[gnome-photos] item-manager: Fix logic to check if a cursor is a collection

[Debarshi Ray <debarshir src gnome org>]

commit 81d21039a06ea65a14508f5d72bbd78c334f3e8d
Author: Debarshi Ray <debarshir gnome org>
Date:   Wed Aug 24 11:05:58 2016 +0200

    item-manager: Fix logic to check if a cursor is a collection
    
    Some collections might not have a nao:identifier. eg., the built-in
    nfo:image-category-screenshot. Instead, we should check the rdf:type
    for nfo:DataContainer. This is also what PhotosBaseItem does.
    
    This wasn't a problem so far because we were miraculously not hitting
    this code path for such collections. Things are going to change in
    subsequent commits when we sprinkle some assertions around the code.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=770342

 src/photos-item-manager.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)
---
diff --git a/src/photos-item-manager.c b/src/photos-item-manager.c
index 42e35bc..fb870a0 100644
--- a/src/photos-item-manager.c
+++ b/src/photos-item-manager.c
@@ -25,6 +25,8 @@
 
 #include "config.h"
 
+#include <string.h>
+
 #include <gio/gio.h>
 #include <glib.h>
 #include <tracker-sparql.h>
@@ -263,10 +265,10 @@ static gboolean
 photos_item_manager_cursor_is_collection (TrackerSparqlCursor *cursor)
 {
   gboolean ret_val;
-  const gchar *identifier;
+  const gchar *rdf_type;
 
-  identifier = tracker_sparql_cursor_get_string (cursor, PHOTOS_QUERY_COLUMNS_IDENTIFIER, NULL);
-  ret_val = g_str_has_prefix (identifier, "photos:collection:");
+  rdf_type = tracker_sparql_cursor_get_string (cursor, PHOTOS_QUERY_COLUMNS_RDF_TYPE, NULL);
+  ret_val = strstr (rdf_type, "nfo#DataContainer") != NULL;
   return ret_val;
 }