/*

* Copyright (c) 2003-2009 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:

* Name          : MSigCompHandler.h

* Part of       : ConnectionMgr

* Version       : SIP/4.0 

*

*/

#ifndef __MSIGCOMPHANDLER_H__

/**

* @internalComponent

*/

#define __MSIGCOMPHANDLER_H__

#include <in_sock.h>

#include "SipHostPort.h"

/**

 * Interface class for sigcomp handler.

 */

class MSigCompHandler 

	{

	public:

	/**

	 * Destructor.

	 */

	virtual ~MSigCompHandler () {}

    /**

     * After calling this function Connection Mgr always uses

     * signalling compression for requests sent to this host.

     * Multiple users can share a compression to a given host.

     * This is implemented as a reference count.

     * If a compression already exists, the referrence count is

     * incremented by one.

     *

     * @param aHostPort for which all the outgoing requests should be sent

     *        compressed.

	 */

    virtual void UseL (const CSIPHostPort& aHostPort) = 0;

    /**

     * Decrements the reference count to a initiated compression.

     * When reference count reaches zero,

     * the compression for this host is stopped. 

     * If no compression for the host was found, the function silently returns.

     *

     * @param aHostPort for which to unuse compression.

	 */

    virtual void UnUse (const CSIPHostPort& aHostPort) = 0;    

	/**

	 * Decompress the message; leaves on failure. 

	 *

	 * SigComp specífic leave codes:

	 * EDecompressionFailure - the decompressor failed to decompress the

	 *						   message.

	 * EIncompleteMessage - the SigComp message was incomplete

	 * The function expects the client to provide complete SigComp message.

	 *

	 * @pre IsSigCompMsg()==ETrue

	 * 

	 * @param aMessage a message to decompress. The message must start with

	 *				   SigComp specific delimeter and end with SigComp specific

	 *				   delimeter

	 *

	 * @param aBytesConsumed on return will contain the number of bytes

	 *						 consumed by the decompression from the original

	 						 message 

	 * @returns decompressed message, the ownership is transferred

	 */

	virtual HBufC8*

		DecompressL(const TDesC8& aMessage, TUint& aBytesConsumed) = 0;

	/**

	 * Compress the message using the algorith provided while

	 * creating the instance of the CSigComp class.

	 *

	 * Leaves with CSigComp::TError::ECompressionError error code if the

	 *	compression fails.

	 * Leaves with KErrNotFound error code if compartment is not found.

	 * 

	 * @param aMessage a message to compress.

	 *					

	 * @param aAddress	A remote destination address

	 *					

	 * @param aSIPHostPort The host where message will be sent after

	 *					   compression.

	 *	The hostport identifies the compartment that will be used for

	 *					   compression.

	 * 

	 * @returns Compressed message, ownership is transfered to the client.

	 */

	virtual HBufC8* CompressL(const TDesC8& aMessage, TInetAddr aAddress, 

							  const CSIPHostPort& aHostPort,

							  TBool aStreamBasedProtocol) = 0;

	/**

	 * Checks if the message contains the delimeter indicating SigComp

	 * message end. This function must be used only with stream-based

	 * transports, otherwise it will always return EFalse.

	 *

	 * @pre IsSigCompMsg()==ETrue

	 *

	 * @returns ETrue is the SigComp message is complete, EFalse otherwise

	 */

	virtual TBool IsCompleteSigCompMessageL(const TDesC8& aMessage) const = 0;

	/**

	 * Checks if the first byte contains bit pattern indicating the start

	 * of the SigComp message. Function examines only the first byte.

	 *

	 * @returns ETrue if the first byte indicates the start of the SigComp

	 *			message, EFalse otherwise

	 */

	virtual TBool IsSigCompMsg(const TDesC8& aMessage) const = 0;

	/**

    * Checks if signalling compression is installed.

    *

    * @returns ETrue if installed, EFalse otherwise.

	*/

	virtual TBool Available() const = 0; 

	/**

	 * Allows the state of the decompressed message to be saved; leaves on

	 * failure.

	 * 

	 * @param aAddress	A remote destination address

	 *					

	 * @param aHostPort A host port

	 */

	virtual void AllowL(TInetAddr aAddr, const CSIPHostPort& aHostPort) = 0;

	/**

	 * Denies the state of the message to be saved.

	 */

	virtual void Deny() = 0;

	/**

	 * Checks if hostport has compartment already

	 *

	 * @param aHostPort A host port

	 *

	 * @returns ETrue if compartment exists

	 */

	virtual TBool HasCompartment(const CSIPHostPort& aHostPort) = 0;

};

#endif // end of __MSIGCOMPHANDLER_H__

// End of File