/*

 * 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

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

 * questions.

 *

 */

#include "precompiled.hpp"

#include "jfr/leakprofiler/chains/edgeQueue.hpp"

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

EdgeQueue::EdgeQueue(size_t reservation_size_bytes, size_t commit_block_size_bytes) :

  _vmm(NULL),

  _reservation_size_bytes(reservation_size_bytes),

  _commit_block_size_bytes(commit_block_size_bytes),

  _top_index(0),

  _bottom_index(0) {

}

bool EdgeQueue::initialize() {

  assert(_reservation_size_bytes >= _commit_block_size_bytes, "invariant");

  assert(_vmm == NULL, "invariant");

  _vmm = new JfrVirtualMemory();

  return _vmm != NULL && _vmm->initialize(_reservation_size_bytes, _commit_block_size_bytes, sizeof(Edge));

}

EdgeQueue::~EdgeQueue() {

  delete _vmm;

}

void EdgeQueue::add(const Edge* parent, const oop* ref) {

  assert(ref != NULL, "Null objects not allowed in EdgeQueue");

  assert(!is_full(), "EdgeQueue is full. Check is_full before adding another Edge");

  assert(!_vmm->is_full(), "invariant");

  void* const allocation = _vmm->new_datum();

  assert(allocation != NULL, "invariant");

  new (allocation)Edge(parent, ref);

  _top_index++;

  assert(_vmm->count() == _top_index, "invariant");

}

size_t EdgeQueue::top() const {

  return _top_index;

}

size_t EdgeQueue::bottom() const {

  return EdgeQueue::_bottom_index;

}

bool EdgeQueue::is_empty() const {

  return _top_index == _bottom_index;

}

bool EdgeQueue::is_full() const {

  return _vmm->is_full();

}

const Edge* EdgeQueue::remove() const {

  assert(!is_empty(), "EdgeQueue is empty. Check if empty before removing Edge");

  assert(!_vmm->is_empty(), "invariant");

  return (const Edge*)_vmm->get(_bottom_index++);

}

const Edge* EdgeQueue::element_at(size_t index) const {

  assert(index >= _bottom_index, "invariant");

  assert(index <_top_index, "invariant");

  return (Edge*)_vmm->get(index);

}

size_t EdgeQueue::reserved_size() const {

  assert(_vmm != NULL, "invariant");

  return _vmm->reserved_size();

}

size_t EdgeQueue::live_set() const {

  assert(_vmm != NULL, "invariant");

  return _vmm->live_set();

}

size_t EdgeQueue::sizeof_edge() const {

  assert(_vmm != NULL, "invariant");

  return _vmm->aligned_datum_size_bytes();

}