doc/src/snippets/threads/threads.cpp
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     1 /****************************************************************************
       
     2 **
       
     3 ** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
       
     4 ** All rights reserved.
       
     5 ** Contact: Nokia Corporation (qt-info@nokia.com)
       
     6 **
       
     7 ** This file is part of the documentation of the Qt Toolkit.
       
     8 **
       
     9 ** $QT_BEGIN_LICENSE:LGPL$
       
    10 ** No Commercial Usage
       
    11 ** This file contains pre-release code and may not be distributed.
       
    12 ** You may use this file in accordance with the terms and conditions
       
    13 ** contained in the Technology Preview License Agreement accompanying
       
    14 ** this package.
       
    15 **
       
    16 ** GNU Lesser General Public License Usage
       
    17 ** Alternatively, this file may be used under the terms of the GNU Lesser
       
    18 ** General Public License version 2.1 as published by the Free Software
       
    19 ** Foundation and appearing in the file LICENSE.LGPL included in the
       
    20 ** packaging of this file.  Please review the following information to
       
    21 ** ensure the GNU Lesser General Public License version 2.1 requirements
       
    22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
       
    23 **
       
    24 ** In addition, as a special exception, Nokia gives you certain additional
       
    25 ** rights.  These rights are described in the Nokia Qt LGPL Exception
       
    26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
       
    27 **
       
    28 ** If you have questions regarding the use of this file, please contact
       
    29 ** Nokia at qt-info@nokia.com.
       
    30 **
       
    31 **
       
    32 **
       
    33 **
       
    34 **
       
    35 **
       
    36 **
       
    37 **
       
    38 ** $QT_END_LICENSE$
       
    39 **
       
    40 ****************************************************************************/
       
    41 
       
    42 #include <QCache>
       
    43 #include <QMutex>
       
    44 #include <QThreadStorage>
       
    45 
       
    46 #include "threads.h"
       
    47 
       
    48 //! [0]
       
    49 void MyThread::run()
       
    50 //! [0] //! [1]
       
    51 {
       
    52 //! [1] //! [2]
       
    53 }
       
    54 //! [2]
       
    55 
       
    56 #define Counter ReentrantCounter
       
    57 
       
    58 //! [3]
       
    59 class Counter
       
    60 //! [3] //! [4]
       
    61 {
       
    62 public:
       
    63     Counter() { n = 0; }
       
    64 
       
    65     void increment() { ++n; }
       
    66     void decrement() { --n; }
       
    67     int value() const { return n; }
       
    68 
       
    69 private:
       
    70     int n;
       
    71 };
       
    72 //! [4]
       
    73 
       
    74 #undef Counter
       
    75 #define Counter ThreadSafeCounter
       
    76 
       
    77 //! [5]
       
    78 class Counter
       
    79 //! [5] //! [6]
       
    80 {
       
    81 public:
       
    82     Counter() { n = 0; }
       
    83 
       
    84     void increment() { QMutexLocker locker(&mutex); ++n; }
       
    85     void decrement() { QMutexLocker locker(&mutex); --n; }
       
    86     int value() const { QMutexLocker locker(&mutex); return n; }
       
    87 
       
    88 private:
       
    89     mutable QMutex mutex;
       
    90     int n;
       
    91 };
       
    92 //! [6]
       
    93 
       
    94 typedef int SomeClass;
       
    95 
       
    96 //! [7]
       
    97 QThreadStorage<QCache<QString, SomeClass> *> caches;
       
    98 
       
    99 void cacheObject(const QString &key, SomeClass *object)
       
   100 //! [7] //! [8]
       
   101 {
       
   102     if (!caches.hasLocalData())
       
   103         caches.setLocalData(new QCache<QString, SomeClass>);
       
   104 
       
   105     caches.localData()->insert(key, object);
       
   106 }
       
   107 
       
   108 void removeFromCache(const QString &key)
       
   109 //! [8] //! [9]
       
   110 {
       
   111     if (!caches.hasLocalData())
       
   112         return;
       
   113 
       
   114     caches.localData()->remove(key);
       
   115 }
       
   116 //! [9]
       
   117 
       
   118 int main()
       
   119 {
       
   120     return 0;
       
   121 }