/* -*- Mode: C++; tab-width: 2; 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/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * 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
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of 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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 * ***** END LICENSE BLOCK ***** */

#include "nsITransaction.h"
#include "nsTransactionItem.h"
#include "nsTransactionStack.h"
#include "nsCOMPtr.h"
#include "nsAutoPtr.h"
#include "nsCycleCollectionParticipant.h"
#include "mozilla/Util.h"

nsTransactionStack::nsTransactionStack(nsTransactionStack::Type aType)
  : mQue(0)
  , mType(aType)
{
}

nsTransactionStack::~nsTransactionStack()
{
  Clear();
}

void
nsTransactionStack::Push(nsTransactionItem *aTransaction)
{
  if (!aTransaction) {
    return;
  }

  /* nsDeque's Push() method adds new items at the back
   * of the deque.
   */
  NS_ADDREF(aTransaction);
  mQue.Push(aTransaction);
}

already_AddRefed<nsTransactionItem>
nsTransactionStack::Pop()
{
  /* nsDeque is a FIFO, so the top of our stack is actually
   * the back of the deque.
   */
  return static_cast<nsTransactionItem*> (mQue.Pop());
}

already_AddRefed<nsTransactionItem>
nsTransactionStack::PopBottom()
{
  /* nsDeque is a FIFO, so the bottom of our stack is actually
   * the front of the deque.
   */
  return static_cast<nsTransactionItem*> (mQue.PopFront());
}

already_AddRefed<nsTransactionItem>
nsTransactionStack::Peek()
{
  nsTransactionItem* transaction = nsnull;
  if (mQue.GetSize()) {
    NS_IF_ADDREF(transaction = static_cast<nsTransactionItem*>(mQue.Last()));
  }

  return transaction;
}

already_AddRefed<nsTransactionItem>
nsTransactionStack::GetItem(PRInt32 aIndex)
{
  nsTransactionItem* transaction = nsnull;
  if (aIndex >= 0 && aIndex < mQue.GetSize()) {
    NS_IF_ADDREF(transaction =
                 static_cast<nsTransactionItem*>(mQue.ObjectAt(aIndex)));
  }

  return transaction;
}

void
nsTransactionStack::Clear()
{
  nsRefPtr<nsTransactionItem> tx;

  do {
    tx = mType == FOR_UNDO ? Pop() : PopBottom();
  } while (tx);
}

void
nsTransactionStack::DoTraverse(nsCycleCollectionTraversalCallback &cb)
{
  for (PRInt32 i = 0, qcount = mQue.GetSize(); i < qcount; ++i) {
    nsTransactionItem *item =
      static_cast<nsTransactionItem*>(mQue.ObjectAt(i));
    if (item) {
      NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "transaction stack mQue[i]");
      cb.NoteNativeChild(item, &NS_CYCLE_COLLECTION_NAME(nsTransactionItem));
    }
  }
}
