/*

* Copyright (c) 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:  Base class for all search condition tree nodes.

*

*/

#ifndef __MDECONDITION_H__

#define __MDECONDITION_H__

#include <e32base.h>

#include <mdccommon.h>

// Forward declaration

class CMdCSerializationBuffer;

/**

 * Base class for all search condition tree nodes.

 */

NONSHARABLE_CLASS(CMdECondition) : public CBase

	{

public:

	/* Destructor. */

	/**

	 * Destructor.

	 */

	virtual ~CMdECondition();

	/* Methods. */

    /**

	 * Returns the type of the condition.

	 *

	 * @return  Condition type.

	 */

	IMPORT_C TConditionType Type() const;

    /**

	 * Determines whether the condition is negated.

	 *

	 * @return  <code>ETrue</code>, if the condition is negated.  

     *          Otherwise <code>EFalse</code>.

	 */

	IMPORT_C TBool Negate() const;

    /**

	 * Sets the negate flag. The negate flag negates the meaning of the 

     * condition like a boolean NOT operator.

	 *

	 * @param aNegate  <code>ETrue</code> to negate.

	 */

	IMPORT_C void SetNegate(TBool aNegate);

    /**

     * Determines whether the condition node has been locked. Attempting to 

     * modify locked conditions causes a panic.

     *

     * @return  <code>ETrue</code>, if the condition is locked. Otherwise

     *          <code>EFalse</code>.

     */

    IMPORT_C TBool Locked() const;     

    /**

     * Locks the condition to prevent changes. Attempting to change a locked

     * condition causes a panic.

     *

     * @param aLocked  <code>ETrue</code> to lock; <code>EFalse</code> to 

     *                 unlock.

     */

    IMPORT_C virtual void SetLocked(TBool aLocked = ETrue);

    /**

     * Get possible query's internal optimization flags from condition.

     *

     * @param aFlaga query's internal optimization flags

     * @return last level internal optimization flags

     */

    virtual TUint32 InternalQueryOptimizationFlags(TUint32& aFlags) = 0;

    /**

     * Get required size of serialized buffer when this is serialized.

     *

     * @return required size of serialized buffer

     */

    virtual TUint32 RequiredBufferSize() const = 0;

    /**

     * Serialize own data to serialized buffer (correct position must be set 

     * before calling).

	 *

     * @param aBuffer  serialized buffer.

     */

    virtual void SerializeL(CMdCSerializationBuffer& aBuffer, 

    		TMdCOffset& aFreespaceOffset) const = 0;

	/* Constructors. */

	/**

	 * Constructor. 

	 *

	 * @param aType  Type of the condition node.

	 */

	CMdECondition(TConditionType aType);

protected:

	/**

	 * Second-phase constructor.

	 */

	void ConditionConstruct();

	/* Utility methods. */

    /**

     * Panics if the condition is not locked.

     *

     * @panic  TMdEPanic::EConditionLocked  Condition is locked against

     *         changes.

     */

    void AssertNotLocked() const;

protected:

    /** Type of the condition. */

    TConditionType iType;

    /** The negate flag negates the result of the condition: if the 

        condition evaluates to True, the result will really be False. */

    TBool iNegated;

    /** Locked conditions can't be modified. */

    TBool iLocked;

    };

#endif  // __MDECONDITION_H__