// 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:

// record.h - the queries and replies from the server

//

#ifndef __RECORD_H__

#define __RECORD_H__

/**

@file record.h

Describes the stored answers (in DNS Cache)

@internalComponent	Domain Name Resolver

*/

#include "message.h"

#ifdef EXCLUDE_SYMBIAN_DNS_PUNYCODE

#undef SYMBIAN_DNS_PUNYCODE

#endif //EXCLUDE_SYMBIAN_DNS_PUNYCODE

const TUint KDndMaxTTL = 604800;	//< Maximum TTL for an RR in seconds == 1 week.

const TUint KDndDefaultTTL = 120;	//< Default TTL, if reply has no RR that matches the query

class CDndEngine;

class CDndNode;

class TDndRecordLRU;

class TDnsReply

	{

public:

	TInt iOffset;			//< Offset of the first answer

	HBufC8 *iBuf;			//< The reply from the DNS server as is

	};

// Represents the query and reply from the server

class CDndRecord : public CBase

	{

	friend class TDndRecordList;

	friend class CDndCache;		// for accessing iLRU!

	~CDndRecord();

public:

	CDndRecord(TDndRecordLRU &aLRU, CDndNode &aOwner, const EDnsQType aQType, const EDnsQClass aClass);

	// Returns the expiration time

	const TTime &ExpireTime() const;

	// Invalidate the record.

	void Invalidate();

	// Record a reference into LRU list

	void HitLRU();

	// Mark record as expired.

	inline void MarkExpired() { iExpired = 1; }

	/*

	// Mark record as "valid", set error code and TTL.

	//

	// @param aErrorCode

	//	The error code to set. This must be negative, if there is no

	//	reply. Also, if the code is KErrNotFound, the function actually

	//	invalidates the record.

	// @param aTTL

	//	The time to live in seconds, counted from current time.

	*/

	void FillErrorCode(const TInt aErrorCode, const TUint aTTL = KDndMaxTTL);

	// Mark record as "valid", containing the received reply.

	void FillData(const TMsgBuf &aReply, const TInt aAnswerOffset, const TUint32 aServer, TInt aErrorCode, TUint aTTL);

	/**

	// Return current error code of the record

	//

	// @return Error Code,

	// @li = 0 (KErrNone), record has a reply stored

	// @li = KErrNotFound, record is Invalid, no reply stored

	// @li < 0, some other error condition, no reply stored

	*/

	inline TInt ErrorCode() const { return iErrorCode;}	

	/**

	// Return a reference to the reply associated with the record.

	//

	// Only valid if ErrorCode() returns KErrNone!

	*/

	inline const TMsgBuf &Reply() const { return TMsgBuf::Cast(*iReply.iBuf); }

	/**

	// Return a reference to the reply associated with the record type cast into header class

	//

	// Only valid if ErrorCode() returns KErrNone!

	*/

	inline const TInet6HeaderDNS &Header() const { return *((TInet6HeaderDNS *)iReply.iBuf->Ptr()); }

	// Return the offset to the answer section of the reply

	inline TInt AnswerOffset() const { return iReply.iOffset; }

	// Return the id of the server from which the reply came

	inline TUint32 Server() const { return iServer; }

	// Increment record lock count (prevent remove via LRU handling)

	inline void Lock() { ++iLocks; }

	// Assign a "worker" to record, if not already present.

	TBool AssignWork(const void *aWorker);

	// Decrement record lock count (allow remove via LRU when 0)

	void Unlock(const void *aWorker);

	// Return TRUE, if lock count > 0

	inline TBool IsLocked() const { return iLocks != 0; }

	// Return Query Type

	inline EDnsQType QType() const { return iType; }

	// Return Query Class

	inline EDnsQClass QClass() const { return iClass; }

	// Delete the record from cache

	void Delete();

#ifdef SYMBIAN_DNS_PUNYCODE	

	// Print out the record content (debug only)

	void Print(CDndEngine &aControl,TBool aIdnEnabled=EFalse) const;	

#else

	// Print out the record content (debug only)

	void Print(CDndEngine &aControl) const;

#endif //SYMBIAN_DNS_PUNYCODE

	static const TInt iOffsetLRU;	//< offset of iLRU

protected:	

	static const TInt iOffset;		//< offset of iDlink

private:

	CDndNode &iOwner;		//< Back link to the node owning this record

	TDndRecordLRU &iList;	//< Back link to the LRU list head

	const EDnsQType iType;	//< Record Type

	const EDnsQClass iClass;//< Record Class

	TDblQueLink iDlink;		//< Links records under single label

	TTime iTTL;				//< Time to live for this cache record

	TUint32 iServer;		//< The id of originating server

	TDnsReply iReply;		//< The cached reply or replies.

	TInt iErrorCode;		//< KErrNone, if record stored, < 0 otherwise

	TUint16 iLocks;			//< Number of locks by TDndReqData objects

	TUint iHasTTL:1;		//< The iTTL on the record has been set.

	TUint iExpired:1;		//< The record has expired, but is locked.

	TDblQueLink iLRU;		//< LRU links

	const void *iWorker;	//< Non-NULL, if querying process is active

	};

// A Least Recently Used (LRU) list of records

class TDndRecordLRU : public TDblQue<CDndRecord>

	{

	friend class CDndRecord;

public:

	TDndRecordLRU();

	// Remove extra records from LRU

	void Cleanup(const TUint aMaxRecords);

private:

	TUint iCount;			//< Count of records in LRU list

	};

// A list of records under one node

class TDndRecordList : public TDblQue<CDndRecord>

	{

	friend class CDndNode;

	TDndRecordList();

	// Searches the list for the Record of type aType and class aClass

	CDndRecord *Find(const EDnsQType aType, const EDnsQClass aClass, const TTime &aReqTime);

	// Add a new record into list

	void Add(CDndRecord &aRecord);

	// Delete record from list (and cache)

	void Delete(CDndRecord *aRecord);

	// Call CDndRecord::Print for each member of the list.

	void Print(CDndEngine &aControl);

	};

#endif