/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * The contents of this file are subject to the Netscape 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/NPL/
 *
 * 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 Netscape are
 * Copyright (C) 1998 Netscape Communications Corporation. All
 * Rights Reserved.
 *
 * Contributor(s): 
 */

#include "nsITransaction.h"
#include "nsTransactionItem.h"
#include "nsTransactionStack.h"
#include "nsCOMPtr.h"

nsTransactionStack::nsTransactionStack()
  : mQue(0)
{
  nsTransactionReleaseFunctor* theFunctor=new nsTransactionReleaseFunctor();
  mQue.SetDeallocator(theFunctor);
} 

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

nsresult
nsTransactionStack::Push(nsTransactionItem *aTransaction)
{
  if (!aTransaction)
    return NS_ERROR_NULL_POINTER;

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

  return NS_OK;
}

nsresult
nsTransactionStack::Pop(nsTransactionItem **aTransaction)
{
  if (!aTransaction)
    return NS_ERROR_NULL_POINTER;

  /* nsDeque is a FIFO, so the top of our stack is actually
   * the back of the deque.
   */
  *aTransaction = (nsTransactionItem *)mQue.Pop();

  return NS_OK;
}

nsresult
nsTransactionStack::PopBottom(nsTransactionItem **aTransaction)
{
  if (!aTransaction)
    return NS_ERROR_NULL_POINTER;

  /* nsDeque is a FIFO, so the bottom of our stack is actually
   * the front of the deque.
   */
  *aTransaction = (nsTransactionItem *)mQue.PopFront();

  return NS_OK;
}

nsresult
nsTransactionStack::Peek(nsTransactionItem **aTransaction)
{
  if (!aTransaction)
    return NS_ERROR_NULL_POINTER;

  /* nsDeque's End() method returns an iterator that is
   * passed the last entry of the deque. We need to decrement
   * to get to the last entry.
   */
  *aTransaction = (nsTransactionItem *)(--mQue.End());

  return NS_OK;
}

nsresult
nsTransactionStack::Clear(void)
{
  nsTransactionItem *tx = 0;
  nsresult result    = NS_OK;

  /* Pop all transactions off the stack and release them. */

  result = Pop(&tx);

  if (NS_FAILED(result))
    return result;

  while (tx) {
    delete tx;

    result = Pop(&tx);

    if (NS_FAILED(result))
      return result;
  }

  return NS_OK;
}

nsresult
nsTransactionStack::GetSize(PRInt32 *aStackSize)
{
  if (!aStackSize)
    return NS_ERROR_NULL_POINTER;

  *aStackSize = mQue.GetSize();

  return NS_OK;
}

nsresult
nsTransactionStack::Write(nsIOutputStream *aOutputStream)
{
  /* Call Write() for every transaction on the stack. Start
   * from the top of the stack.
   */

  nsDequeIterator di = mQue.End();
  nsTransactionItem *tx = (nsTransactionItem *)--di;

  while (tx) {
    tx->Write(aOutputStream);
    tx = (nsTransactionItem *)--di;
  }
  return NS_OK;
}


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

nsresult
nsTransactionRedoStack::Clear(void)
{
  nsTransactionItem *tx = 0;
  nsresult result       = NS_OK;

  /* When clearing a Redo stack, we have to clear from the
   * bottom of the stack towards the top!
   */

  result = PopBottom(&tx);

  if (NS_FAILED(result))
    return result;

  while (tx) {
    delete tx;

    result = PopBottom(&tx);

    if (NS_FAILED(result))
      return result;
  }

  return NS_OK;
}

void *
nsTransactionReleaseFunctor::operator()(void *aObject)
{
  nsTransactionItem *item = (nsTransactionItem *)aObject;
  delete item;
  return 0;
}