/*

 * 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_GC_G1_G1STRINGDEDUPQUEUE_HPP

#define SHARE_GC_G1_G1STRINGDEDUPQUEUE_HPP

#include "gc/shared/stringdedup/stringDedupQueue.hpp"

#include "memory/allocation.hpp"

#include "oops/oop.hpp"

#include "utilities/stack.hpp"

class StringDedupUnlinkOrOopsDoClosure;

//

// G1 enqueues candidates during the stop-the-world mark/evacuation phase.

//

class G1StringDedupQueue : public StringDedupQueue {

private:

  typedef Stack<oop, mtGC> G1StringDedupWorkerQueue;

  static const size_t        _max_size;

  static const size_t        _max_cache_size;

  G1StringDedupWorkerQueue*  _queues;

  size_t                     _nqueues;

  size_t                     _cursor;

  bool                       _cancel;

  volatile bool              _empty;

  // Statistics counter, only used for logging.

  uintx                      _dropped;

  ~G1StringDedupQueue();

  void unlink_or_oops_do(StringDedupUnlinkOrOopsDoClosure* cl, size_t queue);

public:

  G1StringDedupQueue();

protected:

  // Blocks and waits for the queue to become non-empty.

  void wait_impl();

  // Wakes up any thread blocked waiting for the queue to become non-empty.

  void cancel_wait_impl();

  // Pushes a deduplication candidate onto a specific GC worker queue.

  void push_impl(uint worker_id, oop java_string);

  // Pops a deduplication candidate from any queue, returns NULL if

  // all queues are empty.

  oop pop_impl();

  size_t num_queues() const {

    return _nqueues;

  }

  void unlink_or_oops_do_impl(StringDedupUnlinkOrOopsDoClosure* cl, size_t queue);

  void print_statistics_impl();

  void verify_impl();

};

#endif // SHARE_GC_G1_G1STRINGDEDUPQUEUE_HPP