// 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 evaluator declaration

 //

 /**

  @file

  @publishedAll

  @released

 */

 #ifndef XMLENGXPATHEVALUATOR_H

 #define XMLENGXPATHEVALUATOR_H

 #include <xml/dom/xmlengxpathexpression.h>

 #include <xml/dom/xmlengxformsinstancemap.h>

 #include <xml/dom/xmlengnamespaceresolver.h>

 class MXmlEngXPathExtensionFunction;

 class MXmlEngNamespaceResolver;

 /**

 Evaluates XPath expressions on a DOM tree.

 See the XPath specfication here:

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

 */

 class TXmlEngXPathEvaluator

 {

 public:

     /** Default constructor */

     IMPORT_C TXmlEngXPathEvaluator();

 	// XPath 1.0 methods

     /**

     Precompiles and stores an XPath expression, which is returned to caller.

 	Information on how to write XPath expressions can be found here:

 	@see http://en.wikipedia.org/wiki/XPath

     @param aExpression The expression to create

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

     @return The compiled XPath expression.

 	@leave KXmlEngErrXPathSyntax Error compiling expression

 	@leave KErrNoMemory Memory allocation error

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

     */

     IMPORT_C RXmlEngXPathExpression CreateExpressionL(const TDesC8& aExpression,

                                    const MXmlEngNamespaceResolver* aResolver = NULL);

     /**

     Evaluates the XPath expression given as a parameter and returns the result.

     @param aExpression The expression to evaluate

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

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

     @return The result of the 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(const TDesC8& aExpression,

                                    const TXmlEngNode aContextNode,

                                    const MXmlEngNamespaceResolver* aResolver = NULL);

 	// Extensions to XPath 1.0

 	/**

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

 	of the expression.

     @param aExpression The expression to evaluate

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

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

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

     the expression is dependent on.

     @return The 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(const TDesC8& aExpression,

                                    const TXmlEngNode aContextNode,

                                    const MXmlEngNamespaceResolver* aResolver,

                                    RXmlEngNodeSet& aDependents);

     /**

     Registers the instance map to be used when evaluating form expressions. The map 

     contains DOM Documents and their names. For example, when evaluating the expression 

     "instance('a')" the evaluator looks up a document that has the name "a" from the map. 

     @param aInstanceTrees The instance map, ownership is not transferred.

     */

     IMPORT_C void SetInstanceMap(CXmlEngXFormsInstanceMap* aInstanceTrees);

     /**

     Returns the registered instance map.  Ownership is not transferred.

     @return A pointer to the instance map or NULL if not registered.

     */

     IMPORT_C CXmlEngXFormsInstanceMap* InstanceMap();

 private:

     CXmlEngXFormsInstanceMap* iInstanceTrees;

 };

 #endif /* XMLENGXPATHEVALUATOR_H */