// 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 functions

//

#include "xmlengdomdefs.h" 

#include <xml/dom/xmlengxpathevaluator.h>

#include <xml/dom/xmlengxpathextensionfunction.h>

#include <stdapis/libxml2/libxml2_xpath.h>

#include <stdapis/libxml2/libxml2_globals.h>

#include <xml/dom/xmlengxpatherrors.h>

#include <xml/dom/xmlengnode.h>

#include <xml/utils/xmlengmem.h>

#include <xml/utils/xmlengxestrings.h>

// Default constructor

// --------------------------------------------------------------------------------------------

//

EXPORT_C TXmlEngXPathEvaluator::TXmlEngXPathEvaluator() : iInstanceTrees(NULL) 

	{

	}

// --------------------------------------------------------------------------------------------

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

//

// @param[in] aExpression The expression as a string.

// @param[in] aResolver An object that can resolve of namespace prefixes into namespace URIs

// @return Compiled XPath expression.

// 

// May leave with KErrXPath code

// --------------------------------------------------------------------------------------------

//

EXPORT_C RXmlEngXPathExpression TXmlEngXPathEvaluator::CreateExpressionL(

    const TDesC8& aExpression, 

    const MXmlEngNamespaceResolver* /* aResolver */)

    {

    xmlChar* exp = xmlCharFromDesC8L(aExpression);

    xmlXPathCompExprPtr cExpr = xmlXPathCtxtCompile(NULL, exp);

    delete exp;

    if(xmlOOMFlag())

        {

        xmlXPathFreeCompExpr(cExpr);

        OOM_HAPPENED;

        }

    if(!cExpr)

        {

        XmlEngLeaveL(KXmlEngErrXPathSyntax);

        }

    return RXmlEngXPathExpression(cExpr, iInstanceTrees);

    }

// --------------------------------------------------------------------------------------------

// Evaluates the XPath expression given as parameter. The result is returned.

//

// @param[in] aExpression The expression as a string.

// @param[in] aContextNode The node relative to which the expression is evaluated. 

// @param[in] aResolver (for future use) 

// @return Result of evaluation as an RXmlEngXPathResult object.

// May leave with KXmlEngErrXPathSyntax code for invalid XPathExpression and KXmlEngErrXPathResult 

// for undefined result of evaluation.

// --------------------------------------------------------------------------------------------

//

EXPORT_C RXmlEngXPathResult TXmlEngXPathEvaluator::EvaluateL(

    const TDesC8& aExpression, 

    const TXmlEngNode aContextNode, 

    const MXmlEngNamespaceResolver* /* aResolver */ )

    {

    RXmlEngXPathExpression expr = CreateExpressionL(aExpression, NULL);

    CleanupClosePushL(expr);

    RXmlEngXPathResult result = expr.EvaluateL(aContextNode);

    CleanupStack::PopAndDestroy(&expr);

    return result;

    }

// --------------------------------------------------------------------------------------------

// Does the same as #evaluate, but as a side-effect calculates the dependency list of the 

// expression. This is meant to be used by the XForms engine.

//

// @param[in] aExpression The expression as a string.

// @param[in] aContextNode The node relative to which the expression is evaluated. 

// @param[in] aResolver (for future use) 

// @param[in,out] aDependents After the method has returned, contains set of nodes that 

// the expression is dependent on.

// @return Result of evaluation as an RXmlEngXPathResult object.

// 

// May leave with KXmlEngErrXPathResult or KXmlEngErrXPathSyntax codes.

// --------------------------------------------------------------------------------------------

//

EXPORT_C RXmlEngXPathResult TXmlEngXPathEvaluator::EvaluateWithDependenciesL(

    const TDesC8& aExpression, 

    const TXmlEngNode aContextNode, 

    const MXmlEngNamespaceResolver* /* aResolver */,

    RXmlEngNodeSet& aDependents )

    {

    RXmlEngXPathExpression expr = CreateExpressionL(aExpression, NULL);

    CleanupClosePushL(expr);

    RXmlEngXPathResult result = expr.EvaluateWithDependenciesL(aContextNode, aDependents);

    CleanupStack::PopAndDestroy(&expr);

    return result;

    }

// --------------------------------------------------------------------------------------------

// Registers the instance map to be used when evaluating XForms 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. 

// Method does not take owership, caller has to free the map.

//

// @param[in] aInstanceTrees The instance map.

// --------------------------------------------------------------------------------------------

//

EXPORT_C void TXmlEngXPathEvaluator::SetInstanceMap(

    CXmlEngXFormsInstanceMap* aInstanceTrees )

    {

    iInstanceTrees = aInstanceTrees;

    }

// -----------------------------------------------------------------------------

// Returns the registered instance map.

// @return pointer instance map or NULL if not registered.

// -----------------------------------------------------------------------------

//

EXPORT_C CXmlEngXFormsInstanceMap* TXmlEngXPathEvaluator::InstanceMap()

    {

    return iInstanceTrees;

    }