/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: NPL 1.1/GPL 2.0/LGPL 2.1
 *
 * 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 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 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
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the NPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the NPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#define NS_WEAK_OBSERVERS

#define NS_IMPL_IDS
#include "pratom.h"
#include "nsIObserverList.h"
#include "nsString.h"
#include "nsAutoLock.h"
#include "nsCOMPtr.h"
#include "nsIWeakReference.h"

#include "nsObserverList.h"

#define NS_AUTOLOCK(__monitor) nsAutoLock __lock(__monitor)

static NS_DEFINE_CID(kObserverListCID, NS_OBSERVERLIST_CID);


class nsObserverListEnumerator : public nsIBidirectionalEnumerator
	{
		public:
			nsObserverListEnumerator( nsISupportsArray* );
			virtual ~nsObserverListEnumerator() {};
			NS_DECL_ISUPPORTS
			NS_DECL_NSIENUMERATOR
			NS_DECL_NSIBIDIRECTIONALENUMERATOR

		private:
			PRUint32 GetTargetArraySize() const;
			nsresult MoveToIndex( PRUint32 );

		private:
			nsCOMPtr<nsISupportsArray>	mTargetArray;
			PRUint32										mCurrentItemIndex;
	};

NS_IMPL_ISUPPORTS2(nsObserverListEnumerator,
                   nsIBidirectionalEnumerator,
                   nsIEnumerator)

nsObserverListEnumerator::nsObserverListEnumerator( nsISupportsArray* anArray )
		: mRefCnt(0),
			mTargetArray(anArray),
			mCurrentItemIndex(0)
	{
		NS_INIT_REFCNT();
	}

PRUint32
nsObserverListEnumerator::GetTargetArraySize() const
	{
		PRUint32 array_size = 0;
		mTargetArray->Count(&array_size);
		return array_size;
	}

nsresult
nsObserverListEnumerator::MoveToIndex( PRUint32 aNewIndex )
	{
		mCurrentItemIndex = aNewIndex;
		return (aNewIndex < GetTargetArraySize()) ? NS_OK : NS_ERROR_FAILURE;
	}


NS_IMETHODIMP
nsObserverListEnumerator::First()
	{
		NS_ASSERTION(mTargetArray, "must enumerate over an non-null list");

		return MoveToIndex(0);
	}

NS_IMETHODIMP
nsObserverListEnumerator::Last()
	{
		NS_ASSERTION(mTargetArray, "must enumerate over an non-null list");

		return MoveToIndex(GetTargetArraySize()-1);
	}

NS_IMETHODIMP
nsObserverListEnumerator::Prev()
	{
		NS_ASSERTION(mTargetArray, "must enumerate over an non-null list");

		return MoveToIndex(mCurrentItemIndex-1);
	}

NS_IMETHODIMP
nsObserverListEnumerator::Next()
	{
		NS_ASSERTION(mTargetArray, "must enumerate over an non-null list");

		return MoveToIndex(mCurrentItemIndex+1);
	}

NS_IMETHODIMP
nsObserverListEnumerator::CurrentItem( nsISupports** aItemPtr )
	{
		NS_ASSERTION(mTargetArray, "must enumerate over an non-null list");
		NS_ASSERTION(aItemPtr, "must supply a place to put the result");

		if ( mCurrentItemIndex >= GetTargetArraySize() )
			return NS_ERROR_FAILURE;

		nsCOMPtr<nsISupports> elementPtr = getter_AddRefs(mTargetArray->ElementAt(mCurrentItemIndex));

		if ( !aItemPtr || !elementPtr )
			return NS_ERROR_NULL_POINTER;

		nsCOMPtr<nsIWeakReference> weakRef = do_QueryInterface(elementPtr);

    nsresult status;
    if ( weakRef )
      status = weakRef->QueryReferent(NS_GET_IID(nsIObserver), NS_REINTERPRET_CAST(void**, aItemPtr));
    else
      status = elementPtr->QueryInterface(NS_GET_IID(nsIObserver), NS_REINTERPRET_CAST(void**, aItemPtr));

    return status;
	}

NS_IMETHODIMP
nsObserverListEnumerator::IsDone()
	{
		NS_ASSERTION(mTargetArray, "must enumerate over an non-null list");

		return  (mCurrentItemIndex >= GetTargetArraySize()) ? NS_OK : NS_ENUMERATOR_FALSE;
	}



////////////////////////////////////////////////////////////////////////////////
// nsObserverList Implementation


NS_IMPL_ISUPPORTS1(nsObserverList, nsIObserverList)

NS_COM nsresult NS_NewObserverList(nsIObserverList** anObserverList)
{

    if (anObserverList == NULL)
    {
        return NS_ERROR_NULL_POINTER;
    }  
    nsObserverList* it = new nsObserverList();

    if (it == 0) {
      return NS_ERROR_OUT_OF_MEMORY;
    }

    return it->QueryInterface(NS_GET_IID(nsIObserverList), (void **) anObserverList);
}

nsObserverList::nsObserverList()
    : mLock(nsnull)
{
    NS_INIT_REFCNT();
    mLock = PR_NewLock();
}

nsObserverList::~nsObserverList(void)
{
    PR_DestroyLock(mLock);
}


NS_IMETHODIMP nsObserverList::AddObserver(nsIObserver* anObserver)
{
	nsresult rv;
	PRBool inserted;
    
  NS_ENSURE_ARG(anObserver);

	NS_AUTOLOCK(mLock);

	if (!mObserverList) {
    rv = NS_NewISupportsArray(getter_AddRefs(mObserverList));
		if (NS_FAILED(rv)) return rv;
    }

#ifdef NS_WEAK_OBSERVERS
  nsCOMPtr<nsISupportsWeakReference> weakRefFactory = do_QueryInterface(anObserver);
  nsCOMPtr<nsISupports> observerRef;
  if ( weakRefFactory )
  	observerRef = getter_AddRefs(NS_STATIC_CAST(nsISupports*, NS_GetWeakReference(weakRefFactory)));
  else
  	observerRef = anObserver;

	if(observerRef) {
		inserted = mObserverList->AppendElement(observerRef); 
#else
	if(*anObserver) {
		inserted = mObserverList->AppendElement(*anObserver);
#endif
		return inserted ? NS_OK : NS_ERROR_FAILURE;
    }

	return NS_ERROR_FAILURE;
}

NS_IMETHODIMP nsObserverList::RemoveObserver(nsIObserver* anObserver)
{
	PRBool removed;

  NS_ENSURE_ARG(anObserver);

 	NS_AUTOLOCK(mLock);

 if (!mObserverList)
        return NS_ERROR_FAILURE;

#ifdef NS_WEAK_OBSERVERS
  nsCOMPtr<nsISupportsWeakReference> weakRefFactory = do_QueryInterface(anObserver);
  nsCOMPtr<nsISupports> observerRef;
  if ( weakRefFactory )
  	observerRef = getter_AddRefs(NS_STATIC_CAST(nsISupports*, NS_GetWeakReference(weakRefFactory)));
  else
  	observerRef = anObserver;

	if(observerRef) {
		removed = mObserverList->RemoveElement(observerRef);  
#else
	if(*anObserver) {
		removed = mObserverList->RemoveElement(*anObserver);
#endif
		return removed ? NS_OK : NS_ERROR_FAILURE;
    }

    return NS_ERROR_FAILURE;
}

NS_IMETHODIMP nsObserverList::EnumerateObserverList(nsIEnumerator** anEnumerator)
{
	NS_AUTOLOCK(mLock);

  NS_ENSURE_ARG(anEnumerator);

 if (!mObserverList)
        return NS_ERROR_FAILURE;

#ifdef NS_WEAK_OBSERVERS
	nsCOMPtr<nsIBidirectionalEnumerator> enumerator = new nsObserverListEnumerator(mObserverList);
	if ( !enumerator )
		return NS_ERROR_OUT_OF_MEMORY;

	return CallQueryInterface(enumerator, anEnumerator);
#else
	return mObserverList->Enumerate(anEnumerator);
#endif
}


//----------------------------------------------------------------------------------------
NS_METHOD nsObserverList::Create(nsISupports* outer, const nsIID& aIID, void* *aInstancePtr)
//----------------------------------------------------------------------------------------
{
  if (aInstancePtr == NULL)
    return NS_ERROR_NULL_POINTER;

	nsObserverList* it = new nsObserverList;
  if (!it)
		return NS_ERROR_OUT_OF_MEMORY;

  nsresult rv = it->QueryInterface(aIID, aInstancePtr);
  if (NS_FAILED(rv))
  {
    delete it;
    return rv;
  }
  return rv;
}