/*

 * Copyright (c) 2001, 2016, 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_GC_SHARED_SOFTREFPOLICY_HPP

#define SHARE_VM_GC_SHARED_SOFTREFPOLICY_HPP

#include "memory/allocation.hpp"

class SoftRefPolicy {

 private:

  // Set to true when policy wants soft refs cleared.

  // Reset to false by gc after it clears all soft refs.

  bool _should_clear_all_soft_refs;

  // Set to true by the GC if the just-completed gc cleared all

  // softrefs.  This is set to true whenever a gc clears all softrefs, and

  // set to false each time gc returns to the mutator.  For example, in the

  // ParallelScavengeHeap case the latter would be done toward the end of

  // mem_allocate() where it returns op.result()

  bool _all_soft_refs_clear;

 public:

  SoftRefPolicy();

  bool should_clear_all_soft_refs() { return _should_clear_all_soft_refs; }

  void set_should_clear_all_soft_refs(bool v) { _should_clear_all_soft_refs = v; }

  // Returns the current value of _should_clear_all_soft_refs.

  // _should_clear_all_soft_refs is set to false as a side effect.

  bool use_should_clear_all_soft_refs(bool v);

  bool all_soft_refs_clear() { return _all_soft_refs_clear; }

  void set_all_soft_refs_clear(bool v) { _all_soft_refs_clear = v; }

  // Called by the GC after Soft Refs have been cleared to indicate

  // that the request in _should_clear_all_soft_refs has been fulfilled.

  virtual void cleared_all_soft_refs();

};

class ClearedAllSoftRefs : public StackObj {

  bool           _clear_all_soft_refs;

  SoftRefPolicy* _soft_ref_policy;

 public:

  ClearedAllSoftRefs(bool clear_all_soft_refs, SoftRefPolicy* soft_ref_policy) :

    _clear_all_soft_refs(clear_all_soft_refs),

    _soft_ref_policy(soft_ref_policy) {}

  ~ClearedAllSoftRefs() {

    if (_clear_all_soft_refs) {

      _soft_ref_policy->cleared_all_soft_refs();

    }

  }

  bool should_clear() { return _clear_all_soft_refs; }

};

#endif // SHARE_VM_GC_SHARED_SOFTREFPOLICY_HPP