[glade] GladeProject: Identify when we are serializing for a preview

[Tristan Van Berkom <tvb src gnome org>]

commit 98954a4e3a96b0f8c1b420de690b480447b30cd0
Author: Tristan Van Berkom <tristan vanberkom codethink co uk>
Date:   Fri Jan 29 15:09:37 2016 +0100

    GladeProject: Identify when we are serializing for a preview

 gladeui/glade-project.c |   11 +++++++++++
 gladeui/glade-project.h |    1 +
 2 files changed, 12 insertions(+), 0 deletions(-)
---
diff --git a/gladeui/glade-project.c b/gladeui/glade-project.c
index c210031..c92e54a 100644
--- a/gladeui/glade-project.c
+++ b/gladeui/glade-project.c
@@ -156,6 +156,7 @@ struct _GladeProjectPrivate
                                   * for confirmation after a close or exit is
                                   * requested
                                   */
+  guint writing_preview : 1;     /* During serialization, if we are serializing for a preview */
   guint pointer_mode : 3;        /* The currently effective GladePointerMode */
 };
 
@@ -2846,7 +2847,9 @@ glade_project_preview (GladeProject *project, GladeWidget *gwidget)
 
   g_return_if_fail (GLADE_IS_PROJECT (project));
 
+  project->priv->writing_preview = TRUE;
   context = glade_project_write (project);
+  project->priv->writing_preview = FALSE;
 
   text = glade_xml_dump_from_context (context);
 
@@ -2889,6 +2892,14 @@ glade_project_preview (GladeProject *project, GladeWidget *gwidget)
   g_free (text);
 }
 
+gboolean
+glade_project_writing_preview (GladeProject       *project)
+{
+  g_return_val_if_fail (GLADE_IS_PROJECT (project), FALSE);
+
+  return project->priv->writing_preview;
+}
+
 /*******************************************************************
      Verify code here (versioning, incompatability checks)
  *******************************************************************/
diff --git a/gladeui/glade-project.h b/gladeui/glade-project.h
index eb64846..5e6e692 100644
--- a/gladeui/glade-project.h
+++ b/gladeui/glade-project.h
@@ -273,6 +273,7 @@ gchar              *glade_project_verify_widget_adaptor(GladeProject       *proj
 void                glade_project_verify_property      (GladeProperty      *property);
 void                glade_project_verify_signal        (GladeWidget        *widget,
                                                         GladeSignal        *signal);
+gboolean            glade_project_writing_preview      (GladeProject       *project);
 
 /* General selection driven commands */
 void                glade_project_copy_selection       (GladeProject       *project);