Disable various unused libxml features: catalogs, DocBook, legacy APIs, etc.

third_party/WebKit/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
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "core/xml/parser/XMLDocumentParser.h"
 
-#include <libxml/catalog.h>
 #include <libxml/parser.h>
 #include <libxml/parserInternals.h>
 #include <libxslt/xslt.h>
 #include <memory>
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptController.h"
 #include "bindings/core/v8/ScriptSourceCode.h"
 #include "core/HTMLNames.h"
 #include "core/XMLNSNames.h"
 #include "core/dom/CDATASection.h"
@@ skipping 525 matching lines @@
 }
 
 static void finishParsing(xmlParserCtxtPtr ctxt) {
   xmlParseChunk(ctxt, 0, 0, 1);
 }
 
 #define xmlParseChunk \
   #error "Use parseChunk instead to select the correct encoding."
 
 static bool isLibxmlDefaultCatalogFile(const String& urlString) {
-  // On non-Windows platforms libxml asks for this URL, the
-  // "XML_XML_DEFAULT_CATALOG", on initialization.
+  // On non-Windows platforms libxml with catalogs enabled asks for
+  // this URL, the "XML_XML_DEFAULT_CATALOG", on initialization.
   if (urlString == "file:///etc/xml/catalog")
     return true;
 
-  // On Windows, libxml computes a URL relative to where its DLL resides.
+  // On Windows, libxml with catalogs enabled computes a URL relative
+  // to where its DLL resides.
   if (urlString.startsWith("file:///", TextCaseASCIIInsensitive) &&
       urlString.endsWith("/etc/catalog", TextCaseASCIIInsensitive))
     return true;
   return false;
 }
 
 static bool shouldAllowExternalLoad(const KURL& url) {
   String urlString = url.getString();
 
-  // This isn't really necessary now that initializeLibXMLIfNecessary
-  // disables catalog support in libxml, but keeping it for defense in depth.
-  if (isLibxmlDefaultCatalogFile(url))
-    return false;
+  // libxml should not be configured with catalogs enabled, so it
+  // should not be asking to load default catalogs.
+  CHECK(!isLibxmlDefaultCatalogFile(url));
 
   // The most common DTD. There isn't much point in hammering www.w3c.org by
   // requesting this URL for every XHTML document.
   if (urlString.startsWith("http://www.w3.org/TR/xhtml",
                            TextCaseASCIIInsensitive))
     return false;
 
   // Similarly, there isn't much point in requesting the SVG DTD.
   if (urlString.startsWith("http://www.w3.org/Graphics/SVG",
                            TextCaseASCIIInsensitive))
@@ skipping 86 matching lines @@
 
 static void errorFunc(void*, const char*, ...) {
   // FIXME: It would be nice to display error messages somewhere.
 }
 
 static void initializeLibXMLIfNecessary() {
   static bool didInit = false;
   if (didInit)
     return;
 
-  // We don't want libxml to try and load catalogs.
-  // FIXME: It's not nice to set global settings in libxml, embedders of Blink
-  // could be trying to use libxml themselves.
-  xmlCatalogSetDefaults(XML_CATA_ALLOW_NONE);
   xmlInitParser();
   xmlRegisterInputCallbacks(matchFunc, openFunc, readFunc, closeFunc);
   xmlRegisterOutputCallbacks(matchFunc, openFunc, writeFunc, closeFunc);
   libxmlLoaderThread = currentThread();
   didInit = true;
 }
 
 PassRefPtr<XMLParserContext> XMLParserContext::createStringParser(
     xmlSAXHandlerPtr handlers,
     void* userData) {
@@ skipping 1002 matching lines @@
   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