/* -*- Mode: IDL; 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):
 *   Scott Collins <scc@mozilla.org>: |do_QueryElementAt|
 *
 * 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 ***** */

#include "nsISerializable.idl"
#include "nsIEnumerator.idl"

[scriptable, uuid(83b6019c-cbc4-11d2-8cca-0060b0fc14a3)]
interface nsICollection : nsISerializable
{

  PRUint32 Count();
  nsISupports GetElementAt(in PRUint32 index);
  void QueryElementAt(in PRUint32 index, in nsIIDRef uuid, 
                      [iid_is(uuid),retval] out nsQIResult result);
  void SetElementAt(in PRUint32 index, in nsISupports item);
  void AppendElement(in nsISupports item);
  void RemoveElement(in nsISupports item);

  nsIEnumerator Enumerate();

  void Clear();

};

%{C++

#ifndef nsCOMPtr_h__
#include "nsCOMPtr.h"
#endif

class NS_EXPORT nsQueryElementAt : public nsCOMPtr_helper
  {
    public:
      nsQueryElementAt( nsICollection* aCollection, PRUint32 aIndex, nsresult* aErrorPtr )
          : mCollection(aCollection),
            mIndex(aIndex),
            mErrorPtr(aErrorPtr)
        {
          // nothing else to do here
        }

      virtual nsresult operator()( const nsIID& aIID, void** ) const;

    private:
      nsICollection*  mCollection;
      PRUint32        mIndex;
      nsresult*       mErrorPtr;
  };

inline
const nsQueryElementAt
do_QueryElementAt( nsICollection* aCollection, PRUint32 aIndex, nsresult* aErrorPtr = 0 )
  {
    return nsQueryElementAt(aCollection, aIndex, aErrorPtr);
  }

%}