gecko-dev/toolkit/components/feeds/nsScriptableUnescapeHTML.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
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 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is Robert Sayre.
 * Portions created by the Initial Developer are Copyright (C) 2006
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
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#include "nsString.h"
#include "nsIComponentManager.h"
#include "nsCOMPtr.h"
#include "nsXPCOM.h"
#include "nsISupportsPrimitives.h"
#include "nsXPIDLString.h"
#include "nsScriptLoader.h"
#include "nsEscape.h"
#include "nsIParser.h"
#include "nsIDTD.h"
#include "nsNetCID.h"
#include "nsNetUtil.h"
#include "nsParserCIID.h"
#include "nsParserCIID.h"
#include "nsIContentSink.h"
#include "nsIHTMLToTextSink.h"
#include "nsIDocumentEncoder.h"
#include "nsIDOMDocumentFragment.h"
#include "nsIFragmentContentSink.h"
#include "nsIDOMDocument.h"
#include "nsIDOMNodeList.h"
#include "nsIDOMNode.h"
#include "nsIDOMElement.h"
#include "nsIDocument.h"
#include "nsIContent.h"
#include "nsAttrName.h"
#include "nsHTMLParts.h"
#include "nsContentCID.h"
#include "nsIScriptableUnescapeHTML.h"
#include "nsScriptableUnescapeHTML.h"
#include "nsAutoPtr.h"

#define XHTML_DIV_TAG "div xmlns=\"http://www.w3.org/1999/xhtml\""
#define HTML_BODY_TAG "BODY"
#define HTML_BASE_TAG "BASE"

NS_IMPL_ISUPPORTS1(nsScriptableUnescapeHTML, nsIScriptableUnescapeHTML)

static NS_DEFINE_CID(kCParserCID, NS_PARSER_CID);

// From /widget/HTMLConverter
//
// Takes HTML and converts it to plain text but in unicode.
//
NS_IMETHODIMP
nsScriptableUnescapeHTML::Unescape(const nsAString & aFromStr, 
                                   nsAString & aToStr)
{
  // create the parser to do the conversion.
  aToStr.SetLength(0);
  nsresult rv;
  nsCOMPtr<nsIParser> parser = do_CreateInstance(kCParserCID, &rv);
  if (NS_FAILED(rv)) return rv;

  // convert it!
  nsCOMPtr<nsIContentSink> sink;

  sink = do_CreateInstance(NS_PLAINTEXTSINK_CONTRACTID);
  NS_ENSURE_TRUE(sink, NS_ERROR_FAILURE);

  nsCOMPtr<nsIHTMLToTextSink> textSink(do_QueryInterface(sink));
  NS_ENSURE_TRUE(textSink, NS_ERROR_FAILURE);

  textSink->Initialize(&aToStr, nsIDocumentEncoder::OutputSelectionOnly
                       | nsIDocumentEncoder::OutputAbsoluteLinks, 0);

  parser->SetContentSink(sink);

  parser->Parse(aFromStr, 0, NS_LITERAL_CSTRING("text/html"),
                PR_TRUE, eDTDMode_fragment);
  
  return NS_OK;
}

// The feed version of nsContentUtils::CreateContextualFragment It
// creates a fragment, but doesn't go to all the effort to preserve
// context like innerHTML does, because feed DOMs shouldn't have that.
NS_IMETHODIMP
nsScriptableUnescapeHTML::ParseFragment(const nsAString &aFragment,
                                        PRBool aIsXML,
                                        nsIURI* aBaseURI,
                                        nsIDOMElement* aContextElement,
                                        nsIDOMDocumentFragment** aReturn)
{
  NS_ENSURE_ARG(aContextElement);
  *aReturn = nsnull;

  nsresult rv;
  nsCOMPtr<nsIParser> parser = do_CreateInstance(kCParserCID, &rv);
  NS_ENSURE_SUCCESS(rv, rv);

  nsCOMPtr<nsIDocument> document;
  nsCOMPtr<nsIDOMDocument> domDocument;
  nsCOMPtr<nsIDOMNode> contextNode;
  contextNode = do_QueryInterface(aContextElement);
  contextNode->GetOwnerDocument(getter_AddRefs(domDocument));
  document = do_QueryInterface(domDocument);
  NS_ENSURE_TRUE(document, NS_ERROR_NOT_AVAILABLE);

  // stop scripts
  nsRefPtr<nsScriptLoader> loader;
  PRBool scripts_enabled = PR_FALSE;
  if (document) {
    loader = document->ScriptLoader();
    scripts_enabled = loader->GetEnabled();
  }
  if (scripts_enabled) {
    loader->SetEnabled(PR_FALSE);
  }

  // Wrap things in a div or body for parsing, but it won't show up in
  // the fragment.
  nsAutoTArray<nsString, 2> tagStack;
  nsCAutoString base, spec;
  if (aIsXML) {
    // XHTML
    if (aBaseURI) {
      base.Append(NS_LITERAL_CSTRING(XHTML_DIV_TAG));
      base.Append(NS_LITERAL_CSTRING(" xml:base=\""));
      aBaseURI->GetSpec(spec);
      // nsEscapeHTML is good enough, because we only need to get
      // quotes, ampersands, and angle brackets
      char* escapedSpec = nsEscapeHTML(spec.get());
      if (escapedSpec)
        base += escapedSpec;
      NS_Free(escapedSpec);
      base.Append(NS_LITERAL_CSTRING("\""));
      tagStack.AppendElement(NS_ConvertUTF8toUTF16(base));
    }  else {
      tagStack.AppendElement(NS_LITERAL_STRING(XHTML_DIV_TAG));
    }
  } else {
    // HTML
    tagStack.AppendElement(NS_LITERAL_STRING(HTML_BODY_TAG));
    if (aBaseURI) {
      base.Append(NS_LITERAL_CSTRING((HTML_BASE_TAG)));
      base.Append(NS_LITERAL_CSTRING(" href=\""));
      aBaseURI->GetSpec(spec);
      base = base + spec;
      base.Append(NS_LITERAL_CSTRING("\""));
      tagStack.AppendElement(NS_ConvertUTF8toUTF16(base));
    }
  }

  if (NS_SUCCEEDED(rv)) {
    nsCAutoString contentType;
    nsDTDMode mode;
    nsCOMPtr<nsIFragmentContentSink> sink;
    if (aIsXML) {
      mode = eDTDMode_full_standards;
      contentType = NS_LITERAL_CSTRING("application/xhtml+xml");
      sink = do_CreateInstance(NS_XHTMLPARANOIDFRAGMENTSINK_CONTRACTID);
    } else {
      mode = eDTDMode_fragment;
      contentType = NS_LITERAL_CSTRING("text/html");
      sink = do_CreateInstance(NS_HTMLPARANOIDFRAGMENTSINK_CONTRACTID);
    }
    if (sink) {
      sink->SetTargetDocument(document);
      nsCOMPtr<nsIContentSink> contentsink(do_QueryInterface(sink));
      parser->SetContentSink(contentsink);
      rv = parser->ParseFragment(aFragment, nsnull, tagStack,
                                 aIsXML, contentType, mode);
      if (NS_SUCCEEDED(rv))
        rv = sink->GetFragment(PR_TRUE, aReturn);

    } else {
      rv = NS_ERROR_FAILURE;
    }
  }

  if (scripts_enabled)
      loader->SetEnabled(PR_TRUE);
  
  return rv;
}