--- /dev/null	2019-01-28 17:45:46.000000000 +0800
+++ new/src/share/vm/jfr/leakprofiler/chains/bfsClosure.hpp	2019-01-28 17:45:46.000000000 +0800
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2014, 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_JFR_LEAKPROFILER_CHAINS_BFSCLOSURE_HPP
+#define SHARE_VM_JFR_LEAKPROFILER_CHAINS_BFSCLOSURE_HPP
+
+#include "memory/iterator.hpp"
+#include "oops/oop.hpp"
+
+class BitSet;
+class Edge;
+class EdgeStore;
+class EdgeQueue;
+
+// Class responsible for iterating the heap breadth-first
+class BFSClosure : public ExtendedOopClosure {
+ private:
+  EdgeQueue* _edge_queue;
+  EdgeStore* _edge_store;
+  BitSet* _mark_bits;
+  const Edge* _current_parent;
+  mutable size_t _current_frontier_level;
+  mutable size_t _next_frontier_idx;
+  mutable size_t _prev_frontier_idx;
+  size_t _dfs_fallback_idx;
+  bool _use_dfs;
+
+  void log_completed_frontier() const;
+  void log_dfs_fallback() const;
+
+  bool is_complete() const;
+  void step_frontier() const;
+
+  void closure_impl(const oop* reference, const oop pointee);
+  void add_chain(const oop* reference, const oop pointee);
+  void dfs_fallback();
+
+  void iterate(const Edge* parent);
+  void process(const oop* reference, const oop pointee);
+
+  void process_root_set();
+  void process_queue();
+
+ public:
+  BFSClosure(EdgeQueue* edge_queue, EdgeStore* edge_store, BitSet* mark_bits);
+  void process();
+
+  virtual void do_oop(oop* ref);
+  virtual void do_oop(narrowOop* ref);
+};
+
+#endif // SHARE_VM_JFR_LEAKPROFILER_CHAINS_BFSCLOSURE_HPP