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1 /**************************************************************************** |
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2 ** |
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3 ** Copyright (C) 2010 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 Qt Mobility Components. |
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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 #ifndef QPRIVATEIMPLEMENTATION_H |
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43 #define QPRIVATEIMPLEMENTATION_H |
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44 |
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45 // |
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46 // W A R N I N G |
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47 // ------------- |
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48 // |
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49 // This file is not part of the Qt Extended API. It exists purely as an |
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50 // implementation detail. This header file may change from version to |
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51 // version without notice, or even be removed. |
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52 // |
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53 // We mean it. |
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54 // |
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55 |
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56 /* Rationale: |
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57 |
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58 QSharedDataPointer has some deficiencies when used for implementation hiding, |
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59 which are exposed by its use in the messaging library: |
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60 1. It cannot easily be used with incomplete classes, requiring client classes |
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61 to unnecessarily define destructors, copy constructors and assignment |
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62 operators. |
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63 2. It is not polymorphic, and must be reused redundantly where a class with |
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64 a hidden implementation is derived from another class with a hidden |
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65 implementation. |
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66 3. Type-bridging functions are required to provide a supertype with access |
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67 to the supertype data allocated within a subtype object. |
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68 |
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69 The QPrivateImplementation class stores a pointer to the correct destructor |
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70 and copy-constructor, given the type of the actual object instantiated. |
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71 This allows it to be copied and deleted in contexts where the true type of |
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72 the implementation object is not recorded. |
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73 |
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74 The QPrivateImplementationPointer provides QSharedDataPointer semantics, |
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75 providing the pointee type with necessary derived-type information. The |
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76 pointee type must derive from QPrivateImplementation. |
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77 |
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78 The QPrivatelyImplemented<> template provides correct copy and assignment |
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79 functions, and allows the shared implementation object to be cast to the |
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80 different object types in the implementation type hierarchy. |
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81 |
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82 */ |
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83 |
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84 #include "qmailglobal.h" |
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85 #include <QtCore/qglobal.h> |
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86 #include <QtCore/qatomic.h> |
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87 |
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88 class QPrivateImplementationBase |
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89 { |
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90 public: |
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91 template<typename Subclass> |
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92 inline QPrivateImplementationBase(Subclass* p) |
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93 : ref_count(0), |
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94 self(p), |
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95 delete_function(&QPrivateImplementationBase::typed_delete<Subclass>), |
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96 copy_function(&QPrivateImplementationBase::typed_copy_construct<Subclass>) |
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97 { |
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98 } |
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99 |
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100 inline QPrivateImplementationBase(const QPrivateImplementationBase& other) |
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101 : ref_count(0), |
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102 self(other.self), |
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103 delete_function(other.delete_function), |
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104 copy_function(other.copy_function) |
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105 { |
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106 } |
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107 |
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108 inline void ref() |
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109 { |
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110 ref_count.ref(); |
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111 } |
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112 |
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113 inline bool deref() |
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114 { |
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115 if (ref_count.deref() == 0 && delete_function && self) { |
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116 (*delete_function)(self); |
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117 return true; |
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118 } else { |
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119 return false; |
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120 } |
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121 } |
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122 |
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123 inline void* detach() |
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124 { |
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125 if (copy_function && self && ref_count != 1) { |
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126 void* copy = (*copy_function)(self); |
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127 reinterpret_cast<QPrivateImplementationBase*>(copy)->self = copy; |
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128 return copy; |
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129 } else { |
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130 return 0; |
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131 } |
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132 } |
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133 |
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134 private: |
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135 QAtomicInt ref_count; |
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136 |
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137 void *self; |
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138 void (*delete_function)(void *p); |
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139 void *(*copy_function)(const void *p); |
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140 |
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141 template<class T> |
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142 static inline void typed_delete(void *p) |
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143 { |
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144 delete static_cast<T*>(p); |
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145 } |
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146 |
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147 template<class T> |
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148 static inline void* typed_copy_construct(const void *p) |
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149 { |
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150 return new T(*static_cast<const T*>(p)); |
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151 } |
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152 |
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153 // using the assignment operator would lead to corruption in the ref-counting |
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154 QPrivateImplementationBase &operator=(const QPrivateImplementationBase &); |
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155 }; |
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156 |
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157 template <class T> class QPrivateImplementationPointer |
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158 { |
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159 public: |
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160 inline T &operator*() { return *detach(); } |
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161 inline const T &operator*() const { return *d; } |
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162 |
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163 inline T *operator->() { return detach(); } |
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164 inline const T *operator->() const { return d; } |
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165 |
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166 inline operator T *() { return detach(); } |
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167 inline operator const T *() const { return d; } |
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168 |
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169 inline T *data() { return detach(); } |
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170 inline const T *data() const { return d; } |
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171 |
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172 inline const T *constData() const { return d; } |
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173 |
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174 inline bool operator==(const QPrivateImplementationPointer<T> &other) const { return d == other.d; } |
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175 inline bool operator!=(const QPrivateImplementationPointer<T> &other) const { return d != other.d; } |
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176 |
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177 inline QPrivateImplementationPointer() |
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178 : d(0) |
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179 { |
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180 } |
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181 |
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182 inline explicit QPrivateImplementationPointer(T *p) |
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183 : d(p) |
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184 { |
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185 increment(d); |
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186 } |
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187 |
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188 template<typename U> |
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189 inline explicit QPrivateImplementationPointer(U *p) |
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190 : d(static_cast<T*>(p)) |
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191 { |
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192 increment(d); |
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193 } |
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194 |
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195 inline QPrivateImplementationPointer(const QPrivateImplementationPointer<T> &o) |
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196 : d(o.d) |
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197 { |
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198 increment(d); |
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199 } |
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200 |
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201 inline ~QPrivateImplementationPointer() |
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202 { |
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203 decrement(d); |
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204 } |
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205 |
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206 inline QPrivateImplementationPointer<T> &operator=(T *p) |
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207 { |
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208 assign_helper(p); |
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209 return *this; |
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210 } |
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211 |
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212 inline QPrivateImplementationPointer<T> &operator=(const QPrivateImplementationPointer<T> &o) |
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213 { |
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214 assign_helper(o.d); |
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215 return *this; |
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216 } |
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217 |
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218 inline bool operator!() const { return !d; } |
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219 |
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220 private: |
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221 void increment(T*& p); |
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222 |
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223 void decrement(T*& p); |
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224 |
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225 inline T* assign_helper(T *p) |
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226 { |
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227 if (p != d) { |
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228 increment(p); |
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229 decrement(d); |
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230 d = p; |
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231 } |
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232 return d; |
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233 } |
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234 |
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235 inline T* detach() |
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236 { |
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237 if (!d) return 0; |
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238 |
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239 if (T* detached = static_cast<T*>(d->detach())) { |
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240 return assign_helper(detached); |
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241 } else { |
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242 return d; |
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243 } |
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244 } |
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245 |
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246 public: |
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247 T *d; |
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248 }; |
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249 |
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250 template<typename ImplementationType> |
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251 class QTOPIAMAIL_EXPORT QPrivatelyImplemented |
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252 { |
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253 public: |
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254 QPrivatelyImplemented(ImplementationType* p); |
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255 QPrivatelyImplemented(const QPrivatelyImplemented& other); |
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256 |
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257 template<typename A1> |
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258 QTOPIAMAIL_EXPORT QPrivatelyImplemented(ImplementationType* p, A1 a1); |
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259 |
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260 virtual ~QPrivatelyImplemented(); |
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261 |
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262 const QPrivatelyImplemented<ImplementationType>& operator=(const QPrivatelyImplemented<ImplementationType>& other); |
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263 |
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264 template<typename ImplementationSubclass> |
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265 inline ImplementationSubclass* impl() |
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266 { |
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267 return static_cast<ImplementationSubclass*>(static_cast<ImplementationType*>(d)); |
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268 } |
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269 |
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270 template<typename InterfaceType> |
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271 inline typename InterfaceType::ImplementationType* impl(InterfaceType*) |
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272 { |
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273 return impl<typename InterfaceType::ImplementationType>(); |
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274 } |
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275 |
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276 template<typename ImplementationSubclass> |
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277 inline const ImplementationSubclass* impl() const |
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278 { |
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279 return static_cast<const ImplementationSubclass*>(static_cast<const ImplementationType*>(d)); |
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280 } |
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281 |
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282 template<typename InterfaceType> |
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283 inline const typename InterfaceType::ImplementationType* impl(const InterfaceType*) const |
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284 { |
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285 return impl<const typename InterfaceType::ImplementationType>(); |
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286 } |
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287 |
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288 protected: |
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289 QPrivateImplementationPointer<ImplementationType> d; |
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290 }; |
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291 |
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292 |
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293 class QPrivateNoncopyableBase |
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294 { |
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295 public: |
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296 template<typename Subclass> |
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297 inline QPrivateNoncopyableBase(Subclass* p) |
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298 : self(p), |
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299 delete_function(&QPrivateNoncopyableBase::typed_delete<Subclass>) |
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300 { |
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301 } |
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302 |
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303 inline void delete_self() |
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304 { |
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305 if (delete_function && self) { |
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306 (*delete_function)(self); |
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307 } |
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308 } |
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309 |
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310 private: |
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311 void *self; |
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312 void (*delete_function)(void *p); |
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313 |
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314 template<class T> |
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315 static inline void typed_delete(void *p) |
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316 { |
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317 delete static_cast<T*>(p); |
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318 } |
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319 |
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320 // do not permit copying |
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321 QPrivateNoncopyableBase(const QPrivateNoncopyableBase &); |
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322 |
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323 QPrivateNoncopyableBase &operator=(const QPrivateNoncopyableBase &); |
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324 }; |
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325 |
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326 template <class T> class QPrivateNoncopyablePointer |
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327 { |
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328 public: |
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329 inline T &operator*() { return *d; } |
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330 inline const T &operator*() const { return *d; } |
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331 |
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332 inline T *operator->() { return d; } |
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333 inline const T *operator->() const { return d; } |
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334 |
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335 inline operator T *() { return d; } |
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336 inline operator const T *() const { return d; } |
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337 |
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338 inline T *data() { return d; } |
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339 inline const T *data() const { return d; } |
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340 |
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341 inline const T *constData() const { return d; } |
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342 |
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343 inline bool operator==(const QPrivateNoncopyablePointer<T> &other) const { return d == other.d; } |
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344 inline bool operator!=(const QPrivateNoncopyablePointer<T> &other) const { return d != other.d; } |
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345 |
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346 inline QPrivateNoncopyablePointer() |
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347 : d(0) |
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348 { |
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349 } |
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350 |
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351 inline explicit QPrivateNoncopyablePointer(T *p) |
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352 : d(p) |
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353 { |
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354 } |
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355 |
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356 template<typename U> |
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357 inline explicit QPrivateNoncopyablePointer(U *p) |
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358 : d(static_cast<T*>(p)) |
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359 { |
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360 } |
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361 |
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362 ~QPrivateNoncopyablePointer(); |
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363 |
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364 inline bool operator!() const { return !d; } |
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365 |
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366 private: |
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367 inline QPrivateNoncopyablePointer<T> &operator=(T *) { return *this; } |
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368 |
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369 inline QPrivateNoncopyablePointer<T> &operator=(const QPrivateNoncopyablePointer<T> &) { return *this; } |
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370 |
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371 public: |
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372 T *d; |
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373 }; |
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374 |
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375 template<typename ImplementationType> |
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376 class QTOPIAMAIL_EXPORT QPrivatelyNoncopyable |
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377 { |
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378 public: |
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379 QPrivatelyNoncopyable(ImplementationType* p); |
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380 |
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381 template<typename A1> |
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382 QTOPIAMAIL_EXPORT QPrivatelyNoncopyable(ImplementationType* p, A1 a1); |
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383 |
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384 virtual ~QPrivatelyNoncopyable(); |
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385 |
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386 template<typename ImplementationSubclass> |
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387 inline ImplementationSubclass* impl() |
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388 { |
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389 return static_cast<ImplementationSubclass*>(static_cast<ImplementationType*>(d)); |
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390 } |
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391 |
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392 template<typename InterfaceType> |
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393 inline typename InterfaceType::ImplementationType* impl(InterfaceType*) |
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394 { |
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395 return impl<typename InterfaceType::ImplementationType>(); |
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396 } |
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397 |
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398 template<typename ImplementationSubclass> |
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399 inline const ImplementationSubclass* impl() const |
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400 { |
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401 return static_cast<const ImplementationSubclass*>(static_cast<const ImplementationType*>(d)); |
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402 } |
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403 |
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404 template<typename InterfaceType> |
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405 inline const typename InterfaceType::ImplementationType* impl(const InterfaceType*) const |
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406 { |
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407 return impl<const typename InterfaceType::ImplementationType>(); |
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408 } |
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409 |
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410 protected: |
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411 QPrivateNoncopyablePointer<ImplementationType> d; |
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412 }; |
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413 |
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414 #endif |