/*

 * Copyright (c) 2019, Red Hat, Inc. All rights reserved.

 *

 * 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 "runtime/os.hpp"

#include "gc/shenandoah/shenandoahLock.hpp"

#include "runtime/atomic.hpp"

#include "runtime/os.inline.hpp"

#include "runtime/thread.hpp"

ShenandoahSimpleLock::ShenandoahSimpleLock() {

  assert(os::mutex_init_done(), "Too early!");

}

void ShenandoahSimpleLock::lock() {

  _lock.lock();

}

void ShenandoahSimpleLock::unlock() {

  _lock.unlock();

}

ShenandoahReentrantLock::ShenandoahReentrantLock() :

  ShenandoahSimpleLock(), _owner(NULL), _count(0) {

  assert(os::mutex_init_done(), "Too early!");

}

ShenandoahReentrantLock::~ShenandoahReentrantLock() {

  assert(_count == 0, "Unbalance");

}

void ShenandoahReentrantLock::lock() {

  Thread* const thread = Thread::current();

  Thread* const owner = Atomic::load(&_owner);

  if (owner != thread) {

    ShenandoahSimpleLock::lock();

    Atomic::store(&_owner, thread);

  }

  _count++;

}

void ShenandoahReentrantLock::unlock() {

  assert(owned_by_self(), "Invalid owner");

  assert(_count > 0, "Invalid count");

  _count--;

  if (_count == 0) {

    Atomic::store(&_owner, (Thread*)NULL);

    ShenandoahSimpleLock::unlock();

  }

}

bool ShenandoahReentrantLock::owned_by_self() const {

  Thread* const thread = Thread::current();

  Thread* const owner = Atomic::load(&_owner);

  return owner == thread;

}