/*

* Copyright (c) 2000-2009 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: 

*

*/

#ifndef UNIQUEINSTANCEBASE_H_

#define UNIQUEINSTANCEBASE_H_

#include <e32base.h>

// The namespace UniqueInstance contains definitions that are not useful to the

// user, but are useful to the implementation. There is no need to use any symbols

// within it directly.

namespace UniqueInstance

{

/**

@internalComponent

*/

typedef TInt TCompareFn(void*,void*);

/**

destroy free aObject.

@internalComponent

*/

typedef void TDeleteFn(void* aObjectToBeDeleted);

/** 

Copy aObjectToCopy into a newly allocated buffer, return the new object.

aObjectSize is the size of the object that the repository has been specialised

to work with. If this is not a true size of the object (for example in the case

of HBufC) this value should be ignored.

@internalComponent

*/

typedef void* TCopyFnL(void* aObjectToCopy, TInt aObjectSize);

struct SElement;

class CRepositoryImpl;

class RInstanceImpl;

/**

 * Type-unsafe repository with shared equivalent objects.

 *

 * @internalComponent

 * @since App-frameworks6.1

 */

NONSHARABLE_CLASS(CUniqueInstanceRepositoryBase) : public CBase

	{

public:

	static void* DumbCopyL(void* aObjectTocopy, TInt aNumberOfBytes);

	static void DumbDelete(void* aDeleteThis);

	void ConstructL(TCompareFn*, TDeleteFn*, TCopyFnL*,

		TInt aMaxLinks, TInt aObjectSize);

	~CUniqueInstanceRepositoryBase();

	void Test() const;

private:

	friend class RInstanceImpl;

	CRepositoryImpl* iImpl;

	};

/**

 * Type-unsafe repository client.

 *

 * @internalComponent

 * @since App-frameworks6.1

 */

class RInstanceImpl

	{

public:

	explicit RInstanceImpl(CUniqueInstanceRepositoryBase& aRepository);

	~RInstanceImpl();		// asserts that no object is owned

	void TakeL(void* aObject);

	void TakeCopyL(void* aObject);

	void* Peek() const;

	void CopyTo(RInstanceImpl& aOther) const;

	void MoveTo(RInstanceImpl& aOther);

	void* DropL();

	void Close();

private:

	RInstanceImpl(RInstanceImpl&);					// unimplemented

	RInstanceImpl &operator=(const RInstanceImpl&);	// unimplemented

	SElement* iPtr;

	CRepositoryImpl* iRepository;

	};

}

#endif	// UNIQUEINSTANCEBASE_H_