Insert the error message block when stopping parsing and an error occurred

Source/core/xml/parser/XMLDocumentParser.cpp

 /*
  * Copyright (C) 2000 Peter Kelly (pmk@post.com)
  * Copyright (C) 2005, 2006, 2008, 2014 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2007 Samuel Weinig (sam@webkit.org)
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2008 Holger Hans Peter Freyther
  * Copyright (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 404 matching lines @@
 
     // doEnd() call above can detach the parser and null out its document.
     // In that case, we just bail out.
     if (isDetached())
         return;
 
     // doEnd() could process a script tag, thus pausing parsing.
     if (m_parserPaused)
         return;
 
-    if (m_sawError) {
+    // stopParsing() calls insertErrorMessageBlock() if there was a parsing
+    // error. Avoid showing the error message block twice.
+    if (m_sawError && !isStopped()) {
         insertErrorMessageBlock();

[Erik Dahlström (inactive), 2015/01/14 13:35:41]

Under which circumstances would the parser be stopped when we reach here?

     } else {
         exitText();
         document()->styleResolverChanged();
     }
 
     if (isParsing())
         prepareToStopParsing();
     document()->setReadyState(Document::Interactive);
     clearCurrentNodeStack();
     document()->finishedParsing();
@@ skipping 1088 matching lines @@
 TextPosition XMLDocumentParser::textPosition() const
 {
     xmlParserCtxtPtr context = this->context();
     if (!context)
         return TextPosition::minimumPosition();
     return TextPosition(OrdinalNumber::fromOneBasedInt(context->input->line), OrdinalNumber::fromOneBasedInt(context->input->col));
 }
 
 void XMLDocumentParser::stopParsing()
 {
+    if (!m_parsingFragment && m_sawError && !isStopped())

[Erik Dahlström (inactive), 2015/01/14 13:35:41]

What about (m_parsingFragment && m_sawError && !isStopped())? How is that
handled wrt parsing errors?

+        insertErrorMessageBlock();
     DocumentParser::stopParsing();
     if (context())
         xmlStopParser(context());
 }
 
 void XMLDocumentParser::resumeParsing()
 {
     ASSERT(!isDetached());
     ASSERT(m_parserPaused);
 
@@ skipping 100 matching lines @@
     sax.initialized = XML_SAX2_MAGIC;
     RefPtr<XMLParserContext> parser = XMLParserContext::createStringParser(&sax, &state);
     String parseString = "<?xml version=\"1.0\"?><attrs " + string + " />";
     parseChunk(parser->context(), parseString);
     finishParsing(parser->context());
     attrsOK = state.gotAttributes;
     return state.attributes;
 }
 
 } // namespace blink