[gtkmm] Demos: Catch Glib::FileError from demo_find_file().

[Kjell Ahlstedt <kjellahl src gnome org>]

commit b55a57c480a0866f1d53676034ca6c7294b9cc64
Author: Kjell Ahlstedt <kjell ahlstedt bredband net>
Date:   Mon Jul 22 16:46:12 2013 +0200

    Demos: Catch Glib::FileError from demo_find_file().
    
    * demos/gtk-demo/demo-common.cc: Fix description of demo_find_file().
    * demos/gtk-demo/demowindow.cc: Put the call to demo_find_file() in a
    try block, and catch Glib::FileError.

 demos/gtk-demo/demo-common.cc |    5 ++---
 demos/gtk-demo/demowindow.cc  |   13 +++++++++++--
 2 files changed, 13 insertions(+), 5 deletions(-)
---
diff --git a/demos/gtk-demo/demo-common.cc b/demos/gtk-demo/demo-common.cc
index 83e4bc7..0c86ebc 100644
--- a/demos/gtk-demo/demo-common.cc
+++ b/demos/gtk-demo/demo-common.cc
@@ -32,13 +32,12 @@ get_democodedir(void)
 /**
  * demo_find_file:
  * @base: base filename
- * @err:  location to store error, or %NULL.
  * 
  * Looks for @base first in the current directory, then in the
- * location GTK+ where it will be installed on make install,
+ * location where gtkmm will be installed on make install,
  * returns the first file found.
  * 
- * Return value: the filename, if found or %NULL
+ * Return value: the filename, if found, else throws a Glib::FileError.
  **/
 std::string demo_find_file(const std::string& base)
 {
diff --git a/demos/gtk-demo/demowindow.cc b/demos/gtk-demo/demowindow.cc
index 6763ad2..061746e 100644
--- a/demos/gtk-demo/demowindow.cc
+++ b/demos/gtk-demo/demowindow.cc
@@ -26,6 +26,7 @@
 #include <gtkmm/treeviewcolumn.h>
 #include <gtkmm/box.h>
 #include <glibmm/convert.h>
+#include <glibmm/fileutils.h>
 #include "demowindow.h"
 #include "textwidget.h"
 #include "demos.h"
@@ -268,8 +269,16 @@ void DemoWindow::load_file(const std::string& filename)
     FILE* file = fopen (filename.c_str(), "r");
     if (!file)
     {
-      std::string installed = demo_find_file(filename);
-      file = fopen (installed.c_str(), "r");
+      try
+      {
+        std::string installed = demo_find_file(filename);
+        file = fopen (installed.c_str(), "r");
+      }
+      catch (const Glib::FileError& ex)
+      {
+        g_warning ("%s\n", ex.what().c_str());
+        return;
+      }
     }
 
     if (!file)