/*

* Copyright (c) 2007 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:  Iterator class for traversing the tree structure.

*

*/

#ifndef T_FSTREEITERATOR_H

#define T_FSTREEITERATOR_H

#include <e32def.h>

#include "fstreelistconstants.h"

class CFsTree;

class CFsTreeItem;

class CFsTreeNode;

const TUint KFsTreeIteratorNullFlag = 0x00;

/**  Flag indicating that the content of collapsed nodes is not to be

     included in the iteration sequence. */

const TUint KFsTreeIteratorSkipCollapsedFlag = 0x01;

const TUint KFsTreeIteratorSkipHiddenFlag = 0x02;

NONSHARABLE_CLASS( TFsTreeIterator )

    {

    //friend class CFsTree;

public:

    /**

     * Copy constructor.

     *

     * @param aIterator Copied iterator.

     */

    TFsTreeIterator( const TFsTreeIterator& aIterator );

    /**

     * C++ constructor.

     *

     * @param aRoot Root node for the iterated tree (or subtree).

     */

    TFsTreeIterator( CFsTreeNode* aRoot, CFsTree* aTree,

                   CFsTreeItem* aCurrent,

                   const TUint aFlags = KFsTreeIteratorNullFlag);

    /**

     * Assignment operator.

     *

     * @param aIterator Iterator.

     */

    TFsTreeIterator& operator=( const TFsTreeIterator& aIterator );

    /**

     * Returns whether the iterator has next tree item.

     *

     * @return @c ETrue, if there is a next item.

     */

    TBool HasNext();

    /**

     * Returns an identifier to the next tree item. The returned value is @c 

     * KFsTreeNoneID,

     * when there is no more items. This changes also the iterator to point

     * to the returned item.

     *

     * @return Identifier of the next tree item.

     */

    TFsTreeItemId Next();

    /**

     * Returns whether the iterator has previous tree item.

     *

     * @return @c ETrue, if there is a previous item.

     */

    TBool HasPrevious();

    /**

     * Returns an identifier to the previous tree item. The returned value is

     * @c KFsTreeNoneID, if there is no previous tree item. This changes also 

     * the iterator to point to the returned item. 

     *

     * @return Identifier to the previous tree item.

     */

    TFsTreeItemId Previous();

    /**

     * Returns an identifier to the current tree item. The returned value is

     * @c KFsTreeNoneID, if there is no current tree item.

     *

     * @return Identifier to the current tree item.

     */

    TFsTreeItemId Current() const;

    /**

     * Return an identifier to the first item in the sequence.

     *

     * @return An identifier of the first item.

     */

    TFsTreeItemId First();

    /**

     * Returns an identifier to the last item in the sequence.

     *

     * @return An identifier of the last item.

     */ 

    TFsTreeItemId Last();

private:

    /**

     * Returns pointer to the next tree item.

     *

     * @return Pointer to the next tree item. @c NULL, if the next item is not

     *      found.

     */

    CFsTreeItem* FindNext();

    /**

     * Returns pointer ot the previous tree item.

     *

     * @return Pointer to the previous tree item. @c NULL, if previous item is

     *      not found.

     */

    CFsTreeItem* FindPrevious();

private: // data

    /**

     * Tree to iterate in.

     */

    CFsTree* iTree;

    /**

     * Current item.

     */

    CFsTreeItem* iCurrent;

    /**

     * Root of the tree.

     */

    CFsTreeNode* iRoot;

    /**

     * Next item. Contains a pointer to the cached next item.

     */

    CFsTreeItem* iNext;

    /**

     * Previous item. Contains a pointer to the cached previous item.

     */

    CFsTreeItem* iPrevious;

    /**

     * Flags for the iterator.

     */

    TUint iFlags;

    };

#endif // T_FSTREEITERATOR_H