// Copyright (c) 2005-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

// XPath expression declaration

//

/**

 @file

 @publishedAll

 @released

*/

#ifndef XMLENGXPATHEXPRESSION_H

#define XMLENGXPATHEXPRESSION_H

#include <xml/dom/xmlengxpathresult.h>

#include <xml/dom/xmlengnamespaceresolver.h>

class TXmlEngNode;

/**

A compiled XPath expression is a textual expression transformed after

syntactical analysis into some internal representation of the expression.  The

only missing element for evaluation of the expression is evaluation context:

the context node (where to start) and an optional set of prefix-to-namespace bindings.

XPath Expressions are created and instantiated by the Evaluator:

@see TXmlEngXPathEvaluator

See the XPath spec here:

http://www.w3.org/TR/2004/NOTE-DOM-Level-3-XPath-20040226/xpath.html

*/

class RXmlEngXPathExpression

{

    friend class TXmlEngXPathEvaluator;

public:

	/** XPath expression parts */

    enum TXmlEngXPathExpressionPartType

        {

	    EFunction,

        EPrefix

        };

public:

    /** Default constructor */

    IMPORT_C RXmlEngXPathExpression();

	/** Resets the compiled expression and frees the allocated memory */

    IMPORT_C void Destroy();

    /** Resets the compiled expression and frees the allocated memory */

    inline void Close();

	// XPath 1.0 methods

    /**

    Evaluates this expression.

    @param aContextNode The node relative to which the expression is evaluated.

    @param aResolver Not supported in current API.  Reserved for future use.

    @return Result of evaluation

    @leave KXmlEngErrXPathResult Error evaluating expression

	@leave KXmlEngErrXPathSyntax Error compiling expression

	@leave KErrNoMemory Memory allocation error

	@leave - Otherwise, any of the system wide errors.

    */

    IMPORT_C RXmlEngXPathResult EvaluateL(TXmlEngNode aContextNode, 

                                    const MXmlEngNamespaceResolver* aResolver = NULL) const;

	// Extensions to XPath 1.0

	/**

	Does the same thing as EvaluateL(), but also calculates the dependency list

	of the expression.

    @param aContextNode The node relative to which the expression is evaluated.

    @param aDependents After the method has returned, contains set of nodes that

    the expression is dependent on.

    @param aResolver Not supported in current API.  Reserved for future use.

    @return Result of evaluation 

    @leave KXmlEngErrXPathResult Error evaluating expression

	@leave KXmlEngErrXPathSyntax Error compiling expression

	@leave KErrNoMemory Memory allocation error

	@leave - Otherwise, any of the system wide errors.

    */

    IMPORT_C RXmlEngXPathResult EvaluateWithDependenciesL(TXmlEngNode aContextNode, 

                                                    RXmlEngNodeSet& aDependents, 

                                                    const MXmlEngNamespaceResolver* aResolver = NULL) const;

	/**

	Set context data for the expression currently being evaluated.

	Extended Context is data set by API users and available for XPath extension

	functions.  For more information:

	@see RXmlEngXPathExpression

	@param aContext Extended context pointer

    */ 

    IMPORT_C void SetExtendedContext(void* aContext);

	/**

	Gets extended context data for the expression currently being evaluated.	 

	@return Extended context pointer or NULL if not sete

	@see SetExtendedContext

    */ 

    IMPORT_C void* ExtendedContext() const;

private:

    RXmlEngXPathExpression(void* aData, void* aData2);

private:

    void* iInternal;

    void* iInternal2;

    TInt32 reserved1; 

    TAny* reserved2; 

};  

#include <xml/dom/xmlengxpathexpression.inl>

#endif /* XMLENGXPATHEXPRESSION_H */