nsresult 
nsLocalMoveCopyMsgTxn::UndoTransactionInternal()
{
  nsresult rv = NS_ERROR_FAILURE;

  if (mUndoFolderListener)
  {
    nsCOMPtr<nsIMsgMailSession> mailSession = 
      do_GetService(NS_MSGMAILSESSION_CONTRACTID, &rv); 
    NS_ENSURE_SUCCESS(rv,rv);
    
    rv = mailSession->RemoveFolderListener(mUndoFolderListener);
    NS_ENSURE_SUCCESS(rv,rv);
    
    NS_RELEASE(mUndoFolderListener);
    mUndoFolderListener = nullptr;
  }

  nsCOMPtr<nsIMsgDatabase> srcDB;
  nsCOMPtr<nsIMsgDatabase> dstDB;
  nsCOMPtr<nsIMsgFolder> srcFolder = do_QueryReferent(m_srcFolder, &rv);
  NS_ENSURE_SUCCESS(rv,rv);
  
  nsCOMPtr<nsIMsgFolder> dstFolder = do_QueryReferent(m_dstFolder, &rv);
  NS_ENSURE_SUCCESS(rv,rv);
  
  rv = srcFolder->GetMsgDatabase(getter_AddRefs(srcDB));
  if(NS_FAILED(rv)) return rv;

  rv = dstFolder->GetMsgDatabase(getter_AddRefs(dstDB));
  if (NS_FAILED(rv)) return rv;

  uint32_t count = m_srcKeyArray.Length();
  uint32_t i;
  nsCOMPtr<nsIMsgDBHdr> oldHdr;
  nsCOMPtr<nsIMsgDBHdr> newHdr;

  // protect against a bogus undo txn without any source keys
  // see bug #179856 for details
  NS_ASSERTION(count, "no source keys");
  if (!count)
    return NS_ERROR_UNEXPECTED;

  if (m_isMove)
  {
    if (m_srcIsImap4)
    {
      bool deleteFlag = true;  //message has been deleted -we are trying to undo it
      CheckForToggleDelete(srcFolder, m_srcKeyArray[0], &deleteFlag); //there could have been a toggle.
      rv = UndoImapDeleteFlag(srcFolder, m_srcKeyArray, deleteFlag);
    }
    else if (m_canUndelete)
    {
      nsCOMPtr<nsIMutableArray> srcMessages =
        do_CreateInstance(NS_ARRAY_CONTRACTID);
      nsCOMPtr<nsIMutableArray> dstMessages =
        do_CreateInstance(NS_ARRAY_CONTRACTID);

      srcDB->StartBatch();
      for (i = 0; i < count; i++)
      {
        rv = dstDB->GetMsgHdrForKey(m_dstKeyArray[i], 
                                    getter_AddRefs(oldHdr));
        NS_ASSERTION(oldHdr, "fatal ... cannot get old msg header\n");
        if (NS_SUCCEEDED(rv) && oldHdr)
        {
          rv = srcDB->CopyHdrFromExistingHdr(m_srcKeyArray[i],
                                             oldHdr, true,
                                             getter_AddRefs(newHdr));
          NS_ASSERTION(newHdr, 
                       "fatal ... cannot create new msg header\n");
          if (NS_SUCCEEDED(rv) && newHdr)
          {
            newHdr->SetStatusOffset(m_srcStatusOffsetArray[i]);
            srcDB->UndoDelete(newHdr);
            srcMessages->AppendElement(newHdr, false);
            // (we want to keep these two lists in sync)
            dstMessages->AppendElement(oldHdr, false);
          }
        }
      }
      srcDB->EndBatch();

      nsCOMPtr<nsIMsgFolderNotificationService>
        notifier(do_GetService(NS_MSGNOTIFICATIONSERVICE_CONTRACTID));
      if (notifier)
      {
        // Remember that we're actually moving things back from the destination
        //  to the source!
        notifier->NotifyMsgsMoveCopyCompleted(true, dstMessages,
                                              srcFolder, srcMessages);
      }

      nsCOMPtr <nsIMsgLocalMailFolder> localFolder = do_QueryInterface(srcFolder);
      if (localFolder)
        localFolder->MarkMsgsOnPop3Server(srcMessages, POP3_NONE /*deleteMsgs*/);
    }
    else // undoing a move means moving the messages back.
    {
      nsCOMPtr<nsIMutableArray> dstMessages =
        do_CreateInstance(NS_ARRAY_CONTRACTID);
      nsCOMPtr<nsIMsgDBHdr> dstHdr;
      m_numHdrsCopied = 0;
      m_srcKeyArray.Clear();
      for (i = 0; i < count; i++)
      {
        dstDB->GetMsgHdrForKey(m_dstKeyArray[i], getter_AddRefs(dstHdr));
        NS_ASSERTION(dstHdr, "fatal ... cannot get old msg header\n");
        if (dstHdr)
        {
          nsCString messageId;
          dstHdr->GetMessageId(getter_Copies(messageId));
          dstMessages->AppendElement(dstHdr, false);
          m_copiedMsgIds.AppendElement(messageId);
        }
      }
      srcFolder->AddFolderListener(this);
      m_undoing = true;
      return srcFolder->CopyMessages(dstFolder, dstMessages,
                                     true, nullptr, nullptr, false,
                                     false);
    }
    srcDB->SetSummaryValid(true);
  }

  dstDB->DeleteMessages(m_dstKeyArray.Length(), m_dstKeyArray.Elements(), nullptr);
  dstDB->SetSummaryValid(true);

  return rv;
}
NS_IMETHODIMP
nsLocalMoveCopyMsgTxn::RedoTransaction()
{
  nsresult rv;
  nsCOMPtr<nsIMsgDatabase> srcDB;
  nsCOMPtr<nsIMsgDatabase> dstDB;

  nsCOMPtr<nsIMsgFolder> srcFolder = do_QueryReferent(m_srcFolder, &rv);
  NS_ENSURE_SUCCESS(rv,rv);

  nsCOMPtr<nsIMsgFolder> dstFolder = do_QueryReferent(m_dstFolder, &rv);
  NS_ENSURE_SUCCESS(rv,rv);
  
  rv = srcFolder->GetMsgDatabase(getter_AddRefs(srcDB));
  if(NS_FAILED(rv)) return rv;
  rv = dstFolder->GetMsgDatabase(getter_AddRefs(dstDB));
  if (NS_FAILED(rv)) return rv;

  uint32_t count = m_srcKeyArray.Length();
  uint32_t i;
  nsCOMPtr<nsIMsgDBHdr> oldHdr;
  nsCOMPtr<nsIMsgDBHdr> newHdr;

  nsCOMPtr<nsIMutableArray> srcMessages = do_CreateInstance(NS_ARRAY_CONTRACTID);
  nsCOMPtr <nsISupports> msgSupports;
  
  for (i=0; i<count; i++)
  {
    rv = srcDB->GetMsgHdrForKey(m_srcKeyArray[i], 
                                getter_AddRefs(oldHdr));
    NS_ASSERTION(oldHdr, "fatal ... cannot get old msg header\n");

    if (NS_SUCCEEDED(rv) && oldHdr)
    {
      msgSupports =do_QueryInterface(oldHdr);
      srcMessages->AppendElement(msgSupports, false);
      
      if (m_canUndelete)
      {
      rv = dstDB->CopyHdrFromExistingHdr(m_dstKeyArray[i],
                                         oldHdr, true,
                                         getter_AddRefs(newHdr));
      NS_ASSERTION(newHdr, "fatal ... cannot get new msg header\n");
      if (NS_SUCCEEDED(rv) && newHdr)
      {
        if (i < m_dstSizeArray.Length())
          rv = newHdr->SetMessageSize(m_dstSizeArray[i]);
        dstDB->UndoDelete(newHdr);
      }
    }
  }
  }
  dstDB->SetSummaryValid(true);

  if (m_isMove)
  {
    if (m_srcIsImap4)
    {
      // protect against a bogus undo txn without any source keys
      // see bug #179856 for details
      NS_ASSERTION(!m_srcKeyArray.IsEmpty(), "no source keys");
      if (m_srcKeyArray.IsEmpty())
        return NS_ERROR_UNEXPECTED;
    
      bool deleteFlag = false; //message is un-deleted- we are trying to redo
      CheckForToggleDelete(srcFolder, m_srcKeyArray[0], &deleteFlag); // there could have been a toggle
      rv = UndoImapDeleteFlag(srcFolder, m_srcKeyArray, deleteFlag);
    }
    else if (m_canUndelete)
    {
      nsCOMPtr <nsIMsgLocalMailFolder> localFolder = do_QueryInterface(srcFolder);
      if (localFolder)
        localFolder->MarkMsgsOnPop3Server(srcMessages, POP3_DELETE /*deleteMsgs*/);

      rv = srcDB->DeleteMessages(m_srcKeyArray.Length(), m_srcKeyArray.Elements(), nullptr);
      srcDB->SetSummaryValid(true);
    }
    else
    {
      nsCOMPtr<nsIMsgDBHdr> srcHdr;
      m_numHdrsCopied = 0;
      m_dstKeyArray.Clear();
      for (i = 0; i < count; i++)
      {
        srcDB->GetMsgHdrForKey(m_srcKeyArray[i], getter_AddRefs(srcHdr));
        NS_ASSERTION(srcHdr, "fatal ... cannot get old msg header\n");
        if (srcHdr)
        {
          nsCString messageId;
          srcHdr->GetMessageId(getter_Copies(messageId));
          m_copiedMsgIds.AppendElement(messageId);
        }
      }
      dstFolder->AddFolderListener(this);
      m_undoing = false;
      return dstFolder->CopyMessages(srcFolder, srcMessages, true, nullptr,
                                     nullptr, false, false);
    }
  }

  return rv;
}
nsresult 
nsLocalMoveCopyMsgTxn::UndoTransactionInternal()
{
  nsresult rv = NS_ERROR_FAILURE;

  if (mUndoFolderListener)
  {
    nsCOMPtr<nsIMsgMailSession> mailSession = 
      do_GetService(NS_MSGMAILSESSION_CONTRACTID, &rv); 
    NS_ENSURE_SUCCESS(rv,rv);
    
    rv = mailSession->RemoveFolderListener(mUndoFolderListener);
    NS_ENSURE_SUCCESS(rv,rv);
    
    NS_RELEASE(mUndoFolderListener);
    mUndoFolderListener = nsnull;
  }

  nsCOMPtr<nsIMsgDatabase> srcDB;
  nsCOMPtr<nsIMsgDatabase> dstDB;
  nsCOMPtr<nsIMsgFolder> srcFolder = do_QueryReferent(m_srcFolder, &rv);
  NS_ENSURE_SUCCESS(rv,rv);
  
  nsCOMPtr<nsIMsgFolder> dstFolder = do_QueryReferent(m_dstFolder, &rv);
  NS_ENSURE_SUCCESS(rv,rv);
  
  rv = srcFolder->GetMsgDatabase(nsnull, getter_AddRefs(srcDB));
  if(NS_FAILED(rv)) return rv;

  rv = dstFolder->GetMsgDatabase(nsnull, getter_AddRefs(dstDB));
  if (NS_FAILED(rv)) return rv;

  PRUint32 count = m_srcKeyArray.Length();
  PRUint32 i;
  nsCOMPtr<nsIMsgDBHdr> oldHdr;
  nsCOMPtr<nsIMsgDBHdr> newHdr;

  // protect against a bogus undo txn without any source keys
  // see bug #179856 for details
  NS_ASSERTION(count, "no source keys");
  if (!count)
    return NS_ERROR_UNEXPECTED;

  if (m_isMove)
  {
    if (m_srcIsImap4)
    {
      PRBool deleteFlag = PR_TRUE;  //message has been deleted -we are trying to undo it
      CheckForToggleDelete(srcFolder, m_srcKeyArray[0], &deleteFlag); //there could have been a toggle.
      rv = UndoImapDeleteFlag(srcFolder, m_srcKeyArray, deleteFlag);
    }
    else
    {
      nsCOMPtr<nsIMutableArray> srcMessages = do_CreateInstance(NS_ARRAY_CONTRACTID);
      for (i=0; i<count; i++)
      {
        rv = dstDB->GetMsgHdrForKey(m_dstKeyArray[i], 
                                    getter_AddRefs(oldHdr));
        NS_ASSERTION(oldHdr, "fatal ... cannot get old msg header\n");
        if (NS_SUCCEEDED(rv) && oldHdr)
        {
          rv = srcDB->CopyHdrFromExistingHdr(m_srcKeyArray[i],
                                             oldHdr, PR_TRUE,
                                             getter_AddRefs(newHdr));
          NS_ASSERTION(newHdr, 
                       "fatal ... cannot create new msg header\n");
          if (NS_SUCCEEDED(rv) && newHdr)
          {
            newHdr->SetStatusOffset(m_srcStatusOffsetArray[i]);
            srcDB->UndoDelete(newHdr);
            srcMessages->AppendElement(newHdr, PR_FALSE);
          }
        }
      }
      nsCOMPtr <nsIMsgLocalMailFolder> localFolder = do_QueryInterface(srcFolder);
      if (localFolder)
        localFolder->MarkMsgsOnPop3Server(srcMessages, POP3_NONE /*deleteMsgs*/);
    }
    srcDB->SetSummaryValid(PR_TRUE);
  }

  dstDB->DeleteMessages(&m_dstKeyArray, nsnull);
  dstDB->SetSummaryValid(PR_TRUE);

  return rv;
}