| /* |
| * Copyright (c) 2016, 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. |
| * |
| */ |
| |
| #ifndef SHARE_VM_JFR_UTILITIES_JFRLISTITERATOR_HPP |
| #define SHARE_VM_JFR_UTILITIES_JFRLISTITERATOR_HPP |
| |
| #include "memory/allocation.hpp" |
| |
| enum jfr_iter_direction { |
| forward = 1, |
| backward |
| }; |
| |
| template <typename Node> |
| class StopOnNullCondition : public AllStatic { |
| public: |
| static bool has_next(const Node* node) { |
| return node != NULL; |
| } |
| }; |
| |
| template <typename List, template <typename> class ContinuationPredicate> |
| class Navigator { |
| public: |
| typedef typename List::Node Node; |
| typedef jfr_iter_direction Direction; |
| Navigator(List& list, Direction direction) : |
| _list(list), _node(direction == forward ? list.head() : list.tail()), _direction(direction) {} |
| bool has_next() const { |
| return ContinuationPredicate<Node>::has_next(_node); |
| } |
| |
| bool direction_forward() const { |
| return _direction == forward; |
| } |
| |
| Node* next() const { |
| assert(_node != NULL, "invariant"); |
| Node* temp = _node; |
| _node = direction_forward() ? (Node*)_node->next() : (Node*)_node->prev(); |
| return temp; |
| } |
| |
| void set_direction(Direction direction) { |
| _direction = direction; |
| } |
| |
| void reset(Direction direction) { |
| set_direction(direction); |
| _node = direction_forward() ? _list.head() : _list.tail(); |
| } |
| |
| private: |
| List& _list; |
| mutable Node* _node; |
| Direction _direction; |
| }; |
| |
| template <typename List> |
| class NavigatorStopOnNull : public Navigator<List, StopOnNullCondition> { |
| public: |
| NavigatorStopOnNull(List& list, jfr_iter_direction direction = forward) : Navigator<List, StopOnNullCondition>(list, direction) {} |
| }; |
| |
| template<typename List, template <typename> class Navigator, typename AP = StackObj> |
| class IteratorHost : public AP { |
| private: |
| Navigator<List> _navigator; |
| |
| public: |
| typedef typename List::Node Node; |
| typedef jfr_iter_direction Direction; |
| IteratorHost(List& list, Direction direction = forward) : AP(), _navigator(list, direction) {} |
| void reset(Direction direction = forward) { _navigator.reset(direction); } |
| bool has_next() const { return _navigator.has_next(); } |
| Node* next() const { return _navigator.next(); } |
| void set_direction(Direction direction) { _navigator.set_direction(direction); } |
| }; |
| |
| template<typename List, typename AP = StackObj> |
| class StopOnNullIterator : public IteratorHost<List, NavigatorStopOnNull, AP> { |
| public: |
| StopOnNullIterator(List& list, jfr_iter_direction direction = forward) : IteratorHost<List, NavigatorStopOnNull, AP>(list, direction) {} |
| }; |
| |
| #endif // SHARE_VM_JFR_UTILITIES_JFRLISTITERATOR_HPP |