Fix bug # 172450: plug ever-increasing memory leaks. When new internet search results are added, old nodes were being removed, but old attributes hanging off of the old nodes need to be cleared out also (but, IFF there are no other references to the old search result nodes in the graph.) r=sgehani sr=jag

xpfe/components/search/src/nsInternetSearchService.cpp

@@ -2873,6 +2873,44 @@ InternetSearchDataSource::ClearResults(PRBool flushLastSearchRef)
 			{
 				mInner->Unassert(kNC_LastSearchRoot, kNC_Child, child);
 			}
+
+			// *after* (so that we won't thrash the XUL template builder) unasserting
+			// child node, determine if there are any other references to the child
+			// node in the graph
+
+			PRBool hasInArcs = PR_FALSE;
+			nsCOMPtr<nsISimpleEnumerator>	inArcs;
+			if (NS_FAILED(mInner->ArcLabelsIn(child, getter_AddRefs(inArcs)) ||
+				(!inArcs)))
+				continue;
+			if (NS_FAILED(inArcs->HasMoreElements(&hasInArcs)) ||
+				(hasInArcs == PR_TRUE))
+				continue;
+
+			// no other references, so also unassert any outgoing arcs
+
+			nsCOMPtr<nsISimpleEnumerator>	outArcs;
+			if (NS_FAILED(mInner->ArcLabelsOut(child, getter_AddRefs(outArcs)) ||
+				(!outArcs)))
+				continue;
+			PRBool	hasMoreOutArcs = PR_TRUE;
+			while (hasMoreOutArcs == PR_TRUE)
+			{
+				if (NS_FAILED(outArcs->HasMoreElements(&hasMoreOutArcs)) ||
+					(hasMoreOutArcs == PR_FALSE))
+					break;
+				nsCOMPtr<nsISupports>	outArc;
+				if (NS_FAILED(outArcs->GetNext(getter_AddRefs(outArc))))
+					break;
+				nsCOMPtr<nsIRDFResource> property (do_QueryInterface(outArc));
+				if (!property)
+					continue;
+				nsCOMPtr<nsIRDFNode> target;
+				if (NS_FAILED(mInner->GetTarget(child, property, PR_TRUE,
+					getter_AddRefs(target))) || (!target))
+					continue;
+				mInner->Unassert(child, property, target);
+			}
 		}
 	}