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/*
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* Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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#ifndef SHARE_VM_JFR_UTILITIES_JFRLISTITERATOR_HPP
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#define SHARE_VM_JFR_UTILITIES_JFRLISTITERATOR_HPP
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#include "memory/allocation.hpp"
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enum jfr_iter_direction {
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forward = 1,
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backward
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};
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template <typename Node>
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class StopOnNullCondition : public AllStatic {
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public:
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static bool has_next(const Node* node) {
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return node != NULL;
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}
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};
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template <typename List, template <typename> class ContinuationPredicate>
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class Navigator {
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public:
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typedef typename List::Node Node;
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typedef jfr_iter_direction Direction;
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Navigator(List& list, Direction direction) :
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_list(list), _node(direction == forward ? list.head() : list.tail()), _direction(direction) {}
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bool has_next() const {
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return ContinuationPredicate<Node>::has_next(_node);
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}
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bool direction_forward() const {
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return _direction == forward;
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}
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Node* next() const {
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assert(_node != NULL, "invariant");
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Node* temp = _node;
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_node = direction_forward() ? (Node*)_node->next() : (Node*)_node->prev();
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return temp;
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}
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void set_direction(Direction direction) {
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_direction = direction;
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}
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void reset(Direction direction) {
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set_direction(direction);
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_node = direction_forward() ? _list.head() : _list.tail();
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}
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private:
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List& _list;
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mutable Node* _node;
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Direction _direction;
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};
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template <typename List>
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class NavigatorStopOnNull : public Navigator<List, StopOnNullCondition> {
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public:
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NavigatorStopOnNull(List& list, jfr_iter_direction direction = forward) : Navigator<List, StopOnNullCondition>(list, direction) {}
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};
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template<typename List, template <typename> class Navigator, typename AP = StackObj>
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class IteratorHost : public AP {
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private:
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Navigator<List> _navigator;
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public:
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typedef typename List::Node Node;
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typedef jfr_iter_direction Direction;
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IteratorHost(List& list, Direction direction = forward) : AP(), _navigator(list, direction) {}
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void reset(Direction direction = forward) { _navigator.reset(direction); }
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bool has_next() const { return _navigator.has_next(); }
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Node* next() const { return _navigator.next(); }
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void set_direction(Direction direction) { _navigator.set_direction(direction); }
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};
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template<typename List, typename AP = StackObj>
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class StopOnNullIterator : public IteratorHost<List, NavigatorStopOnNull, AP> {
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public:
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StopOnNullIterator(List& list, jfr_iter_direction direction = forward) : IteratorHost<List, NavigatorStopOnNull, AP>(list, direction) {}
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};
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#endif // SHARE_VM_JFR_UTILITIES_JFRLISTITERATOR_HPP
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