[tracker/tracker-0.10] tracker-needle: Avoid g_markup_escape_text() critical with NULL

[Martyn James Russell <mr src gnome org>]

commit 7ddea5c2bbd33d0bdb4882c7d9c2037bfcb0a58e
Author: Martyn Russell <martyn lanedo com>
Date:   Thu Aug 18 10:14:51 2011 +0100

    tracker-needle: Avoid g_markup_escape_text() critical with NULL
    
    This is based on a similar patch in master but done from scratch for conflict
    reasons during cherry-picking:
    
      689d6aa29bec498c15925131ed5c19b4ac45d2fd

 src/tracker-needle/tracker-result-store.vala |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)
---
diff --git a/src/tracker-needle/tracker-result-store.vala b/src/tracker-needle/tracker-result-store.vala
index 2e00ef6..1dc24c1 100644
--- a/src/tracker-needle/tracker-result-store.vala
+++ b/src/tracker-needle/tracker-result-store.vala
@@ -113,8 +113,12 @@ public class Tracker.ResultStore : Gtk.TreeModel, GLib.Object {
 
 				for (j = 0; j < n_columns; j++) {
 					if (j == n_columns - 1) {
-						// FIXME: Set markup for tooltip column in a nicer way
-						result.values[j] = Markup.escape_text (cursor.get_string (j));
+						string s = cursor.get_string (j);
+
+						if (s != null)
+							result.values[j] = Markup.escape_text (s);
+						else
+							result.values[j] = null;
 					} else {
 						result.values[j] = cursor.get_string (j);
 					}