/*

 * Copyright (C) 2005 Frerich Raabe <raabe@kde.org>

 * Copyright (C) 2006, 2009 Apple Inc.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#ifndef XPathStep_h

#define XPathStep_h

#if ENABLE(XPATH)

#include "Node.h"

#include "XPathExpressionNode.h"

#include "XPathNodeSet.h"

namespace WebCore {

    namespace XPath {

        class Predicate;

        class Step : public ParseNode, public Noncopyable {

        public:

            enum Axis {

                AncestorAxis, AncestorOrSelfAxis, AttributeAxis,

                ChildAxis, DescendantAxis, DescendantOrSelfAxis,

                FollowingAxis, FollowingSiblingAxis, NamespaceAxis,

                ParentAxis, PrecedingAxis, PrecedingSiblingAxis,

                SelfAxis

            };

            class NodeTest : public FastAllocBase {

            public:

                enum Kind {

                    TextNodeTest, CommentNodeTest, ProcessingInstructionNodeTest, AnyNodeTest, NameTest

                };

                NodeTest(Kind kind) : m_kind(kind) {}

                NodeTest(Kind kind, const String& data) : m_kind(kind), m_data(data) {}

                NodeTest(Kind kind, const String& data, const String& namespaceURI) : m_kind(kind), m_data(data), m_namespaceURI(namespaceURI) {}

                Kind kind() const { return m_kind; }

                const AtomicString& data() const { return m_data; }

                const AtomicString& namespaceURI() const { return m_namespaceURI; }

                Vector<Predicate*>& mergedPredicates() { return m_mergedPredicates; }

                const Vector<Predicate*>& mergedPredicates() const { return m_mergedPredicates; }

            private:

                Kind m_kind;

                AtomicString m_data;

                AtomicString m_namespaceURI;

                // When possible, we merge some or all predicates with node test for better performance.

                Vector<Predicate*> m_mergedPredicates;

            };

            Step(Axis, const NodeTest& nodeTest, const Vector<Predicate*>& predicates = Vector<Predicate*>());

            ~Step();

            void optimize();

            void evaluate(Node* context, NodeSet&) const;

            Axis axis() const { return m_axis; }

            const NodeTest& nodeTest() const { return m_nodeTest; }

        private:

            friend void optimizeStepPair(Step*, Step*, bool&);

            bool predicatesAreContextListInsensitive() const;

            void parseNodeTest(const String&);

            void nodesInAxis(Node* context, NodeSet&) const;

            String namespaceFromNodetest(const String& nodeTest) const;

            Axis m_axis;

            NodeTest m_nodeTest;

            Vector<Predicate*> m_predicates;

        };

        void optimizeStepPair(Step*, Step*, bool& dropSecondStep);

    }

}

#endif // ENABLE(XPATH)

#endif // XPathStep_h