/*
 * 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.
 */

#pragma once

#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* subexpression(unsigned i) { return m_subExpressions[i]; }
		const Expression* subexpression(unsigned i) const { return m_subExpressions[i]; }

		Expression* subExpr(unsigned i) { return subexpression(i); }
		const Expression* subExpr(unsigned i) const { return subexpression(i); }

	private:
		Vector<Expression*> m_subExpressions;

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

}

}
