[mutter/wip/tablet-protocol-v2: 41/48] backends: Turn MetaInputSettings into a singleton

[Carlos Garnacho <carlosg src gnome org>]

commit 30732a548adefac97d3fa6b17d7d36a389694a74
Author: Carlos Garnacho <carlosg gnome org>
Date:   Fri May 13 13:31:52 2016 +0200

    backends: Turn MetaInputSettings into a singleton
    
    We will need to fetch information from it at certain places.
    The MetaBackend still takes care of freeing it though.

 src/backends/meta-backend.c                |    2 +-
 src/backends/meta-input-settings-private.h |    2 +-
 src/backends/meta-input-settings.c         |   16 +++++++++++++++-
 3 files changed, 17 insertions(+), 3 deletions(-)
---
diff --git a/src/backends/meta-backend.c b/src/backends/meta-backend.c
index 93c8ad3..1188504 100644
--- a/src/backends/meta-backend.c
+++ b/src/backends/meta-backend.c
@@ -314,7 +314,7 @@ meta_backend_real_post_init (MetaBackend *backend)
     g_slist_free (devices);
   }
 
-  priv->input_settings = meta_input_settings_create ();
+  priv->input_settings = meta_input_settings_get ();
 
   center_pointer (backend);
 }
diff --git a/src/backends/meta-input-settings-private.h b/src/backends/meta-input-settings-private.h
index 897ebde..f0429fc 100644
--- a/src/backends/meta-input-settings-private.h
+++ b/src/backends/meta-input-settings-private.h
@@ -99,7 +99,7 @@ struct _MetaInputSettingsClass
 
 GType meta_input_settings_get_type (void) G_GNUC_CONST;
 
-MetaInputSettings * meta_input_settings_create (void);
+MetaInputSettings * meta_input_settings_get (void);
 
 GDesktopTabletMapping meta_input_settings_get_tablet_mapping (MetaInputSettings  *settings,
                                                               ClutterInputDevice *device);
diff --git a/src/backends/meta-input-settings.c b/src/backends/meta-input-settings.c
index 42d799f..4695911 100644
--- a/src/backends/meta-input-settings.c
+++ b/src/backends/meta-input-settings.c
@@ -1030,7 +1030,7 @@ meta_input_settings_init (MetaInputSettings *settings)
     }
 }
 
-MetaInputSettings *
+static MetaInputSettings *
 meta_input_settings_create (void)
 {
 #ifdef HAVE_NATIVE_BACKEND
@@ -1047,6 +1047,20 @@ meta_input_settings_create (void)
   return NULL;
 }
 
+MetaInputSettings *
+meta_input_settings_get (void)
+{
+  static MetaInputSettings *input_settings = NULL;
+
+  if (g_once_init_enter (&input_settings))
+    {
+      MetaInputSettings *settings = meta_input_settings_create ();
+      g_once_init_leave (&input_settings, settings);
+    }
+
+  return input_settings;
+}
+
 GDesktopTabletMapping
 meta_input_settings_get_tablet_mapping (MetaInputSettings  *settings,
                                         ClutterInputDevice *device)