/*

 * Copyright (c) 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#ifndef SHARE_VM_JFR_RECORDER_STORAGE_JFRMEMORYSPACERETRIEVAL_HPP

#define SHARE_VM_JFR_RECORDER_STORAGE_JFRMEMORYSPACERETRIEVAL_HPP

#include "memory/allocation.hpp"

#include "jfr/recorder/repository/jfrChunkWriter.hpp"

#include "jfr/recorder/storage/jfrBuffer.hpp"

#include "jfr/utilities/jfrAllocation.hpp"

#include "jfr/utilities/jfrTypes.hpp"

/*

* Some policy classes for getting mspace memory

*/

template <typename Mspace>

class JfrMspaceRetrieval : AllStatic {

 public:

  typedef typename Mspace::Type Type;

  static Type* get(size_t size, Mspace* mspace, typename Mspace::Iterator& iterator, Thread* thread) {

    while (iterator.has_next()) {

      Type* const t = iterator.next();

      if (t->retired()) continue;

      if (t->try_acquire(thread)) {

        assert(!t->retired(), "invariant");

        if (t->free_size() >= size) {

          return t;

        }

        t->set_retired();

        mspace->register_full(t, thread);

      }

    }

    return NULL;

  }

};

template <typename Mspace>

class JfrMspaceAlternatingRetrieval {

 private:

   // provides stochastic distribution over "deque" endpoints; racy is ok here

  static bool _last_access;

 public:

  typedef typename Mspace::Type Type;

  static Type* get(size_t size, Mspace* mspace, Thread* thread) {

    typename Mspace::Iterator iterator(mspace->free(), (_last_access = !_last_access) ? forward : backward);

    return JfrMspaceRetrieval<Mspace>::get(size, mspace, iterator, thread);

  }

};

template <typename Mspace>

bool JfrMspaceAlternatingRetrieval<Mspace>::_last_access = false;

template <typename Mspace>

class JfrMspaceSequentialRetrieval {

 public:

  typedef typename Mspace::Type Type;

  static Type* get(size_t size, Mspace* mspace, Thread* thread) {

    typename Mspace::Iterator iterator(mspace->free());

    return JfrMspaceRetrieval<Mspace>::get(size, mspace, iterator, thread);

  }

};

template <typename Mspace>

class JfrExclusiveRetrieval : AllStatic {

public:

  typedef typename Mspace::Type Type;

  static Type* get(size_t size, Mspace* mspace, typename Mspace::Iterator& iterator, Thread* thread) {

    assert(mspace->is_locked(), "invariant");

    if (iterator.has_next()) {

      Type* const t = iterator.next();

      assert(!t->retired(), "invariant");

      assert(t->identity() == NULL, "invariant");

      assert(t->free_size() >= size, "invariant");

      t->acquire(thread);

      return t;

    }

    return NULL;

  }

};

template <typename Mspace>

class JfrThreadLocalRetrieval {

public:

  typedef typename Mspace::Type Type;

  static Type* get(size_t size, Mspace* mspace, Thread* thread) {

    typename Mspace::Iterator iterator(mspace->free(), forward);

    return JfrExclusiveRetrieval<Mspace>::get(size, mspace, iterator, thread);

  }

};

#endif // SHARE_VM_JFR_RECORDER_STORAGE_JFRMEMORYSPACERETRIEVAL_HPP