1 /*

     2 * Copyright (c) 2007 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description:  Definition of client side stream buffer

    15 *

    16 */

    17 

    18 

    19 #ifndef __MENUBUF_H__

    20 #define __MENUBUF_H__

    21 

    22 #include "menusrvdef.h"

    23 #include <e32base.h>

    24 #include <s32buf.h>

    25 

    26 class RMenu;

    27 

    28 /**

    29  *  Client side stream buffer. Not seekable.

    30  *  @lib mcsmenu.lib

    31  *  @since S60 v5.0

    32  */

    33 NONSHARABLE_CLASS( RMenuBuf ): public RSubSessionBase, public TStreamBuf

    34     {

    35 

    36 public:

    37 

    38     /**

    39     * Close the object.

    40     */

    41     void Close();

    42 

    43     /**

    44     * Open the object (initially empty).

    45     * @param aMenu Session to be used.

    46     * @return Error code.

    47     */

    48     TInt Open( RMenu& aMenu );

    49 

    50     /**

    51     * Open this object using other object.

    52     * @param aHandle Handle used to open this object.

    53     * @param aFunction Function.

    54     * @param aArgs Arguments. Use arg 0 and 1 only;

    55     * arg 2 and 3 are used internally.

    56     * @return Error code.

    57     */

    58     TInt Open( RMenu& aMenu, TInt aFunction, TIpcArgs& aArgs );

    59 

    60 private:

    61 

    62     /**

    63     * Read data from server.

    64     * @param aLength The number of bytes read.

    65     */

    66     void IpcReadL( TInt& aLength );

    67 

    68     /**

    69     * Write data to server.

    70     */

    71     void IpcWriteL();

    72 

    73     /**

    74     * Get read lag (number of bytes transferred from server side but not

    75     * yet read).

    76     * @return Read lag.

    77     */

    78     inline TInt Lag( TRead aArea ) const;

    79 

    80     /**

    81     * Get write lag (number of bytes written but not yet transferred to

    82     * server side).

    83     * @return Write lag.

    84     */

    85     inline TInt Lag( TWrite aArea ) const;

    86 

    87 // from base class TStreamBuf

    88 

    89     /**

    90     * Re-fill the intermediate buffer and reset the start and end points

    91     * of the read area.

    92     * @param aMaxLength The maximum amount of data required.

    93     * @return The amount of data available.

    94     */

    95     TInt UnderflowL( TInt aMaxLength );

    96 

    97     /**

    98     * Empty the intermediate buffer and resets the start and end points

    99     * of the write area.

   100     */

   101     void OverflowL();

   102 

   103     /**

   104     * Synchronise the stream buffer with the stream. In effect, this

   105     * ensures that buffered data is delivered to the stream.

   106     * Write lag flushed.

   107     * Read lag leaves with KErrNotSupported.

   108     */

   109     void DoSynchL();

   110 

   111 private:    // Data

   112 

   113     TMenuBuf iBuf; ///< Data buffer.

   114 

   115     };

   116 

   117 #include "menubuf.inl"

   118 

   119 #endif // __MENUBUF_H__

   120