third_party/WebKit/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.
 *
 * 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/XSLStyleSheet.h"

#include "core/dom/Document.h"
#include "core/dom/Node.h"
#include "core/dom/TransformSource.h"
#include "core/frame/FrameHost.h"
#include "core/frame/LocalFrame.h"
#include "core/xml/XSLImportRule.h"
#include "core/xml/XSLTProcessor.h"
#include "core/xml/parser/XMLDocumentParserScope.h"
#include "core/xml/parser/XMLParserInput.h"
#include "wtf/text/CString.h"
#include <libxml/uri.h>
#include <libxslt/xsltutils.h>

namespace blink {

XSLStyleSheet::XSLStyleSheet(XSLImportRule* parentRule,
                             const String& originalURL,
                             const KURL& finalURL)
    : m_ownerNode(nullptr),
      m_originalURL(originalURL),
      m_finalURL(finalURL),
      m_isDisabled(false),
      m_embedded(false),
      // Child sheets get marked as processed when the libxslt engine has
      // finally seen them.
      m_processed(false),
      m_stylesheetDoc(0),
      m_stylesheetDocTaken(false),
      m_compilationFailed(false),
      m_parentStyleSheet(parentRule ? parentRule->parentStyleSheet() : 0),
      m_ownerDocument(nullptr) {}

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(nullptr),
      m_ownerDocument(nullptr) {}

XSLStyleSheet::XSLStyleSheet(Document* ownerDocument,
                             Node* styleSheetRootNode,
                             const String& originalURL,
                             const KURL& finalURL,
                             bool embedded)
    : m_ownerNode(styleSheetRootNode),
      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(nullptr),
      m_ownerDocument(ownerDocument) {}

XSLStyleSheet::~XSLStyleSheet() {
  if (!m_stylesheetDocTaken)
    xmlFreeDoc(m_stylesheetDoc);
}

bool XSLStyleSheet::isLoading() const {
  for (unsigned i = 0; i < m_children.size(); ++i) {
    if (m_children.at(i)->isLoading())
      return true;
  }
  return false;
}

void XSLStyleSheet::checkLoaded() {
  if (isLoading())
    return;
  if (XSLStyleSheet* styleSheet = parentStyleSheet())
    styleSheet->checkLoaded();
  if (ownerNode())
    ownerNode()->sheetLoaded();
}

xmlDocPtr XSLStyleSheet::document() {
  if (m_embedded && ownerDocument() && ownerDocument()->transformSource())
    return (xmlDocPtr)ownerDocument()->transformSource()->platformSource();
  return m_stylesheetDoc;
}

void XSLStyleSheet::clearDocuments() {
  m_stylesheetDoc = 0;
  for (unsigned i = 0; i < m_children.size(); ++i) {
    XSLImportRule* import = m_children.at(i).get();
    if (import->styleSheet())
      import->styleSheet()->clearDocuments();
  }
}

bool XSLStyleSheet::parseString(const String& source) {
  // Parse in a single chunk into an xmlDocPtr
  if (!m_stylesheetDocTaken)
    xmlFreeDoc(m_stylesheetDoc);
  m_stylesheetDocTaken = false;

  FrameConsole* console = nullptr;
  if (LocalFrame* frame = ownerDocument()->frame())
    console = &frame->console();

  XMLDocumentParserScope scope(ownerDocument(), XSLTProcessor::genericErrorFunc,
                               XSLTProcessor::parseErrorFunc, console);
  XMLParserInput input(source);

  xmlParserCtxtPtr ctxt = xmlCreateMemoryParserCtxt(input.data(), input.size());
  if (!ctxt)
    return 0;

  if (m_parentStyleSheet) {
    // The XSL transform may leave the newly-transformed document
    // with references to the symbol dictionaries of the style sheet
    // and any of its children. XML document disposal can corrupt memory
    // if a document uses more than one symbol dictionary, so we
    // ensure that all child stylesheets use the same dictionaries as their
    // parents.
    xmlDictFree(ctxt->dict);
    ctxt->dict = m_parentStyleSheet->m_stylesheetDoc->dict;
    xmlDictReference(ctxt->dict);
  }

  m_stylesheetDoc = xmlCtxtReadMemory(
      ctxt, input.data(), input.size(), finalURL().getString().utf8().data(),
      input.encoding(), XML_PARSE_NOENT | XML_PARSE_DTDATTR |
                            XML_PARSE_NOWARNING | XML_PARSE_NOCDATA);

  xmlFreeParserCtxt(ctxt);
  loadChildSheets();
  return m_stylesheetDoc;
}

void XSLStyleSheet::loadChildSheets() {
  if (!document())
    return;

  xmlNodePtr stylesheetRoot = document()->children;

  // Top level children may include other things such as DTD nodes, we ignore
  // those.
  while (stylesheetRoot && stylesheetRoot->type != XML_ELEMENT_NODE)
    stylesheetRoot = stylesheetRoot->next;

  if (m_embedded) {
    // We have to locate (by ID) the appropriate embedded stylesheet
    // element, so that we can walk the import/include list.
    xmlAttrPtr idNode = xmlGetID(
        document(), (const xmlChar*)(finalURL().getString().utf8().data()));
    if (!idNode)
      return;
    stylesheetRoot = idNode->parent;
  } else {
    // FIXME: Need to handle an external URI with a # in it. This is a
    // pretty minor edge case, so we'll deal with it later.
  }

  if (stylesheetRoot) {
    // Walk the children of the root element and look for import/include
    // elements. Imports must occur first.
    xmlNodePtr curr = stylesheetRoot->children;
    while (curr) {
      if (curr->type != XML_ELEMENT_NODE) {
        curr = curr->next;
        continue;
      }
      if (IS_XSLT_ELEM(curr) && IS_XSLT_NAME(curr, "import")) {
        xmlChar* uriRef =
            xsltGetNsProp(curr, (const xmlChar*)"href", XSLT_NAMESPACE);
        loadChildSheet(String::fromUTF8((const char*)uriRef));
        xmlFree(uriRef);
      } else {
        break;
      }
      curr = curr->next;
    }

    // Now handle includes.
    while (curr) {
      if (curr->type == XML_ELEMENT_NODE && IS_XSLT_ELEM(curr) &&
          IS_XSLT_NAME(curr, "include")) {
        xmlChar* uriRef =
            xsltGetNsProp(curr, (const xmlChar*)"href", XSLT_NAMESPACE);
        loadChildSheet(String::fromUTF8((const char*)uriRef));
        xmlFree(uriRef);
      }
      curr = curr->next;
    }
  }
}

void XSLStyleSheet::loadChildSheet(const String& href) {
  XSLImportRule* childRule = XSLImportRule::create(this, href);
  m_children.append(childRule);
  childRule->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.
  DCHECK(!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() {
  for (XSLStyleSheet* styleSheet = this; styleSheet;
       styleSheet = styleSheet->parentStyleSheet()) {
    if (styleSheet->m_ownerDocument)
      return styleSheet->m_ownerDocument.get();
    Node* node = styleSheet->ownerNode();
    if (node)
      return &node->document();
  }
  return nullptr;
}

xmlDocPtr XSLStyleSheet::locateStylesheetSubResource(xmlDocPtr parentDoc,
                                                     const xmlChar* uri) {
  bool matchedParent = (parentDoc == document());
  for (unsigned i = 0; i < m_children.size(); ++i) {
    XSLImportRule* import = m_children.at(i).get();
    XSLStyleSheet* child = import->styleSheet();
    if (!child)
      continue;
    if (matchedParent) {
      if (child->processed())
        continue;  // libxslt has been given this sheet already.

      // Check the URI of the child stylesheet against the doc URI.
      // In order to ensure that libxml canonicalized both URLs, we get
      // the original href string from the import rule and canonicalize it
      // using libxml before comparing it with the URI argument.
      CString importHref = import->href().utf8();
      xmlChar* base = xmlNodeGetBase(parentDoc, (xmlNodePtr)parentDoc);
      xmlChar* childURI = xmlBuildURI((const xmlChar*)importHref.data(), base);
      bool equalURIs = xmlStrEqual(uri, childURI);
      xmlFree(base);
      xmlFree(childURI);
      if (equalURIs) {
        child->markAsProcessed();
        return child->document();
      }
      continue;
    }
    xmlDocPtr result =
        import->styleSheet()->locateStylesheetSubResource(parentDoc, uri);
    if (result)
      return result;
  }

  return 0;
}

void XSLStyleSheet::markAsProcessed() {
  DCHECK(!m_processed);
  DCHECK(!m_stylesheetDocTaken);
  m_processed = true;
  m_stylesheetDocTaken = true;
}

DEFINE_TRACE(XSLStyleSheet) {
  visitor->trace(m_ownerNode);
  visitor->trace(m_children);
  visitor->trace(m_parentStyleSheet);
  visitor->trace(m_ownerDocument);
  StyleSheet::trace(visitor);
}

}  // namespace blink