching is disabled

[Ray Strode <halfline src gnome org>]

commit e5775ea560b290f00d10a1d8a8473baac1ab3457
Author: Halton Huo <halton huo sun com>
Date:   Wed Jan 27 11:49:50 2010 -0500

    Switch User item should be hidden when VT switching is disabled
    
    http://bugzilla.gnome.org/show_bug.cgi?id=607051

 gui/simple-greeter/gdm-user-manager.c |   77 ++++++++++++++++-----------------
 gui/simple-greeter/gdm-user-manager.h |    2 +
 gui/user-switch-applet/applet.c       |    4 +-
 3 files changed, 42 insertions(+), 41 deletions(-)
---
diff --git a/gui/simple-greeter/gdm-user-manager.c b/gui/simple-greeter/gdm-user-manager.c
index c4fb246..58def68 100644
--- a/gui/simple-greeter/gdm-user-manager.c
+++ b/gui/simple-greeter/gdm-user-manager.c
@@ -155,9 +155,7 @@ static char *
 _get_primary_user_session_id (GdmUserManager *manager,
                               GdmUser        *user)
 {
-        gboolean    res;
         gboolean    can_activate_sessions;
-        GError     *error;
         GList      *sessions;
         GList      *l;
         char       *primary_ssid;
@@ -170,25 +168,7 @@ _get_primary_user_session_id (GdmUserManager *manager,
         primary_ssid = NULL;
         sessions = NULL;
 
-        g_debug ("GdmUserManager: checking if seat can activate sessions");
-
-        error = NULL;
-        res = dbus_g_proxy_call (manager->priv->seat_proxy,
-                                 "CanActivateSessions",
-                                 &error,
-                                 G_TYPE_INVALID,
-                                 G_TYPE_BOOLEAN, &can_activate_sessions,
-                                 G_TYPE_INVALID);
-        if (! res) {
-                if (error != NULL) {
-                        g_warning ("unable to determine if seat can activate sessions: %s",
-                                   error->message);
-                        g_error_free (error);
-                } else {
-                        g_warning ("unable to determine if seat can activate sessions");
-                }
-                goto out;
-        }
+        can_activate_sessions = gdm_user_manager_can_switch (manager);
 
         if (! can_activate_sessions) {
                 g_debug ("GdmUserManager: seat is unable to activate sessions");
@@ -344,25 +324,7 @@ _get_login_window_session_id (GdmUserManager *manager)
         primary_ssid = NULL;
         sessions = NULL;
 
-        g_debug ("GdmSlave: checking if seat can activate sessions");
-
-        error = NULL;
-        res = dbus_g_proxy_call (manager->priv->seat_proxy,
-                                 "CanActivateSessions",
-                                 &error,
-                                 G_TYPE_INVALID,
-                                 G_TYPE_BOOLEAN, &can_activate_sessions,
-                                 G_TYPE_INVALID);
-        if (! res) {
-                if (error != NULL) {
-                        g_warning ("unable to determine if seat can activate sessions: %s",
-                                   error->message);
-                        g_error_free (error);
-                } else {
-                        g_warning ("unable to determine if seat can activate sessions");
-                }
-                goto out;
-        }
+        can_activate_sessions = gdm_user_manager_can_switch (manager);
 
         if (! can_activate_sessions) {
                 g_debug ("GdmSlave: seat is unable to activate sessions");
@@ -438,6 +400,41 @@ gdm_user_manager_goto_login_session (GdmUserManager *manager)
 }
 
 gboolean
+gdm_user_manager_can_switch (GdmUserManager *manager)
+{
+        gboolean    res;
+        gboolean    can_activate_sessions;
+        GError     *error;
+
+        if (manager->priv->seat_id == NULL || manager->priv->seat_id[0] == '\0') {
+                g_debug ("GdmUserManager: display seat ID is not set; can't switch sessions");
+                return FALSE;
+        }
+
+        g_debug ("GdmUserManager: checking if seat can activate sessions");
+
+        error = NULL;
+        res = dbus_g_proxy_call (manager->priv->seat_proxy,
+                                 "CanActivateSessions",
+                                 &error,
+                                 G_TYPE_INVALID,
+                                 G_TYPE_BOOLEAN, &can_activate_sessions,
+                                 G_TYPE_INVALID);
+        if (! res) {
+                if (error != NULL) {
+                        g_warning ("unable to determine if seat can activate sessions: %s",
+                                   error->message);
+                        g_error_free (error);
+                } else {
+                        g_warning ("unable to determine if seat can activate sessions");
+                }
+                return FALSE;
+        }
+
+        return can_activate_sessions;
+}
+
+gboolean
 gdm_user_manager_activate_user_session (GdmUserManager *manager,
                                         GdmUser        *user)
 {
diff --git a/gui/simple-greeter/gdm-user-manager.h b/gui/simple-greeter/gdm-user-manager.h
index 6c696e5..b2d0019 100644
--- a/gui/simple-greeter/gdm-user-manager.h
+++ b/gui/simple-greeter/gdm-user-manager.h
@@ -80,6 +80,8 @@ GdmUser *           gdm_user_manager_get_user_by_uid       (GdmUserManager *mana
 gboolean            gdm_user_manager_activate_user_session (GdmUserManager *manager,
                                                             GdmUser        *user);
 
+gboolean            gdm_user_manager_can_switch            (GdmUserManager *manager);
+
 gboolean            gdm_user_manager_goto_login_session    (GdmUserManager *manager);
 
 G_END_DECLS
diff --git a/gui/user-switch-applet/applet.c b/gui/user-switch-applet/applet.c
index 2c364f1..5d73283 100644
--- a/gui/user-switch-applet/applet.c
+++ b/gui/user-switch-applet/applet.c
@@ -703,7 +703,9 @@ static void
 update_switch_user (GdmAppletData *adata)
 {
         GSList *users;
+        gboolean can_switch;
 
+        can_switch = gdm_user_manager_can_switch (adata->manager);
         users = gdm_user_manager_list_users (adata->manager);
         adata->has_other_users = FALSE;
         if (users != NULL) {
@@ -711,7 +713,7 @@ update_switch_user (GdmAppletData *adata)
         }
         g_slist_free (users);
 
-        if (adata->has_other_users) {
+        if (can_switch && adata->has_other_users) {
                 gtk_widget_show (adata->login_screen_item);
         } else {