1 /*

     2 * Copyright (c) 2008-2009 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:    Type-safe unique id template

    15 *

    16 */

    17 

    18 

    19 

    20 

    21 #ifndef T_GLXID_H

    22 #define T_GLXID_H

    23 

    24 #include "e32std.h"

    25 #include "glxpanic.h"

    26 

    27 /** Invalid or undefined id value */

    28 // Use "id == KGlxIdNone" and "id != KGlxIdNone" to check for

    29 // id validity.

    30 class TGlxIdNone {};

    31 const TGlxIdNone KGlxIdNone = TGlxIdNone();

    32 

    33 /**

    34  *  TGlxId

    35  *

    36  *  Type-safe template for ids

    37  *  Id value of KMaxTUint is consided to be undefined.

    38  *  @usage Define like this:

    39  *            class TMyIdBase {}; 

    40  *            typedef TGlxId<TMyIdBase> TMyId;

    41  *            Now use can use TMyId in other code

    42  */

    43 template <class T> 

    44 class TGlxId : public T {

    45 public:

    46     inline TGlxId(); 

    47     inline TGlxId(const TGlxId<T>& aId);

    48     inline TGlxId(TUint aIdValue); 

    49     inline TGlxId(const TGlxIdNone&);

    50     inline TGlxId<T>& operator=(const TGlxId<T>& aId);

    51     inline TGlxId<T>& operator=(TUint aIdValue);

    52         

    53     inline TGlxId<T>& operator=(const TGlxIdNone&);

    54     inline TGlxId<T> operator++(int); // Postfix, keep dummy parameter as int

    55     inline TBool operator!=(const TGlxId<T>& aId) const;

    56     inline TBool operator==(const TGlxId<T>& aId) const;

    57     inline TBool operator!=(const TGlxIdNone&) const;

    58     inline TBool operator==(const TGlxIdNone&) const;

    59     inline TBool operator>(const TGlxId<T>& aId) const;

    60     inline TBool operator<(const TGlxId<T>& aId) const;

    61 

    62     inline TUint Value() const;

    63     inline void SetValue(TUint aIdValue); // Allows setting undefined as value (KMaxTUint)

    64 

    65 private:

    66     TUint iIdValue;

    67 };

    68 

    69 /**

    70  * MGlxIdProvider

    71  * Abstract interface class to provide ids 

    72  * Define as MGlxIdProvider<TMyId>

    73  */ 

    74 template <class T>

    75 class MGlxIdProvider {

    76 public:

    77     /**

    78      * getNextId

    79      * Returns the next unique id.

    80      * Returns value in the argument, since otherwise cannot have the same

    81      * deriving class provide multiple different types of ids

    82      */

    83     virtual void NextId(T& aId) = 0;

    84 };

    85 

    86 /**

    87  * TGlxDefaultIdProvider

    88  * Simple implementation of id provider

    89  */ 

    90 template <class T>

    91 class TGlxDefaultIdProvider : public MGlxIdProvider<T> {

    92 private:

    93     TUint iNextIdValue;

    94 public:

    95     inline TGlxDefaultIdProvider();

    96     virtual void NextId(T& aId);

    97 };

    98 

    99 #include "glxid.inl"

   100 

   101 #endif // T_GLXID_H