[folks] Add some more detailed validation/error reporting to the importing tool.

[Travis Reitter <treitter src gnome org>]

commit 17d54039f6b4a505ca83fbfb88b6dcccb9cd9d8f
Author: Travis Reitter <travis reitter collabora co uk>
Date:   Fri Sep 10 12:13:42 2010 -0700

    Add some more detailed validation/error reporting to the importing tool.

 tools/import-pidgin.vala |   27 +++++++++++++++++++++++++++
 1 files changed, 27 insertions(+), 0 deletions(-)
---
diff --git a/tools/import-pidgin.vala b/tools/import-pidgin.vala
index 22790a4..48a6170 100644
--- a/tools/import-pidgin.vala
+++ b/tools/import-pidgin.vala
@@ -41,6 +41,33 @@ public class Folks.Importers.Pidgin : Folks.Importer
               ".purple", "blist.xml", null);
         }
 
+      var file = File.new_for_path (filename);
+      if (!file.query_exists ())
+        {
+          throw new ImportError.MALFORMED_INPUT ("File %s does not exist.",
+              filename);
+        }
+
+      FileInfo file_info;
+      try
+        {
+          file_info = yield file.query_info_async (
+              FILE_ATTRIBUTE_ACCESS_CAN_READ, FileQueryInfoFlags.NONE,
+              Priority.DEFAULT);
+        }
+      catch (GLib.Error e)
+        {
+          throw new ImportError.MALFORMED_INPUT (
+              "Failed to get information about file %s: %s", filename,
+              e.message);
+        }
+
+      if (!file_info.get_attribute_boolean (FILE_ATTRIBUTE_ACCESS_CAN_READ))
+        {
+          throw new ImportError.MALFORMED_INPUT ("File %s is not readable.",
+              filename);
+        }
+
       Xml.Doc* xml_doc = Parser.parse_file (filename);
 
       if (xml_doc == null)