gecko-dev/widget/nsHTMLFormatConverter.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsHTMLFormatConverter.h"

#include "nsArray.h"
#include "nsCRT.h"
#include "nsIComponentManager.h"
#include "nsCOMPtr.h"
#include "nsXPCOM.h"
#include "nsISupportsPrimitives.h"

#include "nsITransferable.h" // for mime defs, this is BAD

// HTML convertor stuff
#include "nsPrimitiveHelpers.h"
#include "nsIDocumentEncoder.h"
#include "nsContentUtils.h"

nsHTMLFormatConverter::nsHTMLFormatConverter()
{
}

nsHTMLFormatConverter::~nsHTMLFormatConverter()
{
}

NS_IMPL_ISUPPORTS(nsHTMLFormatConverter, nsIFormatConverter)

//
// GetInputDataFlavors
//
// Creates a new list and returns the list of all the flavors this converter
// knows how to import. In this case, it's just HTML.
//
// Flavors (strings) are wrapped in a primitive object so that JavaScript can
// access them easily via XPConnect.
//
NS_IMETHODIMP
nsHTMLFormatConverter::GetInputDataFlavors(nsIArray **_retval)
{
  if ( !_retval )
    return NS_ERROR_INVALID_ARG;

  nsCOMPtr<nsIMutableArray> array = nsArray::Create();
  nsresult rv = AddFlavorToList ( array, kHTMLMime );

  array.forget(_retval);
  return rv;

} // GetInputDataFlavors


//
// GetOutputDataFlavors
//
// Creates a new list and returns the list of all the flavors this converter
// knows how to export (convert). In this case, it's all sorts of things that HTML can be
// converted to.
//
// Flavors (strings) are wrapped in a primitive object so that JavaScript can
// access them easily via XPConnect.
//
NS_IMETHODIMP
nsHTMLFormatConverter::GetOutputDataFlavors(nsIArray **_retval)
{
  if ( !_retval )
    return NS_ERROR_INVALID_ARG;

  nsCOMPtr<nsIMutableArray> array = nsArray::Create();
  nsresult rv = AddFlavorToList ( array, kHTMLMime );
  if ( NS_FAILED(rv) )
    return rv;
  rv = AddFlavorToList ( array, kUnicodeMime );
  if ( NS_FAILED(rv) )
    return rv;

  array.forget(_retval);
  return rv;

} // GetOutputDataFlavors


//
// AddFlavorToList
//
// Convenience routine for adding a flavor wrapped in an nsISupportsCString object
// to a list
//
nsresult
nsHTMLFormatConverter :: AddFlavorToList ( nsCOMPtr<nsIMutableArray>& inList, const char* inFlavor )
{
  nsresult rv;

  nsCOMPtr<nsISupportsCString> dataFlavor =
      do_CreateInstance(NS_SUPPORTS_CSTRING_CONTRACTID, &rv);
  if ( dataFlavor ) {
    dataFlavor->SetData ( nsDependentCString(inFlavor) );
    // add to list as an nsISupports so the correct interface gets the addref
    // in AppendElement()
    nsCOMPtr<nsISupports> genericFlavor ( do_QueryInterface(dataFlavor) );
    inList->AppendElement ( genericFlavor );
  }
  return rv;

} // AddFlavorToList


//
// CanConvert
//
// Determines if we support the given conversion. Currently, this method only
// converts from HTML to others.
//
NS_IMETHODIMP
nsHTMLFormatConverter::CanConvert(const char *aFromDataFlavor, const char *aToDataFlavor, bool *_retval)
{
  if ( !_retval )
    return NS_ERROR_INVALID_ARG;

  *_retval = false;
  if ( !nsCRT::strcmp(aFromDataFlavor, kHTMLMime) ) {
    if ( !nsCRT::strcmp(aToDataFlavor, kHTMLMime) )
      *_retval = true;
    else if ( !nsCRT::strcmp(aToDataFlavor, kUnicodeMime) )
      *_retval = true;
#if NOT_NOW
// pinkerton
// no one uses this flavor right now, so it's just slowing things down. If anyone cares I
// can put it back in.
    else if ( toFlavor.Equals(kAOLMailMime) )
      *_retval = true;
#endif
  }
  return NS_OK;

} // CanConvert



//
// Convert
//
// Convert data from one flavor to another. The data is wrapped in primitive objects so that it is
// accessible from JS. Currently, this only accepts HTML input, so anything else is invalid.
//
//XXX This method copies the data WAAAAY too many time for my liking. Grrrrrr. Mostly it's because
//XXX we _must_ put things into nsStrings so that the parser will accept it. Lame lame lame lame. We
//XXX also can't just get raw unicode out of the nsString, so we have to allocate heap to get
//XXX unicode out of the string. Lame lame lame.
//
NS_IMETHODIMP
nsHTMLFormatConverter::Convert(const char *aFromDataFlavor, nsISupports *aFromData, uint32_t aDataLen,
                               const char *aToDataFlavor, nsISupports **aToData, uint32_t *aDataToLen)
{
  if ( !aToData || !aDataToLen )
    return NS_ERROR_INVALID_ARG;

  nsresult rv = NS_OK;
  *aToData = nullptr;
  *aDataToLen = 0;

  if ( !nsCRT::strcmp(aFromDataFlavor, kHTMLMime) ) {
    nsAutoCString toFlavor ( aToDataFlavor );

    // HTML on clipboard is going to always be double byte so it will be in a primitive
    // class of nsISupportsString. Also, since the data is in two byte chunks the
    // length represents the length in 1-byte chars, so we need to divide by two.
    nsCOMPtr<nsISupportsString> dataWrapper0 ( do_QueryInterface(aFromData) );
    if (!dataWrapper0) {
      return NS_ERROR_INVALID_ARG;
    }

    nsAutoString dataStr;
    dataWrapper0->GetData ( dataStr );  // COPY #1
    // note: conversion to text/plain is done inside the clipboard. we do not need to worry
    // about it here.
    if ( toFlavor.Equals(kHTMLMime) || toFlavor.Equals(kUnicodeMime) ) {
      nsresult res;
      if (toFlavor.Equals(kHTMLMime)) {
        int32_t dataLen = dataStr.Length() * 2;
        nsPrimitiveHelpers::CreatePrimitiveForData ( toFlavor, dataStr.get(), dataLen, aToData );
        if ( *aToData )
          *aDataToLen = dataLen;
      } else {
        nsAutoString outStr;
        res = ConvertFromHTMLToUnicode(dataStr, outStr);
        if (NS_SUCCEEDED(res)) {
          int32_t dataLen = outStr.Length() * 2;
          nsPrimitiveHelpers::CreatePrimitiveForData ( toFlavor, outStr.get(), dataLen, aToData );
          if ( *aToData )
            *aDataToLen = dataLen;
        }
      }
    } // else if HTML or Unicode
    else if ( toFlavor.Equals(kAOLMailMime) ) {
      nsAutoString outStr;
      if ( NS_SUCCEEDED(ConvertFromHTMLToAOLMail(dataStr, outStr)) ) {
        int32_t dataLen = outStr.Length() * 2;
        nsPrimitiveHelpers::CreatePrimitiveForData ( toFlavor, outStr.get(), dataLen, aToData );
        if ( *aToData )
          *aDataToLen = dataLen;
      }
    } // else if AOL mail
    else {
      rv = NS_ERROR_FAILURE;
    }
  } // if we got html mime
  else
    rv = NS_ERROR_FAILURE;

  return rv;

} // Convert


//
// ConvertFromHTMLToUnicode
//
// Takes HTML and converts it to plain text but in unicode.
//
NS_IMETHODIMP
nsHTMLFormatConverter::ConvertFromHTMLToUnicode(const nsAutoString & aFromStr, nsAutoString & aToStr)
{
  return nsContentUtils::ConvertToPlainText(aFromStr,
    aToStr,
    nsIDocumentEncoder::OutputSelectionOnly |
    nsIDocumentEncoder::OutputAbsoluteLinks |
    nsIDocumentEncoder::OutputNoScriptContent |
    nsIDocumentEncoder::OutputNoFramesContent,
    0);
} // ConvertFromHTMLToUnicode


NS_IMETHODIMP
nsHTMLFormatConverter::ConvertFromHTMLToAOLMail(const nsAutoString & aFromStr,
                                                nsAutoString & aToStr)
{
  aToStr.AssignLiteral("<HTML>");
  aToStr.Append(aFromStr);
  aToStr.AppendLiteral("</HTML>");

  return NS_OK;
}