/*

 * 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 "classfile/javaClasses.inline.hpp"

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

#include "jfr/leakprofiler/utilities/unifiedOop.hpp"

Edge::Edge() : _parent(NULL), _reference(NULL) {}

Edge::Edge(const Edge* parent, const oop* reference) : _parent(parent),

                                                       _reference(reference) {}

const oop Edge::pointee() const {

  return UnifiedOop::dereference(_reference);

}

const oop Edge::reference_owner() const {

  return is_root() ? (oop)NULL : UnifiedOop::dereference(_parent->reference());

}

static const Klass* resolve_klass(const oop obj) {

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

  return java_lang_Class::is_instance(obj) ?

    java_lang_Class::as_Klass(obj) : obj->klass();

}

const Klass* Edge::pointee_klass() const {

  return resolve_klass(pointee());

}

const Klass* Edge::reference_owner_klass() const {

  const oop ref_owner = reference_owner();

  return ref_owner != NULL ? resolve_klass(ref_owner) : NULL;

}

size_t Edge::distance_to_root() const {

  size_t depth = 0;

  const Edge* current = _parent;

  while (current != NULL) {

    depth++;

    current = current->parent();

  }

  return depth;

}