// 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:

//

/**

 @file

 @internalComponent

*/

#ifndef CONNECTIONHISTORY_H

#define CONNECTIONHISTORY_H

#include <e32base.h>

class CConnections;

class TRemConAddress;

/**

Encapsulates the history of the connection statuses. 

Each item in the history is a CConnections. So, at any point in time, the 

CConnections given by Last will represent the currently extant connections in 

the system. 

Note that this class allows the client to remove older items from the history 

as they become uninteresting.

Provides APIs to extend or grow the history when connections or disconnections 

occur. In each case a new CConnections is made, based on Last, reflecting the 

new change. 

As an implementation detail, the disconnection API uses memory pre-allocated 

at connection time to make sure that it cannot fail, as required (ultimately) 

by the Bearer API.

*/

NONSHARABLE_CLASS(CConnectionHistory) : public CBase

	{

public:

	/**

	Makes a new connection history- a holder for the connection statuses as 

	they evolve over time. Seeds itself with the initial state of the system 

	(no connections).

	@return Ownership of a new CConnectionHistory object.

	*/

	static CConnectionHistory* NewL();

	/** Destructor. */

	~CConnectionHistory();

public:

	/**

	Destroys the first item in the connection history. Used when no session is 

	interested in it any more. Debug-asserts that the history is empty neither 

	before nor after the call.

	*/

	void DestroyFirst();

	/**

	Gets the number of items in the history. This is always >= 1.

	*/

	TUint Count() const;

	/**

	Accessor for a point in the connection history. If aIndex is out of range, 

	panics.

	@param aIndex Index of the desired point in the connection history.

	@return A specific set of connections.

	*/

	const CConnections& operator[](TUint aIndex);

	/**

	Used to access the last item in the history, i.e. the current set of 

	connections.

	*/

	CConnections& Last();

	/**

	Used when a connection is made. Pre-allocates memory so that any 

	subsequent disconnection is guaranteed to work, and makes a new 'last' 

	item on the history expressing the current state of the system (i.e. the 

	previous state of the system, plus the change expressed by this call).

	@param aAddr The new remote.

	*/

	TInt NewConnection(const TRemConAddress& aAddr);

	/**

	Used when a connection comes down. Uses the pre-allocated memory to make a 

	new latest item in the history expressing the current state of the system 

	(i.e. the previous state of the system, minus the connection which just 

	went away).

	@param aAddr The disappearing remote.

	*/

	void Disconnection(const TRemConAddress& aAddr);

	/**

	Logs the connection history. Note that this might not be the complete 

	connection history, as earlier items are dropped as they become 

	uninteresting. */

	void LogConnectionHistory() const;

private: // utility

	void NewConnectionL(const TRemConAddress& aAddr);

#ifdef __FLOG_ACTIVE

	void LogCollectionPool() const;

	void LogAddressPool() const;

#endif // __FLOG_ACTIVE

private:

	/** Constructor. */

	CConnectionHistory();

	/** 2nd-phase construction. */

	void ConstructL();

private: // owned

	/** The history. */

	TSglQue<CConnections> iHistory;

	/** Pre-allocated pool of CConnections, to be used when a disconnection 

	occurs. */

	TSglQue<CConnections> iConnectionsPool;

	/** Pre-allocated pool of TRemConAddresses, to be used when a 

	disconnection occurs. */

	TSglQue<TRemConAddress> iAddressPool;

	};

#endif // CONNECTIONSTATUSHISTORY_H