import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

dom/xslt/xpath/txRootExpr.cpp

@@ -0,0 +1,43 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "txExpr.h"
+#include "txNodeSet.h"
+#include "txIXPathContext.h"
+#include "txXPathTreeWalker.h"
+
+/**
+ * Evaluates this Expr based on the given context node and processor state
+ * @param context the context node for evaluation of this Expr
+ * @param ps the ContextState containing the stack information needed
+ * for evaluation
+ * @return the result of the evaluation
+**/
+nsresult
+RootExpr::evaluate(txIEvalContext* aContext, txAExprResult** aResult)
+{
+    txXPathTreeWalker walker(aContext->getContextNode());
+    walker.moveToRoot();
+    
+    return aContext->recycler()->getNodeSet(walker.getCurrentPosition(),
+                                            aResult);
+}
+
+TX_IMPL_EXPR_STUBS_0(RootExpr, NODESET_RESULT)
+
+bool
+RootExpr::isSensitiveTo(ContextSensitivity aContext)
+{
+    return !!(aContext & NODE_CONTEXT);
+}
+
+#ifdef TX_TO_STRING
+void
+RootExpr::toString(nsAString& dest)
+{
+    if (mSerialize)
+        dest.Append(char16_t('/'));
+}
+#endif