[gnome-desktop] GnomeRR: refresh the cached view of the screens when mutter restarts

[Giovanni Campagna <gcampagna src gnome org>]

commit b96b8af9ea86765d8a75102a372e30a0656e7ca2
Author: Giovanni Campagna <gcampagn redhat com>
Date:   Wed Sep 18 14:22:51 2013 +0200

    GnomeRR: refresh the cached view of the screens when mutter restarts
    
    Mutter does a modeset when it starts, but doesn't emit signals,
    so we must refresh our structures when we detect that. But most
    important, we must ensure that our serial is properly updated,
    otherwise any further operation will fail with AccessDenied.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=708284

 libgnome-desktop/gnome-rr.c |   42 ++++++++++++++++++++++++++++++++++++------
 1 files changed, 36 insertions(+), 6 deletions(-)
---
diff --git a/libgnome-desktop/gnome-rr.c b/libgnome-desktop/gnome-rr.c
index 167c5df..5e011d3 100644
--- a/libgnome-desktop/gnome-rr.c
+++ b/libgnome-desktop/gnome-rr.c
@@ -511,8 +511,14 @@ diff_outputs_and_emit_signals (ScreenInfo *old, ScreenInfo *new)
     }
 }
 
+typedef enum {
+    REFRESH_NONE = 0,
+    REFRESH_IGNORE_SERIAL = 1,
+    REFRESH_FORCE_CALLBACK = 2
+} RefreshFlags;
+
 static gboolean
-screen_update (GnomeRRScreen *screen, gboolean force_callback, GError **error)
+screen_update (GnomeRRScreen *screen, RefreshFlags flags, GError **error)
 {
     ScreenInfo *info;
     gboolean changed = FALSE;
@@ -523,17 +529,16 @@ screen_update (GnomeRRScreen *screen, gboolean force_callback, GError **error)
     if (!info)
            return FALSE;
 
-    if (info->serial != screen->priv->info->serial)
+    if ((flags & REFRESH_IGNORE_SERIAL) || info->serial != screen->priv->info->serial)
            changed = TRUE;
 
     /* work out if any outputs have changed connected state */
     diff_outputs_and_emit_signals (screen->priv->info, info);
 
     screen_info_free (screen->priv->info);
-       
     screen->priv->info = info;
 
-    if (changed || force_callback)
+    if (changed || (flags & REFRESH_FORCE_CALLBACK))
         g_signal_emit (G_OBJECT (screen), screen_signals[SCREEN_CHANGED], 0);
     
     return changed;
@@ -545,7 +550,28 @@ screen_on_monitors_changed (MetaDBusDisplayConfig *proxy,
 {
     GnomeRRScreen *screen = data;
 
-    screen_update (screen, TRUE, NULL);
+    screen_update (screen, REFRESH_FORCE_CALLBACK, NULL);
+}
+
+static void
+name_owner_changed (GObject       *object,
+                   GParamSpec    *pspec,
+                   GnomeRRScreen *self)
+{
+    GError *error;
+    char *new_name_owner;
+
+    new_name_owner = g_dbus_proxy_get_name_owner (G_DBUS_PROXY (object));
+    if (new_name_owner == NULL)
+       return;
+
+    error = NULL;
+    if (!screen_update (self, REFRESH_IGNORE_SERIAL | REFRESH_FORCE_CALLBACK, &error))
+       g_warning ("Failed to refresh screen configuration after mutter was restarted: %s",
+                  error->message);
+
+    g_clear_error (&error);
+    g_free (new_name_owner);
 }
 
 static gboolean
@@ -569,6 +595,8 @@ gnome_rr_screen_initable_init (GInitable *initable, GCancellable *canc, GError *
     if (!priv->info)
        return FALSE;
 
+    g_signal_connect_object (priv->proxy, "notify::g-name-owner",
+                            G_CALLBACK (name_owner_changed), self, 0);
     g_signal_connect_object (priv->proxy, "monitors-changed",
                             G_CALLBACK (screen_on_monitors_changed), self, 0);
     return TRUE;
@@ -596,6 +624,8 @@ on_proxy_acquired (GObject      *object,
     if (!priv->info)
        return g_task_return_error (task, error);
 
+    g_signal_connect_object (priv->proxy, "notify::g-name-owner",
+                            G_CALLBACK (name_owner_changed), self, 0);
     g_signal_connect_object (priv->proxy, "monitors-changed",
                             G_CALLBACK (screen_on_monitors_changed), self, 0);
     g_task_return_boolean (task, TRUE);
@@ -935,7 +965,7 @@ gnome_rr_screen_refresh (GnomeRRScreen *screen,
 {
     g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
 
-    return screen_update (screen, FALSE, error);
+    return screen_update (screen, REFRESH_NONE, error);
 }
 
 /**