// Copyright (c) 2004-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

// resolver.h - name resolver

//

#ifndef __RESOLVER_H__

#define __RESOLVER_H__

/**

@file resolver.h

Resolver for a query from single client

@internalComponent	Domain Name Resolver

*/

#include <es_sock.h>

class CDndListener;

class CDndEngine;

class MDnsSource;

/**

// Name resolver side of the RHostResolver

//

// When application opens the RHostResolver, a connection through TCP/IP stack

// is created, using a chain of intermediate objects and a socket. A class

// implementing from a MDndResolver is the other end of the "chain":

//

//   RHostResolver <--- .... ---> MDndResolver

//

// There is a limited pool of MDndResolvers, which are reused for new

// different RHostResolver clients.

//

// It has the following simplified state diagram:

//

@verbatim

                   __________________

                 /      reuse        \

                V                     |

 construct -> Start() --> [work] --> Stop() --> destruct

@endverbatim

*/

class MDndResolver

	{

public:

	// Create a new instance of a resolver

	static MDndResolver *New(const TInt aId, CDndEngine &aControl, MDndListener &aListener, MDnsSource &aDnsclient);

	// Start serving a request

	virtual void Start(const TDnsMessageBuf &aMsg) = 0;

	// Stop processing of the current request

	virtual void Stop() = 0;

	// @return The session id of the current request (or 0, if none)

	virtual TUint16 Session() const = 0;

	// @return reference to the time of the last request

	virtual const TTime &RequestTime() const = 0;

	// @return reference to the current reply message

	virtual const TDesC8 &ReplyMessage() = 0;

	// Allow delete via M-class pointer

	virtual ~MDndResolver() {};

	};

#endif