Avoid reparsing an XSLT stylesheet after the first failure.

Source/core/xml/XSLStyleSheetLibxslt.cpp

 /*
  * This file is part of the XSL implementation.
  *
  * Copyright (C) 2004, 2005, 2006, 2008, 2012 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 29 matching lines @@
 
 XSLStyleSheet::XSLStyleSheet(XSLImportRule* parentRule, const String& originalURL, const KURL& finalURL)
     : m_ownerNode(0)
     , m_originalURL(originalURL)
     , m_finalURL(finalURL)
     , m_isDisabled(false)
     , m_embedded(false)
     , m_processed(false) // Child sheets get marked as processed when the libxslt engine has finally seen them.
     , m_stylesheetDoc(0)
     , m_stylesheetDocTaken(false)
+    , m_compilationFailed(false)
     , m_parentStyleSheet(parentRule ? parentRule->parentStyleSheet() : 0)
 {
 }
 
 XSLStyleSheet::XSLStyleSheet(Node* parentNode, const String& originalURL, const KURL& finalURL,  bool embedded)
     : m_ownerNode(parentNode)
     , m_originalURL(originalURL)
     , m_finalURL(finalURL)
     , m_isDisabled(false)
     , m_embedded(embedded)
     , m_processed(true) // The root sheet starts off processed.
     , m_stylesheetDoc(0)
     , m_stylesheetDocTaken(false)
+    , m_compilationFailed(false)
     , m_parentStyleSheet(0)
 {
 }
 
 XSLStyleSheet::~XSLStyleSheet()
 {
     if (!m_stylesheetDocTaken)
         xmlFreeDoc(m_stylesheetDoc);
 
     for (unsigned i = 0; i < m_children.size(); ++i) {
@@ skipping 146 matching lines @@
     m_children.append(childRule.release());
     c->loadSheet();
 }
 
 xsltStylesheetPtr XSLStyleSheet::compileStyleSheet()
 {
     // FIXME: Hook up error reporting for the stylesheet compilation process.
     if (m_embedded)
         return xsltLoadStylesheetPI(document());
 
+    // Certain libxslt versions are corrupting the xmlDoc on compilation failures -
+    // hence attempting to recompile after a failure is unsafe.
+    if (m_compilationFailed)
+        return 0;
+
     // xsltParseStylesheetDoc makes the document part of the stylesheet
     // so we have to release our pointer to it.
     ASSERT(!m_stylesheetDocTaken);
     xsltStylesheetPtr result = xsltParseStylesheetDoc(m_stylesheetDoc);
     if (result)
         m_stylesheetDocTaken = true;
+    else
+        m_compilationFailed = true;
     return result;
 }
 
 void XSLStyleSheet::setParentStyleSheet(XSLStyleSheet* parent)
 {
     m_parentStyleSheet = parent;
 }
 
 Document* XSLStyleSheet::ownerDocument()
 {
@@ skipping 43 matching lines @@
 
 void XSLStyleSheet::markAsProcessed()
 {
     ASSERT(!m_processed);
     ASSERT(!m_stylesheetDocTaken);
     m_processed = true;
     m_stylesheetDocTaken = true;
 }
 
 } // namespace WebCore