[glade] Report parsing error when loading a project. Fixes Bug 712289 "Glade silently fails to open malforme

[Juan Pablo Ugarte <jpu src gnome org>]

commit af72b2dad1f4fa153a7449312841eec4d0a1e1dc
Author: Juan Pablo Ugarte <juanpablougarte gmail com>
Date:   Fri Nov 15 20:59:11 2013 -0300

    Report parsing error when loading a project.
    Fixes Bug 712289 "Glade silently fails to open malformed ui file"

 gladeui/Makefile.am       |    1 +
 gladeui/glade-private.h   |   41 +++++++++++++++++++++++++++++++++++++++++
 gladeui/glade-project.c   |   16 +++++++++++++++-
 gladeui/glade-xml-utils.c |   21 +++++++++++++++++++++
 4 files changed, 78 insertions(+), 1 deletions(-)
---
diff --git a/gladeui/Makefile.am b/gladeui/Makefile.am
index c1e391a..7e78bcb 100644
--- a/gladeui/Makefile.am
+++ b/gladeui/Makefile.am
@@ -194,6 +194,7 @@ noinst_HEADERS = \
        glade-preview-tokens.h \
        glade-preview-window.h \
        glade-preview-template.h \
+       glade-private.h \
        glade-project-properties.h \
        gladeui-resources.h \
        glade-drag.h \
diff --git a/gladeui/glade-private.h b/gladeui/glade-private.h
new file mode 100644
index 0000000..ea35011
--- /dev/null
+++ b/gladeui/glade-private.h
@@ -0,0 +1,41 @@
+/*
+ * glade-private.h: miscellaneous private API
+ * 
+ * This is a placeholder for private API, eventually it should be replaced by
+ * proper public API or moved to its own private file.
+ *
+ * Copyright (C) 2013  Juan Pablo Ugarte
+ * 
+ * Authors:
+ *   Juan Pablo Ugarte <juanpablougarte gmail com>
+ *
+ * This library is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ * 
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public 
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#ifndef __GLADE_PRIVATE_H__
+#define __GLADE_PRIVATE_H__
+
+G_BEGIN_DECLS
+
+/* glade-xml-utils.c */
+
+/* GladeXml Error handling */
+void    _glade_xml_error_reset_last       (void);
+gchar  *_glade_xml_error_get_last_message (void);
+
+G_END_DECLS
+
+#endif /* __GLADE_PRIVATE_H__ */
diff --git a/gladeui/glade-project.c b/gladeui/glade-project.c
index 0553a2e..e1acd14 100644
--- a/gladeui/glade-project.c
+++ b/gladeui/glade-project.c
@@ -54,6 +54,7 @@
 #include "glade-object-stub.h"
 #include "glade-project-properties.h"
 #include "glade-dnd.h"
+#include "glade-private.h"
 
 static void     glade_project_target_version_for_adaptor
                                                     (GladeProject       *project,
@@ -2285,11 +2286,24 @@ glade_project_load_internal (GladeProject *project)
   priv->objects = NULL;
   priv->loading = TRUE;
 
+  _glade_xml_error_reset_last ();
+
   /* get the context & root node of the catalog file */
   if (!(context =
         glade_xml_context_new_from_path (load_path ? load_path : priv->path, NULL, NULL)))
     {
-      g_warning ("Couldn't open glade file [%s].", load_path ? load_path : priv->path);
+      gchar *message = _glade_xml_error_get_last_message ();
+
+      if (message)
+        {
+          glade_util_ui_message (glade_app_get_window (), GLADE_UI_ERROR, NULL, message);
+          g_free (message);
+        }
+      else
+        glade_util_ui_message (glade_app_get_window (), GLADE_UI_ERROR, NULL,
+                               "Couldn't open glade file [%s].",
+                               load_path ? load_path : priv->path);
+
       g_free (load_path);
       priv->loading = FALSE;
       return FALSE;
diff --git a/gladeui/glade-xml-utils.c b/gladeui/glade-xml-utils.c
index e9c9145..9b9424c 100644
--- a/gladeui/glade-xml-utils.c
+++ b/gladeui/glade-xml-utils.c
@@ -987,3 +987,24 @@ glade_xml_node_add_next_sibling (GladeXmlNode *node, GladeXmlNode *new_node)
 {
   return (GladeXmlNode *) xmlAddNextSibling ((xmlNodePtr) node, (xmlNodePtr) new_node);
 }
+
+
+/* Private API */
+#include "glade-private.h"
+
+void
+_glade_xml_error_reset_last (void)
+{
+  xmlResetLastError ();
+}
+
+gchar *
+_glade_xml_error_get_last_message ()
+{
+  xmlErrorPtr error = xmlGetLastError ();
+
+  if (error)
+    return g_strdup_printf ("Error parsing file '%s' on line %d \n%s",
+                            error->file, error->line, error->message);
+  return NULL;
+}