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      1 /*
      2  * Copyright (C) 2005 Frerich Raabe <raabe (at) kde.org>
      3  * Copyright (C) 2006, 2009 Apple Inc. All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  *
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     25  */
     26 
     27 #include "config.h"
     28 #include "XPathExpression.h"
     29 
     30 #if ENABLE(XPATH)
     31 
     32 #include "Document.h"
     33 #include "PlatformString.h"
     34 #include "XPathException.h"
     35 #include "XPathExpressionNode.h"
     36 #include "XPathNSResolver.h"
     37 #include "XPathParser.h"
     38 #include "XPathResult.h"
     39 #include "XPathUtil.h"
     40 
     41 namespace WebCore {
     42 
     43 using namespace XPath;
     44 
     45 PassRefPtr<XPathExpression> XPathExpression::createExpression(const String& expression, XPathNSResolver* resolver, ExceptionCode& ec)
     46 {
     47     RefPtr<XPathExpression> expr = XPathExpression::create();
     48     Parser parser;
     49 
     50     expr->m_topExpression = parser.parseStatement(expression, resolver, ec);
     51     if (!expr->m_topExpression)
     52         return 0;
     53 
     54     return expr.release();
     55 }
     56 
     57 XPathExpression::~XPathExpression()
     58 {
     59     delete m_topExpression;
     60 }
     61 
     62 PassRefPtr<XPathResult> XPathExpression::evaluate(Node* contextNode, unsigned short type, XPathResult*, ExceptionCode& ec)
     63 {
     64     if (!isValidContextNode(contextNode)) {
     65         ec = NOT_SUPPORTED_ERR;
     66         return 0;
     67     }
     68 
     69     EvaluationContext& evaluationContext = Expression::evaluationContext();
     70     evaluationContext.node = contextNode;
     71     evaluationContext.size = 1;
     72     evaluationContext.position = 1;
     73     evaluationContext.hadTypeConversionError = false;
     74     RefPtr<XPathResult> result = XPathResult::create(contextNode->document(), m_topExpression->evaluate());
     75     evaluationContext.node = 0; // Do not hold a reference to the context node, as this may prevent the whole document from being destroyed in time.
     76 
     77     if (evaluationContext.hadTypeConversionError) {
     78         // It is not specified what to do if type conversion fails while evaluating an expression, and INVALID_EXPRESSION_ERR is not exactly right
     79         // when the failure happens in an otherwise valid expression because of a variable. But XPathEvaluator does not support variables, so it's close enough.
     80         ec = XPathException::INVALID_EXPRESSION_ERR;
     81         return 0;
     82     }
     83 
     84     if (type != XPathResult::ANY_TYPE) {
     85         ec = 0;
     86         result->convertTo(type, ec);
     87         if (ec)
     88             return 0;
     89     }
     90 
     91     return result;
     92 }
     93 
     94 }
     95 
     96 #endif // ENABLE(XPATH)
     97