/*

 * Copyright (c) 2014, 2018, 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

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 */

#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