/*
 * 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.
 *
 */

#include "precompiled.hpp"
#include "gc/shared/oopStorage.hpp"
#include "memory/universe.hpp"
#include "oops/access.inline.hpp"
#include "oops/oop.hpp"
#include "oops/weakHandle.hpp"
#include "utilities/debug.hpp"
#include "utilities/ostream.hpp"

WeakHandle WeakHandle::create(Handle obj) {
  assert(obj() != NULL, "no need to create weak null oop");
  oop* oop_addr = Universe::vm_weak_oop_storage()->allocate();
  if (oop_addr == NULL) {
    vm_exit_out_of_memory(sizeof(oop*), OOM_MALLOC_ERROR, "Unable to create new weak oop handle in OopStorage");
  }
  // Create WeakHandle with address returned and store oop into it.
  RootAccess<ON_PHANTOM_OOP_REF>::oop_store(oop_addr, obj());
  return WeakHandle(oop_addr);
}

oop WeakHandle::resolve() const {
  if (_obj == NULL) {
    return NULL; // for initialization
  }
  return RootAccess<ON_PHANTOM_OOP_REF>::oop_load(_obj);
}

oop WeakHandle::peek() const {
  if (_obj == NULL) {
    return NULL;  // needed?
  }
  return RootAccess<ON_PHANTOM_OOP_REF | AS_NO_KEEPALIVE>::oop_load(_obj);
}

void WeakHandle::release() const {
  Universe::vm_weak_oop_storage()->release(_obj);
}

void WeakHandle::print() const { print_on(tty); }

void WeakHandle::print_on(outputStream* st) const {
  st->print("WeakHandle: " PTR_FORMAT, p2i(peek()));
}