Source/WebCore/xml/XPathExpressionNode.h

/*
 * 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 XPathExpressionNode_h
#define XPathExpressionNode_h

#include "Node.h"
#include "XPathValue.h"
#include <wtf/HashMap.h>
#include <wtf/Vector.h>
#include <wtf/text/StringHash.h>

namespace WebCore {

    namespace XPath {
        
        struct EvaluationContext {
            WTF_MAKE_FAST_ALLOCATED;
        public:
            RefPtr<Node> node;
            unsigned long size;
            unsigned long position;
            HashMap<String, String> variableBindings;

            bool hadTypeConversionError;
        };

        class ParseNode {
        public:
            virtual ~ParseNode() { }
        };

        class Expression : public ParseNode {
            WTF_MAKE_NONCOPYABLE(Expression); WTF_MAKE_FAST_ALLOCATED;
        public:
            static EvaluationContext& evaluationContext();

            Expression();
            virtual ~Expression();

            virtual Value evaluate() const = 0;

            void addSubExpression(Expression* expr)
            {
                m_subExpressions.append(expr);
                m_isContextNodeSensitive |= expr->m_isContextNodeSensitive;
                m_isContextPositionSensitive |= expr->m_isContextPositionSensitive;
                m_isContextSizeSensitive |= expr->m_isContextSizeSensitive;
            }

            bool isContextNodeSensitive() const { return m_isContextNodeSensitive; }
            bool isContextPositionSensitive() const { return m_isContextPositionSensitive; }
            bool isContextSizeSensitive() const { return m_isContextSizeSensitive; }
            void setIsContextNodeSensitive(bool value) { m_isContextNodeSensitive = value; }
            void setIsContextPositionSensitive(bool value) { m_isContextPositionSensitive = value; }
            void setIsContextSizeSensitive(bool value) { m_isContextSizeSensitive = value; }

            virtual Value::Type resultType() const = 0;

        protected:
            unsigned subExprCount() const { return m_subExpressions.size(); }
            Expression* subExpr(unsigned i) { return m_subExpressions[i]; }
            const Expression* subExpr(unsigned i) const { return m_subExpressions[i]; }

        private:
            Vector<Expression*> m_subExpressions;

            // Evaluation details that can be used for optimization.
            bool m_isContextNodeSensitive;
            bool m_isContextPositionSensitive;
            bool m_isContextSizeSensitive;
        };

    }

}

#endif // EXPRESSION_H