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1 /**************************************************************************** |
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2 ** |
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3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). |
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4 ** All rights reserved. |
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5 ** Contact: Nokia Corporation (qt-info@nokia.com) |
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6 ** |
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7 ** This file is part of the QtXmlPatterns module of the Qt Toolkit. |
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8 ** |
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9 ** $QT_BEGIN_LICENSE:LGPL$ |
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10 ** No Commercial Usage |
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11 ** This file contains pre-release code and may not be distributed. |
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12 ** You may use this file in accordance with the terms and conditions |
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13 ** contained in the Technology Preview License Agreement accompanying |
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14 ** this package. |
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15 ** |
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16 ** GNU Lesser General Public License Usage |
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17 ** Alternatively, this file may be used under the terms of the GNU Lesser |
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18 ** General Public License version 2.1 as published by the Free Software |
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19 ** Foundation and appearing in the file LICENSE.LGPL included in the |
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20 ** packaging of this file. Please review the following information to |
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21 ** ensure the GNU Lesser General Public License version 2.1 requirements |
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22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. |
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23 ** |
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24 ** In addition, as a special exception, Nokia gives you certain additional |
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25 ** rights. These rights are described in the Nokia Qt LGPL Exception |
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26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. |
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27 ** |
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28 ** If you have questions regarding the use of this file, please contact |
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29 ** Nokia at qt-info@nokia.com. |
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30 ** |
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31 ** |
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32 ** |
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33 ** |
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34 ** |
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35 ** |
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36 ** |
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37 ** |
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38 ** $QT_END_LICENSE$ |
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39 ** |
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40 ****************************************************************************/ |
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41 |
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42 // |
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43 // W A R N I N G |
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44 // ------------- |
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45 // |
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46 // This file is not part of the Qt API. It exists purely as an |
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47 // implementation detail. This header file may change from version to |
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48 // version without notice, or even be removed. |
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49 // |
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50 // We mean it. |
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51 |
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52 #ifndef QPatternist_ReferenceCountedValue_p_h |
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53 #define QPatternist_ReferenceCountedValue_p_h |
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54 |
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55 QT_BEGIN_HEADER |
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56 QT_BEGIN_NAMESPACE |
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57 |
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58 namespace QPatternist |
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59 { |
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60 /*! |
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61 \class ReferenceCountedValue |
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62 \internal |
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63 \since 4.4 |
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64 \brief A template class that reference counts a value. |
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65 |
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66 This class is useful when an instance needs to have ownership semantics |
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67 as if it was value based. A typical examples is a QObject pointer, which |
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68 doesn't have a single owner. |
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69 |
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70 This is achieved through storing a copy of the object as |
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71 a member inside ReferenceCountedValue, which never is copied. It will |
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72 stay in scope until the last reference to the ReferenceCountedValue instance |
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73 is removed, and subsequently ReferenceCountedValue is deleted and hence also |
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74 the contained value. One should use ReferenceCountedValue by passing around |
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75 copies of Ptr, which is a typedef for the QExplicitlySharedDataPointer |
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76 smart pointer. |
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77 */ |
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78 template<typename T> |
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79 class ReferenceCountedValue : public QSharedData |
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80 { |
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81 public: |
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82 typedef QExplicitlySharedDataPointer<ReferenceCountedValue<T> > Ptr; |
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83 |
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84 inline ReferenceCountedValue(T *const v) : value(v) |
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85 { |
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86 } |
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87 |
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88 inline ~ReferenceCountedValue() |
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89 { |
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90 delete value; |
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91 } |
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92 |
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93 T *const value; |
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94 private: |
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95 /*! |
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96 Disabled, no implementation provided. |
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97 */ |
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98 inline ReferenceCountedValue(); |
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99 Q_DISABLE_COPY(ReferenceCountedValue) |
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100 }; |
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101 } |
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102 |
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103 QT_END_NAMESPACE |
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104 QT_END_HEADER |
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105 |
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106 #endif |