// Copyright (c) 2001-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of the License "Symbian Foundation License v1.0" to Symbian Foundation members and "Symbian Foundation End User License Agreement v1.0" to non-members

// which accompanies this distribution, and is available

// at the URL "http://www.symbianfoundation.org/legal/licencesv10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

//

/**

 @file CHeaderCodec.h

 @warning : This file contains Rose Model ID comments - please do not delete

*/

#ifndef __CHEADERCODEC_H__

#define __CHEADERCODEC_H__

// System includes

#include <e32base.h>

#include <http/framework/rheaderfield.h>

// Forward declarations

class CHeaderWriter;

class CHeaderReader;

//##ModelId=3C4C18850126

class CHeaderCodec : public CBase

/**

An abstract HTTP header codec.  

Each instance of a concrete subclass of CHeaderCodec is associated with, and owned

by, a specific	CProtocolHandler.  It provides on-demand encoding/decoding of

HTTP header data, between the generic format used by clients/filters to formulate

requests and interpret responses, and the raw format used by

the transport handlers (and origin servers/gateways/etc.)

The CHeaderCodec has an associated instance of a sub-class of each of

CHeaderReader and CHeaderWriter.  It delegates the actual encoding and

decoding function to these instances.

Header codecs provide a mechanism for extensibility whereby if one codec can't

decode (or encode) a given header, it locates a codec that can, and then delegates

the task to that codec instead.

@publishedAll

@released

*/

	{

public: // methods

/** 

	Intended Usage:	Destructor - cleans up and releases resources to the system.

*/

	//##ModelId=3C4C18850194

	IMPORT_C virtual ~CHeaderCodec();

/**

	Encode the supplied header field.  This method uses the associated

	concrete CHeaderWriter object to do a conversion of the field into

	raw form from the generic internal representation.

	@param aHeader (in) A proxy for the header field to be encoded

	@leave KErrNotSupported if a codec that supports encoding this header

		   cannot be found

*/

	//##ModelId=3C4C1885018C

	IMPORT_C void EncodeHeaderL(RHeaderField& aHeader) const;

/**

	Decode the supplied header field.  This method uses the associated

	concrete CHeaderReader object to do a conversion of the field into

	the generic internal representation from the raw form.

	@param aHeader (in) A proxy for the header field to be decoded

	@leave KErrNotSupported if a codec that supports decoding this header

   		   cannot be found

*/

	//##ModelId=3C4C1885018A

	IMPORT_C void DecodeHeaderL(RHeaderField& aHeader) const;

/**

	Intended Usage: Concrete header codec classes must implement this method to

	indicate to the framework whether their concrete CHeaderWriter is

	capable of encoding the named header field.

	@param aHeaderField	(in) A proxy for the header field to be encoded

	@return A flag indicating ETrue if the field can be encoded.

*/

	//##ModelId=3C4C18850181

	virtual TBool CanEncode(RStringF aHeaderField) const = 0;

/**

	Intended Usage: Concrete header codec classes must implement this method to

					indicate to the framework whether their concrete CHeaderReader is

					capable of decoding the named header field.

	@param			aHeaderField		(in) A proxy for the header field to be encoded

	@return			A flag indicating ETrue if the field can be decoded.

 */

	//##ModelId=3C4C18850178

	virtual TBool CanDecode(RStringF aHeaderField) const = 0;

/**

	Intended Usage: Concrete header codecs must be implement this method if they wish to

					delegate the encoding/decoding of particular header fields to a

					different codec.  

					This would be done if the codec doesn't have the ability itself to

					do the encode/decode but can locate an alternative that does. This 

					function may leave with a Standard Symbian OS error code. eg. KErrNoMemory

					The caller takes ownership of the returned codec.

	@param aHeaderField (in) A proxy for the header field to be encoded

	@return A pointer to the new CHeaderCodec, or NULL if one couldn't be found.

	@leave KErrNoMemory, Not enough memory to create object.	

*/

	//##ModelId=3C4C18850176

	virtual CHeaderCodec* FindDelegateCodecL(RStringF aHeaderField) const = 0;

protected: // methods

/**

	Default constructor.

 */

	//##ModelId=3A914DF20273

	IMPORT_C CHeaderCodec();

/**

	Second phase construction in which any necessary allocation is done

	Implementations of this interface may leave with standard erros like KErrNoMemory if there is

	insufficient memory for allocation in the second phase.

 */

	//##ModelId=3C4C1885016E

	IMPORT_C void ConstructL();

protected: // attributes

	/** The owned header writer object that does actual encoding of header fields.

	*/

	//##ModelId=3C4C18850164

	CHeaderWriter* iWriter;

	/** The owned header reader object that does actual decoding of header fields.

	*/

	//##ModelId=3C4C1885015A

	CHeaderReader* iReader;

private: // methods

/**	

	Intended Usage:	Reserve a slot in the v-table to preserve future BC

 */

	//##ModelId=3C4C1885016D

	inline virtual void Reserved1();

/**	

	Intended Usage:	Reserve a slot in the v-table to preserve future BC

 */

	//##ModelId=3C4C1885016C

	inline virtual void Reserved2();

private: // attributes

	/** The most recently-obtained delegate codec

	*/

	//##ModelId=3C4C18850150

	mutable CHeaderCodec* iDelegateCodec;

	};

//##ModelId=3C4C188601D1

class CHeaderWriter : public CBase

/**

An abstract HTTP header encoder.  CHeaderWriter provides an interface used by its

owning codec to do conversion of header data from the generic internal header

representation to the raw representation used for a particular protocol/transport.

Specific sub-classes of CHeaderWriter are associated with specific protocol handlers.

@publishedAll

@released

*/

	{

public: // methods

/** 

	Intended Usage:	Destructor - cleans up and release resources to the system.

*/

	//##ModelId=3C4C188601FC

	IMPORT_C virtual ~CHeaderWriter();

/**

	Intended Usage:	Encodes the supplied header field.  This method does a conversion

					of the field into raw form from the generic internal representation.

					Implementations of this interface may leave with any of KErrNotSupported, KErrHttpEncodeDoWWWAuthenticate,

					KErrHttpEncodeAuthorization, KErrHttpEncodeDoAge, KErrHttpEncodeDoVary, KErrHttpEncodeDoContentLanguage.

					Specific header writer sub-classes must implement this method.

	@param			aHeader		(in) A proxy for the header field to be encoded

 */

	//##ModelId=3C4C188601FA

	virtual void EncodeHeaderL(RHeaderField& aHeader) = 0;

protected: // methods

/**

	Default constructor.

 */

	IMPORT_C CHeaderWriter();

/**

	Second phase construction in which any necessary allocation is done

	Implementations of this interface may leave with standard errors like KErrNoMemory.

 */

	//##ModelId=3C4C188601F9

	IMPORT_C void ConstructL();

private: // methods

/**	

	Intended Usage:	Reserve a slot in the v-table to preserve future BC

 */

	//##ModelId=3C4C188601F1

	inline virtual void Reserved1();

/**	

	Intended Usage:	Reserve a slot in the v-table to preserve future BC

 */

	//##ModelId=3C4C188601F0

	inline virtual void Reserved2();

	};

//##ModelId=3C4C188602FE

class CHeaderReader : public CBase

/**

An abstract HTTP header decoder.  CHeaderReader provides an interface used by its

owning codec to do conversion of header data from the raw representation used for

a particular protocol/transport to the generic internal header representation.

Specific sub-classes of CHeaderWriter are associated with specific protocol

handlers.

@publishedAll

@released

*/

	{

public: // methods

/** 

	Intended Usage:	Destructor - cleans up and release resources to the system.

*/

	//##ModelId=3C4C1886031E

	IMPORT_C virtual ~CHeaderReader();

/**

	Intended Usage:	Decodes the supplied header field.  This method does a conversion

	of the field from the generic internal representation into raw form.

	Specific header reader sub-classes must implement this method.

	Implementations of this interface may leave with any of KErrHttpDecodeAccept, KErrHttpDecodeAcceptCharset, 

	KErrHttpDecodeAcceptLanguage, KErrHttpDecodeAcceptEncoding, KErrNotSupported.

	@param aHeader (in) A proxy for the header field to be decoded

*/

	//##ModelId=3C4C1886031C

	virtual void DecodeHeaderL(RHeaderField& aHeader) = 0;

protected: // methods

/**

	Default constructor.

 */

	IMPORT_C CHeaderReader();

/**

	Second phase construction in which any necessary allocation is done

	Implementations of this interface may leave with standard errors like KErrNoMemory.

 */

	//##ModelId=3C4C18860315

	IMPORT_C void ConstructL();

private: // methods

/**	

	Intended Usage:	Reserve a slot in the v-table to preserve future BC

 */

	//##ModelId=3C4C18860314

	inline virtual void Reserved1();

/**	

	Intended Usage:	Reserve a slot in the v-table to preserve future BC

 */

	//##ModelId=3C4C18860313

	inline virtual void Reserved2();

	};

inline void CHeaderCodec::Reserved1()

	{}

inline void CHeaderCodec::Reserved2()

	{}

inline void CHeaderWriter::Reserved1()

	{}

inline void CHeaderWriter::Reserved2()

	{}

inline void CHeaderReader::Reserved1()

	{}

inline void CHeaderReader::Reserved2()

	{}

#endif /* __CHEADERCODEC_H__ */