[rygel] core: Prevent XBox showing songs multiple times

[Jens Georg <jensgeorg src gnome org>]

commit 9aff5d6e5d73f813e4e3d6d80bedfe2eb8cf15ba
Author: Jens Georg <mail jensge org>
Date:   Fri Feb 10 16:34:23 2012 +0200

    core: Prevent XBox showing songs multiple times
    
    Due to the way we handle the XBox's search requests it might happen
    that the search result includes items having a @refID which are
    just "aliases" to the real items.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=664184

 src/rygel/rygel-xbox-hacks.vala |   46 +++++++++++++++++++++++++++++++++------
 1 files changed, 39 insertions(+), 7 deletions(-)
---
diff --git a/src/rygel/rygel-xbox-hacks.vala b/src/rygel/rygel-xbox-hacks.vala
index bf3b8bf..5622e53 100644
--- a/src/rygel/rygel-xbox-hacks.vala
+++ b/src/rygel/rygel-xbox-hacks.vala
@@ -132,20 +132,52 @@ internal class Rygel.XBoxHacks : ClientHacks {
                                          out uint            total_matches,
                                          Cancellable?        cancellable)
                                          throws Error {
-        var results = yield container.search (expression,
-                                              offset,
-                                              max_count,
-                                              out total_matches,
-                                              cancellable);
-        if (total_matches == 0 && expression is RelationalExpression) {
+        var set_total_matches = false;
+        var modified_expression = expression;
+
+        // check if the XBox is trying to get all the songs.
+        // If so, rewrite the search to exclude @refID items, otherwise they
+        // songs will show up multiple times in the listing.
+        if (expression is RelationalExpression) {
             var rel_expression = expression as RelationalExpression;
 
             if (likely (rel_expression.operand1 != null) &&
                 rel_expression.operand1 == "upnp:class") {
-                total_matches = results.size;
+                set_total_matches = true;
+
+                if (rel_expression.op == SearchCriteriaOp.DERIVED_FROM &&
+                    rel_expression.operand2 != null &&
+                    rel_expression.operand2 == AudioItem.UPNP_CLASS) {
+                    modified_expression = this.rewrite_search_expression
+                                        (expression);
+                }
             }
         }
 
+        var results = yield container.search (modified_expression,
+                                              offset,
+                                              max_count,
+                                              out total_matches,
+                                              cancellable);
+        if (total_matches == 0 && set_total_matches) {
+            total_matches = results.size;
+        }
+
         return results;
     }
+
+    private SearchExpression rewrite_search_expression
+                                        (SearchExpression expression) {
+        var ref_id_expression = new RelationalExpression ();
+        ref_id_expression.operand1 = "@refID";
+        ref_id_expression.op = SearchCriteriaOp.EXISTS;
+        ref_id_expression.operand2 = "false";
+
+        var new_expression = new LogicalExpression ();
+        new_expression.operand1 = expression;
+        new_expression.op = LogicalOperator.AND;
+        new_expression.operand2 = ref_id_expression;
+
+        return new_expression;
+    }
 }